Gass cS /> ^^< /?/3 IOWA GEOLOGICAL SURVEY Bulletin No. 4 THE WEED FLORA OF IOWA GEORGE F. KAY, State Geologist JAMES H. LEES, Assistant State Geologist DES MOINES: Published for Iowa Geological Survey 1913 ^%' DES MOINES ROBERT HENDERSON, STATE PRINTER JOHN M. JAMIESON, STATE BINDER n. OF 0. 9.' GEOLOGICAL BOARD. His Excellency, George W. Clarke Governor of Iowa Hon. John L. Bleakly Auditor of State Jolin G. Bowman President State University of Iowa Raymond A. Pearson President Iowa State College C. N. Kinney President Iowa Academy of Science ADMINISTRATIVE OFFICERS. George F. Kay State Geologist .Tames H. Lees Assistant State Geologist Nellie E. Newman Secretary LETTER OF TRANSMITTAL Iowa Geological Survey, To Governor George W. Clarke and Members of the Geological Board: Gentlemen : I submit, h,erewitli, a bulletin on The Weed Flora of Iowa and reeommend that it be published for distribution among- the people of the state. The thanks of the whole state are due Dr. L. H. Pammel of the Iowa State College of Agriculture and Mechanic Arts for the preparation of a comprehensive and thorough report, represent- ing many years of careful and painstaking scientific work, on a subject that is most intimately related to lagriculture, the industry that far exceeds in importance all other industries of our great state. The Survey wishes to express its thanks to Dean Curtis, Director of the Iowa Agricultural Experiment Station, for his co-operation, and for his kindness in permitting the Survey to include in the bulletin on weeds results of investigations which were carried for- ward by Doctor Pammel while connected with the Experiment Station. The Iowa Geological Survey had the honor, about ten years ago, to publish a complete monograph by Doctor Pammel on the Grasses of Iowa. This publication proved to be of great value, and it is with the fullest confidence that the bulletin on The Weed Flora of Iowa will be of equal if not of greater service to the agricultural and related interests of the state that it is now pre- sented for publication as Bulletin 4 of the Iowa Geological Survey, I have the honor to be, Yours very sincerely, George F. Kay, State Geologist, THE WEED FLORA OF IOWA By L. H. PAMMEL WITH THE COLLABORATION OF. CHARLOTTE M. KING J. N. MARTIN J. C. CUNNINGHAM ADA HAYDEN and HARRIETTE S. KELLOGG TABLE OF CONTENTS CHAPTER I. Page Descriptive Manual 1 CHAPTER II. The General Characters of Seeds 405 CHAPTER III. The Microscopic Structure of Some "Weed Seeds 503 CHAPTER IV. Morphology of Flowers and Leaves 589 CHAPTER V. Scattering of Weeds 627 CHAPTER VI. Roots and Root-stocks of Weeds 641 CHAPTER VII. Number and Kinds of Weeds in Different Soils 655 CHAPTER VIII. Injuriousness of Weeds 669 CHAPTER IX. Weed Migration 685 CHAPTER X. Medicinal Weeds 771 CHAPTER XI. Phenology of Weeds 783 CHAPTER XII. Weed and Seed Laws 791 CHAPTER XIII. History and Bibliography 817 Glossary 862 PREFACE Weeds do an enormous damage to the crops of Iowa. A con- servative estimate places the injury at $25,000,000 annually. This loss could be largely avoided if we had more concise information on the subject, land if we could conserve the matchless resources of our soil by keeping the weeds down, the farmers would be greatly benefited in a financial way. It would seem appropriate, therefore, to publish a volume of the Weed Flora of the state at this time. The need of a volume dealing with Iowa weeds as a. feature of the flora of the state has long been felt by the public schools. ]\Iany papers have been published by the Iowa Agricultural Ex- periment Station, but these papers are mostly out of print. This work is much more comprehensive than anything heretofore pub- lished in this state. The title indicates that it is not a weed book, but rather a weed flora. Much stress has been laid on the geograph- ical distribution of weeds. It is a contribution to the local flora of the United States. The chapter on the geographical distribution of weeds will be found of special interest to the phytogeographer. I desire to ex- press my thanks to Dr. M. L. Fernald, Messrs. E, I. Cratty, F. W. Faige, 0. M. Olson, J. P. Anderson and Prof. B. Shimek for assist- ance in giving the geographical distribution of Iowa weeds. The chapter on the microscopic structure of weed seeds brings together in English much on the subject which has hitherto been inacces- sible to the student not familiar with German or French litera- ture. The chapter on morphology will greatly help the student to understand the changes occurring in the development of the flower and the formation of the seed. The chapter on the use of weeds in medicine will be of interest to those who occasionally make use of wild plants for medicinal porposes. The chapter on seeds de- scribes la large number of weed seeds ; this will be found of value to those engaged in a study of seeds. The chapter on various weed laws gives a summary of laws in various states in the Mississippi Valley. In compiling these xii PREFACE laws I have been aided by Mr. Small of the Iowa State Library, Mr. ]\Ioore of Wisconsin, J\Ir. Michel of South Dakota, Dr. Howard of Missouri and H. L. Bolley of North Dakota. In the preparation of this Weed Flora, I have been greatly assisted by Professor J. N. Martin, who has written the chapter on morphology of the plant ; Miss Ada Hayden, who has written the chapter on dissemination ; Professor J. C. Cunningham, who has written the chapter on roots and underground organs; Miss Charlotte ^1. King, who is the joint author of the chapters on gross characters and microscopic structure of seeds. Miss King is also responsible for many of the excellent drawings. The chapter on medicinal weeds was prepared by Miss Kellogg. I am greatly in- debted to her for painstaking editorial work and for preparing the bibliography and the index. In the matter of bibliography, it has seemed best to divide the subject into various sections so that the student may easily find the desired literature. The bibliography is not complete but enough papers are given to enable the student to find the important literature. I am indebted to Dr. Clark, of the Canadian Seed Laboratory, for the privilege of using some of the admirable illustrations of the Canadian work on weeds, also to Dr. Ernest Bessey for illustrations from Beal's Weeds of Michigan, and the classical Hillman seed figures in the INIichi- gan bulletin, and to the Nevada Station for the use of the Hill- man cuts. Some of the Hillman and a few other figures have been taken from the government publications. I am also indebted to various publishers for figures which have been taken from sev- eral textbooks of botany, as the Bergen & Davis book published by Ginn & Co.; several botanical works like Thome's published in German, and to the Connecticut Experiment Station. A few fig- ures have been taken from the Botanical Gazette. Credit is given under each figure. The photographs were made by F. E. Colburn, photographer at the Iowa Agricultural Experiment Station, G. T. Hart and C. R. Quade. The clerical work of the volume was per- formed by Miss Bertha Herr and my daughter, ]\Iiss Harriet. Mr. Burlingmair assisted in a study of weeds in different fields. To Mr. James H. Lees for his assistance in proof reading and edi- torial work I am also indebted. To all I wish to express my sincere thanks. The reader will find it advisable to have several of the recent treatises on weeds. Mention may be made of my work "Weeds of the Farm and Garden," a general treatise of three hundred pages PREFACE xiii with numerous illustrations; the work of Fletcher and Clark of Canada; Bolley's "North Dakota Weeds;" Blatchley's "Indiana Weed Book;" W. J. Beal's "The Weeds of Michigan." A list of th.ese publications and where they miay be obtained will be found in the bibliography. Ames, Iowa, December 18, 1912. L. H. PAMMEL. Page 754 Eosenberg, 1882 should be 1782. Page 837 Patrick, P. E., should be Patrick, G. E. Page 838 Blankenship should be Blankinship. Page 842 L. T. Henderson should be L. F. Henderson. Page 858 Panton, J. H. Weeds of Ontario should be listed on page 845. Page 861 T. L. Williams should be T. A. Williams. CHAPTER I. DESCRIPTIVE MANUAL L. H. PAMMEL CHAPTER I. KEY FOR FAMILIES. I. Plants without true flowers; not producing seeds. . .Pteridophyta. Stems jointed, rushlike Eguisetaceae. I. Plants with true flowers, stamens, and pistils and producing seeds. Spermatopliyta. II. Ovules not borne in a closed ovary (Pine, Spruce) Gymnospermae. II. Ovules borne in a closed ovary (Rose, Willow, Corn, etc.) Angiospermae. III. Stems endogenous without central pith; no annual rings; parts of the flower usually in threes; single cotyledon... Monocotyledoneae. 1. Grasslike plants 2. 2. Flowers enclosed by chaff-like scales. Stems hollow; sheaths of leaves split. .. Gramineae. Stems solid; sheaths of leaves not split. Oyperaceae. 2. Flowers not inclosed by chaff -like scales. .Jttncaceae. 1. Plants not grasslike; flowers with a perianth of 6 pieces ;* stamens 6 Liliaceae. III. Stem formed of bark, wood, and pith, exogenous; leaves netted-veined ; embryo with a pair of cotyledons Dicotyledoneae. 1. Corolla absent 2. Plants fleshy or scurfy CJienopodiaceae. 2. Plants not fleshy or scurfy 3. 3. Ovary free 4. 4. Flowers unisexual. Ovary 1-celled Urticaceae. Ovary 3-celled EuphorMaceae. 4. Flowers perfect. Calyx and bracts greenish and scarious Amarantliaceae. Calyx generally corolla-like. 1. Fruit a 1-seeded achene Polygonaceae. 1. Fruit a 5-12 seeded berry. . .PJiytolaccaceae. 3. Ovary inferior Nyctaginaceae. 1. Calyx and corolla present. 2. Corolla of separate petals 3. 3. Plants fleshy, flowers yellow Portulacaceae. WEED FLORA OP IOWA 3. Plants not fleshy 4. 4. Pistil single 5. 5. Flowers regular. Stamens numerous, free ... Ranunculaceae. Stamens numerous; sepals and petals pres- ent, inserted on calyx Rosaceae. Stamens 10; fruit a legume. . .Leguminosae. 4. Pistil compound 6. 6. Ovary free. Ovary 1-celled Caryophyllaceae. Ovary more than 1-celled 7. 7. Ovaries united into a ring. . .Malvaceae. 7. Ovaries not united into a ring 8. 8. Leaves simple. With punctate dots; stamens numer- ous .Hypericaceae. Leaves not with punctate dots; sta- mens 6 Cruciferae. Leaves compound, pinnately 3-foliate. AnacardAaceae. Leaflets 3, obcordate Oxalidaceae. Leaflets 5-7 pairs Zygophyllaceae. Leaflets 3, viscid or fetid herbs Capparidaceae. 6. Ovary adherent; flowers in umbels UTThbelliferae, 6. Flowers not in umbels Onagraceae. 1. Calyx and corolla present, petals more or less united. 2. Flowers regular 3. 3. Plants with milky juice. Stamens united Asclepiadaceae. Stamens distinct Apocynaceae. 3. Plants without milky juice. 4. Plants twining Convolvulaceae. 4. Plants not twining 5. 5. Stamens 5 or more 6. 6, Style 2-cleft; flowers not in heads; fruit 2-4 seedlike nutlets Boraginaceae. Fruit many seeded pod. . .Hydrophyllaceae. Flowers in heads; anthers in ring or tube about the style Compositae. 6. Style 1; fruit many seeded Solanaceae. 5. Stamens fewer than corolla lobes Caulescent, flowers blue Verhenaceae Acaulescent, flowers greenish . Plantaginaceae 2 Flowers irregular. Stems 4-angled; ovary deeply 4-lobed Lahiatae. Stems not 4-angled ; ovary 2-celled . . Scrophulariaceae. DESCRIPTIVE MANUAL PTERIDOPHYTA, FERNS AND THEIR ALLIES, This group of plants, sometimes called vascular cryptogams, is represented in our flora by the maidenhair fern, brake, spleenwort, shield fern, etc. The Boston fern is frequently cultivated. Fig. 1. Common Horsetail (Equi^setum arvense). Roadsides, fields, common everywhere in Iowa. (Photographed by Colburn.) Fig. 1-A. Distribution of Common Horsetail. 6 WEED FLORA OF IOWA EQUISETACEAE, HORSETAIL FAMILY. This small family of rushlike plants contains a few species only and but one that is weedy. Common Horsetail {Equisetum arvense L.). Description. — A rushlike perennial with running rootstocks and annual stems; branches in whorls; fertile and sterile plants, the fertile appearing early in spring with a terminal cone, yellowish in color, bearing the spore cases (sporangia) underneath a scale ; spores provided with hygroscopic bands; sterile frond with whorled branches. Distribution. — Widely distributed in North America, common in sandy moist fields, on railroad embankments; common in Story, Boone, Carroll, Crawford, Harrison, "Woodbury, Clinton, Dubuque, Lee, Page, Polk, Cerro Gordo, Emmet, Webster, Marshall, Johnson, Winneshiek and Allamakee counties Extermination.— This is a most persistent perennial ; only by giv- ing frequent shallow cultivation after small grain is removed during the summer can the weed be kept in check. SPERMATOPHYTA, FLOWERING PLANTS. The seed plants have stamens and pistils and reproduce by seeds. Represented by the pine, spruce, hemlock, wheat, rye, corn, rose, maple, ash, aster, goldenrod, squash, etc. GYMNOSPERMAE, GYMNOSPERMS. The seeds are not inclosed in an ovary. Trees or shrubs gener- ally with needlelike or scalelike leaves ; represented in Iowa by the red cedar, white pine, etc. None are weedy. ANGIOSPERMAE, ANGIOSPERMS. Ovules borne in a closed ovary. Represented by a large number of our native and cultivated plants, like wheat, corn, lily, rose, clover, tomato, etc. MONOCOTYLEDONEAE, MONOCOTS. Plants with endogenous stem, the woody fibers in bundles dis- tributed through the pith. Annual ring absent. Flowers gen- erally on the plan of 3 ; embryo with a single cotyledon. Corn, lily, onion, asparagus, blue grass, switch grass are representatives. DESCRIPTIVE MANUAL GRAMINEAE, GRASS FAMILY. This large family is of great economic importance, since it con- tains many of our food plants, including the well known cereals, Fig. 2. Johnson Grass {Sorghum halepense) ; a, sessile spikelets. A most trou- blesoume weed. (Lamson-Scribner, U. S. Dept. Agr.) Fig. 2 -A. Distribution of Johnson Grass. Reported recently from southwestern Iowa. 8 WEED FLORA OF IOWA rye, wheat, oats, barley, corn, kaffir corn and millet, besides such forage grasses as blue grass, timothy, brome grass, foxtail, and a few ornamental plants, like pampas grass, ribbon grass, etc. Johnson Grass {Sorghum liulepense (L.) Pers.). Description. — A stout perennial, with smooth, erect, simple culms, 3-5 feet high, and strong, creeping root-stocks; leaves elongated, %,-%in. wide, acute; ligule ciliate, and on the back where leaf -blade joins the sheath there is more or less pubescence; panicle open, 6-12 in. long, the whorled branches naked below, the 3-5-flowered racemes clustered towards their extremities; pedicels of the staminate (rarely neutral) spikelets pilose with stout hairs; sessile spikelet broadly lanceolate, acute, 2-3 lines long, pale green or violet, becoming dark or nearly black at maturity; callus small, obtuse, shortly and sparsely barbate; first glume coriaceous, spar- ingly pubescent on the flattened back, 5-7-nerved ; second glume similar and equaling the first, convex below, subcarinate above, acute, the hyaline inflexed margins ciliate; third glume a little shorter than the outer ones, membranous, faintly 2-nerved, the in- folded margins ciliate ; fourth glume broadly oval, obtuse, nearly 1/2 shorter than the second, 2-lobed or bidentate at the apex, ciliate awned ; awn 5-8 lines .long ; palea a little shorter than the glumes, nerveless, ciliate. Introduced and cultivated in many southern states for hay; in many places it has become a dangerous weed, difficult to exterminate. Distribution. — The weed is common in the south, often a most troublesome weed. It has been reported as persisting in the vicinity of Hamburg, Fremont county. Extermination. — Use the same methods as for quack grass. This may become a most troublesome weed. Finger Grass {Digitaria sangiiinalis (L.) Scop.). Description. — ^A much branched, leafy annual, 1-3 ft. high, spreading on the ground, with erect, smooth, spreading culms, fre- quently rooting at the lower joints, joints sometimes smooth, though more frequently bearded with deflexed hairs ; sheaths loose, gener- ally pilose, hairy, ciliate on the margins, with a membranaceous ligule ; leaves 2-4 in. long with rough margins, occasionally pilose at the base ; flowers produced in digitate spikes, hence the common name finger grass ; spikelets less than % in. long in pairs, 1 nearly sessile, the other with a stalk, each flower consisting of 2 sterile DESCRIPTIVE MANUAL Fig. 3. Common Crab Grass (Digitaria sanguinalis). Common in fields, gar- dens, meadows. Rooting at tlie joints. (Pliotographed by Colburn.) Fig. 3-A. Distribution of Common Crab Grass. glumes and the flower proper; the first glume very small, the sec- ong about %-% as long as the spikelet, usually hairy on the mar- gin, the third glume somewhat longer than the fourth, which is 5- 10 WEED FLORA OP IOWA nerved and usually silky-villous along the marginal nerves, fourth glume smooth and acute; fruit minute, pitted and cross-striated, light straw color except where the sterile glumes remain attached, which are gray in color and minutely hairy. Distribution. — This European grass is cosmopolitan ; abundant in the eastern and southern states and in California; common in all parts of Iowa, more particularly in gardens, corn fields, and streets. Extermination. — This grass is much more difficult to remove than the foxtails because it roots so readily at the joints. Thorough cultivation will remove the weed. Do not allow it to go to seed. Chemical Composition. — Common crab grass {Digitaria sanguin- alis) has been used as a forage plant in many parts of the United States and many chemical analyses have been made. Analyses are reported from Mississippi, Tennessee and Iowa. The Iowa analysis reported by Weems is as follows : NATURAL CONDITION Sample Water Eat Protein Albu- minoids Crude Fiber Ash Nitrogen free extract 1 66.95 1.11 2.52 (l.fcS) 8.62 4.10 16.70 WATER FREE SUBSTANCE 3.34 7.61 (5.98) 26.11 12.41 50.53 Smooth Crab Grass (Digitaria humifiisa Fers.) . Description. — An annual 6 in. -2 ft. high, closely resembling D. sanguinalis in habit, but smooth throughout, excepting for a few hairs at the throat of the sheaths; spikelets 2-7, smaller than in D. sanguinalis, about 1 line in length ; first glume very minute or obsolete; second and third glumes nearly equal in length, or the second a little shorter than the fourth, pubescent at the back. Distribution. — Smooth crab grass is native to Europe but is now cosmopolitan ; in eastern North America from New England to Texas and Mexico, Eocky mountains and Pacific coast ; less com- mon in Iowa than common crab grass; rapidly spreading in the state, more particularly in gardens ; common in lawns and pas- tures. Figure 4 Figure 4A Fig 4l' Sr^onS P [^'^'^'''-'''^'^^SulnaUs) . Common in cultivated fields, smklf r^ L? . ' (^^^^^aHa 7^^.m^f««a) ; a, leaf with sheath; J,, spikelet, c, d, scales, stamens and pistils. Common in gardens and lawns (Drawn by C. M. King.) 12 WEED FLORA OF IOWA Fig. 4-B. Distribution of Smooth Crab Grass. Extermmation. — This weed is somewhat more difficult to exter- minate than the foxtail, especially in lawns where it is common. Here it produces seed so close to the ground that the lawn mower will not catch this part of the plant. It may, however, be easily destroyed in fields which are cultivated. Stir the soil with a cul- tivator or hoe, exposing the roots to the sun. Old Witch Grass {Panicum, capillare L.). Description: — An annual with usually coarse, branching stems, 1-3 feet long, with very hairy leaf-sheaths and capillary, widely spreading panicles, terminal on the culm or its branches; culm geniculate and branching near the base, rarely simple, generally pilose or pubescent below the bearded nodes; sheaths pilose to densely hirsute, with spreading hairs; ligule very short, densely eiliate; leaf -blade flat, lanceolate or linear, acute, usually thinly hairy on both sides, margins scabrous and eiliate near the base ; hairs throughout spring from small papillae, those on the leaf -blade being confined chiefly to the principal nerves ; panicle diffuse, 3-12 in. long, the branches solitary in pairs, or rarely whorled, the ulti- mate branches and pedicels strongly hispid; spikelets 1 line long, ovate, acute, or abruptly acuminate-pointed, smooth ; first glume clasping the base of the spikelet, obtuse or acute, 1-3-nerved, about % the length of the 5-7-nerved and nearly equal second and third glumes, the acute tips of which are sometimes minutely pubescent ; flowering glume smooth and shining, elliptical, obtuse, or subacute, a little shorter than the larger outer glumes. Variable. July to October. DESCRIPTIVE MANUAL 13 , _^ ' ' '*. '*'!'> ^ ' , * - » , < ^ • , »- * »V s^ ' > . f ' ■• . * >^^' *>^ v*^ '* ' ^ ^^:^^V%i' -, ^ < \ ■ . ' [ r-*''^^?^%'' '.''^ \ ' ^ . ■'^t^^^ml^'J'. \ ! ' ';' ' // I'y^**' ■■. i^:^K\lv\u. »^HKrv.\. ■ w^ /)/''~_'V^M^:, rr^: ^JKMKi'^VWlffn^' ' ^ '^'^ ' lil ■r'^ y X ^jM-4^-'i,'^ MffinHy^^HHI^^^HB^wK&^L.. . w\ ^Rs %r iA^^^i'.'- '^ ^k|n^o^^i^^^^^mHr\''^w. ^x. s ,« f\ T f^ /^^ ^^S^^M^i^'^ ' "^ " •" A' if^m '.'/ ' ^K];l/|. ^^^ ' " ' 1 1 /^!-^ ' ' I^^P iiM'^^^" —- ' 34.76 3 46.01 i 36.83 40.83 This grass is very nutritions in its young condition. The protein varies from 2.14 per cent to 4.19 per cent, but there is a seeming variation with different plants found under different conditions. Chess, Cheat {Bromus secalinus L.). Description. — An erect annual, 2-3 ft. high; culms smooth or pubescent at the nodes ; sheaths striate smooth, scabrous or some- times pilose; ligule short, blunt; leaf-blade 6-12 in. long, rather broadly linear, smooth beneath, more or less rough and pilose on the upper surface ; panicle 4-8 in. long, erect, the more or less com- pound branches, spreading, even in fruits ; spikelets 6-10 lines long, oblong ovate, turgid, 6-12-flowered, pendulous in fruit, empty glumes oblong lanceolate, acute, the first 3-5, the second 7-nerved; flowering glumes ovate-oblong, obscurely 7-nerved, smooth or mi- nutely downy along the margins and toward the apex, becoming nearly cylindrical in fruit ; palea obtuse, strongly nerved ; nerves toothed or fringed with distant bristles. Distrihution. — Common wherever wheat is cultivated and some- times in waste places, from the Atlantic to the Pacific. At one time common in many parts of Iowa, but now occurring sparingly ex- cept where wheat is cultivated. Extermination.' — Use clean seed and sow in clean soil, succumbs readily to cultivation. The weed Chemical Composition. — The common Bromus secalinus analyzed at the Iowa station by Weems shows the following analysis. DESCRIPTIVE MANUAL 49 Fig. 27. Cheat or Chess {Bromus secalinus). In grain fields (After Clark and Fletcher.) 50 WEED FLORA OF IOWA Fig. 27-A. Distribution of Cheat or Chess. NATURAL CONDITION. Sample o.'S < 1. 5-200 g9fi 6-15- 189€ 25-30 2S-29 79.22 GC.55 1.^ 2.74 (1.E6-) (2.49) 9.15 12.38 2.21 2.61 4.59 2. 1.19 I 3.23 14.01 WATER FREE SUBSTANCE. 1. .. __ ... . 9.59 3.57 13.17 9.66 (9.42) (7.44) 44.04 37.03 10.63 7.91 22.57 9 41.83 There is eonsid?rable nourishment in the nutritive snlistanoe when the plant is young, but when old it can not be considered very nutritious. Downy Brome Gr?ss {Bromus tectorion L.). Description. — A slender, erect, leafy annual. 7-25 in. hiah. with narrow, softly pu^^escent leaves, and open, noddino; panicles. 3-7 i/o in. long; spikelets 5-8-flowered, with unequal, acuminate-pointed, hirsute, empty glumes, and rough or hirsute flowering glumes, 4-6 lines long; awns 6-8 lines long. Distribution. — Common in waste places. Rocky mountains and the Pacific coast, Atlantic states, Maine to Iowa. Not abundant in Iowa. DESCRIPTIVE MANUAL 51 Fig. 28. Downy or Awned Brome Grass (.Bromus tectorum). An annual grass in streets of our larger cities. (Photographed by Quade.) Fig. 28-A. Distribution of Downy Brome Grass. 52 WEED FLORA OF IOWA Extermin-ation. — Care should be used in destroying packing ma- terial. In the few localities in which this weed occurs in Iowa, it has come from packing material. It succumbs readily to cultivation. Poison Darnel {Lolium temulentum L.). Description. — An annual, with smooth, stout culm, 2-.3 ft. high ; sheaths scabrous; ligule short, spike 6-12 in. long; spikelets 5-7- flowered ; empty glumes sharp pointed, as long as the spikelet, flow- ering glumes turgid, awned or awnless, shorter and broader than in L. perenne. Distribution. — ^Introduced from Europe; naturalized in eastern North America and quite abundant on the Pacific coast; found in many counties in Iowa. Fig. 29. Poison Darnel (Loliuiu temulentum). Common in oat and wheat fields in northern Iowa. (Photographed by Hart.) DESCRIPTIVE MANUAL 53 Fig. 29-A. Distribution of Poison Darnel. Extermination. — Sow clean oats or wheat. The weed succumbs readily to cultivation. Quack Grass {Agropyron r opens Beauv.). Description. — ^A perennial with a many-jointed, creeping rhi- zome (root-stock) ; culm from 18 in-4 ft. high, bearing numerous leaves from 5-12 in. long, and from %-% in. wide ; margins rough, very smooth beneath, slightly hirsute above; spikes 6-12 in. long, erect ; spikelets on opposite sides of a jointed and channeled rachis, pubescent on the margin, erect, 4-8-flowered ; lower or sterile glumes acute or short-awned, prominently 5-7-nerved, flowering glumes smooth ; p^let acute or somewhat rounded, smooth or slightly pube- scent. The Western Wheat Grass {Agropyron smithii Rydb.) is closely related to quack grass. The plant is glaucous; leaves are rigid, bluish green in color, scabrous on the margin, edges rolling in; spikelets 7-13 flowered, in a thicker spike ("head") than quack grass; running root-stocks ("roots:"). Common along railways and in northwestern Iowa. This plant is not considered a weed. It may be used to plant railway embankments. The Slender Wheat Grass {Agropyron tenerum Vasey) produces a slender long head, greenish in color, running roots absent. Distribution. — This grass is common and widely distributed from Manitoba, Minnesota, and western Iowa to Arkansas and Texas. In Iowa it has. been found and reported in the folloAving localities: Afton Junction, Ames, Armstrong, Iowa and Minnesota line nea' Ceylon (Minnesota), Elmore, Hampton, Harcourt, Keokuk, Des 54 WEED FLORA OF IOWA Moines, Mason City, Nora Springs, Ontario, Pilot Mound and in Hamilton county. It is especially common in the loess soil from >CuTCH GRASS Fig. 30. Quack Grass, Quick Grass, Scutch Grass {Agropyron repens). Fields, waste places, around elevators, meadows, roadsides and pastures, especially northern Iowa. (After Clark and Fletcher.) DESCRIPTIVE MANUAL 55 Fig. 30-A. Distribution of Quack Grass. Carroll to Lyon county land eastward and northward and is found extensively along railroads. It is found in northern Iowa from Mississippi to Missouri rivers, probably in every county. Extermination. — With reference to the extermination of quack grass, experiments made at Ames indicate that quack grass can be exterminated. When it covers considerable areas it may be neces- sary to summer fallow. The land should be plowed in August when the small grain crop has been removed. The first plowing should be shallow, not more than two or three inches deep. Then harrow with a common drag. This will expose a large number of the "roots". If the grass appears again, run over the field with a disc and drag. This should be continued for the remainder of the sea- son. In the spring plow the soil six or seven inches ; drag and ex- pose the "roots". The field should be kept free from weeds of all descriptions during the entire growing season. It may be neces- sary to go over the field at least once a week to get all of the quack grass. Where land brings as much per acre as in Iowa, no farmer can aford to leave Ms land fallow. The field should le given the same treatment in the fall and early spring as outlined above. Sow thickly luith one of the following crops: Sorghum, Millet, Buck- wheat, or Bye. These crops will not entirely kill the quack grass hut will reduce its vitality to such an extent that what remains may he easily treated hy plowing six or seven inches deep in the fall, follow- ing with a harrow. With sorghum very little quack grass will re- main. Experience has shown that quack grass is shallow-rooted and that the roots will not grow readily through the soil beyond a depth of six inches. 6 \yi']ED FLORA OF IOWA Fig. SO-B. "Western Wheat Grass (Agropyron smithii). Common along rail- ' roads and in northwestern Iowa. The distribution of A. sinithii is shown in fig. C and of Slender TSHieat Grass (A. tenerum) in fig. D. a, empty glumes; b, flowering glumes witli flowers. Fig. 30-C. Distribution of Western Wheat Grass. DESCRIPTIVE MANUAL 57 The following suggestions for exterminating the weed are made by Fletcher and Clark: "Let the plant exhaust its substance in the production of a hay crop, which shoulcl be cut and removed as soon as the head is formed and before it is in bloom. Plow shallow and cultivate until the root-stocks have been brought to the surface by implements that can be forced, after repeated applications, to the full depth of the furrow. A disc is not satisfactory because the cut- tings from the root-stocks are difficult to gather and they perpetuate Fig. 30-D. Distribution of Slender Wheat Grass. the growth, wherever transplanted. When brought to the surface the root-stocks should be gathered and burnt or removed. This should be done at once before the plant has had an opportunity to renew its growth. For Manitoba, S. A. Bedford recommends plowing up the couchgrass late in the spring and seeding at once to barley, three bushels to the acre. ' ' Chemical Composition. — Various chemical analyses have been made of quack grass. The following were reported by Weems from material grown in Iowa. NATURAL CONDITION Sample 01 'S Q '55 13 a '3 o a "3 m £ ° 5 X3 £ aj w 1. 4-18-1806 b- 6-1896 5-20-1896 6- 1-1896 6-15-1896 4- 8 16.24 20-30 26.23 26-28 73.96 79.06 79.56 75.84 80.56 1.15 .81 1.51 1.47 1.28 5.13 4.41 4.64 4.23 1.35 (4.57) (2.47) (2.11) (2.04) (1.32) 6.13 5.66 4.96 6.68 5.05 3.14 3.11 2.09 2.66 2.12 10.49 2. - _ - 6.95 3. .. . 7.24 4. 9.64 5. 9.64 WATER I-REE SUBSTANCE. 1 _ 4.41 3.86 7.37 6.08 6.59 19.70 21.06 22.71 17.52 6.96 (17.i57) (11.80) (10.34) ( 8.44) ( 6.80) 23.55 27.12 24.28 27.56 25.97 12.08 14.84 10.24 11.00 10.93 40.26 2. ... . ^ 33.12 3. .35.40 4. . -. 37.84 5. 49.55 58 WEED FLORA OF IOWA It is not as valuable for pasturage as Hue grass but it compares very favorably with timothy in regard to the amount of protein and nitrogen free extract it contains. Squirrel-tail Grass {Hordeum jubatum L.) • Description. — An annual or winter annual from 6 in. -2 ft. high, producing fibrous roots which form solid, compact bunches, leaves not unlike those of blue grass, but paler in color, from 2-4 in. long, margins scabrous; flowers in a dense spike from 2-4 in. long, pale green or purplish in color ; spike consisting of a number of 1-flow- ered spikelets, 3 occurring at each joint, 1 being perfect, the other spikelets awl-shaped, rudimentary, and borne on short stalks, 1 sterile spikelet occurring on each side of the perfect flower, which bears a long awn ; at each joint will be found 6 empty loug-awned glumes spreading lat maturity giving to the plant its bristly appear- ance ; when mature, the spike breaks up into joints: consisting of the rudimentary spikelets and a perfect flower, so that each joint has one "seed," the number of "seeds" in a spike varying from 35-60. A single cluster of plants may therefore produce from three hun- dred to two thousand mature "seeds". The plant has a wonderful capacity for "stooling". From a single plant as many as forty spikes may be produced, and the number no doubt often exceeds this. Distribution. — Squirrel-tail grass, originally, was abundant in the vicinity of alkali lakes and along the borders of streams west of Missouri river. It also occurred sparingly on the North Atlantic coast ; now, however, it is common across the continent. In low'a it is abundant in all parts of the state not only in pastures but in mea- dows, fields and gardens. Extermination. — Squirrel-tail or wild barley is a most pernicious weed along the roadsides and in pastures and meadows ; pernicious because it not only prevents the growth of the better grasses but is injurious to live stock. As this weed is most common in the pas- ture, the best way to treat it is to mow the pasture before the grass has matured its feeed. Since this weed is an annual, qr winter an- nual, this would ' effectively dispose of the plant were it not for the fact that the seed is blown in from neighboring fields and roadsides. Cultivation-will readily destroy the weed and where it is abundant in fields shallow cultivation followed by the disk and harrow should be effective. DESCRIPTIVE MANUAL 59 Clark and Fletcher, in regard to exterminating tkis grass, which in Canada is known as Skunk-tail Grass, say: "There is no diffi- culty in eradicating this grass from any land which can be plowed, Fig. 31. Squirrel-tail Grass or Wild Barley (Hordeum jubatum). Meadows, pastures and roadsides. (After Clark and Fletcher.) 60 WEED FLORA OF IOWA Fig. 31-A. Distribution of Squirrel-tail Grass. as the usual method of breaking in June Avill destroy it. It gives most trouble in waste places where it ripens its seed, which is spread abroad in every direction by wind ^and water. It grows freely about the edges of hay sloughs on the prairie and is generally ripe before the hay is cut. The remedy in this case would be cutting before the seed is formed. ' ' Fig. 32. Squirrel-tail Grass or Wild Barley (Hordeum jubatum). tributed in Iowa pastures, roadsides, etc. (Photographed by Charlotte M. King.) W'idely dis- Chemical Composition. — Analyses have been reported from Iowa and South Dakota. The following report is by Weems from Iowa. DESCRIPTIVE MANUAL NATURAL CONDITION. 61 Sample 01 Q 1 w a o PL, a if < a, 1) ■a -2 o X3 < f 1 2 I r III ir I 5-20-1896 5^26-1890 fr- 5-18S6 6-17-1896 10.15 23.24 23.24 21.25 80.51 72.60 6Y.97 54.39 .97 1.59 .94 1.68 4. S3 3.S8 3.74 5.80 (3. CO) (2.36) (2.75) ( 3.76) 7.13 10.10 12.47 17.85 2.19 2.3> 2.70 4.00 4.87 9.98 4, __ 12.18 16.28 WATER FREE SUBSTANCE. 1. - - 4.S7 5.82 ?:.S4 3.69 22.21 12. 3e 11.78 12.71 (15.'48) ( 8.68) ( 8.57) ( 8.24) 36.59"' 36.90 88.92 39.14 11.24~ 8.46 8.43 8.78 ~ 24799 2. 36.46 3 37.93 4. 35.68 Little Barley {Hordeum pusillum Nutt.). Description. — An annual, 4-10 in. high ; culms more or less genicu- late at the lower nodes; sheaths smooth, the uppermost often in- flated and enclosing the base of the spike ; leaf -blade 1-3 in. long, usually a little pubescent on the lower surface; spikes narrow, 1-3 in. long ; empty glumes rigid, the 4 internal ones of each group di- lated above the base, those of the central spikelet sublanceolate, all awn-pointed; outer glumes of the imperfect, lateral spikelets seta- ceous ; flowering glume of the central spikelet awned ; awn equaling those of the empty glumes ; florets of the lateral spikelets awnless, or nearly so. Distribution. — Common in Missouri and Illinois and becoming plentiful in southeastern Iowa ; also in Marshall and Pottawattamie counties. Common on the plains. Extermination. — This annual weed is easily destroyed by cultiva- tion. Comes up abundantly in streets and along roadsides. The production of seed in such places makes it possible for farm land to be sown. The plants should be cut to prevent seeding of farms. Chemical Composition. — According to the AA^yoming Experiment Station the composition is as follows :* *Bul. Wyo. Agr. Exp. Sta, 87 ; compiled by Henry G. Knight, Frank E. Hep- ner, Chemists ; and Aven Nelson, Botanist. 62, WEED FLORA OF IOWA Fig. 33. Little Barley (Hordeum pusillum). Roadsides, fields. Common in southern Iowa. (Photographed by Colburn.) Fig. 33-A. Distribution of Little Barley. DESCRIPTIVE MANUAL 63 S o o (SOB S5 Water Ash Ether extract Crude fiber Crude protein Nitrogen free extract 5.79 9.26 1.77 il.58 6.49 45.13 9.82 1.88 33.52 6.89 47.89 CYPERACEAE, SEDGE FAMILY. This family contains few eeonomic plants. The chufas is used as food for hogs. The papyrus of the ancients, and the so-called rushes of our ponds belong to this family. Many of the plants grow in low grounds. Northern Nut Grass {Cy perns esculentus L.). Description. — A grasslike plant growing from l-Si/o ft. high ; with triangular stems, leafy at the base when young, later leaves termin- ating the stems ; spikes of numerous spikelets with from 12-30 light chestnut or straw-colored flowers ; scales of the spikelets rough-mar- gined ; achene longer than broad. This perennial weed spreads extensively by its underground nut- like tubers. It is closely related to the Southern Nut Grass {Cy^' perus rotundtis L.) and in the north entirely replaces it. Listrihution. — It is quite generally distributed in the state and occurs frequently in North America from New Brunswick to Texas ; common especially in low spots. Being somewhat yellowish in ap- pearance it is easily recognized. Extermination. — This weed can be exterminated only by thorough cultivation. Running the harrow over the field when corn is young will not exterminate the weed. The little offshoots merely sprout again giving rise to m^any more plants. Running the cultivator through the field is more effective, but not sufficient. In badly in- fested fields it will be necessary to use the hoe. JUNCACEAE, RUSH FAMILY. These grasslike plants are related to the lilies. They generally grow in low grounds and are of little economic importance. 64 WEED FLORA OF IOWA Fig. 34. Northern Nut Grass (.CyiJerus esciilentiis). Corn fields, especially low grounds. Young plants have a yellowish color. "Weed spreads by the "roots." Fig. 34-A. Distribution of Northern Nut Grass. DESCRIPTIVE MANUAL 65 Slender Rush {J uncus tenuis Willd.). Description. — A leafy perennial, wiry stem, 9-18 in. high; leaves flat or channeled ; flowers in panicles, the panicles shorter than the involucral leaves; flowers green, sepals lanceolate-acute, spreading in fruit ; capsiile green ; seeds small, ribbed. Distribution . — A cosmopolitan weed widely distributed in North America; common along beaten paths and fields, especially in pas- tures, in every part of Iowa. Figure 25 Figure 35A Fig. 35. Wire Grass or Slender Rush (Junciis tenuis). Common in pastures along roadsides. (Photographed by Colburn.) Fig. 35-A. Distribution of Slender Rush. Extermination. — This weed is not difficult to exterminate by cul- tivation. Where it occurs in pastures that cannot be cultivated, an effort should be made to start a leguminous plant like white clover which will kill out the rush to some extent. 5 66 WEED FLORA OF JOWA LILIACEAE, LILY FAMILY. This family contains a number of economic plants like onion, gar- lic, leek, chives, such cultivated ornamental plants as the lily, lily of the valley, and hyacinth and some poisonous plants as the colchi- eum and bunch flower. Common Bunch Flower {Melantliiurti virginicum 'Li..). Description. — Tall, leafy-stemmed plants 3-5 ft. high ; leaves lin- ear, the lower sheathing, the upper similar and sessile ; flowers in an ample panicle, fragrant ; perianth of flat segments greenish yellow ; styles persistent, capsule 3-celled ; 8-10 seeds in each cavit5^ Distribution. — In low meadows and prairies from New England to Iowa river basin, Minnesota, Texas and Florida. Common only in eastern central Iowa to the Missouri line. Fig. 36. Biincli IHower (. Melanthium virginicum) In meadows, eastern and scuthern Iowa. Poisonous. (Photo Gardner.) DESCRIPTIVE MANUAL 67 Fig. 36-A. Distribution of Bunch Flower. Extermination. — This weed is common only in native meadows It is killed when these meadows are broken up and cultivated. Wild Onion {Allium canadense L.). Description. — A perennial herb, with small scapose bulb; bulb coat somewhat fibrous ; flowers umbellate, umbels densely bulbifer- ous; perianth of 6 divisions which are narrowly lanceolate, as long as the 6 stamens or longer ; capsule 3-celled, not crested ; seeds black. Distribution. — Common in moist meadows in many parts of Iowa : Boone, Story, Marshall and Polk counties ; from New Brunswick to Wisconsin, Texas and Florida. Extermination. — This weed is common in native meadows, seldom persists like the wild garlic {Allium vineale) of Europe in cultivated fields; thorough cultivation of the field with a plow and disk and cultivator will destroy the weed. DICOTYLEDONEAE, DICOTS. Stem formed of pith wood and bark ; between the bark and wood, the cambium layer an annual ring of wood formed each year; leaves netted veined ; flowers generally on the plan of five ; embryo with a pair of cotyledons. Rose, pigweed, potato, bean, clover, Russian thistle, horse nettle, Canadian thistle belong to this division. G8 WEED FLORA OP IOWA Fig. 37. "Wild Onion {Allium canadense) . (Photographed by Charlotte M. King.) Fig. 37-A. Distribution of Wild Onion. DESCRIPTIVE MANUAL URTICACEAE, NETTLE FAMILY. 69 This family in the large sense contains such economic plants as the fig, india rubber tree, hemp, hop, and such trees as the hackberry and elm. Nettle ( Urtica gracilis Ait. ) . Description. — A perennial, stinging herb from 2-6 ft. high ; spar- ingly bristly; leaves ovate-lanceolate, sharply serrate, with long petioles, 3-5-nerved sparingly pubescent, petioles usually bristly; flowers inconspicuous, paniculate, dioecious or of staminate and pis- tilate flowers; achene compressed, inclosed by the persistent calyx. Hairs multicellular at base, urticating. Fig. 38. Stinging Nettle (Urtica gracilis) . Common along fences and in waste places, a, stinging hairs of plant. (Photographed by Colburn. a drawn by Charlotte M. King.) 70 WEED FLORA OP IOWA Fig. 38-A. Distribution of Nettle. Distribution. — Eastern Canada to Wisconsin, Minnesota, central Canada and Louisiana ; found along roadsides, borders of thickets and woods ; occasionally in gardens and waste places especially in eastern and southern Iowa. Extermination. — The perennial root stocks make this weed quite persistent and difficult to destroy, because the weed often occurs in inaccessible places along fence-rows ; however, persistent cultivation will exterminate the weed. Chemical Com^position.* FRESH OR AIR DRl MATERIAL. Water Ash Protein Flbe Nitrogen free extract Fat 82.44 2.30 5.50 1.96 7.13 0.67 WATER FREE SUBSTANCE. 13.1 31.4 11.2 40.5 .... Hemp {Cannabis sativa L.). Description. — ^A rough, stout, dioecious annual, 3-10 ft. tall; inner bark of tough fibers ; leaves digitate, of 5-7 linear-lanceolate, coarsely toothed leaflets, the upper alternate; flowers green; stam- inate, in compound racemes; pistillate, in erect spikes, each con- sisting of a calyx of a single sepal folded around the ovary and 2 filiform stigmas; fruit an achene ; endosperm fleshy; embryo curved. ♦Compiled by Jenkins and Winton : Bull. Off. Exp. Sta. 11. DESCRIPTIVE MANUAL 71 Fig. 38-B. Hemp (Cannabis sativa) . Fig. 38-C. Distribution of Hemp. 72 WEED FLORA OF IOWA Distribution. — ^Waste places, New Bnmswiek south to North Carolina and west to Minnesota, Kansas, and Kocky mountains. Widely distributed through cultivation but often becoming a troublesome weed. In many parts of Iowa; reported from Story, Dubuque, Clinton, Polk, Boone, Allamakee, Winneshiek, Marshall, Grundy, Plymouth, Pottawattamie and other counties. Extermination. — Easily killed by cultivation. Practice rotation of crops. Pellitory {Parietaria pennsylvamica Muhl.), Description. — A low, lannual, simple, or sparingly branched mi- nutely downy plant ; oblong-lanceolate, thin leaves with opaque dots ; flowers monoeciously polygamous shorter than involucre ; glomerate except in the lower axils ; stigma sessile. p ■* *^ ^ms A, r V i 1 c %^ j^l^HL^ a ^Hl 1 ^Km^ ' atj^l' a mk ^ ■ \ 4 J ».-^'^ 1 Pig. 39. Pellitory (Parietaria pennsylvanica) . Common in shady places near buildings. (Photographed by Hart.) DESCRIPTIVE MANUAL 73 Fig. 3 9 -A. Distribution of Pellitory. Distrib'wtion.- — Massachusetts to Minnesota and southward. Com- mon in Iowa in shady places, lawns and woods. Fig. 39-B. Pellitory (Parietaria pennsylvanica.) 74 WEED FLORA OF IOWA Extermination. — This weed is usually exterminated by cultiva- tion and may be destroyed by the application of iron sulphate at the rate of 100 pounds to a barrel of water. POLYGONACEAE, SMARTWEED FAMILY. This family contains the pie plant, canaigre, prince's feather, and buckwheat. Curled Dock, Yellow Dock {Runiex crispus L.). Description. — A smooth perennial from 3-4 ft. high; leaves with strongly wavy and curled margins, lanceolate and acute, lower leaves with bases somewhat truncate or inclined to be heart-shaped ; flow- ers collected in dense whorls, extended or prolonged into racemes, entirely leafless above, but below with small leaves ; 6 sepals, the 3 outer, herbaceous, leaflike, the 3 inner, larger and somewhat curled, Fig. 40. Sour Dock, Curled Dock or Yellow Dock (Rumex crispus). in low grounds, clover meadows, fields, etc. (Photographed by Colburn.) Common DESCRIPTIVE MANUAL 75 Fig. 40-A. Distribution of Curled Dock. and after flowering forming the valves of the fruit, wHich surround the 3-angled fruit, each valve bearing a grain. The -B. altissimus Wood, occurs in low ground, and is from 2-6 ft. high, with leaves oblong, lanceolate, acute, pale, thickish, but without curled margins as in R. crispus L., and longer; racemes long, spikelike, panicled, nearly leafless ; has a conspicuous grain. Distribution. — It is native to Europe where it has long been known as a troublesome weed ; common throughout eastern North America, Pacific coast, and Rocky mountains; abundant in Iowa in clover meadows, along roadsides and in pastures. Chemical Composition. — The following analysis has been re- ported.* Water Protein Pat Nitrogen free extract Crude Fiber Ash 81.6 21.7 3.9 39.4 11.4 9.3 Exterm^ination. — One of the most efficient means of destroying this weed is to root it out by the hand and this is done very readily in the spring when the soil is wet by taking hold of the plant just at the surface of the ground, giving the root a slight twist and at the same time an upward pull, when it will readily come from the soil. Where it is com^non, however, it is sometimes plowed or a spud is used. This method is not, hoAvever, so effective as the pulling method. *Storer and Anderson. 76 WEED FLORA OP IOWA Fig. 41. Curled Dock {Rximex crispus). Roadsides, meadows, clover fields, etc. (Photographed by Charlotte' M. King.) Clark and Fletcher suggest the following treatment : ' ' Sow clean seed. The prevalence of dock in meadows is due to sowing con- taminated grass and clover seeds. Land worked under a short rota- tion of crops is never badly infested with docks. When the soil is soft lafter continued rain, they can be pulled from meadows and pastures. Pull or cut and destroy all seed-bearing plants before harvesting a clover seed crop. A handful of salt placed on the crown of docks, after cutting in dry hot weather, will extract the moisture and destroy the root; this is a remedy sometimes used in lawns and pastures when the soil is too hard and dry to permit pulling them. ' ' Smooth Dock {Rumex altissimus Wood.). Description. — A tall, smooth, perennial; leaves pale, ovate, or oblong-lanceolate, thickish ; flowers in paniculate spikelike racemes, in crowded whorls, nodding pedicels, shorter than the fruiting calyx ; valves broadly ovate or obscurely heart-shaped, one with a conspicu- ous pale grain ; achene triangular, pale. Distribution. — Common in the northern states and abundant in low grounds and highways, also in pastures throughout Iowa. DESCRIPTIVE MANUAL 77 Fig. 42. Smooth or Peach-leaved Dock (Rumex altissimus). Low meadows, roadsides and pastures. (Photographed by Colburn.) Fig. 42tA. Distribution of Smooth Dock. WEED FLORA OP IOWA Fig. 43. Smooth or Peach-leaved Pock (Rumex altissimus') , Dandelion {Taraxa- cum officinale), and other weeds. This is where the seed conies from to spread weeds. (Photographed by Charlotte M. King.) Extermination. — This weed has running roots and cannot be de- stroyed in the same way as sour dock. The roots are, however, shal- low, and can be destroyed by giving cultivation exposing the roots to the sun. Bitter Dock {Bumex obtusifolius L.). Description. — A perennial herb, with roughish stem ; leaves some- what wavy, the lowest ovate heart-shaped, obtuse, the upper oblong- lanceolate, lacute; flowers inconspicuous, greenish on jointed pedi- cels ; valves of the fruit conspicuous, toothed at the base. Distribution. — Naturalized from Europe ; eastern Canada to Wis- consin, aiinnesota and south to Texas and Florida. It is found in waste places, sparingly introduced into Iowa with clover seed. Extermination. — The yellow spindle-shaped root is easily pulled by giving the plant a slight twist, especially when the ground is moist. Clover seed containing this weed should not be sown. DESCRIPTIVE MANUAL 79 Fig. 44. Bitter Dock, Red Veined Dock {Rumex obtusifolius) . Common in some clover meadows in southern Iowa. (Photograplied by Colburn. ) Fig. 44-A. Distribution of Bitter Dock. so WEED FLORA OF IOWA Sheep Sorrel {Rumex acetosella L.). Description. — A low smooth annual or perennial, usually the lat- ter, growing from 6-12 in. high, producing an erect stem, with hori- zontal, creeping, woody root-stocks or rhizome ; petioled, narrowly- hastate, narrow, lanceolate leaves, the upper linear; flowers on jointed pedicels, dioecious, small, in a terminal naked panicle ; small green calyx ; exserted stamens ; the valves not enlarging in fruit. Distribution. — Sheep sorrel has long been known ^as a troublesome weed in Europe, and in the northern states; perhaps indigenous to the United States ; at least now common across the continent in the north. It is common everywhere in Iowa, more particularly in sandy or gravelly soils. Extermination. — The plant succumbs quite readily to cultivation, and where the fields are thoroughly cultivated with hoed crops, it is seldom troublesome more than one season. In fact the vast ma- jority of plants may be killed by cultivating the soil once or twice. The roots though produced abundantly seem to be unable to stand drying. The soil on which it occurs should receive a heavy coat of manure. This seems to be approved by Dr. Halsted who says: ' ' This pest can be subdued by keeping the infested land under the plow for a short time. ' ' Clark and Fletcher say in regard to this weed: "Sheep sorrel is said to be an index of soil characters. It seems to thrive best on sandy or gravelly soils deficient of lime. An lapplication of lime .to slightly acid soils produces a more vigorous growth of cultivated crops and curtails the opportunities of the sorrel to groAv and spread. Old meadows and pastures that are overrun with it and that can- not well be brought under cultivation may be pastured mth sheep for two or three years to prevent it from seeding freely. A three-year rotation of crops Avith good cultivation, including shallow plowing directly after hay crop and frequent cultivation until autumn to prepare for hoed crops, will keep sheep sorrel well Tinder control even on lands that seem to be specially suited to its growth. ' ' Wallace's Farmer suggests the following : "To control this weed in the meadows we would suggest applying manure and thickening up the grass stand. Putting the land into a cultivated crop destroys this weed. ' ' DESCRIPTIVE MANUAL 81 Fig. 45. Sheep Sorrel or Horse Sorrel (Rumex acetosella). Common in sandy and gravelly soil. (After Clark and Fletcher.) 82 WEED FLORA OF IOWA Fig. 45-A. Distribution of Sheep Sorrel. Chemical CGmposition. — The ash of this weed is reported by Wein- hold as follows : Phosphoric acid Potash Sodium L.iine Magnesia 9.7 19.7 1.3 14.0 9.4 Erect Knotweed {Polygonum erectumh.) .. Description. — An annual, glabrous, stout, erect, or ascending yel- lowish green herb, 1-2 ft. high, with elliptical leaves ; flowers yellow- ish and inconspicuous, 1-2 in an axil ; stamens 5-6 ; achene dull, included. Distribution. — Widely distributed from the northeast to Mani-. toba, Wisconsin, Minnesota to Arkansas, and eastward. Common in Iowa especially eastward, and in Story, Boone, ]\Iarshall, Polk, Allamakee, Clinton and Dubuque counties. Extermination. — Easily exterminated by cultivation. DESCRIPTIVE MANUAL 83 Fig. 4 6. Erect Knotweed (Polygonum erectum). Common in many parts of the state. (Photographed by Hart.) Fig. 46-A. Distribution of Erect Knotweed. 84 WEED FLORA OF IOWA Dooryard Knotweed {Polygomtm avlculare L.) . Descnption. — A scattered or somewhat ascending, bluish grey an- nual; leaves acute or acutish; flowers greenish with pinkish mar- gins ; achenes triangular, dull and minutely granular-striate. Fig. 47. Dooryard Kjiotweed (Polygonum aviculare). Common in dooryards. (Photographed by Hart.) Fig. 47-A. Distribution of Dooryard Knotweed. DESCRIPTIVE MANUAL 85 Distribution. — Native in the northern hemisphere, Asia and North America, common everywhere in Iowa in gardens and waste places. Usually affected by a white mildew. Extermination. — This annual weed can be destroyed only by giv- ing the soil on which it occurs cultivation. It frequents dry and more or less beaten soil. Where it is abundant in lawns the soil should be stirred and sown to white clover. Bushy Knotweed {Polygonum ramosissimum Mx.). Description. — An erect or ascending, green or yellowish green smooth herb 2-4 ft. high ; leaves linear or lanceolate, tapering into a petiole; flowers inconspicuous, greenish; stamens 3-6; style short; aohene S-iangled. Fig. 48. Bushy or Erect Knotweed (.Polygonum rmnosissimu^n). Common in fields. (Photographed by Hart.) 80 WEf:D FLORA OF IOWA r ./ — H — -r-"^ I ■ s — , — I — iX- ■•\ Fig. 4 8- a. Distribution of Bushy Knotweed. Distribution. — From IManitoba to Texas, also in Pennsylvania; frequent in fields in many parts of Iowa, in Story, Boone, Worth, and Cerro Gordo counties. Extermi'tiation. — Easily exterminated by cultivation. Pink Smartweed [Polygonum lapathi folium L.). Description. — Pink smartweed is ^a native, glabrous, erect annual, with stem swollen at the nodes ; lanceolate, acuminate leaves with short ciliate petioles; racemes panicled, nodding, with many flow- ers ; calyx white or pink, small 5-parted ; 6 stamens, style included ; achene lenticular. Distribution. — This weed occurs from New England to Nebraska and Louisiana. Native to Europe, and common in eastern North America ; everywhere in Iowa, particularly in moist situations. Extermination. — Easily exterminated, after drainage of slough, by cultivation. DESCRIPTIVE MANUAL 87 Fig. 49. Pink or Nodding Smartweed (Polygonum lapathifoUum) . Common in com fields. (Photographed by Colburn.) Fig. 4 9- a. Distribution of Pink Smartweed. 88 WEED FLORA OP IOWA Marsh Smartweed {Polygonum muhlenhergii (Meisn.) Wats.), Description. — A somewhat pubescent or scabrous perennial with large black roots, decumbent or erect; leaves lanceolate to ovate, narrowly acuminate ; flowers in rather long hispid spikes ; sepals 5, Fig. 50. Tanweed, Marsh or Muhlenberg's Smartweed, Devil's Shoe-string or Shoe-string {Polygonum muhlenhergii) ; a, plant hairs. Low meadows and fields. (Photographed by Colburn. Drawing by Charlotte M. King.) Fig. 50-A. Distribution of Marsh Smartweed. DESCRIPTIVE MANUAL 89 bright rose color; stamens 5, styles 2-cleft, exerted. Frequently only sterile plants, or flowering rather late in the season ; trichomes multicellular, at base with thick outer epidermal walls. Distribution. — Common from Canada to Florida and west, found in all parts of Iowa; an exceedingly variable plant; sometimes found in very moist situations, land in stagnant water, or in somewhat higher but poorly drained situations. The black, thickish roots are quite characteristic of the plant. Extermination. — ^Marsh smartweed or tanweed, as it is sometimes called, is a persistent perennial and since the weed grows in wet places it is particularly difficult to destroy. The best method of Fig. 51. Tanweed, Marsh Smartweed (Polygonum muhlenbergii) . (Photographed by "W. Newell.) 90 WEED FLORA OF IOWA treating it is by thorough cultivation, exposing all the root-stocks to the sun, then removing the young plants as rapidly as they mak« their appearance. Wallace's Farmer suggests the following treatment: "It grows less vigorously on well drained land, hence the first step in eradica- tion is to drain the field thoroughly. The summer fallow is perhaps the best course of treatment. Plow the infested patch early and keep the disk and plow working on it regularly all summer long. All the roots that can be located should be pulled up and burned after drying out. A heavy pitchfork and plenty of muscle will soon fill a wagon box with the long, tough, yellow roots. A heavy seed- ing of sorghum helps to weaken the stand, but we have seen patches as vigorous as ever a year after two succeeding crops of sorghum had been grown in an effort to smother out the pest. ' ' Smartweed {Polygonum pennsylvanicum L.). Description. — An annual 1-2 ft. high, with lanceolate leaves ; branches below the flowers beset with numerous stalked glands; flowers whitish or rose-colored ; stamens 6-8, style 2-cleft ; fruit an achene, 1% lines long, flattened, brown, shining, part of the calyx remaining attached to the base. Distribution. — Pennsylvania smartweed is common from New England south westward and westward and in every part of Iowa, coming up abundantly in corn fields, sometimes forming a mass of rose-colored flowers; also growing up abundantly in grain fields after harvest. Extermination. — This smartweed is easily exterminated by cul- tivation. DESCRIPTIVE MANUAL 91 Pig. 51-A. Pennsylvania Smartweed (Polygonum pennsylvanicum) . Common in com fields. (Photographed by Colburn.) Fig. 51-B. Distribution of Pennsylvania Smartweed. 92 WEED FLORA OF IOWA Fig. 51-C. Smartweed (Polygonum pennsylvanicum) . (Photographed by W. Newell.) Water Pepper {Polygonum hyd/ropiper L.). Description. — Much like P. persicari^ but more slender and often decumbent ; flowers greenish on slender nodding spikes ; aclienes dull in color and the whole plant more or less acrid. Distribution. — Water pepper is widely distributed in eastern North America ; naturalized from Europe or may be indigenous in the northwest. Widely distributed in Iowa. Extermination. — This weed is usually found in moist places and is not very troublesome in cultivated fields except in low places. Fields that are badly infested ^^dth it should be plowed and drained and if possible some leguminous plants like alsike clover sown. DESCRIPTIVE MANUAL 93 Fig. 52. Common Smartweed or Water Pepper (Polygonum hydropiper) . (Photographed by Colburn.) Lady's Thumb {Polygonum persicaria L.). Description. — A nodding, smooth, glabrous annual; sheaths bristly ciliate; leaves lanceolate, marked with a conspicuous dark or lunar spot ; spikes short cylindric ; peduncles smooth ; achene flat- tened, smooth and shining. Distribution. — Lady's thumb is native to Europe, common in east- ern North America, Rocky mountains and on the Pacific coast. Common everywhere in Iowa, particularly in waste places and gar- dens, and growing up abundantly after grain has been harvested. Extermination. — This weed is easily destroyed by cultivation. The main point, however, is that seed production must be prevented ; hence it would be well to cut off the plants after they have started to produce flowers ; this will effectually prevent seed production. 94 WEED FLORA OP IOWA Fig. 53. Lady's Thumb (Polygonum perslcaria). Common in gardens, fields and along roadsides.) (After Clark and Fletcher.) DESCRIPTIVE MANUAL 95 Fig. 5 3- a. Distribution of Lady's Tiiumta. Water Pepper or Smartweed (P. hydropiperoides Mx.). Description.— ~A perennial not acrid; leaves narrowly lanceolate or oblong ; small 'flesh-colored flowers in erect slender spikes ; smooth achenes sharply triangular. Fig. 54. Water Pepper (Polygonum hydropiperoides). Common in low places, fields, etc. (Photographed by Colburn.) 96 WEED FLORA OP IOWA Fig. 54-A. Distribution of Water Pepper. Distribution. — Water pepper is distributed in swamps from east- em Canada southwest to Mexico; it is also distributed across the northern states to California; common in low wet places in many parts of Iowa. Fig. 54-B. Water Smartweed (.Polygonum acre). DESCRIPTIVE MANUAL 97 Fig. 54-C. Distribution of Water Smartweed. Extermination. — Since this perennial weed is most abundant in sloughs, drainage must be resorted to before an effective means of extermination can be used. After this it will give little trouble in cultivation. The Water Smartweed {Polygonum acre H B K) is a nearly- smooth perennial with stems rooting at the decumbent base ; erect, dense spikes of whitish or flesh-colored flowers. It is common in low grounds. Black Bindweed or Wild Buckwheat {Polygonum convolvulus It.). Description. — ^An annual, twining, with smooth joints; leaves halberd or heart-shaped ; flowers in corymbose racemes ; achene duU black, triangular and minutely roughened. Distribution. — This weed is widely scattered with grain seed, especially with wheat and oats. It is often most troublesome in small grain fields. In Iowa, however, it occurs in gardens and along roadsides. Extermination. — It is not difficult to destroy the weed by giving clean cultivation, since it succumbs easily to such treatment. Sow only clean seed. Clark and Fletcher recommend as follows: "Sow clean seed grain. The seeds retain their vitality for a relatively short period, probably not longer than three years, except in the drier soils of the western plains. The suppression of this pest is therefore largely dependent on the prevention of a continued supply of fresh seeds to the soil. This weed gives little trouble on land under a short rota- tion of crops, including hay, for two years. 98 WEED FLORA OF IOWA Fig. 55. Bindweed or Wild Buckwlieat (.Polygonum convolvulus). grain fields and waste plaoes.- ( After Clark and Fletcher.) Common in DESCRIPTIVE MANUAL 99 Fig. 55-A. Distribution of Black Bindweed. . The seeds of wild buckwheat do not germinate in the spring until the soil is quite warm. Most of the early plants can be destroyed in the grain crops by an application of the harrow when the grain is about three inches high. The young plants soon root firmly and the harrowing, to be effective, must be done just as they emerge from the ground. ' ' CHENOPODIACEAE, GOOSEFOOT FAMILY. This family contains the spinach, sugar beet, beet and salt bushes. Winged Pigweed (Cycloloma atriplicifolium (Spreng.) Coult.). Description. — An annual with alternate sinuate-toothed petioled leaves ; small inconspicuous flowers in open panicles ; winged seeds ; herb diffusely spreading or often spherical in form similar to the Russian thistle or Iowa tumbleweed. Distribution.- — Native from Manitoba, Minnesota, to Illinois, Ark- ansas and the Rocky mountains. In Iowa it is found along Missis- sippi river in Dubuque and Muscatine counties, in Linn county, and along Missouri river. Extermination.- — This weed is easily exterminated by cultivation. In Iowa has probably heen spread with western grass seed and in stock cars. 100 WEED FLORA OF IOWA Fig. 56. Western Tumbleweed or Winged Pigweed {Cycloloma atriplicifolium) Sandy soil, Muscatine Island, etc. (Photographed by Colburn.) Fig. 56-A. Distribution of Winged Pigweed. DESCRIPTIVE MANUAL 101 Fig. 57. "Winged Pigweed (Cycloloma atripUcifoUum) . Seed and cross section of ovary, (After W. J. Beal, Mich. Agr. Exp. Sta.) Mexican Fireweed {Kochia scoparia Schrad.). Description. — ^An anmial, erect, pubenilent or glabrate herb; leaves lanceolate to linear, ciliate acuminate; flowers sessile in the axils of the upper leaves, forming short dense-bracted spikes ; fruit- ing calyx segments each with a short triangular horizontal wing. 102 WEED FLORA OF IOWA Fig. 58. Mexican Fireweed. (Kochia scoimria). A frequent escape from cul- tivation. (Drawn by F. C Collins.) DESCRIPTIVE MANUAL 1.03 Fig. 5 8- a. Distribution of Mexican Fireweed. Distribution. — In waste places commonly cultivated and now a frequent escape in Iowa. Common in many of the northern states, Rocky mountains and the Pacific coast. From eastern Europe and western Asia. Extermination. — This weed is easily exterminated by cultivation. Mexican Tea {Chenopodiiim amhrosioides L.). Description. — A smoothish annual, or slightly pubescent ; strong scented ; leaves oblong or lanceolate, entire or cut-pinnatifid, nearly sessile ; spikes densely flowered, leafy ; flowers in small, dense, axil- lary spikes; calyx 3-parted enclosing the fruit. The wormseed (C. anthelminticnm) is an annual or sometimes a perennial; leaves more strongly toothed; the flowers usually in bractless panicled spikes. Distribution. — ^Mexican tea is found southward, occurring, how- ever, from Maine to California. The wormseed has nearly the same distribution occuring northward to Minnesota and Wisconsin. Neither of these weeds is common in Iowa. Extermination. — In Iowa both of these weeds are easily extermin- ated by cultivation. Do not permit any of their seeds to mature. 104 WEED FLORA OF IOWA Fig. 59. Mexican Tea iChenopodium ambrosioides) . In southern Iowa; streets and fields. (Photographed by Colburn.) Fig. 5 9- a. Distribution of Mexican Tea. DESCRIPTIVE MANUAL 105 Fig. 59-B. Plant hair or trichome of {Chenopodium hotrys). bj glandular trichomes from calyx. (Drawn by Charlotte M. King.) a, from stem ; Maple-leaved Goosefoot {Chenopodium hyhridum L.)- Description. — A bright green animal from 2-4 ft. high; widely branching, with an unpleasant odor like stramonium; leaves thin, triangular, heart-shaped sinuate-toothed; flowers inconspicuous, in loose, racemose panicles; calyx covering the fruit; seed firmly at- tached to the pericarp. Distribution. — Frequently found in woods and waste places ; ex- tending from Eansas to Manitoba, Wisconsin and Minnesota and southward ; common in Story, Boone, Marshall, Clinton, Polk, Wood- bury, Pottawattamie, Dubuque, Allamakee and Cerro Gordo coun- ties. Extermination: — This annual weed can be killed by giving clean cultivation. Sometimes distributed with clover seed, but less fre- quently than the other species. Sow clean clover seed. 106 WEED FLORA OF IOWA FlQ. 60. Maple-leaved Goosefoot (Chenopodiuvi hyhridum) . Frequent in woods and waste places. (After Mich. Agr. Exp. Sta.) DESCRIPTIVE MANUAL 107 Fig. 60-A. Distribution of Maple-leaved Goosefoot. Lamb's Quarters, Pigweed. {Chenopodium album L,). Description. — An erect annual from 1-4 ft. higli; young plants generally mealy, older plants smooth ; leaves rhombic-ovate to lance- olate or the upper sometimes linear, acute, lower commonly toothed ; flowers produced in clustered, dense-spiked panicles; calyx 5-parted, nearly covering the seed ; seeds surrounded by a loose pericarp form- ing an utricle. Distribution. — Native to Europe ; widely naturalized in eastern North America and the Rocky mountains; occurs in Utah and on the Pacific coast ; found everywhere in Iowa in cultivated fields and in gardens as well as along highways. Extermination. — Plants of this species produce an enormous number of seeds. The young plants are easily destroyed by cutting off below the ground. Covering the young plants is not effective unless the entire plant is covered. Older plants may be destroyed by pulling them up. The weed on account of the shade it produces destroys other vegetation underneath it. Chemical Composition. — According to a report of the Bussey In- stitution, the chemical composition is as follows:* *Bull. Bussey Inst., 1877: Jenkins and Winton ; Office Exp. Sta., Bull. 11. 108 WEED FLORA OF IOWA Fig. 61. Lamb's Quarters (Chenopodium album). Common in gardens and fields. (After Clark and Fletcher.) DESCRIPTIVE MANUAL 109 Fig. 61-A. Distribution of Lamb's Quarters. FRESH OR DRY AIR MATERIAL. Water Ash Protein Fiber Nitrogen free extract Pat 80.80 3.02 3.91 2.55 8.93 0.76 WATER FREE SUBSTANCE. 15.7 20.S 13.3 46.5 4.0 Orach (Atriplex patula L. var. hastata (L.) Gray.). Descripticm. — ^A pale green or purplish, slightly scurfy, annual, 2-3 ft. high ; leaves slender-petioled narrowly lanceolate-hastate, en- tire or somewhat sinuate-dentate ; flowers inconspicuous, interrupted, slender-panicled spikes. Distribution. — Found from eastern Canada northeast to Wiscon- sin and Iowa. In Iowa somewhat widely scattered. Extermination. — Easily exterminated by cultivation. Sheep are fond of it and may be utilized to destroy the weed. 110 WEED FLORA OF IOWA % ^ ^T^^& ^ ^ k A ^.J^jB^ ^V H -^^^^/ / iff ■^^^ X ^wLmt- ^^^ w x*M^ M^ •' i.y^ f ^ nj . ^'^^ TO 7^ '^i- i^ ' ' \ t- Fig. 62. Orach (Atriplex patula yslt. hastata). Streets, gardens, roadsides. (Photographed by Coltaurn.) Fig. 62-A. Distribution of Orach. DESCRIPTIVE MANUAL \ m Russian Thistle {Salsola Kali L. var. tenuifolia G. F. W. Mey). Description. — An herbaceous, smooth or slightly pubescent an- nual, diffusely branched from the base, from l%-3 ft. high, spherical in the mature form; leaves fleshy, alternate, succulent, linear, sub- terete, 1-2 in. long, pointed in the older specimens, upper leaves in the mature plant persistent, each subtending 2 leaf -like bracts and a flower ; stem and branches red ; apetalous flowers solitary and ses- sile; calyx consisting of 5 persistent lobes, enclosing the dry fruit which is usually rose-colored, about 1-12 in. long; 5 stamens nearly as long as the calyx ; pistils with 2 slender styles producing a single obconical depressed seed, dull gray or green, without albumen ; em- bryo spirally coiled; on germination cotyledons are subterete. The plant flowers in July or August, the seeds maturing in August. Distribution. — Russian thistle is native of Russia and western Asia. Since its introduction into the Dakotas it has been widely scattered in the northern states and is common from Minnesota to the Pacific northwest and in the Rocky mountains from Montana to New Mexico. It is widely scattered in Iowa but abundant only dur- ing dry years, along the right of way of railways, and in the vicinity of stockyards. Extermination. — The Russian thistle as said before, is an annual, hence it would seem an easy matter to destroy it ; and as a matter of fact, when taken in time, it is hot a difficult weed to remove. Its nox- iousness comes largely from the fact that the plant is so productive. If a Russian thistle is once cut ofi: at the surface of the ground it never grows again ; hence in cultivated fields it is not likely to prove a great pest. The question is, however, a very different one in pas- tures, meadows and roadsides; here the weeds cannot be removed by cultivation and many of the plants mature their seeds unobserved. The removal of the weeds along the roadsides is important, because it is largely from this source that our fields become infested. The removal of such weeds can be best accomplished by running over the patch with a mower. Fletcher and Clark recommend as follows : ' ' Hand-pull wherever practicable. Harrowing growing crops is an effective remedy ; it is easily killed by this method when young. The harrow should be ap- plied just before the grain emerges from the ground and again when the crop is three inches high. ' ' 112 WEED FLORA OP IOWA Fig. 63. Russian Thistle (.Salsola kali var. tenuifolia). Common in western Iowa. Fleshy herb becoming spiny. (Photographed by Gardner.) Fig. 63-A. Distribution of Russian Thistle. DESCRIPTIVE MANUAL 113 "Wallace's Farmer suggests tlie following treatment: "Russian thistle is easily controlled by cutting it off just below the surface of the ground before it seeds in August. It has not proved a dangerous weed east of Mississippi river." CHEMICAL COMPOSITION. Original Sample Dry Matter Water Dry matter 100 parts contain: Water Crude ash Ether extract (crude fat) Nitrogen free extract (soluble carbohydrates)— Crude fiber. Crude protein (total nitrogen x 6.25) True albuminoids (albuminoid N x 6.25) (2.22) 84.52 15.48 84.52 3.41 .34 6.10 2.78 2.86 lOO.OO (14.35.) 22.01 2.20 39.39 17.94 18.46 lOO.OO AMARANTHACEAE, PIGWEED FAMILY. This family contains few economic plants. Some, like the coek's- eomb, are grown for ornamental purposes. Pigweed, Redroot (Amaranthus retroflexus L.). Description. — A roughish, more or less pubescent annual ; 3-5 ft. tall ; leaves ovate or rhombic-ovate, undulate ; long-margined petiole, entire ; flowers in thick spikes crowded in a stiff or bunchy, spiky panicle; bracts subulate, longer than the mucronate or obtusely- tipped sepals. Distribution. — ^A weed throughout North America, especially east- ward ; abundant in every county in the state. Extermination. — ^Frequently distributed with clover seed; sow clean clover seed in a clean field. Easily exterminated by cultiva- tion. Fletcher and Clark recommend as follows: "When embedded in the soil, the seeds retain their vitality for several years, though prob- ably not more than five in a moist soil, and produce seedling plants only when brought by cultivation within about two inches of the surface. ' ' 114 WEED FLORA OF IOWA Fig. 64. Pigweed, Redroot (Amaranthtis retroflexus) . Common in gardens, roadsides and fields. (After Claris and Fletcher.) DESCRIPTIVE MANUAL 115 Fig. 64A Figure 64B Fig. 64-A. Trichomes or plant hairs from stem of pigweed. (Drawing by Ciiarlotte M. King.) Fig. 64-B. Distribution of Pigweed. Chemical composition. — According to the University of Minnesota the composition is as follows :* Dry Matter Crude Protein Ether Extract Nitrogen free extract and fiber Ash 97.00 26.54 1.36 62.86 9.24 Tumbleweed {Amaraoithus graecizans L.). Description. — A smooth, pale green much-branched annual; at maturity a spherical mass, which separates easily from the root; leaves oblong-spatulate or ovate; smair flowers greenish, inconspicu- ous, polygamous, several together in small axillary clusters, small and pointed. Distridution. — Common in North America especially from Ohio westward. In waste grounds. The detached leafless plants may be seen rolling over fields. Extermination. — Easily exterminated by cultivation. *Bull. Minn. Agr. Exp. Sta.. 11, by Harry Snyder. 116 WEED FT.ORA OP IOWA Fig. 65. Iowa Tumbleweed or Tumbling Pigweed (Amaranthus graecizana) . Common in com fields. Plant grows in circular form, separates from the root in the autumn and rolls over and over, scattering the seeds. (Photographed by Hart.) Fig. 65-A. Distribution of Tumbleweed. DESCRIPTIVE MANUAL 117 Prostrate Pigweed {Amaranthus Mitoides Wats.). Description. — A diffusely branched, prostrate herb, spreading on the ground, often in mats 4 or 5 ft. long ; leaves obovate or spatu- late ; flowers inconspicuous, greenish, in short axillary clusters. Fig. 66. Prostrate Pigweed (.Amaranthus blitoides). Common along roadsides, streets, fields, and in waste places. (Photographed by Hart.) Fig. 66-A. Distribution of Prostrate Pigweed. 118 WEED FLORA OP IOWA Distribution. — Common in every county in the state of Iowa and east to northeast ; indigenous to the Rocky mountains. Extermination. — Easily exterminated by cultivation. Water Hemp {Acnida tuberculata Moq.). Description. — A tall, erect annual; leaves lanceolate to rhombic- ovate, acute, or acutish; flowers dioecious; pistillate flowers small, green, clustered in naked or leafy terminal and axillary spikes; staminate flowers pale; dehiscent pericarp thin. The Acnida tamariscina (Nutt.) Wood, of similar habit. Has circumscissille fruit, otherwise like the A. tuberculata. Distribution. — Common along water courses, prairies and marshes from northeast to Minnesota and Dakota. Found in Iowa in Story, Boone, Polk, Pottawattamie, Woodbury, Emmet, Cerro Gordo, Clin- ton, Linn, Marshall and Allamakee counties. Fig. 6; VS'ater Hemp (Acnida tuberculata). Common plant with yellowish aspect. In old lake beds and prairies. (Photographed by Colburn.) DESCRIPTIVE MANUAL 119 Fig. 67-A. Distribution of Water Hemp. Extermination. — Easily exterminated by cultivation; not infre- quent in clover seed, and not long present in well cultivated fields especially when they are well drained. NYCTAGINACBAE, FOUR-O'CLOCK FAMILY. This family contains the well known cultivated four-o'clock. Four-o'clock, Umbrella Plant (Oxydapkus nyctagineus (Mx.) Sweet.) Description. — A nearly smooth, deep-rooted perennial 2-4 ft. high ; forking leaves, broadly ovate, cordate, or lanceolate, opposite, round- ed or truncate at base ; petioled involucre ; flowers persistent ; fruit obovoid, pubescent ; calyx bell-shaped, rose or purple ; stamens gen- erally 3. Distribution. — From IManitoba to Louisiana, introduced eastward ; common in cultivated fields, on railway embankments and in waste places. Exterminaiion. — This weed propagates both by its seed and root ; however, it is not difficult to destroy when the roots are cut off during dry weather. "Wallace's Farmer suggests the following treatment: "The wild four-o'clock, although not yet very common in the corn belt, has possibilities of becoming a bad weed. It is a perennial, with a big, fleshy root and spreads freely from the seed. It spreads very little from the root. This weed may be exterminated in time by cutting it off close to the ground every year just before it seeds. ' ' 120 WEED FTLORA OF IOWA Fig. 68. Wild Four-o'clock (Oxj/'baphus nyctagineus) . Common in fields, along roadsides and on railway embankments. Plants have a long, stout root. (Photographed by Colburn.) Fig. 68-A. Distribution of Wild Four-o'clock. CARYOPHYLLACEAE, PINK FAMILY.. This family contains the well known carnation, spurrey and gar- den pink. DESCRIPTIVE MANUAL 121 Chickweed (Stellaria media (L.) Cyrill.). Description. — ^An annual, or winter annual, whose spreading stems are marked with, one or more pubescent lines; leaves ovate (After Clark and Fletcher.) Fig. 69. Chickweed (.Stellaria media). Gardens, lawns, dooryards. 122 WEED FLORA OF IOWA Fig. 69-A. Distribution of Chickweed. or oblong, from 1/2 to 21/^ in. long, lower leaves on hairy petioles, sepals 4 or 5, greenish ; petals 4 or 5 ; shorter than the calyx and 2-parted; stamens 3-10; styles 3. Pod ovoid. Distribution.' — Chickweed is widely distributed in the northern states to the Pacific coast; naturalized from Europe; common in many places in lawns and in shady places, not especially trouble- some except on the lawn, where often it runs out blue grass. Extermination. — This weed is easily exterminated by cultivation. Since the lawn, however, cannot be cultivated the best and most ef- fective means of exterminating the weed is to spray with iron sul- phate at the rate of 100 pounds to a barrel of water. Spray as soon as the plants make their appearance and repeat 2 to 5 times during the season. Nodding Chickweed (Cerastium nutans Raf.). Description. — A clammy, pubescent, much-branched annual with slender, erect stems 6-20 in. high; leaves oblong, lanceolate, acute, the lowest spatulate; flowers numerous in open loose cjanes; pods nodding on the stalks, curved upward, larger than the calyx. The larger mouse-ear chickweed {Cerastium viscosum) is a perennial with obovate, clammy, hairy stem; leaves varying from oblong to lanceolate ; flowers clustered at first ; sepals rather obtuse, small. The common mouse-ear or chickweed (C. vulgatum) is a peren- nial with clammy pubescence. Distribution. — From New England to Minnesota, especially south- ward in southern Iowa and Missouri. DESCRIPTIVE MANUAL 123 Fig. 70. Nodding Chickweed (Cerastium nutans). Common in fields, waste places and streets, southern Iowa. (Photographed by Colburn.) Extermination. — This arnnial is easily exterminated by cultiva- tion. . When it occurs in places that cannot he cultivated, like pas- tures and lawns, iron sulphate at the rate of 100 pounds to a barrel of water may be used. 124 WEED FLORA OF IOWA Fig. 70-A. Mouse-ear or Chickweed (Cerastium vulgatum). Common in pas- tures. (Photographed by Colburn.) Fig. 70-B. Distribution of Larger Mouse-ear or Chickweed (.Cerastium vis- cosum). DESCRIPTIVE MANUAL Corn Cockle {Agrostemma githago L.). 125 Description. — A hairy, anniial weed, clothed with long, soft hairs ; leaves linear-lanceolate, acute or long-acuminate ; flowers purple and Fig. 71. Com Cockle (.Agrostevima githago). In grain fields. (After Clark and Fletcher.) 126 WEED FLORA OF IOWA FiG. 71-A. Distribution of Corn Cockle. long peduncled; calyx lobes long, linear, surpassing the purplish red petals ; seeds large, roughened and black. Distribution. — A weed long known as troublesome in European grain fields, and widely scattered throughout the grain growing sec- tion of North America. It is most abundant in Iowa in the wheat- growing section but occasionally is found in other places around grain elevators. Ext elimination.- — ^This weed is an annual and in order that it may be checked in its spread, use only clean seed. The seed should be put in clean soil. Fletcher and Clark recommend as follows : "In the prairie pro- vinces, harrowing the grain crop just before it emerges from the gouncl and again when it is about three inches high keeps down this weed. Where the land is infested with purple cockle, a thorough summer fallow is the best method of getting rid of it. ' ' White Campion {Lychnis aiha Mill.). Description. — A freely branching biennial, with a slightly plea- sant odor ; leaves ovate-oblong or ovate-lanceolate ; flowers loosely paniculate, white or pink, fragrant; capsule ovoid-conical, swelling with the ripening of the pod ; petals 2-clef t, crowned. Distribution. — Introduced with clover seed from Europe, not, however, as common in the east as Lychnis dioica. DESCRIPTIVE MANUAL 127 Fig. 72. White Cockle (Lychnis alba). In clover meadows. (After Clark and Fletcher.) 128 WEED FLORA OF IOWA Fig. 72- a. Distribution of White Cockle. Extermination. — This weed can be exterminated by cutting off the plants when in bloom or by cutting them off a few inches below the surface of the ground. Since this weed is being spread with European clover seed, care should be used to sow only clean clover seed. Catchfly {Silene dichotoma Ehrh.). Description. — A tall, more or less hirsute, annual, somewhat viscid, pubescent; leaves lanceolate or oblanceolate ; flowers in branched racemes, short-pedieeled in the forks, or solitary at the nodes ; calyx 5-ribbed, hirsute ; petals white or pink, bifid. Distribution. — Introduced from Europe, spreading occasionally in clover fields from the northeast to Iowa and Texas, also to the Pacific coast. Extermination. — A remedy in this case is to sow only clean seed, clean clover or alfalfa seed in clean soil in localities where the weed occurs. Give thorough cultivation. Do not allow any of the plants to go to seed. DESCRIPTIVE MANUAL 129 Fig. 73. Catchfly (Silene dichotoma Bhrh.). In waste places. (W. J. Beal, Mich. Agr. Exp. Sta.) 130 WEED FLORA OF IOWA Fig. 73-A. Distribution of Catclifly. Night-flowering CatcMy {Silene noctiflora h.) . Description. — A viscid, pubescent annual from 2-3 ft. higli ; lower leaves spatulate, upper lanceolate and pointed ; flowers few, large, peduneled, white, fragrant; calyx prominent veined; pod enlarged in ripening of the fruit. Distribution. — In waste places in Europe, Canada to Manitoba and southward, found in many counties in Iowa. Extermination. — This weed is easily exterminated by cultivation. It has been widely spread in recent years with clover seed, particu- larly clover seed coming from the east and from Europe. Sow only clean clover seed on clean soil. Fletcher and Clark make the following suggestions for extermin- ating the weed : ' ' Farmers who sow clover and grass seed free from the seeds of catchfly will not long have trouble with it on lands worked under a short rotation of crops. A rotation of crops ex- clusive of alsike seed should be adopted for six or eight years. Grass DESCRIPTIVE MANUAL 131 Fig. 74. Night-flowering Catchfly (Silene noctiflora) . In clover meadows, gar- dens, etc. (After Clark and Fletcher.) 132* WEED FLORA OP IOWA Fig. 74-A. Distribution of Night-flowering Catclifly. or clover seed eontaining eatchfly should be thoroughly cleaned in miUs equipped with screens specially designed to remove this im- purity, and should not be used on land that may later be required for the production of alsike seed. ' ' Cow-herb {Saponariavaccariah.). Description. — A glabrous annual, from 1-2 ft. high with opposite ovate-lanceolate leaves ; flowers in corymbed cymes ; calyx 5-angled, enlarged and angled in fruit; petals pale red. Distribution. — This weed has long been known as troublesome in grain fields of Europe, and is common in North America. It is com- mon in Iowa only where wheat is grown. Extermination. — Clean seed sown in clean soil is the only method of exterminating the weed. Clark and Fletcher suggest the following treatment : * * Sow clean seed. Prevention is the best and least expensive method of fighting it. It is a large showy plant and when not present in excessive num- bers can easily be hand-pulled. The seed will not retain its vitality long ; when land is seeded to timothy or western grass and left for a few years, the supply of vital seeds in the soil will be greatly re- duced, if not entirely exhausted. ' ' DESCRIPTIVE MANUAL 133 Fig. 75. Cow-herb {Saponaria. vaccaria). In grain fields. (Clarlc and Fletcher.) 134 WEED FLORA OF IOWA Fig. 75-A. Distribution of Cow-herb. Bouncing Bet {Saponaria officinalis L.). Description. — Perennial herbs with large flowers in cymose clus- ters; calyx narrowly ovoid or oblong, 5-toothed; petals clawed or unappendaged, stamens 10, styles 2, pod 1-celled or incompletely 2 or 4-celled and 4-toothed at the apex. . Distribution. — About 40 species in Europe, Asia, and Northern Africa. Saponaria officinalis is frequently cultivated in old gar- dens. The mucilaginous juice forms a lather with water and is valuable for taking grease spots out of woollen cloth. Commonly escaped from gardens to roadsides and railway embankments in many parts of Iowa but especially in northeastern and eastern Iowa. Extermination. — Though this weed is a perennial it is not diffi- cult to destroy in cultivated fields and gardens. In lawns and places where the soil is not cultivated it is best to dig up the patches, remove the dirt from the roots and let the sun dry them ; covering with tarred paper will kill the weed, if it is kept covered long enough, say from 6 to 8 weeks. PORTULACACEAE, PURSLANE FAMILY. This family contains the well known moss rose, spring beauty, etc. DESCRIPTIVE MANUAL 135 Fig. 76. Bouncing Bet, Soapwort iSaponaria officinalis). 136 WEED FLORA OF IOWA Fig. 76-A. Distribution of Bouncing Bet. ^•" :i:^ --A^^:^ Fig. 77. Bouncing Bet {Saponaria officinalis) . Near a building. Seeds mature and spread from such places. (Photographed by Charlotte M. King.) Pusley, Purslane {Portulaca oleracea L.). Description. — A fleshy, prostrate, smooth annual with s'cattered obovate or wedge-shaped leaves ; small sessile flowers with a 2-clef t calyx; 5 small, yellow petals, inserted on the calyx; stamens 7-12,. style deeply 5-6-parted ; seeds small, finely rugose. DESCRIPTIVE MANUAL 137 Fig. 78. Purslane or Fusley (Portulaca oleracea). Gardens and corn-fields. (After Clark and Fletcher.) 138 WEED FLORA OF IOWA Fig. 78-A. Distribution of Purslane. Distribution. — Purslane is native to Europe and is common from the Atlantic to the Pacific especially in cultivated soil. Common everywhere in the state in gardens and in corn fields. Extermination. — Purslane is not difficult to exterminate if the green weeds are placed in piles or removed from the garden. They may be fed to hogs. It should be said that the leaves and stems show considerable vitality, since the whole plant is fleshy. Fletcher and Clark say: "A three-year rotation, including summer-fallow directly after the removal of a crop of early clover, followed by a hoed crop and again by cereal grain for the third year, will keep it in check. If given access to corn and potato fields, sheep will feed on late plants, and if their pasture is short, will prevent many of them from seeding." Chemical Composition. — According to a report of the Bussey In- stitution* the chemical composition is as follows : FRESH OR AIR DRY MATERIAL. Water Ash Protein Fiber Nitrogen free extract Fat 92.61 1.56 2.24 1.03 2.16 0.40 WATER FBEB SUBSTANCE. 21.1 30.2 19.9 29.4 5.4 ♦Bull. 1877: Jenkins and Winton, Bull. Off. Exp. Sta. 11. DESCRIPTIVE MANUAL 13 & RANUNCULACEAE, BUTTERCUP FAMILY. The plants of this family are acrid. There are few economic plants among them ; some like the peony, columbine, buttercup, lark- spur, and aconite are cultivated for ornamental purposes. Small-flowered Crowfoot {Ranunculus abortivus L.), Description. — A small, slightly pubescent, succulent biennial; from 6 in.-2 ft. high with multiple roots; root leaves roundish or kidney-shaped, crenate ; stem leaves often 3-5-lobed or parted, mostly toothed; petals small, pale yellow; shorter than the reflexed calyx; carpels minute. Fig. 79. Crowfoot (.Ranunculus abortivus). Common in woodland pastures, pastures. (Photographed by Hart.) 140 WEED FLORA OF IOWA Fig. 79-A. Distribution of Crowfoot. Distribution. — Common everywhere in Iowa in waste places along roadsides and in fields, occasionally eastward to Newfound- land, south to Florida and north to Manitoba, also in the Rocky mountains. ExtermiTmtion. — This weed is easily exterminated by cultivation. Swamp Buttercup {Ranunculus septentrionalis Poir.). Description. — A branching, prostrate, smooth or sometimes pubes- cent perennial with multiple fibrous roots, frequently rooting at the nodes and often forming long runners; leaves large, petioled, 3-divided, divisions mostly cuneate, petals obovate, larger than the spreading calyx ; achenes flat, strongly margined, pointed by a stout straight beak. Distribution. — Common in fields, especially low grounds from eastern Canada to Manitoba ; south to Kansas and Kentucky. Com- mon everywhere in Iowa in low places in Story, Boone, Marshall, Polk, Linn, Clinton, Buchanan, Emmet, Worth, Woodbury, Potta- wattamie, Plymouth, Kossuth, Dallas and Allamakee counties. Extermination. — Drainage of the soil and thorough cultivation will soon exterminate this weed. DESCRIPTIVE MANUAL 141 Fig. 80. Creeping Buttercup (Ranunculus septentrionalis) . Common in low grounds. Flowers yellow. (Photographed by Hart.) FlQ. 80-A. Distribution of Creeping Buttercup, 142 WEED FLORA OF IOWA Prairie Larkspur (Delphinium penardi Huth.). Description. — A perennial pubescent or hairy herb, more or less glandular above, with simple, erect stem, 3-5 ft. high; leaves 3-5 parted, divisions 2-3 cleft; the numerous flowers white, or bluish- white, in elongated raceme, spur ascending or erect ; follicle many- seeded. Distribution. — ^From Illinois and Wisconsin, westward and north- ward. Common on gravelly knolls along railroads throughout the state of Iowa. Extermination. — This perennial is easily exterminated by culti- vation. The roots of the plant readily succumb when exposed to the sun. Fig. 80-B. Prairie Larkspur (Delphinium penardi). Common on gravelly knolls. (Drawing by Ada Hayden.) CRUCIFERAE, MUSTARD FAMILY. This family contains the well known sweet alyssum, cabbage, cauli- flower, rape, radish, turnip, white and black mustard, water cress, etc. They are all pungent herbs. DESCRIPTIVE MANUAL 143 Pennycress {Thlaspi arvense L,.). Description. — An annual or winter annual with simple, smooth, erect or branching stem ; leaves of stem clasping, with arrow-shaped .':St^ %' Fig. 81. Stinkweed or Field Pennycress (Thlaspi arvense). Grain and clover fields. (After Clark and Fletcher.) 144 WEED FLORA OF IOWA Fig. 81-A. Distribution of Pennycress. base ; root leaves petioled ; flowers white ; petals nearly equal ; seeds purplish brown, longer than broad ; cotyledons accumbent. Distributicm. — Common in waste places, particularly in clover fields; Story, Woodbury, Winneshiek, Allamakee and some other counties in the state. Common in Manitoba, Minnesota, Dakota, and eastern Canada, particularly in the prairie provinces. The weed is abundantly distributed by spring floods and also to some extent by clover seed. Large Peppergrass {Lepidium virginicum L.). Description. — An erect annual, at flrst quite simple, later much branched, 8 in.-2 ft. high ; leaves divided, entire or with irregular, pointed teeth ; flowers small, white ; pod circular or oval with a lit- tle notch at the upper end; seeds light brown, elongated, with a prominent ridge on one side, on addition of water becoming muci- laginous; cotyledons accumbent. Distribution. — ^Large peppergrass is native to the Mississippi val- ley, east to New England; more common in Missouri, Illinois and Ohio. It is widely scattered in Iowa, being particularly common in timothy meadows in some years. Extermination. — This peppergrass sometimes comes up abund- antly in the fall. The fields should, therefore, be plowed in the fall and when sowing small grain given a thorough dragging. In corn fields the ordinary methods of cultivation will destroy the weed. Do not permit any of the plants to seed. Frequent in timothy seed. Sow only clean timothy seed. DESCRIPTIVE MANUAL 145 Fig. 82. Large or Virginia Peppergrass (Lepidium virginicum) . Common in fields, gardens, etc. ; along roadsides. (Photographed by Colburn.) Pig. 82-A. Distribution of Large Peppergrass. 10 146 WEED FLORA OF IOWA Small Peppergrass {Lepidium apetalum Willd.). Descnption. — Much like the foregoing, an annual 8 in-2 ft. high, but leaves and pods smaller; flowers small, greenish; seeds light rRGRASS Fig. 83. Small Peppergrass (Lepidium apetalum). Common in timothy meadows, fields, etc. (After Clark and Fletcher.) DESCRIPTIVE MANUAL 147 Fig. 83-A. Distribution of Small Peppergrass. brown, elongated, with prominent ridge on one side, becoming muci- laginous when moistened with water ; cotyledons incumbent. Distribution. — Small peppergrass is common in the northern states from New England across the continent ; apparently native in the west ; in the east introduced from Europe. It is abundant in fields and waste places. In some years it is particularly common in timothy and clover meadows. Extermination. — The peppergrasses are not difficult to extermin- ate in cultivated fields since they are annuals. In growing timothy seed it is important above all to have a field as clean from weeds as possible. Timothy should therefore be sown in a field that has been under thorough and clean cultivation for several years and clean seed only should be used. In this way the peppergrass can largely be prevented from growing. Fletcher and Clark make the following suggestions: "Only autumn plants which live through the winter give trouble in grain. Thorough surface cultivation in the spring, with the plow, disc or broad-shared cultivator, is efficacious. Immature seeds may ripen in the pods when plowed down." Hoary Alyssum (Berteroaincana (L.) DC). Description. — A tall, green, erect annual or biennial with entire, pubescent, pale green, lanceolate leaves; flowers white, 2-parted; pods canescent. 148 WEED FLORA OF IOWA Fig. 84. Hoary Alyssum (Berteroa incana) ; a, flowering stem ; bj flower ; c, pods ; d, section of ovary. Weed of clover fields. Fig. 84-A. Distribution of Hoary Alyssum. DESCRIPTIVE MANUAL 149 Distribution. — Said to be common in northeastern United States and becoming frequent in other Atlantic states ; found in Mississippi and adjacent states ; found not infrequently in Iowa ; reported from Ida county in 1912, and said to have been introduced with clover seed. Extermination. — Sow clean clover and alfalfa seed. Succumbs readily to cultivation. False Flax {Camelina sativa Crantz.). Description. — ^An erect annual with single or sparingly branched stem, 1% ft. long, smooth or slightly pubescent stellate hairs ; leaves erect, lanceolate or arrow-shaped, entire or nearly so ; flowers small, yellow, pedicels in fruit spreading ; pod obovoid 4-6 in. long, smooth, reticulated, margined from beak down along placental side with smaller ribs between them ; seeds light brown, 1 line long, minutely pitted, caulicle prominent, running lengthwise with a prominent groove between it and the cotyledons which are incumbent ; on the addition of water seeds become mucilaginous. ' Distribution. — This weed is particularly common in the grain growing sections of the north, as Dakota, Manitoba and Saskatche- wan. In recent years it has become more common in Iowa, par- ticularly in the northern counties. Extermination. — Clark and Fletcher recommend the following treatment: "When a crop of winter wheat is infested with false flax, harrowing in the spring kills the young plants without injur- ing the whearf;. A thorough summer-fallow, with cultivation the pre- vious fall and continuous cultivation throughout the summer, is recommended for fields badly infested with this weed. ' ' 150 WEED FLORA OP IOWA Fig. 85. False Flax {Camelina sativa). In grain and flax fields, waste places. (After Clark and Fletcher.) DESCRIPTIVE MANUAL 151 Fig. 85-A. Distribution of False Flax. Shepherd's Purse {Capsella hursa-pastoris Moench.) Description. — An annual or winter annual 1-1% ft. high; root leaves clustered, nearly divided or merely toothed; stem leaves ses- sile ; flowers small, white, in fruit spreading ; pods much wider above than below, many-seeded ; seeds light brown, elongated, with a promi- nent ridge, mucilaginous when moistened with water; cotyledons incumbent; trichomes stellate, roughened. Distribution. — Shepherd's purse is native to Europe and one of the most common early spring flowers from the Atlantic to the Pa- cific. Common everywhere in gardens and fields in the state. Extermination. — Clark and Fletcher state : "It has an enormous power of propagation ; a single plant will ripen 50,000 seeds. Waste places should be cleared as far as practicable and seeded to grass. It does not give serious trouble on lands worked under a short rota- tion, with clean cultivation of hoed crops. Sow clean grass and clover seeds. ' ' 152 WEED FLORA OP IOWA Fig. 86. Shepherd's Purse (.Capsella bursa-pastoris) . Common in gardens, fields and waste places. (After Clark and Fletcher.) DESCRIPTIVE MANUAL 153 Figure 86 A Figure 86B Pig. 86-A. Plant hair or trichoma of Shepherd's Purse. (Drawing Charlotte M. King.) Fig. 86-B. Distribution of Shepherd's Purse. I'lG. 86-C. Shepherd's Purse {Capsella bursa-pastoris). Weed in city streets. (Photographed by Charlotte M. King.) Jointed Charlock {Baphmius raphanistrum L.) . Description. — Biennial or annual, having a slender root, rough leaves, lyrate, pinnatifid, with a large terminal lobe; flowers yel- lowish fading to white, or purplish veined; pods linear or oblong, jointed, 2-8-seeded. 154 WEED FLORA OP IOWA Fig. 87. Wild Radisli or Jointed Charlock (Raphanus raphanistrum) . In oat fields in northern Iowa. (After Clark and Fletcher.) DESCRIPTIVE MANUAL 155 Fig. 8 7- A. Distribution of Jointed Cliarlocli. Distribution. — Common; spreading eastward in fields and waste places; reported in grain fields in Worth and a few other counties in the northern part of Iowa. It is said to have been largely dis- tributed with oats seed. Extermination. — Exterminated by cultivation. Sow only clean oats seed in clean fields. Mustard or English Charlock {Brassica arvensis (L.) Ktze.). Description. — Lower leaves nearly divided to the middle^ with divisions unequal, terminal lobe larger, upper leaves not stalked as a rule, much smaller than the lower; flowers yellow, large and very fragrant; pods 1-2 in. long, irregular in outline, appearing somewhat nodose, 3-7-seeded or occasionally more, upper part of pod forming a beak; seeds round, brownish black, darker than in B. nigra and minutely pitted, when moistened becoming mucilaginous. Distribution. — Mustard or charlock has been known as a pest of the grain fields from the earliest historical record, throughout the grain growing section of the world; common everywhere in Iowa, but most abundant in the grain growing section of northern and northwestern Iowa where it was introduced with flax. Extermination. — The first and most important consideration in connection with the extermination of mustard is that the oats or wheat should be freed from mustard seed. Then this grain should be sown on clean fields, preferably fields that have been in pasture or meadow. Nothing has done so much to remove the weeds from the fields of northwestern Iowa as the pasture and meadow. If the grain is sown in a corn field there should have been no mustard the 156 WEED FLORA OF IOWA • Fig. S8. Wild Mustard or Charlock iBrassica arvensis). Common in road- sides and grain fields. (After Clark and Fletcher.) DESCRIPTIVE MANUAL 157 Fig. 8 8- A. Distribution of Wild Mustard. previous season. Having sown the small grain on a clean field there is always a chance that some of the seeds will retain their vitality in the soil. If much of this mustard should come up it may become necessary to spray it with iron sulphate. Where the mustard is abundant this is a very effective means of destroying the weeds, using the sulphate at the rate of 100 pounds to a barrel of water. Chemical Composition. — According to the University of Minne- sota the chemical composition is as follows :* Dry Matter Crude Protein Ether Extract Nitrogen tree extract and fiber Ash 91.79 15.75 1.55 75.59 7.11 Black Mustard (Brassica nigra Koch,). Description. — A tall, coarse, much-branched annual, 2-5 ft. high ; leaves variously divided or only deeply cut, the terminal lobe the largest, sharply toothed, upper leaves small, simple, as a rule linear; leaves as a rule not smooth, but somewhat bristly, at least on the veins ; flowers yellow, smaller than in charlock ; pods smooth, about % in. long, 4-cornered, tipped with a slender beak; seeds black or reddish brown, smaller than in charlock; cotyledons incumbent; trichomes not stellate, simple, rough. •Snyder: Bull. Minn. Agr. Exp. Sta., 101. 158 WEED FLORA OP IOWA Fig. 89. Black Mustard {Brassica nigra). Fields, gardens and roadsides. (Photographed by Colburn.) Fig. 89-A. Distribution of Black Mustard. DESCRIPTIVE MANUAL 159 Distribution. — This weed is common in the northern states and extends across the continent. It is abundant in Iowa, at times, in waste places and vacant lots; apparently, however, it is less com- mon than common charlock. Extermination. — This weed can he exterminated by the same method that is used with common charlock. Eocket {Eruca sativa L.). Description. — ^An annual or biennial herb with stout, 4-sided stem; lower leaves lyrate, incised or pinnatifid, upper leaves, Fig. 90. Rocket {Eruca sativa). Introduced with alfalfa seed. (Drawn by F. C. Collins.) 160 WEED FLORA OF IOWA Fig. 90- A. Distribution of Rocket. smaller, lobed, or entire ; flowers white or yellowish-white with dark veins; fruit an oval, elongated silique containing many, more or less compressed, seeds in 2 rows. Distribution. — ^A native of western Asia and the Mediterranean region, but cultivated as a salad plant and often an escape. Intro- duced into Iowa with alfalfa seed in Woodbury, Plymouth, 'Brien, Clay, Mitchell, Pottawattamie, Mills, Ida, and Sac counties. Extermination. — The weed can be exterminated by cutting the plants off a few inches below the surface of the ground or by giving thorough cultivation. Hare 's-ear Mustard {Conringia orientalis (L.) Dumort). Description. — Slightly succulent annual; leaves light green, ses- sile, obtuse, racemes becoming elongated in fruit; petals much longer than the sepals ; pods long, linear 4-angled, spreading ; coty- ledons incumbent. Distribution. — Common eastward and appearing in the Missis- sippi valley; occurring in Woodbury, Webster and Page counties and probably in many other places in Iowa. Extermination. — Easily exterminated by cultivation. DESCRIPTIVE MANUAL 161 Fig. 91. Hare's-ear Mustard (Conringia orientalis) . In grain fields, and waste places in northwestern Iowa. (After Clark and Fletcher.) 11 162 WEED FLORA OF IOWA Fig. 91-A. Distribution of Hare's-ear Mustard. Fig. 91-B. Hare's-ear Mustard (.Conringia orientalis). Flowering stem, seed and cross section of seed. Appearing in several counties in lowa. DESCRIPTIVE MANUAL Ball Mustard {Neslia paniculata (L.) Desv.). 163 Description. — An erect, slender annual or biennial, 1-3 ft. high "with stem simple up to the inflorescence; stem and leaves, both being covered with stellate pubescence; sessile leaves oblong, very Fig. 91-C. Ball Mustard (Neslia paniculata) ; a.j flowering stem; by pod; Cj seed. (Schuyler Mathews in Mich. Agr. Exp. Sta. Bull.) narrow, sagittate at base; racemes elongate; flowers small, yellow, about Ys in. in diameter; seed-pods nearly spherical, 2-celled with 1 small yellow seed in each cell, sometimes but one developing. Distribution. — In grain fields, Canada, the Dakotas and occa- sionally in northwestern Iowa. Extermination. — Clean seed; easily destroyed by cultivation. 164 WEED FLORA OF IOWA j Hedge Mustard (Sisymbrium officinale (L.) Scop.)- Description. — A slender, erect annual or winter annual, 1^-2^ ft. high ; lower leaves divided, upper entire or hastate at base ; flow- ers small, yellow, borne in spikelike racemes; seeds small, brown; cotyledons incumbent. Distribution.-, — Found everywhere in the state, notably in Story, Boone, Polk, Clinton, Linn, Marshall, Hardin, Black Hawk, Wood- bury, Pottawattamie, Carroll, Jasper, Monroe, Scott, Lee, and Alla- makee counties. Extermination. — Easily exterminated by cultivation ; also by us- ing the formula 100 pounds of iron sulphate to one barrel of water. Fig. 92. Hedge Mustard (Sisymbrium officinale). Common in gardens, fields and waste places. (General aspect of plant photographed by Hart. Drawing by Charlotte M. King.) DESCRIPTIVE MANUAL 165 Fig. 9 2- A. Distribution of Hedge Mustard. Chemical Composition. — According to the University of Minne- sota it is as follows :* Dry Matter Crude Protein Ether Extract Nitrogen free extract and fiber Ash 94.5 16.52 1.43 74.18 7.87 Tumbling Mustard {Sisymhriwm aUissimmm L.). Description. — A leafy, branched annual from 1-4 ft. high, lower leaves runcinate, pinnatifid, irregularly toothed, or wavy margined, upper leaves smaller, threadlike. Distribution. — This weed is native to east Europe. It has become widely scattered in the northern states, particularly in the west from Minnesota to Washington and in Canada. It is widely scattered in Iowa in the vicinity of railroad watering tanks, elevators and stock- yards. It is less common in the southern half of the state. Extermination. — The young mustard plants are easily killed by cultivation. They are likely to occur in some commercial seed like timothy, therefore, sow only clean seed. * Snyder: Bull. Minn. Agr. Exp. Sta., 101. 166 WEED FLORA OF IOWA Fig. 93. Tumbling Mustard {Sisymbrium altissimum). In grain fields, rail- ways, etc. (After Clark and Fletcher.) DESCRIPTIVE MANUAL 167 Fig. 93-A. Distribution of Tumbling Mustard, Marsh Cress {Badicula palustris (L.) Moench..). Description. — An annual or biennial; erect, smootli, or slightly pubescent herb; from I-II/2 ft. high; leaves pinnately cleft or parted, pinnatifid; the lobes toothed; upper leaves sessile; flowers yellowish in racemes ; pods ellipsoid or ovoid. Fig. 94. Marsh Cress {RaMcula palustris). Common in low grounds. (Photographed by Colbum.) • 168 WEED FLORA OF IOWA Fig. 94-A. Distribution of Marsh Cress. Distribution. — In wet places or in low grounds; frequent in oat fields and meadows ; abundant in Iowa especially in northern Iowa ; common throughout the northern United States. Not infrequently- distributed with clover seed that is grown in Iowa. Extermination. — This weed may be exterminated by first drain- ing the soil and then giving clean cultivation. Horseradish {EadAcula armoracia (L.) Eobinson). Description. — A stout perennial with long, deep roots; leaves large, oblong, crenate or pinnatifid, the latter produced in the spring; stem leaves lanceolate, or oblong cordate; flowers with 4 green sepals and 4 white petals, not common ; pods short, globular, but fruit seldom found. At least I have never observed any in Iowa. Distribution. — Horseradish is native to eastern Europe and in- troduced in west Europe and the United States ; common from the Atlantic to the Pacific; largely an escape from cultivation; found in every part of Iowa. Extermination. — The horseradish is one of the most persistent of our weeds ; no other weed will stand such rough treatment. It may be hoed and cultivated and still it persists in coming up. Some years ago we tried the following plan : The land was plowed, then harrowed ; the roots were picked up and the process repeated after the lapse of a week, when young plants again made their appear- ance. After that, young plants were cut off with a hoe below the ground as soon as they appeared. This treatment was kept up for DESCRIPTIVE MANUAL 169 Fig. 94-B. Horseradish (Radiciila armoracia). Escaped from cultivation; a rather persistent weed. (Drawing by Charlotte M. King.) Fig. 94-C. Distribution of Horseradish. two years, and in this way most of it was removed. Quack grass near the horseradish received the same treatment and was killed in a single season, the season being dry. Yery little progress in de- stroying the plant would have been made in a wet season. 170 WEED FLORA OF IOWA Winter Cress {Barharea vulgaris R. Br.). Description. — A biennial, with yellow flowers 1-2 ft. high ; stem furrowed, simple or branched; lower leaves simple or pinnately parted, terminal lobe the largest, round or ovate ; upper leaves obo- vate, cut, toothed or pinnatifid at the base; flowers bright yellow; pods erect or slightly spreading ; cotyledons accumbent. Distribution. — Eastern North America from Labrador to Mary- land, Iowa, Manitoba, Rocky Mountains, Pacific slope; common in northern Iowa. A cosmopolitan weed in Europe, Asia, Africa and Australia. Extermination.' — This perennial weed is not difficult to kill if the field is given an early plowing followed by a subsequent disking and harrowing, thus getting the field in a good state of tilth for a crop. Fig. 95. Winter Cress {Barbarea vulgaris). (Photographed by Colburn.) DESCRIPTIVE MANUAL J71 Fig. 95-A. Distribution of Winter Cress. CAPPARIDACEAE, CAPER FAMILY, This family contains the caper which is used for pickling, the Rocky Mountain bee plant, etc. Stinkweed {Polanisia graveolens Baf.). Description. — A fetid annual with glandular hairs; leaves with 3 oblong leaflets ; flowers in leafy racemes ; 6 petals, white, with claws, notched at the apex ; stamens about 11, scarcely exceeding the petals ; not elongated, bearing a gland behind the base of the ovary; pod short, stalked; seeds rough. The P. tracJiysperma T. & G. has larger flowers with long exserted stamens and sessile pods. Distribution. — Iowa to Kansas and eastward to New England; common in sandy soil, railroad embankments, Muscatine Island. Extermination. — Easily exterminated by cultivation. The land should be cultivated as soon as a fresh growth of the weed develops. Great care must be taken not to plow down any full-sized pods, even though they may be green, as it has been proven that in the dry climate of the west such seeds can ripen beneath the soil. The most important measure to be used in order to clear the land of stink- weed is harrowing the growing crop to kill the seedlings. The har- rowing should commence before the crop emerges from the ground and be repeated when the grain is about three inches high. 172 WEED FLORA OF IOWA Fig. 96. Clammy Weed or Stinkweed (Polanisia graveolens) . In sandy places, gravelly soils, etc. (Photographed by Hart.) Fig. 96-A. Distribution of Stinkweed. DESCRIPTIVE MANUAL 173 %,]'- Fig. 97. Stinkweed {Polanisia trachysperma) . Common in sandy soils, rail- way embankments and gravelly soils. (Photographed by Colburn.) Rocky Mountain Bee-plant or Stinking Clover {Cleome serrulata Pursh..). Description. — A smooth annual; leaves of 3 laneeolate, oblong' leaflets, somewhat fleshy; flowers in braeteate racemes; petals usually rose-colored, short-clawed ; stipe of pod as long as the pedicel. Distribution. — From western Iowa, Minnesota and northward, Utah, Colorado, Montana and westward; common in Iowa in Fre- mont, Mills, Pottawattamie, and Woodbury counties, occasionally eastward in Polk county. Extermination. — Easily exterminated by cultivation. 174 WEED FLORA OP IOWA ^^ X^raF ^Sk^^^ V^ Fig. 98. Rocky Mountain Bee-plant (Cleome serrulata). Fields, roadsides in western Iowa. (Photographed by Colburn.) Fig. 98-A. Distribution of Rocky Mountain Bee-plant. DESCRIPTIVE MANUAL 175 Fig. B-B. Rocky Mountain Bee-plant (Cleome serrulata}. (Drawing by Charlotte M. King.) ROSACBAE, ROSE FAMILY. This family contains the well known rose, apple, pear, quince, I)]um, peach, almond, strawberry, blackberry, raspberry, spiraea, etc. Cinquefoil, False Strawberry {Potentilla monspeliensis L.). Description. — ^A hairy annual or winter annual from l-2i^ ft. high; leaves 3-foliolate, leaflets obovate to oblanceolate, the upper- most toothed, nearly the whole length ; flowers in close cymes, calyx large, 5-cleft with 5 bractlets ; petals 5, yellow, small; stamens 15-20 j style terminal ; trichomes simple, long pointed, thick walled. Distribution. — ^Naturalized from Europe; eastern Canada, New England, to Kansas ; common in Iowa, in Story, Boone, Polk, Clin- ton, Lyon, Carroll, Woodbury, Kossuth, Webster, Marshall, Cerro Gordo, Worth, Winnebago, Allamakee and other counties. Extermination. — Frequently introduced with clover seed. Sow only clean clover seed in a clean field. Cut the weed off below the surface of the ground and give thorough cultivation. 176 WEED FLORA OF IOWA Fig. 99. Cinquefoil, False Strawberry, Five-finger (Potentilla monspeliensis). Common in gardens, timothy meadows, etc. a. Plant hair ; i, showing cell-wall. (a and h, drawn by Charlotte M. King, general aspect of plant photographed by Hart.) Fig. 99-A. Distribution of Cinquefoil. DESCRIPTIVE MANUAL 177 Silverweed {Potentilla anserina L.). Description. — Herbaceous perennial, spreading by slender run- ners j numerous white-tomentose and silky-villous leaves, all radi- Fig-. 100. Silverweed (Potentilla anserina). In marshes. (Drawing by Ada Hayden.) Fig. 100-A. Distribution of Silverweed. 12 178 WEED FLORA OF IOWA cal ; pinnate leaflets, 7-21 with smaller ones between, oblong, sharply- serrate, silky 4omentose beneath ; flowers with 5 bright yellow petals ; peduncles elongated ; styles filiform. Distribution. — Conmion eastward in brackish marshes; also in the Dakotas and the Rocky mountains ; common in Wright county, Iowa ; perhaps in other places. Extermination. — Give a shallow cultivation; expose the roots to the sun. Care must be used to kill the weed on its first appearance as it is quite persistent. Wild Rose {Eosa pratincola Greene). Description. — ^Low shrub with very prickly stem; compound leaves of 7-11 leaflets, broadly elliptical to oblong-oblanceolate, sub- cuneate at base, short stalked or sessile, serrate; ^ipule narrow, Fig. 101. Wild Rose (.Rosa pratincola). Grain fields, roadsides. (Photographed by Colbum.) DESCRIPTIVE MANUAL 179 Fig. 101-A. Distribution of Wild Rose. Fig. 101-B. Wild Prairie-rose {Rosa pratincola). (Drawn by Ada Hayden.) 180 WEED FLORA OF IOWA glandular toothed; flowers corymbose, calj^x tube urn-shaped, 5 sepals, smooth or occasionally hispid, petals 5, rose-colored; fruit oblong, ovaries hairy. Distribution. — Common in prairies and field from Texas to Min- nesota, west to Colorado. Common everywhere in Iowa; Story, Polk, Enunet, Dickinson, Palo Alto, Clay, Kossuth, Winnebago, Allamakee, Clinton, Muscatine, Scott, Decatur, and Pottawattamie counties. Extermination. — This weed often persists in grain fields of northern Iowa. Thorough cultivation for a few seasons will, how- ever, usually destroy the weed. Stickweed ( Geum canadense Jacq. ) . Description. — A perennial herb from l%-2 ft. high; leaves pin- nate, the lower of 3-5 leaflets or undivided ; stem leaves 3-divided or 3-lobed, sharply toothed ; stipules ovate-oblong ; flowers white ; calyx bell-shaped ; deeply 5-clef t ; petals 5 ; stamens many ; pistils numer- ous ; styles jointed and bent near the middle, the upper part falling away and the lower part hooked. Distribution. — Widely distributed in northern United States, and frequently found in woods or fields adjacent thereto ; common espe- cially in northeastern Iowa. Extermination. — This weed is easily scattered by animals because of the hooked achenes; thorough cultivation will, however, destroy it. LEGUMINOSAE, PULSE FAMILY. This family contains the clover, pea, beans, cowpea, soybean, honey locust, lupines, vetches, coffee bean, senna, and ornamental plants as red bud, sweet pea, caragana, etc. DESCRIPTIVE MANUAL 181 Fig. 102. Stickweed, White Avens (Geum canadense) . White flowers with bur- like fruit scattered 'by animals. In pastures and fields. (Photographed by Hart.) ig. 102- ". Distribution of Stickweed. 182 WEED FLORA OP IOWA Rattle-box {Crotalaria sagittalis L.). Description. — A hairy annual from 3 in-1 ft. high, with a small tap root; stem branched, villous, terete or wing-margined; leaves oval or oblong-lanceolate, from %-% in. wide, edge of the leaf en- tire or somewhat wavy and hairy; stipules united and decurrent on the stem, becoming inversely arrow-shaped; peduncles produce a few yellow flowers about i/4 in. in diameter; calyx 5-cleft, stand- ard of the flower large, heart-shaped ; keel scythe-shaped ; stamens monadelphous, anthers of two sizes, 5 smaller and roundish; pod large, inflated, bears a close resemblance to that of the garden pea, greenish at first, becoming blackish varying in size from %-l in. in length and about 1 in. in diameter; seeds from %-l/10 in. in diameter, flattish, kidney-shaped, when mature breaking away from the point of attachment and rattling in the pod, hence the name ''rattle-box". Pig. 103. Rattle-box {Crotalaria sagittalis). Common in sandy soil, Missouri river bottoms. (Photographed by Colburn.) DESCRIPTIVE MANUAL 183 Fig. 103-A. Distribution of Rattle-box. Distribution. — Common from New England to Minnesota, south- west to North Texas, In Iowa abundant only along Missouri river, the Des Moines near Ft. Dodge, and at other points along sandy beaches of our streams. Extermination. — This weed occurs mostly in the Missouri bot- toms, generally on more or less sandy soil. It succumbs readily to cultivation. The raw sandy prairies on which it occurs should be broken up and sown to some leguminous crop, like alfalfa, which will crowd the weed out. The Yellow Clover {Trifolium agrarium L.). Description. — A smoothish annual, usually upright, with obovate- oblong leaflets, all 3 from the same point (palmate) and nearly ses- sile ; stipules narrow ; corolla yellow, persistent. Distribution. — Common in sandy fields and roadsides from east- ern Canada west to Wisconsin and Minnesota and to Iowa ; common along roadsides in northeastern Iowa. Extermination. — Same as for low hop-clover. 184 WEED FLORA OF IOWA Fig. 104. Yellow or Hop Clover (Trifoliuvi agrarium). Along roadsides. Tel- low flowers. (Photographed by Colburn.) Low Hop-clover {Trifolium procumbens L.). Description. — A pubescent annual with spreading or ascending stems; leaves of 3 leaflets pinnate, the lateral at a small distance from the other, obovate, notched at the end; stipules ovate, short; flowers yellow, persistent, becoming dry in age. Distribution. — Naturalized from Europe; common in eastern staites. Extermination. — Readily succumbs to cultivation. The seeds, however, may retain their vitality for some time in the soil. Sow clean seed in clean soil. DESCRIPTIVE MANUAL 185 Fig. 105. Low Hop-clover, Yellow Clover (.TrifoUum procumbens) . Clover fields, meadows, waste places. (1. Drawn by Charlotte M. 'King, the general aspect photographed by Hart.) Fig. 105-A. Distribution of Low Hop-clover. 186 WEED FLORA OP IOWA Yellow Sweet Clover (Melilotus offioinalis (L.) Lam.). Description. — An upright, usually tall, fragrant annual cr bien- nial; leaves compound, leaflets obovate-oblong, obtuse, closely ser- rate; flowers yellow, pod smooth, prominently cross-ribbed. The M. indica also with yellow flowers has a gibbous and alveolate pod. This has recently been introduced. Distribution. — Yellow sweet clover is also native to Europe. Widely scattered throughout the United States, more abundant upon the Pacific coast, in the Great Basin country and the Rocky moun- tains. Not abundant in the northern Mississippi valley. More or less frequent in many parts of Iowa, however, as in Humboldt and parts of Greene and Woodbury counties. Fig. 106. Yellow Sweet Clover {Melilotus officinalis). some fields. (Photographed by Colburn.) Roadsides, streets and DESCRIPTIVE MANUAL 187 Fig. 106-A. Distribution of Yellow Sweet Clover. Extermination. — The seeds preserve their vitality for some time. The weed is easily destroyed by cultivation. Sweet Clover (MeUlotus alba Lam.). Description. — ^An erect annual or biennial 2-4 ft. high ; rather dis- tant, compound leaves, leaflets obovate, oblong, obtuse, serrate, nar- rowed at the base, truncate, emarginate or rounded at the apex; flowers with white petals, small, fragrant; pod ovoid, reticulated and smooth. Distribution. — Sweet clover is native to Europe and abundant in all parts of the United States. It has been widely scattered by bee- keepers who sowed it as a honey-bee plant. Abundant now along highways, right of ways of railways ; also in some fields ; found in every part of Iowa. Extermination. — The only way to exterminate this plant is to prevent seed formation. This may be done by cutting the plants underneath the ground. In fact the young plants are easily ex- terminated in this way. The plants occur in the meadows and pas- tures, coming largely from the weeds left growing along the road- sides. Eoad overseers should see that these chance plants are re- moved. According to a recent investigation of Prof, Ewart of Aus- tralia some of the seeds retain their vitality for .a long time, some- times more than half a century. It is imperative, therefore, to pre- vent the formation of seeds so as not to sow for a future generation to eradicate. Sweet clover is used as a forage plant and considered quite valuable. Mr. Coverdale of Maquoketa considers it a most valuable plant. Mr. Westgate has recently brought together many valuable points in its favor. 188 WEED FLORA OF IOWA Fig. 107. "White Sweet Clover (Melilotus alba). Common along roadsides. (Photographed by Colburn.) The Farmer 's Review says regarding the plant : "In Minnesota, Wisconsin, and Ohio there are laws against the plant known as sweet clover. We fail to see why this plant should be singled out and denominated as a weed. It certainly is not objectionable as a cover for waste places, and is easily controlled where its presence is not desired. ' ' Chemical Composition. — The chemical composition according to the University of Wyoming is as follows.* •Bull. No. 70 compiled by Henry G. Knight, Frank E. Hepner, chemists, and Aven Nelson, botanist ; Wyoming Experiment Station. DESCRIPTIVE MANUAL 189 Fig. 108. White Sweet Clover (.Melilotus alha). Along roadsides. (Photographed by Charlotte M. King.) Fig. 108-A. Distribution of White Sweet Clover. 190 WEED FLORA OP IOWA >. a a> HI o < 79.36 6.02 2.10 9.57 0.53 2.42 4.78 21.77 3.96 18.00 9.28 42.22 Water - - Ash Ether extract Crude fiber Crude protein Nitrogen free extract 10.18 2.52 23.16 19.15 44.99 Black Medic {Medicago lupulina h.) . Description. — A procumbent, pubescent, annual; compound leaves trifoliate; leaflets wedge-shaped, obovate, toothed at the apex ; flowers yellow, in short spikes ; pods kidney-form, 1-seeded. Distribution. — Native from Europe, common in alfalfa fields in the Eocky mountains and on the Pacific coast; common in waste places in eastern North America; reported from a number of coun- ties in Iowa, as "Wright, Kossuth and Story. Extermination. — This annual is not difficult to exterminate by giving thorough cultivation ; care should be used in planting clover and alfalfa seed, because this weed seed is a common impurity of the latter. The seed also retains its vitality for some time. Chemical Composition.* FRESH OR AIR DRY MATERIAL. Water Ash Protein ^ Fiber Nitrogen free extract Fat 78.52 1.37 3.40 6.31 9.20 1.11 WATER FREE SUBSTANCE. 6.4 15.8 29.3 43.4 5.1 ♦Compiled by Jenkins and Winton, Bull. Off. Exp. Sta., Bull. 11. DESCRIPTIVE MANUAL 191 Fig. 109. Black Medic {Medicago lupulina). Clover and alfalfa meadows. (Photographed by Hart.) Fig. 109-A. Distribution of Black Medic. 192 WEED FLORA OF IOWA Pink Parosela {Dalea alopecuroides Willd.). Description. — An erect annual from 2-3 ft. high, with pinnately- eompound leaflets; smooth flowers, Avhitish or light rose-eolor, in cylindrical spikes; calyx villous; seeds kidney-shaped. Distribution. — From Minnesota to Alabama and the Rocky moun- tains, common in western Iowa and introduced eastward in Wright, Boone, and Story counties. Extermination. — It is sometimes found in clover seed grown in western Iowa, also in alfalfa seed from the west, therefore care should be used in the selecting of seed ; succumbs readily to culti- vation. Fig. 110. Parosela (.Dalea alopecii^roides) . Common in western Iowa and along railroads. (Photographed by Quade.) DESCRIPTIVE MANUAL 193 Fig. 110-A. Distribution of Parosela. Rattle-box or Milk Vetch {Astragalus canadensis L.)- Description. — A tall, erect, smooth or pubescent perennial, 1-4 ft. high; leaves compound, leaflets 21-27, oblong; flowers greenish cream-colored in spike of variable length; pods crowded, smooth, terete, occasionally somewhat suleate; the seeds separate from the pod, rattling, hence the common name. Distribution. — Common in the northern Mississippi valley, east to New York and south to Georgia. Common on borders of thick- ets, woods and native meadows. Extermination.— This weed is easily exterminated by cultivation. 13 194 WEED FLORA OF IOWA Fig. 111. Rattle-box (Astragalus canadensis). (Photographed by Charlotte M. Woodland pastures. King.) Purple or Stemless Loco "Weed (Oxytropis lamherti Pursh.). Description. — Nearly acaulescent, perennial herbs or shrubby plants, with tufts of very numerous short stems coming from a hard and thick root-stock containing many scaly stipules; stems and leaves covered with silky and finely appressed hairs, or smoothish ; leaves pinnate; leaflets linear; flowers racemose or spicate, rather large and elongated, purple, violet, or sometimes white ; stamens dia- delphous ; keel tipped with a sharp projecting point. This is one of the loco weeds, poisonous to cattle. Distribution. — Western Minnesota, western Iowa, and Missouri to Texas, and New Mexico, north to British Columbia, and northwest territory. . Extermination. — It seldom gives much trouble in cultivated fields. DESCRIPTIVE MANUAL 195 Pig ]]2. Purple Loco Weed (Oxytropis lamberti). A weed poisonous to cattle. (Drawn by F. C. Collins.) Fig. 112-A. Distribution of Purple Loco Weed. 196 WEED FLORA OF IOWA Wild Liquorice {Glycyrrhiza lepidota (Nutt.) Pursh.). Description. — A branching perennial 2-3 feet high, leaves com- pound of 15-19 oblong-lanceolate leaflets with mucronate points; young leaflets sprinkled with a resinous material ; .flowers in spikes ; short peduncled; whitish; pods oblong, covered with hooked prickles, resembling a cocklebur. Distribution. — Common in the west, western Iowa to Rocky mountains, Utah, New Mexico, and Montana to Canada, also re- Fig. 113. Wild Liquorice (Glycyrrhiza lepidota.) Occurs in western and cen- tral parts of the state. DESCRIPTIVE MANUAL 197 Fig. 113-A. Distribution of Wild Liquorice. ported from the Great Lakes; commonly reported from Story, Greene, Pottawattamie, Harrison, Monona, Fremont, and Decatur counties. i Extermination. — This perennial plant whose burs resemble the cocklebur is easily exterminated by cultivation. Do not permit the seeds to mature. Cut off the plants at the surface of the ground to prevent flowering, if they occur in the pasture or meadow. Where the land can be cultivated, give the ordinary plowing, fol- lowed with harrowing to bring the roots to the surface so they are exposed to the sun. A few days ' exposure to the sun will kill them. Common Vetch {Vicia saliva L.), Description. — ^A smooth or slightly pubescent annual from l-2l^ ft. high with simple stem; leaflets 5-7 pairs, obovate-oblong to lin- ear, notched or mucronate at the tip ; 1 or 2 nearly sessile flowers borne in the axils of the leaves, corolla violet-purple; pod linear, several-seeded, seeds black. Distribution. — This weed has long been known as troublesome in the grain flelds of Europe, and in the northern states. It is particu- larly abundant in northeastern and northwestern Iowa and in some of the grain growing sections of the southern part of the state. Extermination. — Clean seed sown in clean soil is the only method of displacing the weed. 198 WEED FLORA OF IOWA Pig. 114. Common Vetch (Vicia sativa) . Common in grain fields, especially wheat fields, frequently found in screenings from flour mills. (Photographed by Colburn.) Fig. 114-A. Distribution of Common Vetch. DESCRIPTIVE MANUAL 199 Chemical Composition. — The chemical composition of vetch (Vicia sativd) according to U. S. Dept. Agr., 1880; p. 152, is as follows: FRESH OR AIR DRY MATERIAL. t4 a) < p "S> o 111 s 1 Cut 6-4; in full bloom— 86.20 1.60 4.14 2.11 5.34 0.61 WATER FREE SUBSTANCE. 11.6 3. GO 15.3 38.7 4.4 "Wild Bean (Strophostyles helvola (L.) Britton). Description. — An annual, with prostrate stem; compound leaves ovate to oblong-obovate, with a prominent rounded lobe at the base ; corolla greenish white and purplish ; pod 4-8-seeded, large, usually pubescent. Distribution. — Common in sandy places in northern United States; from Wisconsin, Minnesota, and Texas east to Massachu- setts ; common in gravel pits on Muscatine Island, along Des Moines, Cedar and Iowa rivers. Extermin^.tion.— 'Easily exterminated by cultivation. OXALIDACEAE, WOOD SORREL FAMILY. This family contains the cultivated yellow and purple-flowered oxalis. Few of the plants are economic. 200 WEED FLORA OF IOWA Fig. 115. 'VS^ild Bean (Strophostyles helvola). Common in sandy or gravelly soil, sandy river bottom. (Photographed by Colburn.) Fig. 115-A. Distribution of Wild Bean. DESCRIPTIVE MANUAL. Field Sorrel {Oxalis stricta L.). 201 Description. — ^A pale green pubescent annual or perennial ; leaves compound, with evident stipules; flowers pale yellow, cymose, 1-4, at length, deflexed ; in fruit columnar, short-pointed. Distribution. — Common in fields and waste places from New Eng- land to Dakota ; common in Iowa probably over the entire state. Extermination. — Persistent cultivation and crop rotation will usually exterminate the weed. Fig. 116. Yellow Field Sorrel {Oxalis stricta). Common in fields, a. Trichoma or plant hair. (a drawn by Charlotte M. King. The whole plant photographed by Hart.) 202 WEED FLORA OP IOWA Fig. 116-A. Distribution of Yellow Field Sorrel. Field Sorrel {Oxalis corniculata L.). Description. — An erect or decumbent perennial herb, spreading by numerous slender, pale runners ; leaflets 3 ; flowers in eymose clusters, yellow; peduncle ascending and sparingly pubescent. Fig. 117. Field Sorrel (.Oxalis corniculata). Fields, gardens, etc. (Photographed by Colburn. 1. Drawn by Charlotte M. King.) DESCRIPTIVE MANUAL 203 Pig. 11 7- A. Distribution of Field Sorrel. Distribution. — A very common weed in dry or moist soil through- out eastern North America. Extermination. — ^Apply the same method as to the preceding species. ZYGOPHYLLACEAE, CALTROP FAMILY. A small family. Caltroip {Trihulus terrestris h.) . Description. — The caltrop is a hairy, procumbent annual, branch- ing from the base, producing a stem which is a foot or more long, branches bear numerous small, compound leaves with short pe- duncles and small stipules at the base; each compound leaf has 4-8 pairs of short-stalked leaves; small, yellow, axillary flowers about % in, across with peduncle much shorter than leaves; fruit very spiny and divided into two nearly equal parts, each part consists of 2 long spines, 2 shorter and a row of very short ones, forming a crest on the back ; 5-angled, spiny fruit splits into 3-5 divisions. Distribution. — Introduced from the Old World and occurs from the Atlantic states to Nebraska and Kansas ; in Iowa has been found only on Muscatine Island. Extermination. — Caltrop is disseminated by wool, and hence the waste of woolen mills should not be thrown in fields. The v/eed is easily destroyed by cultivation. 204 WEED FLORA OF IOWA DESCRIPTIVE MANUAL 205 Fig. 118-A. Distribution of Caltrop. EUPHORBIACEAE, SPURGE FAMILY. Many of the plants of this family contain an irritating milky juice. Few are of economic importance. The poinsettia commonly cultivated in greenhouses, snow-on-the-mountain in gardens, and castor-oil beaH belong to this family. Three-seeded Mercury {Acalypha virginica L.) . Description. — A smoothish or hairy annual from 1-2 ft. high, turning purple especially in the autumn; leaves ovate or oblong- ovate, sparingly serrate, long-petioled ; sterile spike, few-flowered, pistillate flowers 1-3 at the base of staminate peduncle surrounded by a large leaf -like bract; capsule 3-lobed, subglobular, 2-valved carpels. Distribution. — From Nova Scotia to Texas and northward to Min- nesota. Common everywhere in Iowa along roadsides and in fields. Especially noticeable in the fall on account of the purple bracts. Extermination.-^Th.vee-seeded Mercury is not a difficult weed to exterminate. The small, reddish, striate seeds are expelled from the plant to some little distance in a manner similar to the dispersal of the castor-oil bean. Thorough cultivation by preventing the for- mation of seed will eradicate the weed. 206 WEED FLORA OF IOWA Fig. 119. Three-seeded Mercury (^Acalypha virginica). Common in many parts of the state. (Drawing by Charlotte M. King.) DESCRIPTIVE MANUAL 207 Fig. 119-A. Distribution of Three-seeded Mercury. Spurge {Euphorbia preslii Guss.). Description. — An annual from 1-11/2 ft. high ; erect or ascending ; leaves oblique at the base, ovate, oblong, or sometimes oblong-linear, Fg. 120. Spotted Spurge (Euphorbia preslii). Common everywhere in the state. (Drawing by Charlotte M. King.) 208 WEED FLORA OF IOWA Fig. 120-A. Distribution of Spotted Spurge. frequently falcate, serrate, generally with a conspicuous red spot, or margin ; flowers pedunculate in terminal cymes ; appendages en- tire ; pod glabrous ; seeds ovate sometimes wrinkled. Distribution. — In loose soils and fields from New England and Canada to Wisconsin, Minnesota and Nebraska, also southward. Extermination. — This annual weed is easily exterminated by cul- tivation ; therefore practice rotation of crops and give thorough cul- tivation. Seeds of several species of this genus retain their vitality for some length of time. Milkweed or Creeping Spurge {EupJiorhia maculata L.). Description. — Slightly pubescent or hairy annual, with prostrate stems; leaves oblong-linear, oblique at the base; pubescent or some- times nearly smooth, usually with a brown-red spot in the center; serrulate above, stipules lanceolate; flowers pedunculate in lateral clusters; glands of the involucre minute; appendages usually red; pods acute-angled; seed sharply 4-angled with 4 shallow grooves across the sides ; trichomes several-celled, gradually tapering to apex. Distribution. — Found in sandy fields, or generally in fields from New England and Canada westward; common in every part of Iowa. Extermination. — May be exterminated in the same way as the preceding species. DESCRIPTIVE MANUAL 209 Fig. 121. Milkweed or Prostrate Spurge (Euphorbia maculata). Sandy fields. (Photographed by Quade. a, drawn by Charlotte M. King.) Fig. 121-A. Distribution of Prostrate Spurge. 14 210 WEED FLORA OF IOWA Snow-on-the-mountain {Euphortia marginata Pursh.). Description. — Stems stout, high, erect, hairy or smoothish ; annual, from 2-3 ft. high ; leaves sessile ovate-oblong, acute ; uppermost leaves white, petal-like margins. The flowering spurge {Euphorbia corollata L.) with white flowers in forked umbels; long peduncles; involucres showy, white append- ages appearing like petals ; deep perennial root ; is common in grav- elly and sandy soils in many parts of the state, and it is often weedy. Distribution. — Snow-on-the-mountain occurs from Minnesota to Missouri and Colorado ; also reported eastward to Ohio and South Carolina. A frequent escape from gardens in Iowa; common only in the western part. Fig. 122. Snow-on-the-Mountain (Euj)lwrbia marginata). A frequent escape from gardens. a. Whole plant, one-third natural size ; b, seed capsule, natural size. DESCRIPTIVE MANUAL 2ii Fig. 122-A. Distribution of Snow-on-the-Mountain. Pig. 123. Flowering Spurge (Euphorbia corollata). Common in sandy fields, gravel knolls, and roadsides. (Drawing by Lois Pammel.) Extermination. — This annual weed is easily exterminated by cul- tivation. The young plant should be cut off below the surface of the ground. 212 WEED FLORA OF IOWA Cypress Spurge {Euphorhia cyparissias L.). Description. — Plant with perennial running root-stocks and densely clustered stems from 6 in.-l ft. high ; linear, crowded leaves ; many-rayed umbel with glands crescent-shaped and granular pods. Distribution. — Common westward from New England to Nebraska usually in the vicinity of gardens and cemeteries. Extermination. — This perennial weed because of its running root- stocks is often difficult to exterminate. The ground should be given a shallow plowing and the root-stocks exposed to the sun. It may be necessary to repeat this process two or three times during the summer. In addition to its propagation by the running root-stocks it also propagates by its seeds. Fig. 124. Cypress Spurge (Euphorbia cyparissias). Yellow "flowered" plant with milky juice and narrow leaves. Escaped from gardens to roadsides. (Photographed by Colburn.) DESCRIPTIVE MANUAL 213 Fig. 124-A. Distribution of Cypress Spurge. ANACARDIACEAB, SUMACH EAMILY. Many of the plants are poisonous. 'Many, like sumach, contain tannin. Some, as the smoke tree, are cultivated for ornamental purposes. Poison Ivy {Bhus toxicodendron L.). Description. — A climbing or trailing" shrub sometimes erect, cling- ing to trees or other objects by aerial rootlets ; 3 leaflets ; inconspicu- ous flowers ; waxy fruit, frequently remaining on plant until late winter or early spring. It is often mistaken for Virginia creeper {Psedera quinquefolia (L.) Greene) which, however, has 5 leaflets. Many persons are sensitive to poisoning from this plant, every part of which contains the poisonous principle. The usual remedy for in- fection from it is to wash the skin with a solution of sugar of lead. Distribution. — Poison ivy is abundant throughout eastern North America and the Rocky mountains. It is common everywhere in Iowa, in hedge rows, thickets or woods. Extermination. — Poison ivy is not easily destroyed' because in most cases it is. troublesome in wood lots along fences and in yards. It is difficult to destroy except by giving thorough cultivation. If persistently cut off below the surface of the ground it can be de- stroyed. Sodium arsenite at the rate of one and one-half to two pounds to 52 gallons of water will help to destroy the weed. It is not, however, safe to use this since it is a strong poison. MALVACEAE, MALL0V7 FAMILY. Cotton, hollyhock and okra are well known plants of the family. 214 WEED FLORA OF IOWA Fig. 125. Poison Ivy (Rhus toxicodendron). Common in woods and along fences. • (Photographed by Colburn.) Fig. 125-A. Distribution of Poison Ivy. DESCRIPTIVE MANUAL 215 Fig. 125-B. Poison Ivy (Rhus toxicodendron), a, spray showing rootlets; b, fruit. (After Chesnut, U. S. Dept. Agr.) Indian Mallow or Velvet-leaf, Butter-print {Abutilon theophrasti Medic). Description. — A usually tall annual from 2-4 ft. high ; plant with strong odor; leaves velvety, roundish heart-shaped, taper-pointed; peduncles shorter than the petioles ; corolla yellowish ; carpels 12-15, hairy-beaked seeds rough, rather large and blackish. Distribution. — Common in waste places, corn fields, vacant lots, barnyards, etc. Common throughout eastern North America, naturalized from tropical regions, probably India. Extermination. — This plant propagates only by its seed, which retains its vitality for some length of time, having been known to germinate after a period of 60 years. The young plants are easily exterminated. The plant should be pulled up before it begins to 216 WEED FLORA OF IOWA Fig. 126. Indian Mallow, Velvet Leaf, or Butter-print (.Aiutilon theophrasti) . Common in corn fields, waste places, barnyards. (Photographed by Colburn.) flower. Wallace 's Farmer suggests -the following treatment : "It has been seriously thought of by some persons as a substitute for manilla or sisal in the manufacture of binder twine. It is an an- nual, and if not allowed to go to seed, the farm can in time be cleared of it. But it will be a long time. The seeds have a most astonishing vitality. We have known cases where it has been pulled up for fifteen years, not a plant allowed to go to seed, and yet it makes its appearance every spring. Fortunately, it grows only on rich land, and is therefore found in evidence largely in hog yards and feed lots and other places where the land is exceedingly rich. In fact, in sections of the country where it is being introduced, it may be found in almost every farmyard. Why farmers allow it to mature seed passes our comprehension. It goes variously by the DESCRIPTIVE MANUAL 217 Fig. 126-C. Pigweed, Foxtail, and Velvet Leaf, in a potato patch. Too many such garden patches in Iowa. (Photographed by Pammel.) Fig. 126-B. Distribution of Indian Mallow. 218 WEED FLORA OF IOWA names of velvet weed, butter print and in the locality of one of our farms, Davis weed, from the fact that it was introduced many years ago by a man named Davis, who regarded it as a rather good orna- mental plant. ' ' ^idsi {Sida spinosah.) . Description. — An annual from 10-20 in. high ; frequently much- branched; leaves ovate-lanceolate; serrate with a long petiole, pe- duncles in axils of leaves, 1-flowered ; flowers small, yellow ; 5 car- pels, each 2-beaked. Distribution. — Common in the southern states, as far north as Massachusetts to southern Iowa and Kansas. Extermination.- — This weed propagates entirely by its seeds which retain their vitality for a considerable length of time, as the seed coat is hard. The growing plant is, however, easily destroyed by pulling the weed or by cultivation. Fig. 127. Sida (Sida spiiiosa). Common in fields in southern Iowa. (Photographed by Hart.) DESCRIPTIVE MANUAL 219 Fig. 127-A. Distribution of Sida. Cheeses or Common Mallow {Malva rotundifolia L.). Description. — A procumbent biennial ; leaves round, heart-shaped on long petioles, erenate ; flowers white, petals longer than the calyx ; a 3-leaved involucre at the base of the calyx ; carpels pubescent. Distribution. — A widely distributed weed in eastern North Amer- ica, native to Europe, common in eastern and central Iowa in door- yards, barn lots, etc., in Story, Marshall, Polk, Marion, Linn, Clin- ton, Winneshiek and Allamakee counties. Extermination. — This weed is easily exterminated by cultivation. Do not permit any of the seeds to mature. The seeds retain their vitality for a considerable length of time. 220 WEED FLORA OF IOWA Fig. 127-B. Common Mallow or Cheeses (Malva rotundifolia) . Common in door- yards, barn lots, etc. (Mich. Agr. Exp. Sta.) DESCRIPTIVE MANUAL 221 Fig. 127-C. Distribution of Common Mallow. Shoo-fly {Hibiscus trionum L.). Description. — A low, rather hairy annual from 1-2 ft. high ; upper leaves 3-parted with 3 lanceolate divisions, the middle longest ; calyx inflated in fruit, membranous, 5-winged, with numerous dark nerves ; flowers sulphur-yellow with a blackish eye, ephemeral. Distribution. — Common in fields and waste grounds in the south- ern states and eastward ; abundant in some places in Iowa, especially in gardens where it has become naturalized from cultivation. Extermination. — A growing plant is not difficult to exterminate. A thorough cultivation and exposing the roots to the sun will de- stroy the plant. The seeds, however, retain their vitality for a con- siderable length of time. A correspondent of southeastern Iowa stated that this weed kept coming up in spite of constant and thor- ough cultivation. This was owing to the prolonged vitality of the seed. HYPERICACEAE. ST. JOHN'S-WORT FAMILY. This small family contains a few ornamental plants with yellow flowers, commonly found in northern states. 222 WEED FLORA OF IOWA Fig. 127-D. Bladder Ketmia or Shoo-fly, {Hibiscus trionum). Gardens and corn fields. Large white flower with a dark spot at the base of each petal. a and 5 trichomes or plant hairs. (a and b drawn by Charlotte M. King. The general aspect photographed by Colburn. ) Fig. 127-E. Distribution of Shoo-fly. DESCRIPTIVE MANUAL 223 St. John's-wort {Hypericum perforatum L.). Description. — A branched perennial, l%-2 ft. high with runners ; leaves elliptical, or linear-oblong, with pellucid dots; flowers numerous in cymes, petals deep yellow, black-dotted, twice the length of the lanceolate sepals. Distribution. — Common in eastern North America in clay soils. Abundant in Iowa only in eastern counties, especially northeast- ward. Extermination — This weed spreads both by seeds and by runners. It is difficult to exterminate. Clark and Fletcher give the follow- ing methods: "Close cutting several times during the summer will reduce it in pastures. An application of salt — a small handful to Fig. 128. St. John's-wort {Hypericum perforatum). Old fields and woodland pastures, eastern and northeastern Iowa. (Photographed by Quads.) 224 WEED FLORA OF IOWA Fig. 128-A. Distribution of St. John's-wort. each plant after close cutting in hot dry weather — will kill it and may be practicable where the pest is not abundant and the land cannot be brought under cultivation. Prevent it from going to seed. St. John's-wort is easily suppressed on land that cart be cultivated under a systematic rotation of crops. Where it is established, it would be well not to seed to grass until it is suppressed. ' ' ONAGRACEAE. EVENING PRIMROSE FAMILY. A small family, some plants with showy flowers, a few cultivated for ornamental purposes. Evening Primrose {Oenothera biennis L.). Description. — A stout, erect, pubescent or hirsute perennial, 3-5 feet high, sparingly branched ; leaves lanceolate, or rarely ovate- lanceolate, denticulate, acute, bracts shorter or as hmg as the cap- sule ; flowers yellow, petals obovate, stigma lobes linear, capsule sub- cylindrical; seeds small, brownish. Distribution. — Common everywhere in eastern North America, Rocky mountains and Utah. Occurs in every county in Iowa. Extermination. — Spreads by seed. This plant is not difficult to exterminate. Cut off the young plants a few inches below the sur- face of the ground. UMBELLIPERAE, CARROT FAMILY. Carrot, celery, parsnips and caraway are members of this family. It includes also many poisonous plants. DESCRIPTIVE MANUAL 225 Fig. 129. Evening Primrose (Oenothera hiennis) . Fences, gardens, meadows and pastures. (Photographed by Hart, a^ drawn by Charlotte M. King.) Fig. 129-A. Distribution of Evening Primrose. 15 226 WEED FLORA OF IOWA Caraway {Carum carvi L.). Description. — A smooth, erect, slender herb l-2i/^ feet high with fusiform roots; leaves pinnate with filiform divisions; flowers in umbels, white; calyx teeth small; fruit ovate, or oblong with fili- form ribs. Distrihution. — Common in eastern North America, the Rocky mountains, Utah and scattered in places in Iowa. Extermination. — Easily exterminated; cut off the plants below the surface of the ground. Fig. 130. Caraway (Carum carvi). Commonly escaped from gardens. Flowers white. (Photographed by Quads.) DESCRIPTIVE MANUAL 227 Fig. 130-A. Distribution of Caraway. "Wild Carrot (Daucus carota L.). Description. — A bristly, hirsute biennial from 2-2% feet high; leaves pinnately decompound; involucral bracts foliaceous; flow- ^ K Fig. 131. Wild Carrot (Daucus carota). Common in clover meadows. Flowers in wliite umbels. (Photographed by Colburn.) 228 WEED FLORA OF IOWA Fig. 131-A. Distribution of Wild Carrot. ers in compound umbels, white, or occasionally pink ; fruit oblong, flattened dorsally, carpel with 5 slender bristly primary ribs, and 4 winged secondary ones, each of these bearing a single row of barbed prickles. ' Distribution. — Common in eastern North America, especially in dry fields. Becoming common in Iowa clover fields in Scott, IStory, Polk, Franklin, Linn, Clinton, Cerro Gordo, Boone, Webster, Sac and Clay counties. Extermination: — Plant clean seed in a clean field. Easily killed by cutting off the plant a few inches below the surface of the ground. Parsnip (Pastinaca sativ a Ij.) . Description. — A tall, stout, glabrous biennial with grooved stem ; leaves pinnately compound, cut-toothed; flowers yellow, small; calyx teeth obsolete; fruit oval, flattened dorsally, the lateral ribs with broad wings. Distribution. — Common in eastern North America, Rocky moun- tains and the Pacific coast. Common on roadsides in every part of Iowa, Extermination.- — Propagated by seeds. Easily exterminated by cultivation ; cut off the young plants a few inches below the surface of the ground. DESCRIPTIVE MANUAL 229 Fig. 132. Wild Parsnip (Pastinaca sativa) . Common along roads. (Mich. Agr. Exp. Sta.) 230 WEED FLORA OP IOWA Fig. 132-A. Distribution of Wild Parsnip. Cowbane {Cicuta maculata L.), Description. — A smooth, marsh perennial, 2-5 ft. high, with pin- nately compound leaves, 2 or 3 times pinnate ; leaves with long petioles; coarsely serrate leaflets lanceolate to oblong-lanceolate, 1-5 in. long; stalks of nmbellets numerous and unequal; flowers white; fruit broadly ovate to oval, small, 1% in. long. The plant grows in marshes and in low grounds, the stems springing from thick fleshy underground roots tapering at the lower end, usually numbering from 3-8 although single specimens are also met with. On cutting the roots there is given off a sharp pungent odor,* which becomes intensifled on boiling. Distribution: — Common throughout the northern states, south- west to Louisiana, Rocky mountains and Utah. Very common in low grounds and swales in northern Iowa, less common in southern Iowa. Extermination. — The field where cowbane occurs needs drain- age ; plow the field, break ,up the sod, and expose the fascicled roots to the sun. This will soon destroj^ the weed. DESCRIPTIVE MANUAL 231 Fig. 133. Cowbane (,Clcuta niaculata) . In low moist meadows and roadsides. (Photographed by Colburn.) Fig. 133-A. Distribution of Cowbane. 232 WEED FLORA OF IOWA ^^ # ,♦ f :»^ ^wfj My- ^i HK^ ' ' f" : ll. ■" -^v. ■ ' -^^^f '^'^''^ -'V' 1 ^ ,%: i -'.m ^.^JH^ f ^ {; ■■^^K *^ ■I'm ■v.^ A' fra^Bi" -^ - Up •■■■-,/'- / Fig. 133-B. Cowbane (Cicuta maculata). In low woods. (Photographed by Caughey.) DESCRIPTIVE MANUAL 233 Fig. 133-C. Cowbane roots (Cicuta maculata). In low places. (Photographed by Gardner.) 234 WEED FLORA OF IOWA Cow Parsnip {Heracleum lanatiim Michx.). Description. — A stout, hairy, pubescent perennial 4-8 ft. high; leaflets broad and large, irregularly cut-toothed; flowers white, in broad umbels. * , ■ • ''^'^^^•^i^^^T'W^'^S^M i^§ ^^^^S }^^^1^'|f^ r^w.--. <•"*. !7'r .^?5^^^ r^El^SteS^MM \^ " ~* -.^' '' m P /'•'" ".^^ \^ „ ' ', 4' ^ V ' p ' fo X i A ;> •|.| ■ ; V Fig. 182. Large-flowered Goldenrod (SoUdago rigida). In pastures and road- sides. ( Pliotograplied by Colburn.) DESCRIPTIVE MANUAL 317 Fig. 182-A. Distribution of Large-flowered Goldenrod. long, feather-veined, thick and rigid, the upper sessile; heads large, collected in a large compound corymb, terminating the stem. Distribution. — Abundant in dry soils from New England to Manitoba, Dakota, Nebraska and Missouri; common in pastures in Iowa, in Story, Boone, Polk, Linn, Marshall, Hardin, Cerro Gordo, Winnebago, Emmet and Woodbury counties. Extermination. — Though it is often a very troublesome weed in pastures it is easily killed by cultivation; spreads largely by ''seeds." Many-flowered Aster {Aster m.ultiflorus Ait.). Description. — A pale or hoary pubescent, branched perennial, 9 in-1% ft. high; heads on spreading, racemose branches; leaves rigid, crowded, spreading, with ciliate margins; ray flowers white, small. Distribution.— Common along roadsides and fields, gravelly knolls, etc. Extermination. — Though abundant in fields readily succumbs to cultivation. 318 WEED FLORA OP IOWA Fig'. 183. White or Many-flowered Aster CAster mulUflorus) . Common on road- sides. (Photographed by Quade.) Fig. 183--A. Distribution of White Aster. DESCRIPTIVE MANUAL 319 Willow-leaved Aster {Aster salicifolius Ait.). Description. — A branched, leafy perennial 2-8 ft. high ; leaves ob- long to narrowly lanceolate, pointed, entire, or slightly serrate, firm, often scabrous ; heads racemose, clustered ; ray flowers purplish. Distriltution. — Common in low grounds, thickets or borders of fields from New England to Wisconsin and Minnesota. An allied species, A. paniculatus Lam., is much like A. salicifolius except that the leaves are more pointed, serrate and less scabrous. It is a very variable species, with distribution similar to that of A. mulUflorus. Extermination. — Easily exterminated by cultivation. Fig. 184. Willow-leaved Aster {Aster salicifolius). Common in low grounfls. (Photographed by Quade.) 320 WEED FLORA OP IOWA Fig. 184-A. Distribution of Willow-leaved Aster. Fig. 185. Aster pcmiculatus. a. Plant Hair. Common in low grounds every- where in Iowa. "White ray flowers, sometimes purplish. (Photographed by Colburn. Drawing by Charlotte M. King.) The Aster tradescanti L., is closely related to A. paniculatus, but has smaller leaves and shorter rays. The leaves are lanceolate to linear. The bracts are linear or acutish. DESCRIPTIVE MANUAL 321 Whiteweed or Fleabiane {Erigeron annuus Pers.). Description. — A sparingly pubescent annual 3-5 ft. high; leaves thin, coarsely and sharply toothed, the lower one ovate, or ovate- lanceolate, acute, and entire on both ends; heads corymbed; rays white, tinged with purple. Distribution. — This weed occurs from New England to Texas. Common in the Mississippi valley. Common throughout the state of Iowa, particularly in timothy and clover meadows. This weed is also naturalized in Europe. Extermination. — Both this and E. ramosus are easily exter- minated by thorough cultivation. They are seldom troublesome out- side of meadows, though in some parts of Iowa the meadows and pastures are white with flowers of these species. Fig. 186. Whiteweed or Daisy Pleabane ^Erigeron annuus). Common in clover and timothy meadows. (Photographed by Colburn. Drawings a and & by Cliarlotte M. King.) 21 322 WEED FLORA OF IOWA Fig. 186-A. Distribution of Whiteweed. Wallace 's Farmer states concerning its eradication : ' ' One of tlie worst enemies of the meadow, and especially the timothy meadow in the west, is .a peculiar form of daisy to which farmers give the name of whiteweed. It may be seen in full bloom about the time timothy heads out, and if not dealt with on its first ap- pearance in the timothy field it is only a question of time when the hay will be from one-fourth to one-half whiteweed. If the farmer is vigilant and goes through and pulls out these weeds on their first appearance, he can protect his timothy meadows. If he fails to do this, it is only a question of time when he will have to plow them up." Daisy Fleabane {Erigeron ramosus ('Walt.).B S P). Description. — This resembles the preceding species except that the stem and leaves are somewhat more hirsute and hairy; leaves roughish, entire or nearly, so, the upper lanceolate, the lowest ob- long or spatulate ; flowers white and smaller than in the preceding species. Distribution. — Daisy fleabane is native from New England to Arkansas. Common in Iowa, particularly in drier situations, clover meadows and timothy fields. Extermination. — This weed is common in timothy and clover meadows. The seed is often found in clover and timothy seed. Care should be used to sow only clover and timothy seed that does DESCRIPTIVE MANUAL 323 t''iK- ] 87. Daisy Fleabane (Erigeron ramosus). (Mich. Agr. Coll. Exp. Sta. Bull.) 324 WEED FLORA OF IOWA Fig. 187-A. Distribution of Daisy Fleabane. not contain these weed seeds. This weed is easily destroyed by cul- tivation. The meadows are sown from seed coming from the neigh- boring roadside or field. The weeds should, therefore, be cut in waste places. Horseweed {Erigeron canadensis L.). Description. — Bristly, hairy, or sometimes glabrate stem, 1-6 ft. high, simple or paniculately branched; leaves usually pubescent or ciliate, the lower spatulate, incised or entire, obtuse or acutish, the upper generally linear and entire ; heads numerous, with in- conspicuous white ray flowers shorter than the pappus ; pappus simple; trichomes several-celled, straight with long cells, curved with short cells. Distribution. — Horseweed is common throughout eastern North America; naturalized in Europe, the Rocky mountains and along the Pacific coast. Everywhere in Iowa in waste places and in cul- tivated fields. Extermination. — This weed is an annual and is very easily de- stroyed. Cutting off just below the surface of the ground will exterminate it, provided, of course, that the new seeds are not per- mitted to re-seed the soil. The weed is common everywhere and the fact that it is so easily blown by the wind makes it difficult to keep it in cheek. DESCRIPTIVE MANUAL 325 Fig. 188. Horseweed (Erigeron canadensis). In fields and waste places. (Mich. Agr. Exp. Sta.) 326 WEED FLORA OF IOWA Fig. 188- A. Distribution of Horse weed. Great Ragweed {Ambrosia trifida L.). Description. — A stout, scabrous, hispid or nearly glabrous an- nual, 3-12 ft. high ; leaves all opposite and petioled, 3-nerved, deeply 3-5-lobed; lobes ovate-lanceolate and serrate, upper leaf sometimes ovate and undivided ; flowers monoecious, staminate, borne in spikes surrounded by the larger bract-like leaves ; involucre turbinate to obovoid, 5-7-ribbed, beaked, each rib bearing a tubercle near the summit ; involucre enclosing a single oily seed. Distrihution. — This North American weed is most abundant in the Mississippi valley from Texas to Minnesota and in the Da- kotas; however, it also occurs east from New England to Quebec. It is abundant in every part of Iowa, especially along highways, in grain fields and corn fields. Extermination. — It is certain that cultivating the young plants followed by three or four other similar treatments will remove the weed in a single season. DESCRIPTIVE MANUAL 327 Fig. 189. Greater Ragweed (Ambrosia trifida), sometimes, but incorrectly, called Ironweed. Common in fields, along roadsides, etc. (Photographed by Colbum.) Fig. 189-A. Distribution of Greater Ragweed. 328 WEED FLORA OP IOWA Smaller Ragweed {Ambrosia artemisiifoUa L.). Description. — A puberulent or hirsute annual, branched, 1-3 ft. high; leaves thin, 1-2 pinnatifid; upper leaves alternate, lower usually opposite, pale or canescent beneath ; flowers monoecious, staminate above and pisillate in lower axils of the leaves; fertile heads obovoid or globose; short-beaked, 4-6 spined; trichomes sev- eral-celled, cells short or long. Distribution. — Ragweed or hogweed is originally from Europe but is common throughout eastern North America; also found in the Rocky mountains, the Pacific northwest, and in Mexico, West Indies and South America. It is common throughout the state of Iowa in gardens and fields and is abundant in pastures. Extermination. — This weed is too common in pastures, along roadsides and in waste places. The weed is easily exterminated by cutting the plants off below the surface of the soil. The commonly used cultivator will destroy most of the young plants in a corn field. Clark and Fletcher recommend the following treatment: "Sow clean red clover seed. Stubble lands where this weed is prevalent should be shallow plowed directly after harvest, or, if seeded, the autumn growth should be closely cut with a mowing machine within two weeks after the grain crop is cut. ' ' "Wallaces' Farmer says concerning this serious pest of the pas- ture : ' ' We suggested that the reason why the ragweed grows in the blue grass pastures is because for some reason the stand of grass has been weakened and thus the ragweed seeds, which are present in all cultivated soils in the west in great abundance, have a chance to grow. We suggested further that the stand of grass may have been weakened by overpasturing in a dry time, thus giv- ing the sun opportunity to burn the roots and lower their vitality. We suggested also that it may have been weakened by the ravages of larvae of the various insects known as the white grub worms. We suggested still further that blue grass, not being able to ob- tain nitrogen from the atmosphere, was nitrogen hungry, and there- fore weak. To meet all these various suggestions we proposed that farmers who 'have blue grass pastures of long standing should re-seed them next year with one or other of the various kinds of clover, filling DESCRIPTIVE MANUAL 329 Fig. 190. Small Ragweed or Hogweed (Amhrosia artemisiifolia) . In pastures, waste places, gardens and clover meadows. (After Clark and Fletcher.) 330 WEED FLORA OF IOWA Figure 190A Figure 190B Fig. 190-A. Plant hairs or trichomas of ragweed. (Drawing by Charlotte M. King.) Fig. 190-B. Distribution of Small Ragweed. up the land with a preferred food for stock and at the same time restoring the nitrogen content to the soil, enabling the blue grass to make more rapid growth. Fig. 191. A weedy Iowa field ; Ragweed, Foxtail, Barnyard Grass, etc seeds are sown in the field for nexi year. (Photographed by Pammel.) The DESCRIPTIVE MANUAL 331 We did try it on a neighbor's farm under the most disadvantag- eous circumstances imaginable. The field was a pasture of blue grass and wool grass with a very little white clover. The ground was dry; as dry as we have ever seen it at that time of the year. We found it easy even under these hard conditions to drill in clover on this tough sod and cover it from an inch to an inch and a half, using a Hoosier drill with two horses. We found that the clover was dropped in the very bottom of the slit made by the disk, a seed every two or three inches, using six pounds to the acre. It lay there until the 23d of May, apparently as dry as it came out of the drill, except in some of the lower spots, where it had sprouted. The 23d of May there was a two-inch rain on that field, and at once the clovers began to grow. ' ' Perennial Ragweed (Am,irosia psilostachya D C). Description. — A branched hairy and rough perennial with slen- der running root-stock, 2-3 ft. high; leaves once pinnatifid, acute lobes, lower leaves incised; monoecious flowers, staminate flowers with flattish involucres, involucre of fertile flowers, obovoid, tuber- cles absent or very small. ■ Distribution. — Common on gravel hills and sandy plains from Illinois, Wisconsin to the Saskatchewan to the Rocky mountains, common gravel knolls and sandy plains; Clinton, Muscatine, Car- roll, Kossuth, Pottawattamie counties. Extermination. — Succumbs readily to cultivation. 332 WEED FLORA OP IOWA Fig. 192. Perennial Ragweed (Ambrosia psilostachya) . Pastures, drift soils, roadsides. (Photographed by Quade. ) Marsh 'Elder (Iva xantliifoliaNutt.) . Description. — An annual 1-8 ft. high; stem frequently pubescent when young ; leaves opposite, rhombic, ovate, or lowest heart-shaped, doubly .serrate, or cut-toothed, obscurely lobed ; upper surface minutely scabrous, canescent beneath, especially when young; petiole frequently ciliate at its upper end ; flowers borne in spikelike clusters forming a compound panicle; heads small, crowded; outer bracts of the involucre broadly ovate, greenish; inner membrana- cecus; achenes glabrate. This plant is also known botanically as Cyclachaena xanthifolia Fr. DistrihuUon. — Common in the eastern Rockies, to Saskatchewan and western Wisconsin, most abundant in Iowa along Missouri river where it is troublesome in fields, along highways, and in DESCRIPTIVE MANUAL 333 Fig. 193. Halfbreed Weed, Marsh Elder (Iva xanthifolia) . Common in western Iowa, fields and roadsides. (Photographed by Colbum.) Fig. 19 3-A. Distribution of Marsh Elder. 334 WEED FLORA OF IOWA yards, spreading into north and northeastern Iowa, ]Mason City and Allamakee county and also in central Iowa, in Boone and Story counties, ■ Extermination. — Marsh elder is an annual and hence thorough cultivation for a single season will destroy it, provided it is not allowed to form seeds. Cocklebur {Xantliium canadense Mill.). Description. — A coarse, rough annual from 1-2 ft. high, stem marked with brown punctate spots; leaves alternate, cordate or ovate, 3-nerved, long petioled ; flowers monoecious, staminate and pistillate flowers in different heads, the pistillate clustered below ; involucre of staminate flowers somewhat flat, of separate scales; re- ceptacles cylindrical; scales of the fertile involucre closed; fruit 2-beaked, containing 2 achenes; bur densely prickly and hispid, achenes oblong, without pappus. The spiny clotbur X. spinosum has spines in the axils of the lanceolate leaves. Distribution. — Common in Mississippi valley from Texas to ]\Iin- nesota and eastward. Common in fields in many parts of the state, but more common in southern than in northern Iowa. Extermination. — The best method of combating this weed is the rotation of crops and clean culture. Where a field is in corn, the field should be thoroughly cultivated and none of the plants al- lowed to mature seed. If they cannot be caught by the cultivator, it may pay to kill the remaining plants with a hoe, or to pull them by hand. The corn should be followed with winter rye, and then oats, using the oats as a nurse crop for clover and timothy. Leave the field in meadow for at least two years and then if possible turn it into pasture. Mr. E. B. "Watson found in soil badly infested with cocklebur that clover seed would not germinate as well, and it is rather dif- ficult to get clover to start in fields of this kind. The Homestead says concerning the eradication of cocklebur: "Needless to say there is no easy way of eradicating the pest. Where the winter wheat can be grown the following plan can be depended upon. Start on fields that have been in small grain and plow the land as soon as the crop is removed. HarroAv as often DESCRIPTIVE MANUAL 335 Fig. 194. Cocklebur (Xanthium canadense). Corn fields, roadsides, alluvial bottoms. (Photographed by Colbum. ) Fig. 194-A. Distribution of Cocklebur. 336 WEED FLORA OF IOWA as necessary to kill weeds aud put in wheat when the time comes. The next season as soon as the wheat is harvested remove from the field and go on with the mower. This will clip all or most all of the young cocklebur plants, as well as other weeds, and following this operation the stubble should be plowed as rapidly as possible and prepared for another crop of wheat. Another season's treat- ment of this sort will generally reduce the burs to such an extent that very few will be left and these can be pulled by hand. Fig. 195. Spiny Clotbur {XantMum spinosum) . Waste places from Maine to Kansas. Perhaps in southern Iowa. ( Pliotographed by Colburn. ) "One of our Nebraska subscribers, Mr. J. J. Bishop, stated some time ago that he succeeded in almost clearing out a badly infested field of eockleburs in two years by employing the following method: Just as soon as the removal of the oat crop the soil was plowed and prepared for winter wheat, this crop being sown at DESCRIPTIVE MANUAL 337 the proper time. Mr. Bishop stated that before plowing this ground after removing the oats the surface was covered with burs just about as thick as they could grow. After harvesting the first crop of winter wheat the soil was again plowed and seeded for the second time to winter wheat. After this it was followed by corn and other crops, with the result that even in the corn crop a very short time spent in pulling burs freed the field entirely of these pests. ' ' Mr. Albert Wiltz says in Wallaces ' Farmer : ' ' When I moved to this farm nine years ago the land was very badly infested with cockleburs, and farmers told me that each bur had two seeds, one growing one year and the other one the next year. I left a patch of ground where the cockleburs were lying thick without a crop, plowed in June once, and again in August. That settled the cockle- burs. That year was a good corn year, with plenty of moisture. Now, would not that way be the cheapest way to deal with them — to put three years, yes, sometimes ten years ' fighting into one year ? That is, take a field one year to fight cocklburs, and finish it; next year take another, and so on, if the farmer is a renter on a long term lease or owns the land. ' ' Wallaces' Farmer states concerning the extermination of cockle- bur : " If it is desirable to put some of this kind of land in alfalfa, we would not put it in corn, but disk it every week or two during the summer to sprout the burs, and then kill them by subsequent disking, and keep on that way all summer, missing the crop for the first year. Then in the fall, when the ground has sufficient mois- ture, say in August or in the first part of September, seed it to al- falfa alone, we would not sow alfalfa in the spring on that kind of land; but by continuous summer cultivation it can be gotten in shape to grow alfalfa and thus avoid not only cockleburs but also crabgrass, another great foe to alfalfa in that part of the country. ' ' Speaking now on the subject of cockleburs generally. Where the land is not so badly infested with them as this farm seems to be, and it is not desirable to grow spring grains and seed to clover, we would make the stand of grain rather thin, put in a good seeding of clover, put the clover deep enough to insure germination, use as early a variety of grain as possible, get it off the land as soon as possible, and then keep the cockleburs mowed down by clipping the clover until a good stand is secured." 22 •^^S WEED FLORA OF IOWA Ox-eye {Heliopsis scabra Dunal.). Description. — A rough, pubescent, perennial with opposite, petiolecl, triple-nerved leaves; heads large, peduncled; scales of involucre in 2-3 rows, nearly equal; ray flowers yellow, 10 or more, fertile ; achenes smooth, thick, 4-angled, truncate ; pappus chaffy or 2-3-toothed. Distribution. — From New York west to Wisconsin, Minnesota and British Columbia and southwest to Missouri, Kansas and Arkansas. Extermination. — Though this weed is perennial, it is rather easily destroyed by cultivation. (I'lLi" 196. Ox-eye (Helioiisis scahra). a, plant hair or trichome. Common in orchards, waste places. Ratl:er large yellow heads, and rough, opposite leaves. (Photograph by Colburn. a, drawing by Charlotte M. King.) DESCRIPTIVE MANUAL 339 Fig. 196-A. Distribution of Ox-eye. Black-^yed Susan, Nigger-liead, Cone-fiower {Budheckia hirta L.). Description. — A rough, hairy biennial 1-2 ft. high with stems simple, or branched, bearing a long pedunculate head; leaves nearly entire, the upper sessile, oblong or lanceolate, the lower Fig. 197. Black-eyed Susan (.Rudbeckia Mrta). Common in sandy fields. (Pliotographed by Colburn.) 340 WEED FLORA OF IOWA Fig. 197-A. Distribution of Black-eyed Susan. petioled and spatulate; heads many-flowered, radiate, neutral; receptacle columnar or conical; chaff hairy at tip, acutish; ray flowers yellow, disk dull brown; achenes 4-angled; pappus none. Distribution. — This weed is indigenous to the northern Missis- sippi valley but has been naturalized eastward ; is common through- out the state of Iowa, occuring not only in meadows but in some- what sandy fields in Linn and Muscatine counties. Extermination. — This weed succumbs to cultivation but care should be used in the sowing of clover seed as seed of this weed is sometimes found with it. It is largely in this way that it has been spread in the east. Common Sunflower (Helianthus annuus L.), Description. — A tall, rough annual, 6-8 ft. high, leaves 3-ribbed, ovate or the lower cordate, serrate; large heads with yellow ray flowers, disk flowers brownish. Distribution. — Widely distributed west of Missouri river from Saskatchewan to Texas, California and Mexico. Common in west- ern Iowa, from Woodbury to Fremont county, occurring in fields along highways, meadows, vacant lots and com fields ; widely scat- tered, but not abundant in many other sections of the state, as Boone, Story, Polk, Cerro Gordo, Webster, Lyon, Linn and Mus- catine counties. Extermination. — The seeds of this plant do not retain their vi- tality very long. The young plants are easily destroyed by cultiva- tion. The plant should not be permitted to go to seed. DESCRIPTIVE MANUAL 341 Figr. 198. Common Sunflower (Helianthus annuus) . Common in western Iowa fields, roadsides. (Photographed by Coltaurn. ) Fig. 19 8- A. Distribution of Common Sunflower. 342 WEED FLORA OF IOWA .-V; ^■^■^HM U,r ^^>? ^A-^*' ^^ > ir «*« WM^HSh ■^ *■•%' "a.^ - - .1 ; ^-j .v. -*^, j^K^finn •-*;M^ i^'^vll .**-i^ i-'i^t'^'^Si^i ^>,: V/«MBrlFMwi '^^^'''" • -\. •«,»-'ty^y,-v'5.*v;'>'.- w.-; '^¥1^'" "^M^^ . i^■• ft 1 Fig. 198-B. A patch of Wild Sunflowers (Helianthus annuus). western Iowa. (Photographed by Pammel.) Common in Prairie Sunflower {Heliantlius petiolaris Nutt.). Description.— ^h-Q prairie sunflower is an annual 1-3 ft. high; lower branches rough ; stem leaves 1-3 in. long, oblong to ovate- lanceolate, sparingly toothed, lower leaves abruptly contracted into a long slender petiole; ray flowers yellow, disk flowers brownish; bracts lanceolate or oblong-lanceolate, usually not ciliate ; head flowers smaller than in common sunflower; flowers half an inch or more in diameter. Distribution. — Prairie sunflower is most abundant in dry prairies from IMinnesota to the northwest territory and Oregon and south to Missouri. It has become naturalized more or less in Iowa. It is not uncommon from Council Bluffs to Sioux City and around Muscatine. Extermination. — This weed is easily exterminated by cultivation. DESCRIPTIVE MANUAL 343 Fig. 199. Prairie or Western Sunflower (Helianthus petiolaris) . In Muscatine Island and western Iowa. Similar to large Sunflower. (PTiotographed by Colburn. ) Fig. 199-A. Distribution of Prairie Sunflower. 344 WEED FLORA OP IOWA Meadow or Saw-toothed Sunflower {Helianthus grosseserratus . Martens) . Description. — ^A tall, glabrous perennial 6-10 ft. liigh, bear- ing numerous short peduncled heads; lower stem leaves 8-10 in. long and petiole 1-2 in. long; leaves opposite or alternate with a slender petiole, oblong, lanceolate, acuminate with sharp teeth, or the upper merely denticulate, somewhat scabrous above, whitish below ; heads % in. high with deep yellow rays about an inch long ; bracts of the involucre slender. Distribution. — Common in the central states and northward, also westward to Texas. Abundant throughout the state of Iowa in corn fields, low swales and roadsides, particularly in northern Iowa. Fig. 200. Meadow Sunflower (Helianthus gi-osseseiTatus) . pastures and fields. ( Pliotographed by Colburn.) Common in meadows, DESCRIPTIVE MANUAL 345 Fig. 200-A. Distribution of Meadow Sunflower. Fig. 200-B. Meadow Sunflower {Helianthus grosseserratus) . In meadows and fields. (Photographed by Pammel.) 346 WEED FLORA OP IOWA Extermination. — It is certain that cultivating the young plants followed by three or four other similar treatments will remove the weed in one or at most two seasons. It would be well to use clover, planted as a rotation after the field had had clean cultivation. Artichoke {Helianthus tuderosus L.). Description. — A pubescent or hirsute perennial with tuberous underground stems; leaves oblong-lanceolate or ovate-acuminate, scabrous, minutely pubescent; flowers yellowish, large. Distribution. — Common from New York to Minnesota; in Iowa most abundant in the northern counties; particularly troublesome in Mitchell, Howard and Cerro Gordo counties. However, it is not infrequent along highways and fields in many other parts of the state. ' Fig. 201. Artichoke {Helianthus tuherosus). Common in corn fields, road- sides, etc., north Iowa. ( Fliotographed by Colburn.) DESCRIPTIVE MANUAL 347 Fig. 202. Artichoke {Helianthus tuberosus). In grain fields, roadsides and waste places. Fig. 202-A. Distribution of Artichoke. 348 WEED FLORA OF IOWA Extermination. — This is a most troublesome weed in corn and smaller grain fields of northern Iowa. The somewhat thickened underground stems spread the plant freely by cultivation. The small-grain field should be plowed after the grain is removed, then dragged so as to expose the ''roots" to the sun. Before planting corn in the spring run a disk over the field, then har- row, plant to corn, and give thorough cultivation. When the weed is very bad it may be well to get the field into meadoAV or pas- ture. Maximilian's Sunflower (HeliantKus maximiliani Schrad.). Description. — Stem scabrous and hispid, 2-12 ft. high, the latter height being obtained in alluvial bottoms ; leaves usually alternate, thick, becoming rigid, scabrous above, hairy beneath, lanceolate, Fig. 203. Maximilian's Sunflower. (.Helianthus maximiliani). Common In meadows and fields of northern Iowa. Yellow flowers, hairy elongated leaves. (Photographed by Colburn.) DESCRIPTIVE MANUAL 349 Fig. 203-A. Distribution of Maximilian's Sunflower. narrowing at both ends, nearly sessile, entirely or sparingly dentic- ulate ; heads large, i/2-% in. high ; short peduncle terminating the simple stem and later appearing in the axils of lower leaves ; invo- lucre consisting of rigid bracts about II/2 iJi- long; ray flowers golden yellow, disk flowers birownish, flowering in late summer and early autumn. Distribution. — This weed is common in places from Alberta and Manitoba to Texas. In Iowa it is most abundant in the northwestern and western counties, in the alluvial bottoms of Missouri river and on high prairies of Pocahontas, Dickinson, Emmet and Palo Alto counties; also found east in Worth, Howard and Cerro G-ordo counties. ' Extermination. — This perennial weed has the habit of the arti- choke. The more or less thickened underground stems freely prop- agate the plants. Give the field a shallow plowing then drag and expose the roots to the sun for a few days. This will destroy the most of the plants. If the field is put into corn give thorough cul- tivation and follow corn with a small-grain crop and then clover. Boot-jack {Bidens discoidea (T. & G.) Britton). Description. — A diffusely branched annual with alternate, di- vided leaves and slender petioles ; leaflets ovate-lanceolate, pointed, coarsely serrate, small heads of yellow flowers surrounded by a double involucre, the outer of 4 bracts; achenes linear, wedge- shaped, smooth or tuberculate, bearing a pair of short, upwardly barbed awns. 350 WEED FLORA OP IOWA Kiii. 204. Tall Boot- jack or Spanish Needle {Bidens discoidea) . Commcn in corn fields, pastures, and meadows. (Photographed by Colburn.) Fig. 204-A. Distribution of Tall Boot-jack. DESCRIPTIVE 'MANUAL 351 Distribution. — Moist situations from New England to Missouri. Common in southern Iowa. Extermination. — This annual is most abundant in low fields. It succumbs readily to cultivation. The plants should not be allowed to go to seed as the seed is scattered by animals; its spreading, therefore, can be prevented by cutting the plant off close to the surface of the ground when it begins to blossom. Beggar-ticks, Stick-tight, Boot-jack {Bidens frondosa L.). Description. — A branching, hairy or smooth annual 2-6 ft. high; leaves petioled, 3-5-divided, terminal leaflet long-stalked, pointed, coarsely toothed, frequently divided again ; rays small, yellow invo- Fig. 205. Boot-jack, Spanish Needle, {Bidens frondosa). Common in gardens. The "seeds", more properly achenes, are scattered by animals. .(Photographed by Colbum.) 352 WEED FDORA OP IOWA Fig. 205-A. Distribution of Boot- jack. lucre double, the outer foliaceous; bracts ciliate, longer than the head; receptacle flattish with deciduous chaff; achenes narrowly acuminate, 2-awned, the awns downwardly barbed. Distribution. — Widely distributed in moist places throughout the northern states ; often a very troublesome weed in gardens. It is widely scattered because of the "seeds" adhering to clothing, pelts of animals, etc. Extermination. — Boot-jack is easily exterminated by cultivation. The weed is disseminated by animals and man. It would be well to cut off the plant close to the surface of the ground when in flower. Tickseed {Bidens aristosa (Michx.) Britton). Description.— A smoothish, slightly pubescent, annual 2-4 feet high ; leaves 1-2-pinnately, 5-7-divided, petioled ; leaflets lanceolate, cut-toothed or pinnatifid; heads panicled-corymbose ; scales of the involucre in 2 series, the outer about as long as the inner, ciliate; ray flowers conspicuous, yellow ; achenes obovate with ciliate mar- gins', usually with 2 divergent teeth ; a somewhat showy plant with yellow flowers. Distribution. — From Michigan and southern Iowa to Kansas and Texas. Abundant in Missouri ; probably indigenous to south- ern Iowa; in recent years has made its appearance in Wapello, (Pammel) Marion, (Pammel) Polk (Bakke) and Decatur (Ander- son) counties. DESCRIPTIVE MANUAL 353 Fig. 206. Tickseed (Bidens arisiosa). (Mich. Agr. Exp. Sta.) 23 354 WEED FLORA OF IOWA Fig. 206-A. Distribution of Tickseed. Extermination. — This weed is easily exterminated by cultiva- tion. Do not permit seeds to mature. Sneezeweed {Helenium autumnale L.). Description. — A smooth, angular, branching perennial, 1-5 ft. high; mostly toothed, lanceolate-ovate oblong; heads yellow, ap- pearing in autumn ; involucre of the head or flower consists of small reflexed scales ; ray and disk flowers yellow and fertile ; seeds top-shaped and ribbed; pappus consisting of 5-8 thin, 1-nerved, chaffy scales. Distribution. — Native to the northern states, particularly from Missouri and Illinois to Wisconsin and Minnesota; in the Dakotas as well as in the Rocky mountains, Utah and the northwest. Extermination. — This weed occurs only in low grounds. The soil should be drained. Then sow to some useful leguminous crop like alsike clover. The weed succumbs readily to cultivation. D'ESCRIPTIVE MANUAL 355 Fig. 207. Sneezeweed {Helenium autumnale) . Common in low grounds, pas- tures and along streams. (Photographed by Colbum.) Fig. 207-A. Distribution of Sneezeweed 356 WEED FLORA OP IOWA Fig. 207-B. Sneezeweed (Helenium autumnale) . Fetid Marigold (Dyssodia papposa (Vent.) Hitch.). Description. — ^A nearly smooth or somewhat pubescent, branched annual with strong odor, 6 in.-2 ft. high; leaves opposite, sessile, pinnately parted, bristly-toothed, with large pellucid glands; heads many-flowered ; disk and ray flowers small, yellow ; involucre with a few scales at the base, one row of scales united to form a cup ; achenes slender, 4-angled, pappus a row of chaffy scales fine- ly divided into numerous rough bristles. Distribution. — Common from western Iowa and IMinnesota to Il- linois and to the southwest. Common in western Iowa along right of ways, streets, barnyards and fields. Extermination. — This weed is not difficult to destroy by cultiva- tion. It sometimes occurs in clover seed and alfalfa seed. DESCRIPTIVE MANUAL 357 % #^ ? ^m^ f gn^ 1 i ^ ^i^^V ^l^^^^4\ Fig. 208. Fetid Marigold (Dyssodiia papposa). Pungent smelling herb. Road- sides, fields, waste places, etc. Especially in western Iowa. (Photographed by Hart.) Fig. 208-A. Distribution of Fetid Marigold. 358 WEED FLORA OF IOWA Fig. 209. Fetid Marigjld (Dyssodia pojjposa). (Drawing- by Charlotte M. King.) Yarrow (Achillea millefolium L.)- Description. — A perennial with simple stem 1-21/2 feet high; leaves twice-pinnately parted, the divisions linear ; 3-5-eleft flowers in corymbose heads, flat-topped ray flowers usually white, 4-5. sometimes pink; plant with a somewhat pungent odor. Distribution. — ^Widely distributed in fields, especially gravelly knolls and drift soils through the state; particularly common in northeastern Iowa, found from the Atlantic to the Pacific, also in Europe and Asia. Extermination. — The weed is not difficult to destroy by cultiva- tion. It is not uncommon in clover seed. Practice rotation of crops; when in the pasture where it is apt to be very common cut DESCRIPTIVE MANUAL 359 Fig. 210. Yarrow (Achillea THillefolium) . Common In pastures, especially northwestern Iowa. "White flowers." FlG. 2 10- A. Distribution of Yarrow. 360 WEED FLORA OP IOWA the roots off with a small spade. This will effectually destroy the plant. In Europe, it is sometimes recommended as a forage plant but it is of doubtful value. Mayweed or Dog Fennel {Anthemis cotula L.). Description. — ^An acrid, branching, strong-scented perennial, white ray flowers ; plants 1-2 feet high ; leaves pinnately dissected ; solitary and many-flowered, outer ray flowers pistillate, fertile, or neutral ; disk flowers yellow, small, and tubular ; involucre of num- erous, small, dry scarious scales; achenes small, tuberculate ; pap- pus roughened, none, or merely a minute crown. Distribution. — This weed is native to Europe; early introduced in the United States, now common from the Atlantic: to the Pacific. In Iowa more common in northeastern part than westward; es- pecially abundant in some gardens and along roadsides. Extermination. — A weed easily exterminated by cultivation. It is especially common in clover seed in eastern United States. Clark and Fletcher recommend as follows : ' ' Clean up the waste places about the farmyards and seed to permanent grass that will take full possession of the soil to the exclusion of this and other weeds. This plant is usually prevalent in gardens fertilized with manure from city stables." DESCRIPTIVE MANUAL 361 Fig. 211. Mayweed or Dog Fennel {Antliemis cotula) . Barnyards, roadsides, etc. (After Clark and Bletcher.) 362 WEED FLORA OF IOWA Fig. 211-A. Distribution of Mayweed. Ox-eye Daisy (Chrysanthemum leucanthemum L. var. pinnatiftdum (Lecoq) Lamotte). Description. — A perennial herb with erect stem; spatulate, peti- oled, root leaves, those of the stem partially clasping, all leaves cut or pinnatifid-toothed ; nearly simple stem bearing a large, many-flowered head with numerous white rays ; scales of involucre with scarious margins, both disk and ray flowers producing achenes, marked with longitudinal lines; pappus absent. Distribution. — This European weed has long been known as a troublesome weed in New England and the central states. It is not abundant in Iowa except in a few places. Extermination. — This weed is not troublesome as yet in Iowa. There is much danger, however, that it may be introduced with clover seed, as it frequently occurs in eastern and European grown clover seed. Sotv only clean clover seed. It succumbs quite readily to cultivation. Clark and Fletcher m^ake the following recommendations : ' ' Shal- low plowing of sod in August, with thorough cultivation from time to time until frost, Avill suppress it. This pest does not give trouble on lands worked under a short rotation of crops. Clover for hay in which this weed is plentiful should be cut early. ' ' DESCRIPTIVE MANUAL 363 Pig. 212. Ox-eye Daisy. (Chrysanthemum leucanthemum var. pinnatifidum) . Pastures occasionally. (After Clark and Fletcher.) 364 WEED FLORA OF IOWA Fig. 212-A. Distribution of Ox-eye Daisy. Chemical Composition.- — Its chemical composition according to Me. Bull. Agr. Ex. Sta. 26:6 (1888), is as follows.* FRESH OR AIR DRY MATERIAL. Water Ash Protein Fiber Nitrogen free Extract Fat 9.63 6.85 8.44 29.00 51.72 4.36 WATER FREE SUBSTANCE. 7.6 9.3 32.1 46.2 4.8 Tansy {Tanacetum vulgare L.). Description. — A bitter, acrid, strongly scented, poisonous herb or branched perennial 2-4 ft. high; leaves pinnately divided into linear-pinnatifid divisions, lobes serrate; heads many-flowered, few ray flowers, disk yellow ; marginal flowers fertile ; scales of the invo- lucre in several series; receptacle flat or convex, naked; branches of the style brush-like at the summit ; achenes 5-angled or 5-ribbed, truncate or obtuse ; pappus none or a short crown. Distribution. — Common throughout the southern states from the Atlantic to the Pacific but more common in eastern North America. Common in many parts of the state of Iowa, especially in some communities, in gardens and along roadsides. Extermination. — Easily exterminated by cultivation. •Compiled by Jenkins and Wanton ; Bull. Off. Exp. Sta. 11 :78. DESCRIPTIVE MANUAL 365 Fig. 213. Tansy {Tanacetum vulgare) Common in old gardens, roadsides, etc (Photographed by Colbum.) Fig. 213-A. Distribution of Tansy. 366 WEED FLORA OP IOWA Western Mugwort {Artemisid liidoviciana Nutt.)- Description. — A branching perennial with inconspicuous flow- ers; leaves and stems white, woolly; leaves lanceolate, the upper usually entire, the lower cut-toothed ; heads in narrow panicles, ray flowers absent; involucre of dry scarious scales; receptacle naked; flowers small, yellowish; achenes obovoid; no pappus; trichomes long, simple, cylindrical, tortuous. Distribution. — This weed is common from Illinois north to Sas- katchewan, southwest to Texas, and west to Utah. It is quite widely distributed in the state of Iowa. Extermination. — This weed is easily exterminated by cultivation. After the crop has been removed the field should be plowed thus leaving the soil in good condition. Fig. 214. Western Mugwort, or White Wormwood (Artemisia ludoviciana). Common in gravelly places, fields and pastures, a, plant hairs. (Photographed by Golburn. a. Dra,wn ,by Charlotte M. King.) DESCRIPTIVE MANUAL .367 Fig. 214-A. Distribution of Western Mugwort. Wormwood {Artemisia biennis Willd.). Description.- — ^An aromatic, somewhat bitter, smooth amiual, or biennial herb, 1-3 ft. high, with leafy stems and erect branches ; Fig. 215. Biennial Wormwood. (Artemisia biennis). Pungent smelling herb, fields, woods, etc. (Photographed by. Colbum.) 36B WEED FLORA OF IOWA Fig. 215-A. Distribution of Biennial Wormwood. lower leaves twice pinnately parted, the upper pinnatifid, the lobes linear or linear-oblong, serrate or eut-toothed; inconspicuous flowers; ray flowers absent; heads numerous in short axillary spikes; bracts of involucre green, scarious, margined. Distribution. — Common in the northern Mississippi valley; now widely scattered east to Nova Scotia and south to Kentucky. It occurs in many parts of the state of Iowa. Extermination. — Readily succumbs to cultivation. The plant should be cut off close to the surface of the ground. Fireweed {Erechtites hieracifolia L. Raf.). Description. — A coarse, annual weed of rank odor and grooved, often hairy stem; leaves simple, lanceolate or oblong, acute, cut- toothed, the upper with auricled base ; heads many-flowered ; re- ceptacle naked; flowers tubular and perfect; achenes oblong, tap- ering; soft, white, capillary bristles. Distribution. — This weed is common in moist woods; in the north especially in recent clearings which have been burned over, hence the common name fireweed; also occurs in the Rockies, and Kansas ; common in many parts of Iowa, especially along streams. Extermination. — Easily exterminated by cultivation, should be cut off close to the surface of the ground. Plants DESCRIPTIVE MANUAL 369 y Fig. 216. Fireweed (Erechtites Meracifolia) . Common in clearings, woodland pastures. (Pliotographed by Colburn.) Fig. 216-A. Distribution of Fireweed. 24 370 WEED FLORA OP IOWA Burdock {Arctium lappa L.). Description. — A coarse, branched biennial 1-3 ft. high ; hairy ; leaves large, roundish or heart-shaped, thin, obtuse, entire or den- tate, floccose, tomentose beneath; petioles deeply furrowed, heads of purplish or whitish flowers, clustered or somewhat corymbose; involucre surrounding the flowers lengthened into hooked tips, glabrous or slightly cottony; trichomes simple, long, twisted. Distribution. — Burdock has long been known as a troublesome weed in the northern states and in Europe. Quite common from New Brunswick to Alabama and the Rocky mountains, the Great Basin country and on to the Pacific coast. Common in grain fields and waste places in many parts' of the state. P''iG. 217. Burdock (Arctium lappa). Common in waste places, weed ; "seeds" scattered by animals. (Photographed by Gardner.) A biennial DESCRIPTIVE MANUAL 371 "Figure 217 A Figure 217B Fig. 217-A. Trichome or plant hair from leaf of Burdock. (Drawing by Charlotte M. King.) Fig. 217-B. Distribution of Burdock. Extermination. — Burdock is easily destroyed. Since it is a biennial, cut off below the crown during spring or summer. If it comes up again, cut off once more, or as often as may be necessary. Dr. Vasey says: "It may also be killed by being mowed when the seed has fully formed, and the tops burned. ' ' Prof. Shaw says: "Farmers who go over their fields twice a year with the spade will soon have no burdock." Prof. Goff says : " During the first year of growth the plant is readily destroyed by pulling out by the roots when the ground is very wet." The important thing is not to allow it to go to seed ; it will then die if left to itself. But we may always expect an abundance of the weed as long as it is allowed to grow in waste places. Then add to this its excellent means of dispersal and no wonder it is con- stantly coming up in out-of-the-way places. 372 WEED FLORA OF IOWA Bull Thistle {Cirsium lanceolatum (L.) Hill). Description. — Branching biennial, 3-4 ft. high, tomentose, be- coming dark green and villous or hirsute with age, branchlets bearing large heads; leaves lanceolate, cleeurrent on the stem with prickly wings deeply pinnatifid, the lobes with rigid prickly points, upper face roughened with short hairs, lower face Avith a cottony tomentum; heads l%-2 in. high; bracts of the involucre lanceolate, rigid when young, more flexible with age, long-attenuated, prick- ly, pointed, spreading tips, wholly arachnoid; flower hermaphro- dite ; tube of the corolla 10 lines long ; anther tips acute, filaments pubescent; achenes smooth, 1% in. long; pappus of numerous plumose bristles. Distribution. — Bull thistle is native and indigenous to Europe. It has long been an inhabitant of the northern states and now ex- tends across the continent. In Iowa it is abundant in every county, frequently found in fields and particularly in pastures and wood- lots. Extermination. — This weed should be treated like all other bien- nials. The most important point is to prevent the seeds from forming. For this purpose the plant should be cut off in early spring below the surface of the ground. The seeds germinate in the spring and during the first season produce a flattened mass of leaves. The second season, a flowering stem shoots up rapidly; early in August the flowers begin to appear and these are continued till frost. The only method of treating is to cut down and remove all the "roots" as far as it is possible to do so. If this is done frequent- ly and thoroughly the weed can be exterminated. If the patch is a small one, cutting off the parts as soon as they appear above the ground, several times during the season, will certainly destroy this thistle. In larger patches, plow the ground, harrow and re- move the thistle, either burn the material, or put into compost heaps. This should be done five or six times during the season or as often as occasion may require. DESCRIPTIVE MANUAL 373 Pig. 218. Bull Thistle {Cirsium lanceolatum) . Common in woodland pastures, roadsides and waste places. (Pliotographed by Colbum.) Fig. 218-A. Distribution of Bull Thistle. 374 WEED FLORA OF IOWA Woolly Thistle {Cirsiwri canescens Nutt.). Description. — Branching perennial, 2-4 ft. high, woolly through- out, branches bearing single, medium-sized heads; stem angled, white-woolly; leaves, radical, 8 in.-l ft. long, the division usually 2-lobed, prominently ribbed, ending in stout spines; stem leaves, except the lower, 1-4 inches long, pinnatifid, the upper sessile, slightly roughened, with a slight cottony down, the lower white- woolly; heads iy2-2 in. high; bracts of the involucre somewhat arachnoid; lower scales with a broad base, glutinous ridge, and ending in a minutely serrated spine, inner scales long, attenuated, tips straw-colored; flowers purple. Distrihuiion. — This species is distributed from ]\Iason City and southwestern Minnesota, west to the Rocky mountains. It was collected by Chas. A. Geyer in 1839 and described by Nuttall. The Fig. 219. Woolly Thistle {Cirsium canescens). Common in western Iowa fields and roadsides. (Photographed by Quade.) DESCRIPTIVE MANUAL 375 Fig. 219-A. Distribution of Woolly Thistle. writer has seen it very abundant in both Wyoming and Colorado. The species occurs in Emmet, Dickinson, Sioux, Plymouth, Wood- bury, Cerro Gordo, Worth, Ida and Carroll counties in Iowa. Fig. 220. Woolly Thistle (Cirsiuni canescens). In pastures and fields of northwestern and western Iowa. (Photographed by Pammel.) Extermination. — Correspondents sending this weed frequently refer it to Canada thistle. It occurs not only in pastures and mead- 376 WEED FLORA OP IOWA ows, but also in corn and grain fields. It grows in patches like the Canada thistle. These patches increase in size from year to year. It was described as a doubtful perennial by early botanical writers and so far as I have been able to determine, it is a perennial. It may be exterminated by thorough cultivation, plowing well and then following with the cultivator. Prairie Thistle {Cirsium discolor (Muhl.) Spreng.). Description. — Tall, branching, leafy biennial, 5-7 ft. high, with heads larger than in Canada thistle ; stem striate, slightly hirsute ; leaves radical, 12-14 in. long, deeply pinnatifid, the divisions fre- quently divided, prickly-toothed, the upper surface smoothish, and the lower white ; woolly single heads terminating the branches, with Fig. 221. Prairie or Wood Thistle (.Cirsium discolor). Common border of woods, etc. ( Pliotographed by Colburn. ) DESCRIPTIVE MANUAL 377 Fig. 221A Figure 221B Fig. 221-A. Trichomes or plant liairs of wood thistle. Fig. 221-B. Distribution of Prairie Thistle. purple flowers ; heads 1-1% in. long ; bracts of the globose involucre somewhat suppressed, slightly arachnoid, lower bracts ovate with a broad base and a weak prickly recurved bristle, slight dorsal gland, inner linear-lanceolate with a nearly colorless entire appendage; flowers purple, tube of the corolla 11-12 lines long, lobes of the corolla terminating in clavate tips; anther tips acute, filaments pubescent; bristles of pappus plumose; achene 22 lines long, smooth, upper part yellow. Distribution. — Common in many portions of Iowa ; Marshall, Johnson, Winnebago, Lee, Winneshiek, Allamakee, Greene, and Emmet counties ; at Keokuk, Muscatine, Ames, Cedar Rapids, Car- roll, Des Moines, Polk City, Steamboat Rock, Mason City, Belle Plaine and Iowa City. Extermination.— This field thistle should be treated like all other biennial weeds. The flattened masses in the spring should be cut off below the ground and none of the plants allowed to go to seed. We have received numerous inquiries in regard to this weed from western and northwestern Iowa. . Iowa Thistle {Cirsium iowense (Pammel) Fernald). Description. — Biennial with downy, branching stem; leaves roughly hairy above but white-woolly beneath, oblong-ovate to nar- rowly lanceolate, sinuate-toothed, or somewhat pinnatifid, lobes or 378 WEED FLORA OF IOWA Pig. 222. Iowa Thistle iCirsium iowense). Common in pastures and meadows ( Fliotographed by Colbum.) Fig. 222-A. Distribution of Iowa Tliistle. DESCRIPTIVE MANUAL 379 teeth with weak prickles; rather large heads; involucre l-iy2 in. long; bracts with broad glandular back, the inner with a some- what attenuated colorless tip. Distribution. — Common in borders of woods and in fields. From Iowa to South Dakota and Kansas. In Story, Emmet, Kossuth, Marshall, Boone, Linn, Clinton, Webster and Carroll counties in prairie meadows. Extermination. — This biennial is readily destroyed by cutting the plants off below the surface of the ground. When left to ■flower it dies but in meadows where cut off above the surface of the ground it acts like a perennial. Canada Thistle {Cirsium arvense (L.) Scop.). Description. — Smooth perennial, spreading by roots and root- stocks, 1-3 ft. high, corymbosely branched at the top ; stem smooth ; leaves lanceolate, sessile, and deeply pinnatifid, lobes and margins of leaf with spiny teeth; heads small, %-l in. high, bracts ap- pressed, the outer with a broad base, inner narrow, all with an acute, never spiny, tip; somewhat arachnoid flowers purple, di- oecious; in staminate plant, flowers exserted with abortive pistils, in pistillate less so, scarcely exceeding the bracts; tube of the corolla 6 lines long; stamens with abortive anthers, anther tips acute, filaments minutely pubescent ; young achene pubescent ; all of the bristles of the pappus plumose; trichomes simple, long, floecose. Distribution. — This European weed is widely distributed in Can- ada to the Pacific coast; found in Iowa in many counties, more common in northern counties than in the southern. It is more or less abundant in Hardin, Pocahontas, Clinton, and Worth coun- ties, frequently in clover meadows and in pastures. Extermination. — The Canada thistle can be treated with sodium arsenite. No other chemicals, so far as our experiments extend, will entirely destroj^ this weed. Carbolic acid only partially de- stroys the roots and the plants shoot up again from below the point of injury, but by repeating the process the Canada thistle can ulti- mately be exterminated. A good method of eradicating the weed is to plow shallow and cultivate frequently during the summer. The roots of the Canada thistle extend deeply dow^n into the soil, hence for this reason deep cultivation will be of no avail. After 380 WEED FLORA OF IOWA Fig. 223. Canada Thistle (.Cirsmm arvense) . Common and widely distributed in Iowa. (After Clark and Fletcher.) DESCRIPTIVE MANUAL 381 Figure 223A Fig. 2 2 3- a. Figure 223B . Trichome or plant hair from leaf of Canada Thistle. (Drawing by Charlotte M. King.) Fig. 223-B. Distribution of Canada Thistle. plowing, the soil should be dragged and the roots exposed to the sun and removed, when possible. It may be necessary to run over the field with a hoe to cut off the stray plants which appear. This method was tried on a patch several years ago and no Canada thistles have since made their appearance in this place. Various crops, such as clover and sorghum, are said to be ef- fective in subduing the thistles. Of the various chemicals which have been used to exterminate Canada thistles none are more effective than sodium arsenite. It is applied at the rate of l%-2 pounds to 52 gallows of water. Carbolic acid at the rate of one part to one part water destroys the root when it comes in contact with the mixture, and for a little distance beyond. This is not an effective method, as the roots sprout out from below. In response to circulars of inquiry sent out by the Iowa Experi- ment Station, the majority of correspondents recommend shallow plowing, disking, and harrowing ; and continuing cultivation and hoeing as long as the thistles make their appearance. Some report successful treatment with salt when scattered thickly about the thistles, especially if cattle or sheep are given access to it. Some report success with carbolic acid when it is applied directly to the stem. Tarred paper in a few cases gave success, as did also the method where the thistle was covered thickly with straw or ma- nure. The depth of covering was not, however, given. 382 WEED FLORA OF IOWA Clark and Fletcher recommend the following treatment : "The chief safeguard against the Canada thistle and all similar deep-rooted perennials is undoubtedly a regular short rotation. A three-year rotation, including two cuttings of early red clover for the first year, followed by a deep fall plowing for hoed crops with clean cultivation, and a cereal crop for the third year, will sup- press it." A correspondent in The Prairie Farmer on the resisting quali- ties of Canada thistle says : "I have been debating in my mind and endeavoring to determine whether or not root-stocks or por- tions thereof have to some extent the hibernating qualities of the seed. For instance, take two seeds of the cocklebur — one hiber- nates for one season and the other for two seasons, with growth always present. Now the question is may not a Canada thistle with its root-stock or a portion of it lie dormant for a season or more? If this be true, then some of the best known methods of extermination are useless." To this Prof. R. A. Moore says : "In regard to Canada thistle roots hibernating and retaining their vitality for several years, will say, that I think your correspondent's version seems reason- able, and it is quite conclusive from this fact that the eradication of the pest is all the more difficult. It seems that many of the seeds and plants are given this power of remaining dormant when subjected to adverse conditions. In the lower order of plants, many of the species of bacteria when subjected to adverse environ- ments are transformed into resistant spores and will not vegetate until the conditions are favorable." Wallace's Farmer says concerning its eradication: "We believe if we had a quarter of an acre of Canada thistles we would let them alone until August, when the thistle will put forth its utmost efforts to produce seed. While the thistles are in full blossom we would mow them, rake them up and burn them, and then plow the ground about eight inches deep, throwing the furrow flat. Letting them put forth their full strength to produce seed and thwarting that by mowing and burning would weaken the roots materially. Then by plowing them under eight inches deep, if possible, you would attack them at their weakest point. DESCRIPTIVE MANUAL 383 Knapweed {Centaurea solsUtialis L.). Description. — Annual erect, branched,, cottony stem ; lower leaves lyrate, deeply pinnatifid, upper leaves, linear, entire or nearly so, decurrent wings on the stem; outer bracts, with long spreading spines, those at base few and smaller; flowers yellow, with soft pappus. Fig. 224. Knapweed, Star Thistle {Centaurea solsUtialis). In alfalfa fields. (Mich. Agr. Exp. Sta.) 384 WEED FLORA OF IOWA Fig. 224-A. Distribution of Knapweed. Distribution. — Massachusetts to Ontario and Iowa; introduced with alfalfa seed into other western states. Extermination. — This annual weed has been introduced largely with alfalfa seed. Sow clean seed. Use seed coming from the Rocky mountains or Kansas where the weed is not common. It is an extremely objectionable weed because of the spiny heads. It is easily killed by cultivation. Chicory or Succory {Cichorium intyhus L.). Description. — A branching perennial with deep roots, alternate leaves ; blue flowers, or sometimes pink or purple ; basal leaves spreading on the ground ; stem leaves oblong or lanceolate, partly clasping. Distribution. — It is common along roadsides in fields and waste places from New England to Canada to Nebraska, especially com- mon where chicory has been cultivated; it has become a trouble- some weed in "Wisconsin and Minnesota. It is allied to endive, cul- tivated as a salad plant. Extermination. — Chicory is not difficult to destroy where ro- tation of crops is practiced. Though a perennial, the roots are easily killed by repeated cultivation. Clark and Fletcher recommend the following treatment: "A short rotation of crops will soon suppress it. Chicory is not often seen in good farming districts except as a wayside weed. Individual plants may be destroyed by close cutting and applying salt to the root in hot, dry weather." DESCRIPTIVE MANUAL 385 Fig. 225. Chicory (Cichorium intybus). In clover and alfalfa fields, some- times in waste places. (After Clark and Fletcher.) 25 386 WEED FLORA OF IOWA Fig. 225-A. Distribution of Chicory. Dandelion (Taraxacum officinale Weber). Description. — A smooth, or at first pubescent, biennial or per- ennial ; the many-flowered head borne on a slender hollow scape ; root leaves pinnatifid or runeinate ; involucre double, the outer of Pig. 226. Dandelion (^Taraxacum officinale) . Long root, sometimes to a depth of three and one-half feet in the soil. (Photographed by Gardner.) DESCRIPTIVE MANUAL 387 Fig. 226-A. Distribution of Dandelion. short scales, the inner of long, linear, erect scales in a single row; after flowering the inner involucre closes, the fruit is ripened close to the ground, and when ripe the hollow scape elongates and the whole involucre is reflexed permitting the wind to scatter the "seeds;" "seeds" oblong, long-beaked, the beak being 2 or 3 times as long as the remainder of the achene, bearing at the end the pappus. Fig. 226-B. A patch of Dandelion in a lawn, early in June. (Photograplied by Charlotte M. King.) 388 WEED FLORA OF IOWA Distribution. — The dandelion is cosmopolitan. It is quite as common in Europe as in the United States, being common and abundant at high elevations, as in the Rocky mountains. Found everywhere in Iowa on lawns and pastures. Fig. 227. Common Dandelion (Taraxacum officinale). lawns, pastures, etc. (Photographed by Colburn.) A weed common in Extermination. — The dandelions are not difficult to exterminate in cultivated fields but in garden crops it is more difficult to do so, especially in strawberry beds. As the dandelions are perennial herbs, seed formation should be prevented. Where they occur in small patches a spud may be used successfully. Where they are abundant in lawns it is only necessary to keep the lawn closely cropped and dig them up with a small spud to prevent seeding. Blue grass and clover, especially the latter, will crowd them out. It is rare that dandelions give trouble after the middle of June. DESCRIPTIVE MANUAL 389 Fig. 227-A. Common Dandelion (Taraxacum officinale). 1, head; 2, sihgle flower ; 3, achene ; li, receptacle and seed with pappus. Experiments have been made with herbicides and the one most commonly used is iron sulphate which is usually applied at the rate of 100 pounds to one barrel of water. The weed where prop- erly sprayed will be destroyed, but owing to the fact that the dan- delion possesses a long perennial root, sometimes 4 feet long, it will sprout again. The spraying must be kept up until fall. Chemical Composition. — According to the report of the Bussey Institution the chemical composition of the dandelion is as follows : FRESH OR AIR DRY MATERIAL. Water Ash Protein Fiber Nitrogen free Extract Pat 85.54 1.99 2.81 1.52 V.45 0.69 WATER FREE SiUBSTANCE. 13.8 19.4 10.5 51.5 4.8 *Bull. 1877. Compiled by Jenkins and Winton ; Bull. 11, Off. E!xp. Sta., U. S. Dept. Agr. 390 WEED FLORA OF IOWA Red-seeded Dandelion {Taraxacum erythrospermum Andrz.). Description. — A perennial weed with long root; leaves deeply runcinate-pinnatifid or pinnately divided into narrow segments; heads somewhat smaller than in common dandelion, sulphur yel- low; involucre glaucous, the inner bracts corniculate, appendaged at tip; the outer short, spreading or ascending; achene reddish, tuberculate above. Distribution. — Red-seeded dandelion is a much more recent in- troduction than common dandelion. It occurs from Maine to Kansas. Naturalized from Europe, in similar situations to com- mon dandelion in Iowa; sometimes less abundant and sometimes more abundant than the latter. Extermination. — May be exterminated in the same way as the common dandelion. Fig. 228. Red-seeded dandelion (Taraxacum erytlirospermum) . Common in lawns. (Photographed by Colburn.) Clark and Fletcher recommend the following treatment: ''It is important to prevent dandelions from seeding in lands adjacent to lawns. Though entailing much labor, the most satis- factory way to deal with them, when deeply rooted in laAvns, is to loosen the soil with a digging fork and pull them up. The use of DESCRIPTIVE MANUAL 391 the fork may not be necessary in some wet and soft soils. The ap- plication of kerosene to the crown of the plant, in the centre of the rosette of leaves, is recommended. Sulphate of ammonia or sulphate of iron in excess is also recommended. A small table- spoonful of salt applied in the morning of a hot day, when the soil is dry, will kill them. Annual Sow-thistle (Sonchus oleraceus L.). Description. — ^Annual, succulent herb with leafy, smooth stems, and pale yellow flowers in corymbose or umbellate clusters; leaves of stem dentate, runcinate-pinnatifid, terminal with a large seg- ment; heads numerous; blossoms in late summer and fall. Distribution. — This weed is common in fields and waste places throughout North America, especially in the north. It is common in Europe and also occurs in Mexico and South America. Extermination. — Sow thistle is easily exterminated by cultiva- tion. It can also be exterminated by the use of iron sulphate at the rate of 100 pounds to a barrel of water; where it is abundant it may be necessary to make two or three applications. Clark and Fletcher recommend as follows: "Prevent them from seeding in waste places by cleaning them up and seeding them to permanent, vigorous grasses. This annual weed, with its rela- tively small, pale yellow flowers, when compared with perennial species is not difficult to control by ordinary methods of cultivation and alternation of crops. Sheep, if sufficient in numbers, will pre- vent sow thistles from seeding in pasture lands." The Iowa Homestead says concerning its eradication: ''We have seen the sow thistle take complete possession of a soil, growing so thickly that other crops were entirely choked out. Nec- essarily the best way to destroy it is to cultivate freely. If it makes its appearance in stubble ground we would advise plowing as early as possible after harvest and the cultivation of surface at intervals during the late summer and fall in order to keep the thistles below the ground. 392 WEED FLORA OP IOWA Fig. 229. Common Sow Thistle (Sonchus oleraceus). "^^aste places. (After Clark and Fletcher.) DESCRIPTIVE MANUAL 393 Fig. 229-A. Distribution of Annual Sow Thistle. Sow Thistle (Sonchus asper (L.) Hill). Description. — Like the preceding species except that stem leaves are less divided and more spiny-toothed, with auricles of the Fig. 230. Sow Thistle {Sonchus asper), Waste places, yellow flowers and milky juice. (Photographed by Colburn.) 394 WEED FLORA OF IOWA Fig. 230-A. Distribution of Sow Thistle. clasping base rounded; achenes 3-nerved on each side and margined, smooth. Distribution. — Common with the preceding species, in waste places. Extermination. — This annual is not difficult to exterminate by giving thorough cultivation. Perennial Sow Thistle {Sonchus arvensis L.). Description. — ^A perennial with creeping root-stock, and milky juice; leaves runcinate, pinnatifid and spiny toothed, heart-shaped base; flowers yellow; peduncle and involucre bristly; achenes ob- compressed, wrinkled on the ribs. Distribution. — Common from Nova Scotia west to Saskatchewan, North Dakota, Minnesota, occasional in Iowa to New Jersey and New England. Extermination. — A most difficult weed to exterminate and should be treated like the Canada thistle. Summer fallow with frequent cultivation is the only successful method. Clark and Fletcher of Canada, recommend the following: "Small patches may be eradicated by digging out the roots as thoroughly as possible and destroying them. This may have to be done several times during a season. Great care must be taken not to distribute pieces of the rootstocks over the fields by harrows or other implements. To exterminate Perennial Sow Thistle, some system must be adopted which will prevent the development of leaves for a period sufficiently long to kill the roots by smothering DESCRIPTIVE MANUAL 395 Fig. 231. Perennial Sow Thistle (Sonchus arvensis). Plants with bright yel- low flowers, milky juice. Not common in Iowa. A difficult weed to exter- minate. (Photographed by Colbum.) Fig. 231-A. Distribution of Perennial Sow Thistle. 396 WEED FLORA OF IOWA them. Wlien a field is badly infested it requires special treatment for a season and close attention for a number of years. One of the most effective methods is to plow lightly immediately after the hay or grain crop is removed and follow with frequent use of a broad-shared cultivator. Late in the fall plow again, somewhat deeper. In the spring give frequent cultivation, so as to prevent the development of any leaves and thus weaken the roots to the greatest possible extent. About the middle of June or first of July sow rape in drills at the rate of about 11/2 lbs. per acre. Cultivate between the drills as soon as possible and repeat at short intervals until the rape completely covers the ground. Some hand hoeing may be necessary to keep all the thistles down. This should pretty well exterminate the pest but if some plants still remain when the rape is cut or pastured off, the field maj^ be fall plowed and put into hoed crop the next season, when special attention can be given to any small patches that may appear. Buckwheat is sometimes used instead of rape for a smothering crop." Prickly Lettuce {Lactuca scariola L. var. integrata Gren. & Godr.). Description. — Tall, erect herbs, glaucous, green, 2-5 ft. high, simple or branched except the lower part of stem which has stiff bristles; leaves glaucous, green, smooth except the midrib which is beset with weak prickles lanceolate to oblong in outline, with spinulose, denticulate margins, occasionally sinuate-toothed; flow- ers pale yellow. The leaves of L. scariola are pinnatifid and more prickly; trichomes multicellular. Distribution. — Prickly lettuce was introduced into Massachu- setts about 1863 from Europe. It is quite widely distributed in northern Africa and Europe and has become frequent throughout the northern Mississippi valley to the Pacific coast. It is com- mon everywhere in Iowa particularly along roadsides, highways and in gardens. The L. scariola is becoming more frequent in Iowa, in Ames, Des Moines, Boone, etc. Extermination. — The weed is easily exterminated from culti- vated fields and in waste places by cutting off young plants below the ground. "Where the stem is cut off below the surface of the ground it will give no trouble, but in meadows and lawns where the plants are cut off above the ground the weed will continually reappear, producing from 3-6 branches. The following excellent suggestions are made by L. H. Dewey : DESCRIPTIVE MANUAL 397 Fig. 232. Prickly Lettuce {Lactuca scariola var. integrata). Common road- sides and gardens. (After Clark and Fletcher.) 398 WEED FLORA OP IOWA Figure 232A. Figure 232B Fig. 2 32 -A. Bristles on Prickly Lettuce (integrata). (Drawing by Charlotte M. King.) Fig. 232-B. Distribution of Pi-ickly Lettuce. "Sheep and sometimes cattle will eat the young prickly lettuce, and in some localities their services have been found very effective in keeping it down, especially in recently cleared land where culti- vation is impossible. Repeatedly mowing the plants as they first begin to blossom will prevent seeding and eventually subdue them. Thorough cultivation with a hoed crop, by means of which the seed in the soil may be induced to germinate, will be found most effective. The plowing should be shallow so as not to bury the seeds too deep. Under no circumstances should the mature seed- bearing plants be plowed under, as that would only fill the soil Fig. 232-C. Distribution of Prickly Lettuce (Lactuca scariola). DESCRIPTIVE MANUAL 399 with seeds buried at different depths to be brought under condi- tions favorable for germination at intervals for several years. Ma- ture plants should be mowed and burned before plowing. The seed appears as an impurity in clover, millet and the heavier grass seeds, and the plant is doubtless most frequently introduced by this means. As the seeds may be carried a long distance by the wind, the plants must be cleared out of the fence rows, waste land and roadsides." Clark and Fletcher recommend as follows: "The seed is short-lived and if the plant is kept closely cut and prevented from seeding in waste places for two or three years it will soon disappear from cultivated areas. Clean waste lands and seed to permanent vigorous grasses. Ordinary methods of cultiva- tion will suppress it in the fields." Wild Lettuce {Lactuca canadensis L,). Description. — Stem leafy, glabrous or nearly so, glaucous; lower leaves sinuate, pinnatifid, upper entire; heads numerous, in a rather long, open panicle ; flowers yellow. Distribution. — ^Nova Scotia to Ontario, Ohio and westward; fre- quently found in Iowa. Extermination. — This perennial is not . difficult to destroy by cultivation. 400 WEED FLORA OF IOWA Fig. 233. Wild or Canadian Lettuce (Lactuca canadensis). Fields, roadsides and meadows. (Photographed by Quade.) DESCRIPTIVE MANUAL 401 :• ,^ P ■ ^ ' .\ W^" ' ' ■ ^53L#*^',':i &^'^' .^.-^ fe- ■%A ^ W^^wfJ^ ^% mA : ^ 1^. . ; :/ . ^ ^::-^ ■■■ Fig. 233-A. Wild or Canadian Lettuce (.Lactuca canadensis) . Plant with milky juice and yellow flowers. (Photographed by Quade.) 36 Fig. 2 33-B. Distribution of Wild Lettuce. 402 WEED FLORA OP IOWA Blue Lettuce (Lactuca pulchella {Pursh.) DC). Description. — Perennial plant, deep-rooted, pale or glaucous; stem simple, about 1 foot high; leaves sessile, oblong or linear- lanceolate, glabrous, entire, or lower leaves somewhat pinnatifid; racemose heads large, erect; peduncles with scaly bracts; bracts of involucre imbricated in 3-4 ranks ; flowers blue. Distribution. — ^Northern Michigan and Ontario southward; re- ported from several localities in Iowa. Extermination. — Prevent from distributing seed by continued cutting before flowering. If it becomes established in a field, try- thorough summer fallow with deep cultivation so as to check growth of long rootstocks. Fiu. 234. Blue Lettuce (Lactuca pulchella). Blue flowered lettuce, milky juice. Common in western Iowa. (Photographed by Quade. ) Plant with DESCRIPTIVE MANUAL 403 Fig. 234-A. Distribution of Blue Lettuce. Rushlike Lygodesmia (Lygodesmia juncea (Pursh.) D. Don.). Description. — A tufted, smooth, frequently glaucous perennial a foot or more high, coming from a thick woody root, with copious Fig. 235. Lygodesmia or Skeleton Weed (Lygodesmia juncea). A deep rooted perennial with a yellowish milky juice. (Photographed by Colburn.) 404 WEED FLORA OF IOWA Fig. 235-A. Distribution of Lygodesmia. yellowish juice; lower leaves rigid, linear-lanceolate, small, entire, the upper sealelike ; flowers purple in erect heads ; achenes nar- row-ribbed, pappus light brown. This weed is sometimes called skeleton weed. Distribution. — This weed is common from Missouri river to west- ern Montana and east to St. Croix river in Wisconsin. A some- what troublesome weed in northwestern Iowa ; easily recognized by the yellowish juice and rushlike stems. Extermination. — This plant produces a long root which enables the plant to spread rapidly. It also produces a large number of "seeds." Where the weed is common, plough the field after harvest and disk the plants. It is a good plan to follow up with a hoe, cutting off the plants. CHAPTER II. THE GENERAL CHARACTERS OF SEEDS By L. H. PAMMEL and CHARLOTTE M. KING CHAPTER II. f^ CYPERACEAE, SEDGE FAMILY. Sedge {Car ex vulpinoidea Mx.). Achene enclosed by an utricle called the perigynium, hardly 3- angled, somewhat flattened, tipped by lanceolate 2-toothed beak, the persistent base of the flower-style; achene flask-shaped, about Figure 236A. figure 236B Fig. 236. Forms of Sedges, a^ Eleocharis palustris; b, Carex vulpinoidea. (After Gray.) one-sixteenth of an inch in length, light brown; surface incon- spicuously nerved; whitish, projecting scar. Spike Rush {Eleocharis paUistris R. Br.). Aehenes slightly flattened, somewhat lenticular, with 2 or 3 ob- tuse angles one-twelfth to one-tenth in. long, brown, smooth, shin- ing, minutely cross-striated ; seed with persistent tubercle from tip ; tubercle conical, triangular, constricted; bristles pale, longer than 408 WEED FLORA OF IOWA Fig. 237. Achenes, "seeds," of common forms of Sedges {Carex). (After Hillman, Bull. Nevada Agr. Exp. Sta.) achene; seed may appear with or without tubercle and bristles. Seed occasionally found in seed of alsike and red clover from wet grounds. GR AMINE AE, GRASS FAMILY. Johnson Grass (Sorghum halepense (L.) Pers.). Sessile spikelet broadly lanceolate, acute, 4-6 mm.* long, be- coming dark at maturity ; callus small, obtuse, shortly and sparsely barbate ; first glume coriaceous, slightly pubescent on the flattened back, 5-7 nerved; second similar, equal to first, with hyaline, ciliate, Fig. 238. Spikelet of Johnson Grass (Sorghum halepense). (Drawn by Charlotte M. King.) inflexed margins; the third glume shorter, membranous, faintly 2-nerved, with ciliate, infolded margins; fourth glume broad, ob- tuse, shorter than second, 2-lobed at apex, ciliate, a.wned; awn 10-16 mm. long ; palea shorter than glumes, without nerves, ciliate. Smooth Crab Grass {Digitaria humifusa Pers.). Spikelets lanceolate or elliptical, one-twelfth in. in length, acut- ish ; glumes usually present, first glume wanting, sometimes rudi- mentary, 3-nerved ; the first and second, hairy on the margins ; *1 mm. = 0.0394 inch, or nearly one -twenty -fifth inch. THE GENERAL CHARACTERS OP SEEDS 409 Fig. 239. Seeds of Smooth Crab Grass {Digitaria huviifusa.) . A and B, spike- lets ; A showing the second glume, B showing the third glume. C, D and E, florets ; D, bearing a portion of the second glume, B, the inner face, showing the edges of the flowering glume. F, a spikelet of Digitaria filiformis, show- ing the shorter second glume. G, the natural size of both of these species. (After Hillman, Bull. Nevada Agr. Exp. Sta.) the third, 7-nerved; the fourth, dark purplish brown. Occurrence very frequent in alfalfa clovers and commercial grass seed. Crab Grass {Digitaria sanguinalis (L.) Scop.). Spikelets one-seventh in. in length with usually persistent scale- like glumes, lanceolate, pedicellate; second glume usually ciliate on margins, short ; fourth glume silky-villousi along marginal nerves, 5-nerved, color pale. Frequently occurs in red and alsike clover, as well as in timothy. Figure 240A Fig. 240B i^ «=.* Figare 240C A, an enlarged view A, spikelets showing Fig. 240. Common Crab Grass {Digitaria sanguinalis). of Crab Grass. B, with small glume attached. C. the second glume, floret, and edges of the third glume. B, the opposite face, showing the minute first glume and third glume. D and E, the two faces of the floret. F, seeds, natural size. (A and B, Drawings by C. M. King; C, after Hillman, Bull. Nevada Agr. Exp. Sta.) 410 WEED FLORA OF IOWA Tickle or Hair Grass {Panicum capillare L.). Spikelets small, ovate or acute, one-fifteenth to one-twelfth in. long, acuminate-pointed, smooth, shining; sterile glumes usually absent, when present not shining ; first glume 1-3-nerved, obtuse to Figure 241A Figure 241A Figure 241B Fig. 241. A. Tickle or Hair Grass (.Panicum capillare).. At the left a spikelet opened, at the right various views. A, B and C, the outer, inner and edge views, respectively, of a floret. D and E are views of the spikelet, D showing the second glume and the first in part, and E the first and third and the second in part. F, a group showing the natural size of the pre- ceding. B. Sprouting Crab Grass. Various views of spikelets. (A, at the left, drawn by C. M. King; A, at the right, after Hillman, Bull. Mich. Agr. Exp. Sta. ; B, drawn by C. M. King.) acute; second and third glumes 5-7-nerved, tips acute; flowering glume shining, smooth, elliptical, obtuse, or subacute. Often found in clovers and in timothy. Sprouting Crab Grass (Panicum proliferum Lam.). Spikelet lanceolate, ovate, acute, one-tenth in. in length, smooth; lower glume obtuse, nerveless or 1-3-nerved ; second and third glume equal, acute, 5-7-nerved; flowering glume smooth and shining; pedi- cels scabrous. Rarely found in clover. Switch Grass (Panicum virgatum L.). Spikelets ovate, acuminate, 3-5-nerved; flowering glume shorter than the outer glumes, smooth, shining, minutely striated; with outer glumes removed, the spikelet resembles a small jassid. Rarely found in clovers. THE GENERAL CHARACTERS OF SEEDS 411 Figure 242A Figure 242B Fig. 242. A. Switch Grass (Panicum virgatum). spikelet ; d, "seeds," natural size. B. A single spikelet. C. Millet {Panicum mtliaceum'i. (A, after Hillman, Bull. Mich. Agr. Exp. Sta. ; B lotte M. King.) Figure 242C a, h, c, various views ol and C, drawings by Char- Millet {PaTdcum mUiaceum Ix). Spikelets acnminate, one-eighth to one-fifth in. long, lower glume acuminate, 5-7-nerved; third glume subtending the empty palet, 7-13-nerved ; flowering glume indurated, obtuse, shining, min- utely cross-striated; the hulled seeds ovoid, yellowish. Found in clover and alfalfa seed. Barnyard Grass {Echinochloa crusgalli {It.) Beauv.). Spikelets with hispid or pubescent nerves; first glume shorter than the third, awned; second awnless or short-awned; third with long rigid awn ; flowering glume generally ovate ; one-tenth to one- ninth in. longitudinally striate; palet smooth. Not infrequently found in clovers. Fig. 243. A. Barnyard Grass (.Echinochloa crusgalli). A, a floret, back view of the glume. B, front view of floret, showing the palea. C, edge view or the same. D, the spikelet, showing the small first glume, the awned third glume, and the tip of the second. E, a group showing the natural size of the preceding. 412 WEED FLORA OF IOWA Fig. 243. B. Sandbur {Cenchrus trihuloides) . a. bur enlarged; b, spine; c and d, spikelet ; e, seed. (After Hillman ; A, Bull. Nevada Agr. Exp. Sta., B, Bull. Michigan Agr. Exp. Sta.) Sandbur {Cenchrus tribuloides L.). Burs with sharp, straight, pubescent prickles; each bur with 6-20 globose spikelets. Green Foxtail {Setaria viridds (L.) Beauv.). "Seeds" about one-twelfth in. in length, biconvex, color light green, or greenish; with flowering glume rounded, slightly granu- Figure 244A Figure 244B Figure 244C Pig. 244. A. Green Foxtail (Setaria viridis) . A and B, views of the floret; A, the back of the glume ; B, showing the palea, its sliining edges partially covered by the edges of tlie glume. C, a floret covered by the empty glumes (a spikelet), the figure showing the first and third glumes. D, a group showing the natural size. B. Slightly enlarged spikelet. C. Whorled Millet (Setaria verticillata) . (A, after Hillman, Bull. Nevada Agr. Exp. Sta. ; B and C, drawings by Char- lotte M. King.) THE GENERAL CHARACTERS OF SEEDS 413 lar, striate lengthwise and with cross-ridges ; palea shining; com- monly brownish or greenish. In alfalfa., clovers and grass seed. Whorled Millet {Setaria verticillata (L.) Beauv.). Spikelets elliptical-ovate, one-twelfth in. long; first glume tri- angular-ovate, acute or obtuse, 3-nerved; second glume ovate, ob- tuse, 5-7-nerved ; third glume, 5-7-nerved, bears short palet in its axil ; flowering glume about one-fifteenth in. in length, striate, near- ly smooth; bristles about the flower, 1 or 2, retrorsely scabrous, one-twelfth to one-third in. long. Found in clover seed. Yellow Foxtail {Setaria glauca (L.) Beauv.). "Seeds" about one-eighth in. in length, very variable; color, yellowish, brovsnaish, or even pale; perfect flower with flowering glume plano-convex, partially covering edges of palet; back of Figure 245B Fig. 245. Yellow Foxtail or Pigeon Grass (Setaria glauca). A and B, the outer and inner faces, respectively, of a floret ; B, showing the palea. C and D, the same showing the empty glumes of the spikelet ; C, showing the second glume, and the first and third in part ; D, showing the first and third glumes and the second slightly. E and F, the grain ; E, the convex, embryo-bearing face ; F, the plane face. G, a group showing the natural size. B. Slightly enlarged spikelet. (A, after Hillman, Nevada Agr. Exp. Sta. Bull. ; B, drawing by Charlotte M. King.) flowering glume with prominent transverse branching ridges ; flow- ering glume minutely granular. In alfalfa, clovers and grass seed. Mexican Dropseed (Muklenbergia mexicana (L.) Trin.). Spikelet about one-twelfth in. long, on very short pedicel; empty glumes nearly equal, acuminate ; flowering glume lanceolate, 3- nerved, scabrous on keel, pilose near base; sterile and flowering 414 WEED FLORA OF IOWA glumes marked by dark, longitudinal lines ; seed brown, about one- twelfth in. in length, marked at embryo by darker elliptical area. Occurs in alfalfa and the clovers. Marsh Muhlenberg {Muhleiibergia racemosa (Mx.) B. S. P.). Spikelets one-sixth to one-quarter in. long; lower glume acumi- nate-pointed ; flowering glume acute, densely bearded at base, min- utely pubescent and marked by black lines; seed slender, cylindri- r Figure 246B Fig. 246C Fig. 246. Dropseed Grasses. A. Seed of Mexican Dropseed Grass (Muhlen- bergia mexicana). B. Spikelet of Marsh Muhlenberg (.M. racemosa). C. Nimble Will (M. schreberi) . (Drawings by Charlotte M. King.) cal, brown, with black area at one end. Found in timothy and clover seed. Nimble Will {Muhlenbergia schreheri J. F. Gmel.). Spikelet one-twelfth in. in length, as long as or longer than pedi- cel ; empty glume minute ; lower sometimes absent ; flowering glume lanceolate, slender, awned, scabrous on nerves. Found in clover seed. Timothy {Phleum pratense L.). Flowering glume or larger scale marked by several veins, truncate at top, shorter scale or palet also prominent ; seed usually with flowering glume; one-sixteenth to one-twelfth in. long; color light THE GENERAL CHARACTERS OF SEEDS 415 ^ , -/"c ' <•'- ^#. Figure 247B Fig. 247. A. Timothy (Phleum pratense). Hulled and unhuUed seed. B. Red Top {Affrostis alba). (A, drawing by Charlotte M. King; B, after Hillman, U. S Dept. Agr.) gray; seeds somewhat transparent with darker elongated area at lower end, marking the location of the embryo. Red Top {Agrostis alba L.). Spikelet one-twelfth to one-eighth in. long, empty glumes lanceolate, acute ; the first scabrous on the keel ; the second a little shorter, and smooth or scabrous near the apex; flowering glume a little shorter than the empty ones, obtuse or truncate ; palet one- half to three-quarters as long as glume ; rachilla frequently present in seed, roughened ; fruit brownish, ovate. Wild Oats {Avena fatua L.). Fruit sipindle shape, and of a light yellow color on the tip, bal- ance darker yellow to blackish brown; bears one long geniculate awn with lower end twisted ; basal scar oval, sloping, with a bunch of soft hairs just above ; size 15 mm. 416 WEED FLORA OF IOWA *- AlBft. Figure 248A Figure 248B Fig. 248. Wild Oats (Avena fatua). a, spikelet ; b, floret; c, natural size. (A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; B, Bull. Mich. Agr. Exp. Sta.) Crowfoot or Goose Grass {Eleiisine indica Gaertn.). Spikelets closely imbricated, l%-2 lines (3%-5 mm.) long, 3-6- flowered ; glumes obtuse, the first small, 1-nerved, the second larger, with flowering glumes 3-5-nerved; seeds rugose, enclosed within a thin, loose pericarp. Figure 249B Figure 2490 Fig. 249. A. Crowfoot or Goose Grass {Eleusine indica). a, florets; b, c, d, views of seed. B. Tufted Eragrostis (Erar/rostis pilosa) , a, spikelet; b. fruit. C. Candy Grass (E7-agrostis megastachya) . A. Seeds enlarged. B. Seeds natural size. THE GENERAL CHARACTERS OF SEEDS 417 Candy Grass {Eragrostis megastachi/a (Koeler) Link.). Spikelets ovate to linear, many-flowered, one-sixth to two-thirds in. long; empty glumes nearly equal, ovate-lanceolate, one-twelfth in. long, prominently nerved, scabrous on keel ; palet ciliate on keel; seed small, ovoid to elliptical, one-thirty-second in. in length, color brown. Found in commercial grass seed and alsike clover. Southern Spear G-rass (Eragrostis pilosa (L.) Beauv.). Spikelet narrow, lanceolate, 3-15-flowered, equaling or exceeding the capillary pedicels, one-sixth to five-twelfths in. long; empty glume ovate, acute, scabrous on keel ; flowering glume broadly ovate, obtuse, 8-nerved, scabrous on keel, one-seventh in. in length; palet ciliate on keel ; seeds small, elliptical or ovoid ; one-twenty-eighth in. in length. Found in commercial grass seed. Orchard Grass {Dactylis glomerate L.). Spikelets compressed, 3-5-flowered, in crowded, 1-sided clusters; flowering glumes lanceolate, acute or awn-pointed, one-sixth to one- quarter in. in length, ciliate on keel, and otherwise minutely pu- FiG. 250. Orchard Grass {Dactylis glqmerata). (After Hillman. U. S. Dept. Agr.) bescent ; callus at base ; palet serrate on margin near upper end and minutely pubescent. 27 418 WEED FLORA OF IOWA Wire Grass {Poa conipressa L.). Spikelets lanceolate, 5-9-flowered, one-sixtli to one-quarter in. in length, flowering glumes about one-seventh in. in length, obscurely 5-nerved ; marginal teeth of palet continue to extreme apex. Found with seed of Kentucky blue grass and other commercial grass seed. Figure 251A d ^'^• Figure 251B a, b, two views of seed ; c, Fig. 251. A. Wire Grass (Poa conipressa'). natural size ; d, upper portion of palet showing marginal spines, tucky Blue Grass {Poa pratensis). a, b, two views of seed; size ; d, upper part of palet showing marginal spines. (Hillman, Bull. Mich. Agr. Exp. Sta.) B. Ken- , natural Kentucky Blue Grass {Poa pratensis L.). Spikelet 3-5-flowered, one-sixth in. long, on short scabrous pedi- cels; empty glumes slightly unequal, lower nearly lanceolate, 1- nerved, upper glume broader, 3-nerved ; flowering glume ovate, scarious towards the apex, base cobwebby, raehilla slender; palet with marginal teeth disappearing short of the apex. Found oc- casionally in fescue grass seed and the commercial grass seed. Meadow Fescue {Festuca elatior L.). Spikelet lanceolate, 5-10-flowered ; empty glume lanceolate, acute, one-quarter in. long, smooth, faintly striate ; indistinctly 5-nerved ; raehilla slender. Occasionally found in brome grass and rye grass seeds. Fig. 252. Meadow Fescue (Festuca elatior). (Drawing by Ada Hayden.) THE GENERAL CHARACTERS OF SEEDS Soft Cliess {Bromus hordeaceus L.). 419 Flowering spikelet 7-9 mm. in length, obtuse and awned; awns 6-8 mm. in length; roughened; glume with 3 nerves on each side; glume bearing numerous hairs upon the surface; caryopsis 5 mm. long, 2 mm. wide, light brown, scar at base, extending one-third length of seed. Figure 253A p( Figure 253B Fig. 253. A. Soft Chess (Bromus hordeaceus). a, to, views of enlarged seed; c, natural size. B. Chess {Bromus secalinus). a, b, c, d, views of seed, enlarged; e, natural size. (After Hlllman.) Smooth Brome or Hungarian Brome Grass {Bromus inermis Leyss.). Empty glumes unequal; flowering glumes awnless or short- awned, with broad scarious margin at obtuse or emarginate apex; veins of flowering glume conspicuous, roughened; veins of palet roughened; seed flattened, boat-shaped, one-third in. in length, one-twelfth in. in width. 420 WEED FLORA OF IOWA Figure 254B Figure 254A Fig. 254. A. Smooth Brome {Bromus inermis). B. Awned Brome {Bromus tectorum) . (A, after Hillman ; B, drawn bj' Ada Hay den.) A^^Tied Brome Grass {Bromus tectorum L.). Spikelet with unequal, acuminate-pointed, hirsute empty glumes, and rough or hirsute flowering glumes 8-12 mm. long; awn 12-16 mm. long. Chess {Bromus secalinus L,.). Spikelets tinged, 6-12-flowered, pendulous in fruit, one-twelfth to two-fifths in. long ; empty glume oblong-lanceolate ; flowering glume ovate-oblong, obscurely 7-nerved, nearly a^^Tiless, or short- awned from the back of apex ; pubescent along margins and toward the apex; palet obtuse, strongly nerved: toothed or fringed with distant bristles; seed brownish. Found in oats and other small grain. Perennial Eye Grass' {Lolium perenne L.). Spikelets about one-half in. in length, 5-12-flowered ; empty glume much shorter than the spikelet; flowering glume obscurely nerved, obtuse, cuspidate, or very short awn-pointed, bearing callus at base; palet granulate; serrulate on margin. THE GENERAL CHARACTERS OF SEEDS 421 Figure 255A Fig. 255A Figure 255B Fig. 255B Fig. 255. A. Perennial Rye Grass (Lolium perenne). B. Italian Rye-grass {Lolium italicum). (A, after Hillman ; B, drawn by. C. M. King.) Italian Rye Grass {Lolium italicum A.). Spikelets two-fifths to three-fifths in. long, 6-15-flowered ; flower- ing glume scabrous near the summit, awned; awn slender, about length of glume ; margin of palet serrate. Quack Grass {Agropyron repens (L.) Beauv.). Spikelets 4-8-flowered ; empty glumes 5-7-nerved, obtuse or notched, acute or acuminate; flowering glume awned near apex; two-fifths in. in length ; 5-7-nerved above the middle, finely rough- 422 WEED FLORA OF IOWA II 1 J! #■ Figure 256B Fig. 256. A and B. Quack Grass {Agropyron repens)_ showing various forms. C. Slender Wheat Grass iAgropyron tenerum) . THE GENERAL CHARACTERS OF SEEDS 423 i I 1' X\ Vf iu>^' Figure 256D ^;jd: Fig. 256. D. Western Wheat Grass (Agropyron smithii) ; a, large spikelet ; b and d, small spikelet ; c, edge view of spikelet ; e, empty glumes ; f, empty glume attached to axis of spikelet. (After Hillman. A, Cir. IT. S. Dept. Agr. ; B. Bull. Mich. Agr. Exp. Sta. ; V,. Cir. U. S. Dept. Agr.; D, Cir. U. S. Dept. Agr.) ened, granular-serrate on margins, finely pubescent at apex ; rachilla prominent, liairy, minutely roughened. Occasionally oc- curs in clovers. Western Wheat Grass {Agropyron smithii Rydb.). Fruit similar in shape and size to A. repens, but the broadest portion nearer the tip, giving it more of the characteristic outline of brome grass; tip generally awned, surface finely pubescent; toothing on edge of palea seems finer than in A. repens. Poison Darnel {Lolium temulentuni) . Flowering glume about three-tenths in. long, awned or awnless, smooth, obscurely nerved; margins folded in over the palet; tur- gid ; shorter than in Lolium perenne. Wild Barley {Hordeum juhatum L.). Spikes narrow, 1-3 in. or more long; empty glumes rigid; the 4 internal ones of each group dilated above the base, those of central sublanceolate, all awn-pointed; outer glumes of lateral spikelets setaceous; flowering glume of central spikelet awned; florets of lateral spikelets awnless. 424 WEED FLORA OF IOWA Figure 257a A B Figure 257B Figure 257C Fig. 257. A. Seed of Darnel {Lolium temulentum) . a, b, with awns enlarged, c, natural size. B. Wild Barley {Hordeum jubatiim.) C. Little Barley (Hordeum pusillum). (A, after Winton ; B, after Hillman, Bull. Mich. Agr. Exp. Sta ; C, drawn by C. M. King.) Little Barley {Hordeum pusillum Xutt.). Spikelet 1-3-flowered ; fempty glumes rigid, the 4 internal ones of each group dilated above the base, those of the central spikelet sublanceolate, all awn-pointed; outer glumes of the imperfect lat- eral spikelets setaceous; flowering glume of the central spikelet awned, awn equaling those of the empty glumes ; florets of the lateral spikelets awnless, or nearly so. URTICACEAE, NETTLE FAMILY. Hemp {Cannabis sativa L.). Achene ovoid, brown with more or less light markings, -4 mm. in diameter; surface smooth. THE GENERAL CHARACTERS OF SEEDS 425 III Figure 258A / \ Figure 258B Fig. 258. A. Hemp (^Cannabis sativa). I. Seed in envelope. II. Seed withoui envelope. III. Cross section of seed. F. pericarp ; S. testa ; B. endosperm. B. Nettle iUrtica gracilis), a, seed in envelope; b, seed enlarged; d, natural size. (A, after 'Winton ; B, after Hillman, Bull. Mich. Agr. Exp. Sta.) Nettle {Urtica gracilis Ait.). The fruit enclosed in membranous calyx ; seed .pale straw-color, 1 mm. long, flattened, ovate, slightly pointed toward the ends, smooth; point of attachment at broader end. POLYGONACEAE, BUCKWHEAT FAMILY. Sour Dock (Bumex acetosa L.). Inner sepals of calyx in fruit, with wings; achene convex be- tween angles; one-twelfth in. in length, variable, smooth, shining; dark reddish brown. Probably occurs in European grown clover seed. Sheep Sorrel (Bumex acetosella L.). Calyx usually persistent, not wing-margined in fruit, roughened, with prominent veins ; closely fitting achene, elliptical or ovate 426 WEED FLORA OF IOWA ^ Figure 259A ?4\ ^ % Figure 259B Fig. 259. A. Sour Dock {Runiex acetosa). A, various acheijes. B, diagram of the calyx. C, aclienes and calyx, natural size. H. Sheep Sorrel (Rumex acetosella). A, seeds bearing the calyx segments. B, one having the segments partially broken away. C, achenes from which the calyx is removed. D, seeds, natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) with blunt angles, one-twenty-fonrth to one-twentieth in. in length; color of fruit grayish to brownish. Common in red, white and alsike clover. Curled Dock {Euniex crispus L.). Perianth frequently persistent, consisting of thin veined lobes ■of the calyx, winged in fruit; wings cordate or notched at base; Figure 260 Fig. 260. Curled Dock (Rumex crispus). A, views of achenes. B, a cross- sectional view of the same. C, diagram of the calyx. D, achenes and calj'ces, natural size. E, a shrunken achene. (After Hillman, Bull. Nev. Agr. Exp. Sta.) THE GENERAL CHARACTERS OF SEEDS 427 margins entire, each with tubercle on the back ; color brown ; achene triangular, elliptical, with pointed apex ; one-twelfth to one- eighth in. in length ; color brown ; surface smooth, shining ; mar- gins minutely roughened. ■ Tall Dock {Bumex altissimus Wood). Usually but one wing of fruiting calyx bearing tubercle ; pedicel as long as wings; perianth segments veined; margins nearly en- tire; achene triangular, widened at the base; one-sixteenth to one- twelfth in. in length; sear prominent. Fig. 261A Figure 261B Qi B Figure 2610 Figure 261D Fig. 261. A and B, Tall Dock {Rumex altissimus}. C and D, Broad-leaved Dock (Rumex obtusifolius). C, tubercle and calyx. (A, drawn by L. R. Collins ; B and C, drawn by Ada Hayden ; D, after Hill- man, Bull. Nev. Agr. Exp. Sta.) Broad-leaved Dock {Rumex oMusifolius L.). Wings of the fruit small, only 1-tubercled; margins of wings deeply toothed, backs rugose; fruit three-sixteenths in. long; achenes convex between angles, one-twelfth to one-eighth in. in length; conspicuous scar at base. 428 WEED FLORA OF IOWA Water Smartweed {Polygonum acre HBK.). Achenes oblong, thick, generally 3-angled, somewhat lenticular, one-tenth to one-eighth in. in length, smooth, finely reticulated ; color dull J base of perianth adhering. Dooryard Knotweed {Polygonum amculare L.). Achenes 3-angled, ovoid, acute, sides deeply concave, one-eighth to one-seventh in. in length; color light to dark and reddish brown; surface finely granulated and striated leng-thwise. Figure 262A Figure 262B Figure 2620 Figure 262D Fig. 262. A. Water Smartweed {Polygonum acre). B. Dooryard Knotweed {Polygonum aviculare). A, group of seeds (achenes) showing the usual forms ; that at the right is one of the smooth, light colored specimens; B, a group showing the natural size; C, a cross section showing the relative positions of embryo and endosperm. C. and D. Prince's Feather {Polygonum orientale). (A and D, drawn by C. M. King; C, drawn by Ada Hay den ; B, after Hillman.) Prince's Feather {Polygonum orientale L.). Achenes usually orbicular, flattened, with prominent remnant of style, one-ninth in. in length, finely reticulated; color dull brown- ish to black ; base with large scar ; remnant of colored calyx at base. THE GENERAL CHARACTERS OF SEEDS 429 Black Bindweed {Polygonum convolvulus L.). Aclienes large, prominently 3-angied, ovoid-pyramidal, one- eighth to one-sixteenth in. in length; surface dull, with minute striae; color blackish; perianth usually removed, when present straw-colored. Figure 263A Figure 263 B Fig. 263. A. Black Bindweed {Polygonum convolvulus). A and B, views of two seeds, the latter bearing a portion of the perianth about the base. C, a view of an entire perianth covering a seed. D, a group showing the natural size. B. Erect Knotweed (Polygonum erectum). (After Hillman, Bull. Mich. Agr. Exp. Sta.) Erect Knotweed {Polygonum erectum L.). Achenes 3-angied, ovoid, less deeply concave between the angles than in preceding (P. aviculare) ; one-ninth to one-tenth in. in length ; dull, minutely reticulated. Figure 264A Fig 264B Pig. 264. Water Pepper (Polygonum liydropiper) . Seeds enlarged and natural size ; the embryo at C. B. Mild Water Pepper (Polygonum hydroinperoicles') . (A, after Hillman; B, drawing by Ada Hayden.) 430 WEED FLORA OF IOWA Water Pepper {Polygonum hydropiper L.). Achene lenticular, trianeiilar ; form broadly oblong or ovoid, slightly gil)bous ; one-tenth in. in length ; dull, color light. Mild Water Pepper {Polygonum hydropiperoides Mx.). Achenes 3-angied, ovoid, angles between flattened, sides rounded, one-eighth to one-tenth in. in length; smooth, shining. Slender Pink Smartweed {Polygonwrn lapathifolium L.). Achenes ovoid-oblong, lenticular, edges slightly angled along the center, ^^'ith a prominent remnant of the style at upper end, one- Figure 265A Figure 265B Fig. 265. A. Slender Pink Smartweed (Polygonum lapathifolium'). A, a side view of an aciiene bearing a part of the perlantli at the base, enlarged. B, a group showing the natural size, one shown edgewise. C, a cross section of an achene. B. Lady's Thumb (Polygonum persicaria). A, B and C, side views of com- mon forms of achenes ; C, a three-angled specimen. D, one covered by the perianth (reduced from the size of A, B and C). E, a group showing the natural size. F, a cross section of an achene. (After Hillman, Bull. Nev. Agr. Exp. Sta.) twelfth to one-tenth in. long; color light brown to dark brown, shining; base of achene with remnant of perianth adhering. Pennsylvania Smartweed {Polygonum pennsylvanicum L.). Achenes orbicular, usually broader than long, with edges as in P. lapathifolium, remnant of style short, one-seventh to one-sixth in. long; color blackish, dull, base of achene with perianth ad- hering. Lady's Thumb {Polygonum persicaria L.). Achenes broadly ovate, lenticular, often somewhat 3-angled at base, one-eleventh in. in length; surface smooth, shining; color dark; remnant of perianth present at base. THE GENERAL CHARACTERS OF SEEDS 431 # # ..-•r m Fig. 266. Pennsylvania Smartweed (Polygonum pennsylvanicum). A, a side view of a seed (achene). B, one surrounded by the calyx; the opposite side has two segments between those on the edges. C, a cross section of a seed. D, seeds, natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) Bushy Knotweed {Polygonum ramosissimum ]\ix.). Achenes. sharply 3-angled, sides less deeply concave than in P. aviculare, one-eighth in. in length; color blackish, dull; calyx greenish, light straw-colored in dried specimens. Figure 267A Figure 2670 Figure 267C Figure 267B Fig. 267. A. Pennsylvania Smartweed (Polygonum pennsylvanicum.) . B. Tan- weed (Polygonum mulilenhergii) . C. Bushy Knotweed (Polygo^ium ramos- issimum). (A and B, drawings by Charlotte M. King; C, drawings by L. R. Collins.) CHENOPODIACEAE, GOOSEFOOT FAMILY. Cycloloma (Cycloloma atripUcifolium (Spreng.) Coult.). Fruit enclosed by the calyx, lower surface prominently rayed, upper surface depressed, wing-margined, one-tenth to one-eighth in. in diameter ; seed nearly spherical, somewhat flattened, one-twelfth in. in diameter, blackish; scar whitish; embryo slender, forming a ring about the endosperm. Fig. 268. Cycloloma (Cycloloma atripUcifolium). sl, b, seed in envelope; c, d, enlarged views ; e, seeds, natural size ; f, cross section. (After Hillman, Bull. Mich. Agr. Exp. Sta.) 432 WEED FLORA OF IOWA Lamb's Quarters {Clienopoclium album L.). Seeds one-twentieth in. in diameter, often surrounded by thin glandular utricle which varies from grayish to straw-color; seed dark brown, shining, firmly attached to pericarp, edge rounded, lower, convex with a curved groove ; seed somewhat irregular in shape ; some seeds also surrounded by the pericarp and star-shaped calyx. In seed of small grains, clover and grasses. Figure 269A Figure 269B Figure 2690 Fig. 269. A. Lamb's Quarters {CUenopodium albnin). a to b, different views of seed ; d, g, f, seed witli utricle ; i, calyx attached. B. Maple-leaved Goosefoot {Chenopodium hybridum). a, seed in envelope; b, c,. general view of seed ; d, cross section ; e, natural size. C. Western Lamb's Quarters {Chenopodium murale). A, B and C, views of seed ; D, the natural size. (After Hillman, A and B, Bull. Mich. Agr. Exp. Sta. ; C. Bull. Nev. Exp. Sta.) Maple-leaved Goosefoot {Chenopodium hyhriclum L.). Seeds dark grayish black, circular, 2.5-3 mm. in diameter, flat- tened double-convex, with distinct margin, slightly indented by a notch ; scar on middle of one face ; seed shining, black, when en- velope is entirely removed. Spinach {Spinacia olerocea L.). Fruit broadly ovate, one-sixth in. in length, size variable ; utricle unarmed, wrinkled, sometimes tuberculate, straw-colored; aehene closely enveloped by utricle; scar elevated. THE GENERAL CHARACTERS OF SEEDS 433 '^■^;'^/f^^iJiS-^;:^;B^^^^;^?^^^^ Figure 270A Figure 270B F"iG. 270. A. Spinach (Spinacia oleracea) . B Orach (Atriplex patula var. hastata) . a, ta, c, different views of seed in envelope ; d, e, f, views of seeds. (A, drawing by Charlotte M. King; B, after Hillman, Bull. Mich. Agr. Exp. Sta.) Orach (Atriplex patula Yar. hastata (L.) Gray). Fruiting bracts ovate-triangular, entire toothed, often muricate on the back, united to near the middle; seed jet black, shining, nearly circular, edge bluntly rounded, bearing a notch ; a groove leads from protuberance on the margin part way to center of face. Russian Thistle {Salsola kali var. tenuifolia G. F. W. Mey.). Calyx persistent, 5-parted, membranaceous, enclosing the flat- tened utricle by a broad, flat, membranaceous wing ; seed conical. Figure 271A Figure 271B Fig. 271. A. Russian Thistle (Salsola kali var. tenuifolia), a, seed in envelope; b, d, e, views of seed enlarged ; c, natural size. B. Kochia or Mexican Fireweed {Kocliia scoparia). (A, after Hillman, Bull. Mich. Agr. Exp. Sta. ; B, drawing by Miss King.;; upper end truncate, with a depression one-eighteenth in. in diameter, brownish ; seed without endosperm, embryo coiled in a spiral ; cotyledons slender. 28 434 WEED FLORA OF IOWA AMARANTHACEAE, AMARANTH FAMILY. Spreading Amaranth {Amaranthus hlitoides Wats.). Seeds lenticular or round to broadly egg-shaped, one-sixth in. in diameter, both sides convex with distinct margin, glossy, black; Fig. 272. Spreading Amaranth (.Amaranthus Hit aides) . A, seeds. B, a broken specimen. C, an edge view. D, the natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) seeds borne in ovoid-oblong utricle, 2-3-beaked by the persistent style. Reported in western alfalfa seed. Tumbleweed {Amaranthus graecizans L.). Seeds lenticular or roundish, one-twenty-fourth in. in diameter, glossy black, much like the preceding but smaller. In grasses and lawn mixtures. a Fig. 273. Tumbleweed (Amaranthus graecizans). A, seeds. B, a broken one. C, the natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) Rough PigAveed {Amaranthus retroflexus L.). Seeds from one-eighteenth to one-tAventieth in. in length ; oval, spherical or nearly spherical, both sides convex with a continuous ring on the margin ; sear small ; smooth, black, shining ; seeds much like A. hlitoides but somewhat smaller. In seeds of red clover,, alsike, and timothy. THE GENERAL CHARACTERS OF SEEDS 435 Fig. 274. Rough Pigweed (Amaranthus retroflexus) . A, seeds; B, one having the seed-coat broken ; C, the natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) Water Hemp {Acnida tiiberculatui Moq.). Seeds erect, lens-shaped, one-fifteenth in. in diameter, smootli, bhining, black, 2-5 remnants of stigmas, sometimes with the at- FiG. 275. Water Hemp {Acnida tuberculata) . a, b, c, difterent views of seed; d, cross section ; e, in seed envelope ; f, natural size. (After Hillman, Bull. Mich. Agr. Exp. Sta.) tached calyx and mucronate bracts; utricle longer than bracts; circumseissile, not angled. In seed of clover and alsike. CARYOPHYLLACEAE, PINK FAMILY. - Chickweed {S.tellaria media (L.) Cyrill.), Kidney-shaped, broadly egg-shaped, to wedge-shaped, one- twentieth in. in length, finely and closely tubercled; color grayish Fig. 276. Chickweed (Stellaria media). A, seeds, side view. B, one shown in edge view. C, a sectional view showing the embryo and endosperm. D, group showing the natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) to light brown ; scar marked by a longitudinal groove at basal end. Occasionally found in clover. 436 WEED FLORA OF IOWA Corn Cockle {Agrostemma gitliago L.). Seeds large, angular, broadly wedge-shaped, one-eighth in. in length; tubercles prominent, lines of tubercles beginning at basal end of seed ; color brown to black ; size of seed variable ; according m # Fig. 277. Corn Cockle (Agrostemma gitliago), a, seed enlarged; b, seed in cross section ; c, natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) to Dewey the larger ones hard to screen out. Most commonly found in wheat; seed has poisonous properties. "Pest in grain fields." Pound in wheat and in chicken feed. Bladder Campion (Silene laiifolia (Mill.) Brit. & Rendle). Seed kidney-shaped, more nearly spherical than in Silene nocti- flora, one-fifteenth in. in length; shape of seed more nearly or- bicular than in S. noctiflora. Found in some clovers. Fig. 27 8. Bladder Campion (Silene latifolia). A, common forms of seeds; side view. B, edge view of a seed, showing the scar-cavity. C, the nat- ural size of the seeds. (Alter Hillman, Bull. Nev. Agr. Exp. Sta.) Forked Catchfiy {Silene dicliotoma Ehrb.). General shape of seed roundish triangular, somewhat flattened, about 1.5 mm. in breadth ; color dull reddish brown ; 5-7 rows of tubercles on each side in curved rows following the rounding out- line of the shape of the seed; scar on the straight side of seed. THE GENERAL CHARACTERS OF SEEDS 437 ^ ^ # Figure 279A Figure 279B Fig. 279. A. Forked Catchfly (Silene dicliotoma). a, seed enlarged; b, nat- ural size. B. Night-flowering Catchfly (Silene noctiflora) . A, side view of a seed; B, edge view of the same, showing the scar-cavity. C, a longitudinal section of a seed, showing the embryo curved about the endosperm. D, the nat- ural size of the seeds. (After Hillman; A, Bull. Mich. Agr. Exp. Sta., B, Bull. Nev. Agr. Exp. Sta.) Night-flowering Catchfly {Silene noctiflora L.). Seeds kidney-shaped, thick, with ronnded edges, one-fifteenth to one-tenth in. in length ; surface roughened by peculiar tubercles ; on shorter side a black elevated scar; immature seeds red. Found in clover and grass seed. Figure 280A Fig. 2S0. A. Evening Catchfly (.Silene vesvertina). B. Evening Catchfly (Lychnis alba). (Drawings by L. R. Collins and Ada Hayden.) Evening Catchfly {Silene vespertina Sibth. Seed smaller than that of S. noctiflora, which resembles it, one- fifteenth of an in. in length; ash-colored. Found in alfalfa and clover seed. 438 WEED FLORA OF IOWA Cowlierb {Saponaria vaccariaJj.). Seed nearly spherical, one-twelfth in. in length, minutely tu- l)ercled ; color black ; immature seeds reddish ; scar whitish, in de- pression. Occurs in wheat and in red clover. Fig. 281. Cowherb (Saponaria vaccaria). A, different views of the seeds; tlie one at the left and the lower one show the scar ; the light spots show the minute surface-projections. B and C, parts of a broken seed, B re- taining a part of the embryo. D, a sectional view of a seed. E, seeds, nat- ural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) PORTULACACEAE, PURSLANE FAMILY. Purslane (Portulaca oleracea L.). Seeds broadly ovate, inclined to kidney-shaped, flattened, one- thirtieth in. in length, roughened by minute tubercles in concentric rows; small scar at smaller end, whitish. Fig. 282. Purslane (Portulaca oleracea). A, a side view of a seed, enlarged, showing the whitish scar ; B, a group, natural size ; C, section of a seed, taken parallel with the faces. (After Hillman, Bull. Nev. Agr. Exp. Sta.) RANUNCULACEAE, CROWFOOT FAMILY. Meadow Eue (Thalictrum dasycarpum Fisch. and Lall.). Fruit an achene, ovoid, one-fifth in. in length, -with remnant of curved style, prominently ribbed, with from 6-8 wings, short- stalked, glabrous or pubescent ; seed elongated, ovoid, one-tenth in. long, brownish, smooth, with prominent veins near base of seed. Occasionally found in clover seed. THE GENERAL CHARACTERS OF SEEDS 439 (I. Figure 283A Figure 283 B Fig. 283. A. Meadow Rue (Thalictnim dasycarpum) . B. Long-fruited Anemone {Anemone cylindrica) . (A, drawing by L. R. Collins, B, by Ada Hayden.) Long-fruited Anemone {Anemone cylindrica Gray) . Achenes one-qnarter in. in length and one-fifth in. in width, flat, compressed, 1-seeded, nearly orbicular, greenish, covered by dense pilose mass of whitish hairs. Prairie Larkspur {DelpJiinum Penardi Huth.). Seeds somewhat flattened, upper end wider, nearly square, 4- angled or triangular, one-sixteenth to one-twelfth in. long, surface scabrous, becoming rougher on angles; color grayish. Fig. Figure 284A ' Figure 284B 284. A. Prairie Larkspur (.Delphinmrn Penardi). Figure 2840 B. and C. Field Larlcspur {Delphinium consolida). (A, drawing by Ada Hayden; B, drawn by L. R. Collins; C, drawn by C. M. King.) Field Larkspur {Delphinium consolida L.). Seed angular, somewhat convex on back, one-twelfth in. long and equally wide, surface scabrous or scaly, with whitish margins; color blackish, brownish or grayish; seed with sharp bitter taste. Reported as- of frequent occurrence in Russian clover seed. 440. WEED FLORA OF IOWA Small-flowered Crowfoot {Iiauuncidus ahortivus L.). Achene flattened-circular, with 2 convex faces, orange-brown in color, smooth and shining, very slightly impressed with wrinkles; remnant of style present as a short curved point on margin. 1^ f^ Figure 285A Figure 285B Fig. 285. A. Small-flowered Crowfoot {Raniincuhis ahortivus). a, enlarged ; b, end view ; c, achenes natural size. B. Tall Buttercup {Ranunculus acris). a, b. different views of seed; section ; d, natural size. (After Hillman, Bull. Mich. Agr. Exp. Sta.) achenes c, cross Tall Buttercup {Ranunculus acris). Carpel 1-ovuled; achene flattened, tipped by remnant of curved style, one-tenth to one-eighth in. long ; color greenish to brownish ; surface apparently smooth, minutely pitted; scar minute, in a wdiitish depression at base of achene. PAPAVERACBAE, POPPY FAMILY. Poppy {Papaver somniferum L.). Seed about 1 nun. in length, kidney-shaped, one end being slightly larger than the other; hilum and chalaza in a notch, connected by a short raphe ; surface covered with fine, beautiful reticulations ; embryo straight ; considerable endosperm. Figure 2S6A Fig. 2S6. A. Poppy {Papaver somniferin)i) . Figure 2S6B To the left embryo of seed. fi. Prickly Poppy {Argemone intermedia). (A, after Wanton. B, drawing. C. M. King.) THE GENERAL CHARACTERS OF SEEDS 441 Prickly Poppy (Argemone intermedia Sweet). Pod ellipsoid, prickly; seeds spherical, crested, about 2 mm. in diameter; dark brown, surface reticulate and deeply pitted. CRUCIPERAE, MUSTARD FAMILY. Pennycress {Thlaspi arvense L.). Seed oblong, flattened, one-twelftli to one-tenth in. long; sur- face marked by curved ridges, simple or occasionally forked, which curve from base to apex in regular rows ; color brownish to dark reddish brown ; f unicle sharp pointed. Found largely in wheat, barley and oats. "A pest of grain (wheat) fields of Manitoba." / / Figure 287B Fig. 287. A. Pennycress (Thlaspi arvense). A, side view of a seed; B, seeds, natural size ; C, the embryo. B. Cress {.LepicUum sativum) . (After Hillman, Bull. Mich. Agr. Exp. Sta.) Ci^ess {Lepidium sativum L.). Seed oval, one edge nearly straight, the other convex, one-tenth in. in length, apparently slightly marginate at basal end, basal portion bearing scar, also with white projecting tip, and end of funicle prominent, smooth, brownish. Small Peppergrass {Lepidium apetalum Willd.). Seeds oblong, flattened, margin colorless, prominent ridge on one side, one-sixteenth to one-twelfth in. long, minutely rough- ened ; cotyledons incumbent ; seed coat becomes mucilaginous when wet ; funicle prominent. Generally found in small grains and commercial grass seed. 442 WEED FLORA OF IOWA (2' ^ Figure 288A Figure 2S8B Fig. 288. A. Small Peppergrass (Lepidium aiietalum) . A, seeds shown in side view ; B, a half-section of a pod ; C, a seed in cross section, showing the three parts of the embryo, the caulicle being at the right; D, the embryo, the caulicle at the left ; B, group of seeds, natural size. B. Lepidiuni apetalum, with section of seed coat showing action of mucilagin- ous cells after moistening. (A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; B, drawn by C. M. King.) Large Peppergrass {Lepidium virginicum L.). Seed elongated with prominent ridge on one side, one-twelfth in. in length ; color light reddish brown ; cotyledons incnmbent ; seed -^-^ ^-^--^ Fig. 289. Large Peppergrass (Lepidiuni virginicum). A, three seeds shown in side view. The upper two show the narrow, curved groove of one face, the lower one shows the broader, shallow depression of the opposite face. The one immediately at the right of A shows the widened border and its light colored edge. B, entire pod. C, a seed showing the mucilage as it appears while wet. D is a cross sectional view of a seed, showing the flattened form of the cotyledons and the edgewise position of the caulicle. E, the embryo in side view. F, seeds, pod, and half-pod, natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) coat becomes mucilaginous when wet. Generally found in small grains and commercial grass seed. Frequent in timothy. THE GENERAL CHARACTERS OP SEEDS 443 Shepherd's Purse {Capsellahursa-pastoris (L.) Medic). Seed small, flattened, oblong, with 2 longitudinal grooves; one- twenty-fourth to one-twentieth in, in length ; color light brown ; scar whitish, funicle prominent. In alsike clover. *» ^A Fig. 291. False Flax (Camelina sativa) . A, various forms of seeds. B, a seed showing the mucilage. C, a seed in cross- section. D, seeds, natural size. (After Hillman, Bull. Mich. Agr. Exp. Sta.) between it and the cotyledons which are incumbent. On addition of water the seeds become mucilaginous. In seeds of clovers and grasses. 444 WEED FLORA OF IOWA "Radish (Raphanus sativus L.). Seed spherical, ovate to oval, frequently angular, one-eighth to one-fifth in. in length, minutely pitted, brownish with glaucous or shining surface; scar inconspicuous, usually surrounded by small dark area; radicle near scar, prominent. Fig. 292. Radish (RapJianus sativus), two different views. (Drawn by C. M. King.) White Mustard {Brassica alba Boiss.). Seed nearly spherical, occasionally somewhat oblong, one-twelfth to one-ninth in. long, light colored, reticulations inconspicuous; scar whitish, projecting; seed coats mucilaginous when wet. Pig. (A, rigure 293A Figure 293A 293. A. White Mustard (Brassica alba). Figure 293B B. Charlock (Brassica arven- sis). a, tip of pod; b, seeds enlarged, and natural size; c, cross section, drawings by Ada Hayden and li. R. Collins ; B, after Hillman, Bull. Mich. Agr. Exp. Sta.) English Charlock (Brassica arvensis (L.) Ktze.). Seed nearly spherical, sometimes oblong, one-fourteenth to one- twelfth in. in diameter, marked Avith fine ridges, reticulated or honeycombed in appearance, light brown or grayish, with paler appearance; scar wdiitish, an elevated point at one end of the seed ; embryo large ; cotjdedons conduplicate. Only a small amount of mucilage produced in presence of water. THE GENERAL CHARACTERS OF SEEDS 445 Wild Turnip {Brassica campestris L.). Seeds generally nearly spherical or oblong; the caulicle and radicle usually conspicuous along the middle, one-twentieth to one- twelfth in. in diameter, cultivated forms larger, roughened and e A Fig. 294. Wild Turnip {Brassica i ^ ). A and B, various forms of seeds. C, a seed in cross section showing cotyledons and caulicle. D, the embryo. E, seeds, natural size. (After Hillman, Bull. Mich. Agr. Exp. Sta.) more finely ridged than in B. nigra and B. arvensis; color grayisli or brownish; scar at one end. With clover and grass seed. Rape {Brassica napus L.). Seed nearly spherical or sometimes oblong, one-fourteenth to one- twelfth in. in length, prominently reticulated; closely resembles B. arvensis. Found in mustard and clover seed. O <3 o o Figure 295A Figure 295B Fig. 295. A. Rape (Brassica napus). B. Black Mustard (Brassica nigra). A, seed enlarged, showing the surface network of dark lines. B, a group of seeds, natural size. (A, drawings by Ada Hayden ; B, after Hillman, Bull. Mich. Agr. Exp. Sta.) Black Mustard {Brassica nigra (L.) Koch.). Seed nearly spherical, more generally broadly oblong, one-twen- tieth to one-fifteenth in. in diameter; surface marked with fine ridges; frequently whitish scar at one end; embryo as in B. 446 WEED FLORA OP IOWA arvensis; taste pungent. Generally found in seed of clover and alfalfa. Indian Mustard {Brassica juncea). Seed about the size of wild mustard seed ; surface rather coarsely reticulated. Color dark reddish brown. Figure 296A Figure 296B Fig. 296. A. Indian Mustard (Brassica juncea). B. Hare's-ear Mustard (Conringia orientalis). a, b, different views of seed; c, cross section; d, natural size. (After Hillman, Bull. Mich. Agr. Exp. Sta.) Hare's-ear Mustard {Conringim orientalis (L.) Dumort.). Pod rigid, 4-angled; seeds brown, oblong narrowed to rounding at the ends, 2-2.5 mm. long; surface finely reticulated in checks; scar at end of seed lighter in color; position of cauliele indicated by two distinct, lengthwise grooves. Tumbling Mustard {Sisymhrium altissimum L.). Seed oblong flattened, one-twenty-fifth in. in length ; color reddish yellow ; radicle prominent, variable in shape ; form of embryo marked by deeper color, by lines; seed coat becomes mucilaginous when wet. A tumbling w^ed. Distribution wide, reported as a serious weed in commercial seeds of the northwest and Canada. Hedge Mustard {Sisymhrium officinale (L.) Scop.). Seed oblong, sometimes with upper end truncate, some almost trapezoidal in outline, one-twenty-fourth to one-sixteenth in. long ; color yellowish, or brownish, variable ; cauliele evident from promi- nent white scar; funicle sometimes present and pointed; seed coat mucilaginous. Found in alsike and white clovers. THE GENERAL CHARACTERS OF SEEDS 447 "nJ***' Figure 297A Figure 297B Fig. 297. A. Tumbling Mustard (.Sisymbrium altissim/um) . A, a group of seeds indicating the usual forms ; a, one showing the hairy appearance due to the mucilage, either when wet or after drying. B, several seeds, natural size. B. Hedge Mustard (Sisymbrium officinale). A, a group of seeds showing the prevailing forms ; a, one showing the fine hairlike mucilage as it appears when wet or after drying. B, group showing the natural size. (After Hillman, Bull. Mich. Agr. Exp. S^a.) Marsh Cress (Badicula palustris (L.) Moench.). Pod ovoid; seed pale reddish, brown, oval, finely reticulated, length about .6 2-3 mm. ; scar near one end, occupying a deep notch in the contour of the margin. Fig. 298. Marsh Cress (Radicula palustris). (Drawing by Ada Hayden.) Winter Cress {Barbarea vulgaris R. Br.). Seed oblong, flattened, one-sixteenth in. in length ; surface finely reticulated ; the scar la light-colored appendage at one end ; position Fig. 299. Winter Cress (Barbarea vulgaris). A, various forms of seeds. B, a seed in cross section. C, seeds, natural size. (After Hillman, Bull. Mich. Agr. Exp. Sta.) 448 WEED FLORA OP IOWA of caulicle marked by groove ; color light brown ; seed coats do not develop mucilage in water. Occasionally with clover. CAPPARIDACEAE, CAPER FAMILY. Rocky Mountain Bee-plant {Cleome serrulata Pursh.). E-oughly wedge-shaped to triangular in outline, and wedge- shaped in cross section; mature seeds of a grayish brown color, immature seeds a creamy yellow ; size 3 by 2.5 mm. ; basal scar ex- FiG. 300. Rocky Mountain Bee-plant (^Cleome serrulata). (Drawing by Ada Hayden.) tends from the edge of the wedge, well up on both flat faces ; tuost of the surface of the seed roughly tubercled. ROSACEAE, ROSE FAMILY. Silver Weed {Potentilla anserina L.). Seed pointed, egg-shaped, unsymmetrical, about 1.6 mm. in length ; color yellowish to brown ; surface furrowed throughout its length. Fig. 301. Silver V\^eed (.Potentilla anserina). (After Burchard. ) Cinquefoil {Potentilla canadensis L.). Seed small, about 0.5 mm. in length, short, oblicjuely egg-shaped ; light brown. THE GENERAL CHARACTERS OP SEEDS 449 Figure 302A Figure 302B Fig. 302. A. Cinquefoil (Potentilla canadensis). B, Five-finger (Potentilla mon- speliensis var. norvegica). A, two seeds (achenes), side view. B, a seed in edge view. C, group showing the natural size. (After Hillman; A, Bull. Mich. Agr. Exp. Sta. ; B, Bull. Nev. Agr. Exp. Sta.) Five Finger (Potentilla monspeliensis L. var. norvegica (L.) Rydb.). • Achenes small, ovate or kidney-sbaped, one-twenty-fourth in. in length, prominently ridged ; the ridges simple or branched, starting from base of seed ; color light brown or straw-colored. Frequently occurs in alsike clover and timothy, as well as in red clover. Avens (Geum canadense Jacq.). Achene pale greenish brown, length 3 mm., width 1% mm., gen- eral shape ovate, tapering to base, rounded at apex which bears persistent hooked style 5 mm. in length tipped with a hook ; achene slightly flattened, with a narrow ring along each edge. Figure 303A Figure 303B Fig. 303. A, Avens (.Geum canadense). B, Rose {Rosa pratincola) . (Drawings by C. M. King.) 29 450 WEED FLORA OP IOWA Prairie Rose {Bosa pratincola Greene). Achenes dark to light brown, smooth, shining; length 3-5 mm., width 2-3 mm., general shape ovoid, modified by some flattening of portions at the surface, and corresponding angulation of the seed's form; scar at broader end, with dark line extending to the apex which is tipped with a slight remnant of the style. LEGUMINOSAE, PULSE FAMILY. Rattlebox (Crotalaria sagittalis L.). Pod blackish, cylindrical, inflated, many seeded; seed greenish brown, shining, smooth, somewhat flattened, circular-kidney-shaped. Fig. .304. Rattlebox (Crotalaria sagittalis). (Drawing by Ada Hayden.) with one side interrupted by a deep rounded notch, bearing the conspicuous scar with dark center and light rim; width of seed 2.5 mm. White Clover {Trifolium repens L.). Seeds varying from nearly square to triangular, margins rounded, flattened, often concave on one margin, one-twentieth to one-thir- tieth in. long; smooth; color dull yellow to light reddish brown, or slightly green; radicle slender club-shaped, about as long as the cotyledons. Alsike Clover (Trifolium hyhridum L.). Seed more nearly round than that of alfalfa or red clover; one- twentieth to one-sixteenth in. in length; color a peculiar yellowish green, often brown and mottled, individual seeds even yellow or brown; the projecting radicle gives the seed the appearance of hav- ing a nearly square top. THE GENERAL CHARACTERS OF SEEDS 451 Figure 305A Figure 305C Figure 305D enlarged ; b, natural size. D Fig. 305. A. White Clover {Trifolium repens) B. Alsike Clover (TrifoUum hybridum) . a, enlarged; b, natural size. C. Red Clover (TrifoUum pratense). a, enlarged; b, natural size. Low Hop Clover {TrifoUum procumbens). a, enlarged; b, opposite face; c, flower ; d, seeds, natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) Red Clover {TrifoUum pratense L.). Seeds roughy triangular, with angles rounded ; no two sides equal length, sides somewhat convex with rounded edges, one-sixteenth to one-tenth in. long; color light yellow, purple, or of yellow and purple ; old seeds more brownish ; sear near radicle, which is not so prominent as in other clovers; the seeds of mammoth clover re- semble those of red clover but are usually larger. Low Hop Clover {TrifoUum procumtens L.). Seed light brown, shining, oval, length 1-1.3 mm., width 0.6 mm. ; scar in a notch a short distance from one end. Sweet Clover, Bokhara Clover {MeUlotus alba Desv.). Seeds contained in an ovoid pod, one-twelfth to one-fifteenth in. long, reticulated, nearly smooth, elliptical, somewhat triangular, variable ; color yellowish to greenish, scar brown in color ; mieropi- lar processes near scar, not conspicuous. Found in seeds of alfalfa and clover. 452 WEED FLORA OF IOWA Fig. 306. White Sweet Clover (Melilotus alba). A, a group of seeds. B, the pods ; the central one without the calyx. C, the embryo. D, a group of seeds and pods, natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) Yellow Sweet Clover {Melilotus officinalis (L.) Lam.). Pods one-seventh in. in length ; rugose, more evenly transversely wrinkled than in M. alba; seeds subspherical or elliptical to kidney- \i^' Fig. 307. Yellow Sweet Clover (^Melilotus officinalis). A, seeds. B, pods; the one at the right without the calyx, and showing the contracted base. C, a view of a seed in cross section, showing cotyledons and caulicle. D, a group of seeds and pods, natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) shaped, one-twelfth to one-tenth in. in length, smooth ; yellowish or brownish to greenish; mth small micropilar processes. Bur Clover {Medicago hispida Gaertn.). Seeds kidney-shaped, occasionally sausage-shaped, both sides con- vex, one-sixth in. in length, larger than alfalfa, variable in size ; color lighter than in alfalfa seed; scar about middle of seed, close to prominent micropilar processes ; pods large, spirally twisted into several flat coils, covered by pointed projections; the prickles either straight or curved ; each pod several-seeded ; seeds have general re- semblance to 'alfalfa seed in form and color. THE GENERAL CHARACTERS OF SEEDS 453 ItfC Fig. 308. Bur Clover (Medicago hispida). A, seed; B, pod. (Drawings by Ada Hayden and L. R. Collins.) Yellow Trefoil {Medicago lupuUna L.). Seeds kidney to egg-shaped, much shorter than bur clover seed, one-twelfth to one-tenth in, long; about the size of alfalfa, which it closely resembles ; color yellowish, reddish, or greenish ; scar near Fig. 309. Yellow Trefoil (Medicago hipulina). A, seeds showing the prevail- ing forms. B, pods ; the central one with the calyx removed ; the one at the left an immature, lighter colored specimen. C, a view of a seed in cross section, showing cotyledons and caulicle. D, the embryo. E, seeds and pods, natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) one end; micropilar processes prominent; the pods clustered at the end of the peduncle small, black, wrinkled, and coiled at tip, marked by prominent veins and hairs; each pod contains one seed. Dalea {Dalea alopecuroides Willd.). Seeds triangular to kidney-shaped, one-tenth in. in length ; mi- cropilar scar prominent, with whitish border and 2 micropilar processes; surface shining, slate-colored. Found in clover seed, from which it is separated with difficulty. 454 WEED FLORA OF IOWA Figure 810A Figure 310B Figure 310C Fig. 310. A, Dalea (Dalea alopecuroides) . B, seed of Pink Dalea (Dalea laxiflora). C, seed-pod of the same species. (A, drawing by L,. R. Collins; B and C, by C. M. King.) Pink Dalea {Dalea laxiflora Pursh..), Seeds one-tenth in. in length, generally triangular, somewhat kidney-shaped, one end projecting beyond sac, which is circular and has two micropilar processes on one side ; yellowish or brownisk in color ; leaves have pellucid dots. This should enable one to recog- nize the impurity. Occasionally found in clover seed. Stemless Loco Weed {Oxytropis lamberti Pursh.). Pods coriaceous, silky pubescent, cylindrical; seed flattened, brown, about 2 mm. broad and 2.5 mm. long. Figure 311A Figure 311B Figure 311C Fig. 311. A, Stemless Loco Weed (Oxytropis lamberti). B, Bush Clover {Lespedeza capitata), pod and seed. (Drawings A, by Ada Hayden ; B, by Charlotte M. King.) Bush Clover {Lespedeza capitata Michx.). Pod ovate-oblong, one-sixth in. in length, sessile, 1-ovuled, pu- bescent, brownish, reticulated, indehiscent, seed scarcely kidney- shaped, one-tenth in. in length, greenish to purplish. THE GENERAL CHARACTERS OF SEEDS 455 Common Vetch. {Vicia sativa L.). Pod linear, several-seeded; seeds nearly spherical or compressed on the sides, variable, blackish to brownish. Fig. 312. Common Vetch (.Vicia sativa). (After Hillman, Circular U. S. Dept. Agr.) Hairy Vetch {Vicia villosa Roth.). Seeds spherical to subspherical ; one-tenth to one-sixth in. in diam- eter; blackish or brownish, surface smooth; scar elongated, repre- FiG. 313. Hairy Vetch {Vicia villosa). (Hillman, U. S. Dept. of Agriculture.) sented by a narrow line slightly elevated, with depressed center, light in color, brownish to straw-colored. Trailing Wild Bean {Strophostyles helvola (L.) Britton). Pod terete, 5-7.5 cm. long, nearly glabrous, 4-8-seeded, dark brown; seed cylindrical, rounded, truncate at both ends; length 6 mm., width 4.5 mm. ; color dull brown slightly mottled ; narrow white scar along inner angle, nearly the entire length of the seed; seed strongly angled longitudinally on side opposite scar. Fig. 314. V^ild Bean (.Strophostyles helvola). (Drawing by L. R. Collins.) 456 WEED FLORA OF IOWA LINACEAE, FLAX FAMILY. Common Flax {Linum usitatissimum L.). Seeds ovate, flattened, one-fifth in. long, one-tenth in. wide, basal end curved on one side; color brown, margins with whitish luster, Em Figure 315A Figure 315 B Fig. 315. Common Flax (Linum usitatissimum). A, seed. B, cross section of seed. (A, drawing by Ada Hayden ; B, after Winton.) smooth, shining; scar on one side, near lower end, small, incon- spicuous; embryo, large, straight. OXALIDACEAE, SORREL FAMILY. Lady's Sorrel {Oxalis corniculata L.). Pod prismatic, cylindrical, seeds 1 mm. in length ; shape and markings similar to preceding. Oxalis {Oxalis stricta L.). Pod angled, awl-shaped ; seeds 1 mm. in length, elliptical, pointed at one end ; surface marked by broken transverse lines of white ; seed longitudinally ribbed, slightly flattened. THE GENERAL CHARACTERS OF SEEDS 457 Figure 316A Figure 316B Figure 316B Fig. 316. A, Storksbill or Alfilaria (.Erodium cicutarium) ; A, a seed-vessel with a portion of its spirally coiled awn. B, a seed-vessel and its awn, natural size. (In many the awn is smaller.) C, a seed, magnified. D, a line showing the length of the seed. E, the embryo removed from the seed coats, the parts spread. B. Lady's Sorrel or Yellow Field Sorrel (Oxalis corniculata) . (A, after Hillman, Bull. Mich. Agr. Exp. Sta. ; B, drawings by C. M. King.) GERANIACEAE, GERANIUM FAMILY. Storksbill {Erodium cicutarium L'Her.). Lobes of capsule 1-seeded, with elastic, dehiscent style, coiled at maturity, villous inside ; hairs at base pointing obliquely upwardly ; awn coiled for half its length; seed broadly club-shaped, one-fifth in. in length without awn; soar removed one-third length of seed from base; groove from scar to tip of seed. EUPHORBIACEAE, SPURGE FAMILY. Three-seeded Mercury {AcalypJia virginica L.). Seeds ovoid; one-twelfth to one-twentieth in. long; reddish, min- utely striate, line running from apex to base; soar at smaller end. Found in clover seed. b ^' Figure 317B Fig. 317. A. Three-seeded Mercury (Acalypha virginica). a and b, different views of seed ; c, sectional view showing embryo and endosperm ; d, seed, natural size. B. Prostrate Spurge or Milk Spurge (EupJwrMa maculata) . A. Different views of seed. B. Seeds, natural size. (After Hillman, Bull. Mich. Agr. Exp. Sta.) 458 WEED FLORA OF IOWA Upright Spurge {Euphorbia preslii Guss.). Seeds lead-colored, obovoid-oblong, with 4 unequal sides ; surface pitted and transversely wrinkled; a narrow dark raphe along one edge; length 1-1.3 mm. ''h Fig. 318. Seeds of Spotted Spurge (Euphorbia preslii). A and B, different views of seed. D. Fruit. E. Seed, natural size. (After Hillman, Bull. Mich. Agr. Exp. Sta.) Flowering Spurge {Euphorbia corollafa L.). Seeds ovoid, one-tenth in. in length, smooth, brownish, a line extending from apex to base on one side, with whitish bordered depression at base ; apical point on larger end ; seed coat mucilagin- ous. Figure 319A Figure 319B Fig. 319. A. Flowering Spurge CEuphoriia corollata.) B.. Snow-on-the-Mountain (Euphorbia marginata) . (Drawing by Ada Hayden.) Milk Purslane {Euphorbia maculata It.). Seeds ovoid or oblong, obtusely angled, one-twentieth in. in length, minutely pitted and transversely wrinkled ; grayish. Snow-on-the-mountain {Euphorbia marginata Pursh,). Seed ovoid, slightly flattened at apical end, length 4 mm., width 3 mm.; color light brown; surface roughly tuberculate; one side marked by a dark longitudinal line. THE GENERAL CHARACTERS OF SEEDS 459 MALVACEAE, MALLOW FAMILY. Velvet-leaf, Butterprint (Abutilon theophrasti Medic). Carpels 2-valved, beaked, each usually 2-seeded; seeds somewhat triangular, kidney-shaped, one-eighth in. in length, minutely granu- lar and pubescent ; color blackish gray ; f unicle extending to notch of seed. May occur in small grain. Figure 320A Figure 320B Fig. 320. A. Indian Mallow or Butterprint (Abutilon theophrasti). a, b, c, different views of seed ; d, cross section showing embryo and caulicle ;, e, seeds, natural size. B. Seeds of Bladder Ketmia. a and b, different views, c, natural size. (After Hillman. Bull. Mich. Agr. Exp. Sta.) Prickly Sida {Sida spinosa L.). Seeds oval, one-sixteenth to one-twelfth in. long, one face eon- vex, the other with a prominent ridge across its length; scar at broad end ; surface dull, smooth ; color brownish. Reported in seed of Missouri red clover. Fig. 321. Prickly Sida (Sida spinosa). A, different views of seeds. B, a seed in section taken midway between the two extremities, showing embryo and caulicle. C, seeds, natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) 460 WEED FLORA OF IOWA Common Mallow {Malva rotundifolia L.). Commonly called cheeses. Carpels arranged about a center, flat, beakless, indehiscent; each carpel a single seed, kidney- shaped, one- sixteenth to one-twelfth in. in diameter, flattened, with a prominent Fig. 322. Common Mallow (Malva rotundifolia). A, two seeds in side view. B, a seed retained by a carpel of the seed-vessel. C, a seed in cross section taken midway between the scar and the opposite edge. D, seeds, showing the natural size. (After Hillman, Bull. Mich. Agr. Exp. Sta.) notch at base; seeds brownish or gray, minutely granular; sear small, frequently containing spongy tissue; embryo curved; small amount of endosperm. Reported in alfalfa and red clover seed. Bladder Ketmia {Hibiscus trionum L.). C'apsule 5-valved, globose-ovoid, hairy ; seeds kidney-shaped, one- fifteenth in. in length, blackened, roughened by short tubercular processes, minutely granular; basal end of seed of much smaller diameter ; scar brownish ; funicle extending to the notch. ONAGRACEAE, EVENING PRIMROSE FAMILY. Evening Primrose {Oenothera biennis L.). Seeds prismatic, 4 or 5-sided, sometimes curved, variable, one- sixteenth in. in length, slightly "wing-margined, rugose, brown, scar indistinct at one end, embryo straight. UMBELLIFERAE, PARSLEY FAMILY. Water Hemlock {Cicuta macidata L.). Fruit ovate to oval, curved or nearly straight, one-eighth in. in length, smooth, with longitudinal brown and straw-colored lines; apex widened with 2 styles; ribs corky; oil-tubes solitary, in the intervals. THE GENERAL CHARACTERS OF SEEDS 461 Figure 323A Figure 323B Fig. 323. A. Evening Printirose (Oenothera biennis). A, different views of seed. B, cross section of seed. C, natural size. B. Water Hemlock (Cicuta maculata) . (After Hillman, Bull. Mich. Agr. Exp. Sta.) Wild Parsnip {Pastinaca sativa L.). "Seeds", carpels one-quarter in. in length, thin, circular or oblong; color light or dull yellowish brown; lighter conspicuous margin, ribs brownish or reddish ; apex notched, with a conspicuous remnant of the style; oil tubes four, alternating with the ribs; inner face concave, with a central longitudinal ridge and one oil- tube on each side. "Wild Carrot {Daucus carota L.). Fruit one-eighth in. long, oblong, flattened dorsally; carpel with 5 slender, bristly, primary ribs bearing numerous spines, and 4 secondary wings; color whitish yellow; oil tubes one under each row of spines, and two between the ridges of the inner face; seeds commonly found with spines broken off. In alfalfa and clover seeds. 462 WEED FLORA OF IOWA Figure 324A IffC. Figure 324 A' § % Figure 324B Fig. 324. A and Al. Wild Parsnip (Pastinaca sativa). B. Wild Carrot (Daucus carota). A, the outer (at left) and inner (at right) faces of a seed (carpel). The spines occupy the margin and two rows along the outer face. The slender, hairy ridges alternate with the rows of spines. The Inner face bears two, separated by a slender ridge or line which is not hairy. B, an oblique view of the outer face of a seed found with clover seed. C and D, views of the inner face of seeds similarly found. E, seeds, natural size. (A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; Al, drawing by L. R. Collins; B, after Hillman.) ASCLEPIADACEAE, MILKWEED FAMILY. Swamp Milkweed {Asclepias incarnata L.). Seeds oval, wing-margined, three-tenths in. in length ; surface less prominently veined than in A. syriaca; raphe marked by distinct ridge ; coma attached to smaller end of fine silky hairs. Probably never in commercial seed. Common Milkweed {Asclepias syriaca). Seeds flattened, oval or elliptical, apical end truncate, three- tenths in. in length, wing-margined; seed and wing distinctly veined ; the raphe occurs in form of a distinct ridge on inner face of seed ; coma a tuft of silky hairs attached to apical end, easily sepa- rated from seed. Not apt to be found in commercial seed. li THE GENERAL CHARACTERS OF SEEDS 463 '¥• Figure 325A Figure 325B Figure 325C Figure 325D Fig. 325. A. Swamp Milkweed (Asclepias incarnata}. B. Common Milkweed (Asclepias syriaca}. a, b, different views of seed; c, cross section; d, e, natural size. C. Butterfly Weed {Asclepias iuherosa). D. Whorled Milkweed {Asclepias verticillata) . (A, drawing by L. R. Collins; B, after Hillman ; C, D, by C. M, King.) Butterfly Weed {Asclepias tuberosa L.). Seed ovate or eliptieal, three-tenths in. in length ; surface rough- ened by ridges on both back and inner faces; winged margin, lighter brown than middle part of seed ; raphe marked by a distinct ridge; coma fine, silky, smooth. Whorled Milkweed {Asclepias verticillata L.). Seeds ovate, one-sixth in. in length, margin distinct, lighter in color than the rest of the reddish brown seed; surface veined, but not ridged or roughened; raphe a distinct ridge on inner face; coma soft, silky ; very smooth. CONVOLVULACEAE, CONVOLVULUS FAMILY. Common Morning-glory {Ipomoea purpurea (L.) K-oth.). Seed dark brown, with one convex side opposite to 2 flattened faces meeting at an angle, length 5 mm., width 4 mm. at the base of the seed; at lower end of the angle between the two flattened faces is the scar, also dark brown ; surface dull, finely roughened. Small Bindweed {Convolvulus arvensis L.). Seeds large, oval, one side convex, the other side with a broad ridge ; one-sixth in. long, a depression at one extremity representing the scar ; surface of seed roughened, dark brown in color ; embryo large, surrounded by the fleshy endosperm. Found in cereal grains. 464 WEED FLORA OF IOWA c --^ d Figure 326B Figure 3260 Fig. 326. A. Common Morning-glory (.Ipomoea purpurea). B. Small Bind- weed {Convolvulus arvensis). a, b, different faces of seed, c, cross section, d, natural size. C. Wild Morning-glory (.Convolvulus sepium). a, b, dif- ferent faces of seed, c, natural size. (A, drawing by Charlotte M. King; B and C, after Hillman.) Wild Morning-glory {Convolvulus sepium L.). The outer surface rounded ; inner face with prominent ridge and a depression on each side ; seed one-quarter in. long ; smooth, brown- ish or blackish, with minute projections over the surface; hilum prominent, light brown, in semicircular depression. Field Dodder {Cuscuta arvensis Beyrich.). Capsule globose, indehiscent; seed spherical to kidney-shaped, or ovate, occasionally with prominent angles; one-twenty-fourth to one-sixteenth in. long; roughened but not pitted, dull yellowish^ grayish or light brown; scar at one extremity, frequently elevated and prominent ; Mr. Hillman finds field dodder seeds usually lighter than those of Chilean dodder; in some samples the Chilean dodder seeds are the lighter in color. Appears in clover seed, in many cases abundantly. » /2 Fig. 327. Field Dodder (Cuscuta arvensis). (A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; B, drawing by C. M. King.) THE GENERAL CHARACTERS OF SEEDS 465 Clover Dodder {Ciiscuta epithymwm Murr.). Seed spherical or subspherieal, one-thirtieth to one-twenty-fourth in. in diameter ; surface roughened, with appearance of sponginess, dull, usually ashy, yellowish to light or dark brown, or purplish; embryo coiled, without cotyledons, consisting of slender tapering Fig. 328. Clover Dodder (.Cuscuta epithyinum) . A, a group showing various forms and views of seeds. B and C, seeds having the scurfy appearance. T> and E show tlie angled, scar-bearing face, E, being one of the light- colored, sterile seeds. F, a torn, dried flower having the seed-vessel intact. G, the embryo. H, group of seeds showing the natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) body, with caulicle and radicle embedded in fleshy endosperm. Commonly distributed in seed of clovers and alfalfa. Brown and Hillman state that this dodder is almost entirely confined to Euro- pean grown seed, since the plant does not generally produce seed in this country. Chilean Dodder {Cuscuta sp.) Seeds spherical to subspherieal or oval, inclined to be more angu- lar than the preceding species, flattened on one side, one-seventeenth to one-fifteenth in. in diameter, about the size of large field dodder seeds; dull brownish, minutely roughened; scar prominent, at end of flattened surface, lighter in color than rest of seed. Found in both clover and alfalfa seed, from which it is screened with dif- ficulty. Fig. 329. Chilean Dodder (Cuscuta chilensis). (Drawing after Burchard.) 30 466 WEED FLORA OF IOWA BORAGINACEAE, BORAGE FAMILY. Common Hound's Tongue (Cynoglossum officinale L.). Ovary dividing into 4 achenes, each 5-7 mm. in length, ovate to round, flattened; lower side bearing large ovate scar; surface cov- ered with straight, stiff, barbed prickles. Fig. 330. Common Hound's Tongue (Cynoglossum officinale), a, b, views of different faces of seed ; c, natural size. (After Hillman, Bull. Mich. Agr. Exp. Sta.) Wild Comfrey {Cynoglossum boreale Femald.). Nutlets convex on the upper face, somewhat triangular, one- seventh in. in diameter, bearing short barbed prickles on convex surface; color brown. Fig. 331. W^ild Comfrey (Cynoglossum boreale). (Drawing by Ada Hayden.) Stiekseed {Lappula ecliinata Gilibert). Ovary separating into 4 achenes, 2.5 mm. long, slightly flattened from ovate, under surface tuberculate, bearing straight ridge from point to middle ; on the upper side, the margins bear a double row of slender barbed prickles. Beggar's Lice {Lappula virginiana (L.) Greene). Achenes 3 mm. long, borne in clusters of 4, broadly ovate, flat- tened on outer side; the outer surface bearing short stiff barbed prickles, the inner side cone shaped, free from hairs, and bearing a triangular scar. THE GENERAL CHARACTERS OF SEEDS 467 y h^- 4i^ Si Figure 332B Figure 332A Fig. 332. A. Stickseed {Lappula echinata). a, b, views of different faces of seed ; c, natural size. B. Beggar's Lice (Lappula virginiana). a, b, views of different faces of seed; c, natural size. (After Hillman, Bull. Mich. Agr. Exp. Sta.) Narrow-leaved Puecoon {LitJiospermum angustifolnim Michx.). Nutlets ovoid, keeled on inner face, one-eighth in. long; surface smooth, shining, pitted ; color white to yellowish white ; base irreg- ular with projecting margin; bearing base with projecting ridges. Fig. 333A Fig. 333B Fig. 333. A. Narrow-leaved Puecoon (.Lithospermum angustifolium). B. American Grpmwell (Lithospermum latifoUum). (Drawings by L. R. Collins). American Gromwell (Lithospermimi latifoUum Michx.). Nutlets ovoid to globose, one-sixth in. in diameter, white, shining ; glabrous but prominently pitted; base oblique. Com Gromwell {Lithospermum arvense L.). Ovoid nutlets 4 or fewer, convex on back, inner face with distinct ridge ; one-sixteenth to one-twelfth in. in length ; color from whitish to dark brown, surface glabrous, but wrinkled and pitted; base obliquely flattened, bearing the scar. Eeported to occur with grain seed. 468 WEED FLORA OF IOWA Figure 334A Fitrure 8o4B Fig. 334. A, Corn Gromwell (LitJwspermum arvense). A, different views of nutlets, B, one bearing the flower-receptacle and portion of the stem, C, the natural size of the larger nutlets. B, Viper's Bugloss (.Echium vulgare) . (A, after Hillman, Bull. Mich. Agr. Exp. Sta. ; B, drawn by L. R. Collins.) Viper's Bugloss {Echium vulgare L.). Nutlets erect, ovoid, one-eleventh in. in length, back distinctly convex; seed straight or curved; outer face with distinct ridge; surface rugose ; color white, base flattened. VERBENACEAE, VERVAIN FAMILY. Large-bracted Vervain {Verbena bracteosa Mx.). Nutlets cylindrical, 3-sided, outer face convex, one-tenth in. in length, outer face rugose at upper end, lower end marked by lines, inner face pitted, scar somewhat elevated, whitish. In seeds of clovers and grasses. ,^«te ^m^, fSV Figure 335A Figure 335B Fig. 335. A. Large-bracted Vervain {Verbena bracteosa). B. Blue Vervain (Verbena hastata). A, the outer face, and B, the inner face of a nutlet; the latter shows the whitish, spongy scar at the base. C, a group showing the natural size. D, a section of a nutlet, talven lengthwise. (A, drawing by C. M. King; B, after Hillman, Bull. Nev. Agr. Exp. Sta.) THE GENERAL CHARACTERS OF SEEDS 469 • Blue Vervain (Verbena^ hastata L.). Nutlets 3-sided, with a distinct line of separation, back convex, rugose, inner face 2-sided ; one-fifteenth to one-thirteenth in. long ; color light brown; scar slightly elevated, whitish, at base of nut- let. Often found in seed of clover. Hoary Vervain {Verbena strict a Vent.). Nutlets cylindrical, 3-sided, one-eighth in. in length, outer face convex, back with 4 prominent veins, upper portion slightly pitted ; color dark brown; whitish scar at base. Seed found in clover. Figure 336B C Fig. 336. A. Hoary Vervain {Yerhena strictd). B. White Vervain {Verbena urticaefolia) . (A, drawing by L. R. Collins; B, after Hillman, Bull. Mich. Agr. Exp. Sta.) White Vervain (Verbena urticaefolia L.). Nutlets cylindrical, convex on back, 2-faced on inner side, with prominent central line ; one-tenth to one-eighth in. in length ; back somewhat rugose, with 2 or 3 prominent lines extending from base to apex and some cross lines ; inner face somewhat granular ; scar a whitish elevated point. Found in seeds of clovers. LABIATAE, MINT FAMILY. Catnip (Nepeta cataria L.). Oval, dark brown seeds, about 1.5 mm. in length, slightly flat- tened, surface smooth ; one face bears a broad central, longitudinal ridge, the base of which is marked by two white characteristic spots, which are a part of the scar. American Germander {Teucrium canadense L.). Nutlets obovoid, one-tenth in. in length, outer surface convex; color brown ; surface prominently rugose, reticulated except the scar at the lower end. Common in commercial seed. 470 WEED FLORA OF IOWA • ^ % % Figure 337A Figure 337B Fig. 337. A. Catnip (Nepeta cataria). A, views of various seeds (nutlets), three showing the scar-marking. B, one having the nutlet wall partially broken away, exposing the seed proper. C, a nutlet in longitudinal section, showing the embryo. D, group showing the natural size. B. American Germander (.Teucrium canadense). (A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; B, drawn by L. R. Collins.) Horekound (Marruiium vulgar e L.). Seed ovate, one side convex, flattened side divided into 2 faces by strong central ridge ; one-twelfth of an inch in length ; brownish Figure 338B Fig. 338. A. Giant Hyssop {Agastache scrophulariaefoUa). B. Common Horehound (.Marrubium vulgare) ; a, angled face; b, convex face; c, longitudinal section ; d, transverse section ; e, natural size of seed. (A, drawing by L. R. Collins; B, after Hillman, Mich. Agr. Exp. Sta.) or blackish, with straw-colored markings; scar inconspicuous, in a slight depression somewhat paler in color than seed. Self-heal {Prunella vulgaris L.). Nutlets ovoid, faces convex, marked by longitudinal grooves; one-twelfth of an inch in length; smooth, shining; color brown; small bud marked by white, scar appendage. Found in red clover. Motherwort (Leonurus cardiaca L.). Nutlets 3-sided, occasionally flattened, 1.10 in. long, smooth ex- cept upper end, which is papillose; minutely roughened; straw- colored to brownish. Found in cultivated grass seed. THE GENERAL CHARACTERS OF SEEDS 471 Figure 339A a b Figure 339B j'ls. 339. A. Self-heal (Prunella vulgaris). A, a group of seeds, enlarged, the lower left-hand one with the scar-appendage broken away ; the upper left- hand one showing the outer face. B, a group showing the natural size ; C, a longitudinal section of a seed, showing the embryo. E Motherwort (.Leonurus cardiaca). a and b, different views of seed, c, seed, natural size. (After Hillman, A, "Bull. Nev. Agr. Exp. Sta. ; B, Bull. Mich. Agr. Exp. Sta.) SOLANACEAE, NIGHTSHADE FAMILY. Horse Nettle {Solanwm carolinense L.). Berry orange-yellow, 1.6 to 2 cm. in diameter; seeds pale dull yellow, much flattened, obovate, 2 to 3 mm. in length ; finely granu- lar, or indented over whole surface. Black Nightshade {Solanum nigrum L.). Berries black, globular, smooth; seed asymmetrically ovate, flat- tened, pale yellowish brown, finely granular; diameter about 1.5 mm. Buffalo Bur (Solatium rostratum Dunal.). Black berry enclosed in spiny yellow calyx ; seeds nearly circular, bearing a dent on one side of the margin; flattened, pitted on the surface ; both sides irregularly indented with depressions ; color, dull dark brown; seed about 2.5 mm. broad. Jimson Weed (Datura stramonium L.), Seed one-eighth in. in length, brownish or blackish, kidney-shaped, elliptical or nearly spherical, with numerous large depressions and smaller pits; hilum with a small depression. 472 WEED FLORA OF IOWA Figure 340A Figure 340B Figure 340C Figure 340D Fig. 340. A. Horse Nettle (Solanmn carolinense). a, b, c and d, different views of seed ; e, fruit. B. Black Nightshade (Solanum nigrum), a, two seeds, side view, enlarged; b, group showing the natural size ; c, a section of a seed, parallel with the faces, showing the spirally curved embryo imbedded In the endosperm. C. Buffalo Bur (Solanum rostratum). a, prickly calyx; b, seeds with pits; c, seed, natural size ; d, cross section of seed with embryo. D. Jimson Weed (Datura stramonium), a and b, seeds from different views; between a and b, seeds, natural size ; c, cross section of seed showing embryo. (After Hillman, A, C, D, Mich. Agr. Exp. Sta. Bull; B, Bull. Nev. Agr. Exp. Sta.) SCROPHULARIACEAE, FIGWORT FAMILY. Moth Mullein {Verhascum hlaUaria L.). Seeds light to dark brown, 0.5 to 1 mm. in length, prismatic, 6-sided, base truncate, broader than the rounded apex ; each side face pitted in longitudinal rows. Mullein {Ver'bascum thapsiis L.). Seeds columnar, 4-6-sided, top usually truncate, base nearly so ; one-thirtieth in. in length ; faces deeply transversely pitted ; surface dull; color brown; scar in middle of flattened base. Reported as frequently found in seeds of timothy and similar grasses. THE GENERAL CHARACTERS OF SEEDS 473 Figure 341A Figure 341B Figure 341C Fig. 341. A. Moth Mullein (Verbascum Mattaria). A, a group of seeds, en- larged, showing different forms, and kinds of surface markings, a, b and c were produced from seeds of V. l>lattaria, and d from Y. thavsus. B rep- resents a group natural size. C, a section taken lengthwise through the center of a seed, showing the embryo and surrounding endosperm. B. Common Mullein iVerbascum thapsus\. C. Toad Flax (Linaria vulgaris). A, a side view of a seed much enlarged, tiie scar within the notch on the upper right-hand margin. B, a group show- ing the natural size. C, a section through the center of a seed showing the embryo. (A, after Hillman, Bull. Mich. Agr. Exp. Sta^ ; B, drawing by L. R. Collins ; C, after Hillman, Bull. Mich. Agr. Exp. Sta.) Toad-flax {Linaria vulgaris Hill.). Seeds flattened, wing-margined, orbicular in outline, wing wavy, notched at one end; one-twelfth in. in diameter; surface rugose; wings one-thirtieth to one-twenty-fifth in. wide; embryo slender, curved. Commonly occurs in grass seed and occasionally in clover. Speedwell {Veronica peregrina L.). Seeds oblong to egg-shaped, flattened, one-thirty-second to one- thirtieth in. long, slightly curved, the outer face with a central ridge; embryo straight, surrounded by the endosperm; raphe on the inner face; sear projecting. 474 WEED FLORA OF IOWA Fig. 342. Speedwell (Vernonia peregrina). a, b, d, different views of seeds; c, seeds, natural size. (After Hillman, Mich. Agr. Exp. Sta.) PLANTAGINACEAE, PLANTAIN FAMILY. Bracted Flantain '{Plantago aristata Mx.). Seeds oval or oblong, back of seed convex with, transverse ring across the middle or nearly so, one-twelfth to one-eighth in. long; inner face with white marginal ring, in center of inner face 2 pit- like markings each surrounded by whitish area, giving appearance of 2 rings, or 2 links of a chain. Figure 343B Figure 343 A ■ y Figure 343C Fig. 343. Bracted Plantain {Plantago aristata). A, group of seeds. B and C, the convex and grooved faces, respectively. (A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; B and C, drawings by Char- lotte M. King.) THE GENERAL, CHARACTERS OF SEEDS Ribgrass, Buckhorn {Plantago lanoeolata L.). 475 Seeds oblong, convex on back, one-twelfth to one-seventh in. in length, edges folded inwardly to deep central longitudinal groove Fig. 344. Buckhorn (Plantago lanceolata) . A and B, group of seeds showing both the convex and grooved faces. C, a sterile seed. D, a seed in crosB section. B, seed showing the mucilage. F, the natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) on inner face; brown, smooth, shining; scar at center of groove frequently of dark color. Dooryard Plantain (Plantago major L,). Seeds oblong to trapezoidal in shape, usually 4-sided, some of them 3-sided, one-twenty-second to one-sixteenth in. long; brown- ish to black ; surface bearing 5 ridges radiating from scar ; scar on middle of inner face, often with white markings. Bugel's Plantain (Plantago rugelii Dene.). Seeds oblong, rhomboidal, generally trapezoidal with flattened edges, one-eighteenth to one-twelfth in. in length ; color brownish to black ; surface minutely roughened, ridgelike markings absent ; scar circular, whitish. 476 WEED FLORA OF IOWA Figure 345A Figure 345B Fig. 345. A. Common Plantain {Plantago major}, a, a group of seeds, en- larged, showing the relative form and size, also the surface ridges as dark lines ; b, a group showing the natural size ; c, a cross section of a seed. B. Plantago rugelii. A, ^eeds, the upper two showing the scar. B, seed show- ing the mucilage. C, a seed-vessel. D, seeds, natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) RUBIACEAE, MADDER FAMILY. Cleavers {Galium aparine L.). Fruit indehiscent, spherical, one-tenth to one-eighth in. in diam- eter, roughened with prickles, tuberculate when prickles are rubbed off ; color blackish ; embryo curved ; endosperm horny ; fruit covered with hooked trichomes. Fig. 346. Cleavers, or Bedstraw (Galium aparine). (After Winton.) THE GENERAL CHARACTERS OF SEEDS 477 COMPOSITAE, COMPOSITE FAMILY. Baldwin's Ironweed {Vernonia haldwini Torr.). Achenes practically indistinguishable from those of the follow- ing species. Figure 347A Figure 347B Fig. 347. Ironweed seeds. A. Vernonia fasciculata. B- Vernonia baldwini. Achenes with pappus. (Drawings Charlotte M. King.) Ironweed (Vernoma fasciculata Mx.). Achenes 3-3.5 mm. long, and 1 mm. broad; general form slender, cylindrical, often slightly curved; strongly 9-10-ribbed, ribs of same color as achene, pale brown ; tuft of purplish brown pappus bristles attached at larger end; length of pappus hairs 6 mm. "White Snakeroot {Eupatorium urticae folium Reichard). Achene long, 5-angled, prominently grooved between the angles oue-twelfth to one-tenth inch; generally blackish except at the base where it is yellowish; the scar at base with a small circular opening, and whitish border; smoothish (see figure), pappus of fine white capillary bristles ; the upper part of beak expanded into candelabra form, bearing the somewhat fragile pappus. Joe-Pye Weed (Eupatoriuni purpureum L.). Achenes smooth, prominently ribbed ; 5-angled, truncate ; about one-eighth of an inch long ; base white ; pappus with numerous tawny-colored, capillary bristles. Miss Mary Nichols, who studied the achenial hairs of E. villosum, finds that they are short with lateral canals. The achenial hairs of E. purpureum, according to Mr. Fracker, are simple, in E. villosum duplex. 478 WEED FLORA OF IOWA Figure 348B Figure 348C Figure 348A Fig. 348. Seeds of Snakeroot (.Eupatorium urticaefoUum) and Joe-Pyeweed {Eupatorium purpureum). A. Eupatorium purpureum. B. Achenial hairs of same. C Eupatorium urticaefoUum. (A and C, drawings by Ada Hay den ; B, drawing by S. B. Fracker.) Figure 349 1 Figure 349 2 Fig. 349. 1. Hairs from achenium of Eupatorium villosum. achenium of Eupatorium, urticaefoUum. (Drawings by S. B. Fracker.) Surface of ■ False Boneset {Euhnia eupatorioides L.). Achenes oblong, columnar, 10-15-ribbed ; blackish or reddish, base with prominent disklike area marked by circular, somewhat bulging ring; from one-eighth to one-tenth inch in length; pappus of fine tawny colored capillary, somewhat brittle, bristles. The achenial hairs of Euhnia eupatorioides, according to Miss Mary A. Nichols, are mostly simple and short ; a few duplex hairs also occur. Blazing-star {Liatris punctata Hook.), Achenes 10-ribbed; slender, tapering to the base; one-quarter to one-third inch long ; grayish, pubescent, almost pilose ; apex brownish; scar at base indistinct; pappus or numerous plumose" bristles. The achenial hairs of Liatris gracilis, according to Miss Nichols, are duplex with an indistinct wall arising from the base. The hairs of L. punctata, , according to Mr. Fracker, are duplex and simple. THE GENERAL CHARACTERS OF SEEDS 479 Figure 350A Figure 350B Fig. 350. Seeds (achenes) of: A. Blazing Star iLiatris punctata). B. False Boneset (.Kuhnia eupatorioides) . (Drawings by Ada Hayden.) ■ Figure 351A Figure 351B Fig. 351, Achenial hairs of: A. Kuhnia eupatorioides. B. Liatris punctata. (Drawings by Fracker.) Broad-leaved Gum-plant {Orindelia squarrosa Dunal). Achenes short, thickened, faintly 4-angled, with veins between the angles ; curved ; one-twelfth to one-eighth of an inch in length ; straw-colored; apex truncate; base with light scar. The related Bigelovia nudaia, according to Mr. Fracker, has duplex hairs. Canadian Goldenrod {Solidago canadensis L.). Achenes minute, nearly terete, obovate, many-ribbed; brownish or greenish, somewhat pubescent ; pappus of numerous fine capillary equal bristles. 480 WEED FLORA OF IOWA Figure 35zA Pig. 352B Figure 352C Fig. 352D Fig. 352. Seeds (achenes) of: A. Gum "Weed (.Grindelia squarrosa), enlarged and natural size. The one at the top shows the wrinkled appearance of the corky-thickened angles. B, Canadian Goldenrod iSolidago canadensis). C, Stiff Goldenrod {SoUdago rigida). D, Late Goldenrod (^Solidago serotina). (A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; C, drawing by Charlotte M. King; B and D, drawings by Ada Hayden). Stiff Goldenrod {SoUdago rigida L.). Achenes ribbed, somewhat 4-angled, with minute ribs between the angles; scar at base small, whitish, one-sixth to one-twelfth in. long, pale straw-colored; pappus of minute capillary bristles of nearly equal size, spreading. Late Goldenrod {SoUdago serotina Ait.). Achenes minute, somewhat teretish, many-ribbed, minutely pu- bescent, straw-colored, one-twentieth in. in length; small obovoid scar at base, whitish; pappus spreading, of fine white capillary bristles. THE GENERAL CHARACTERS OP SEEDS 481 Willow-leaved Aster {Aster salicifolius Ait.) . Achene slender, pale brown, about 1.5 mm. long and .25 mm. broad ; 5 longitudinal ribs at angles of seed ; pappus straw-colored, hairs or bristles 6 mm. in length. The aehenial trichomes are long, the duplex character very pronounced, according to Mr. Fracker. Fig. 353A rig. 353B Fig. 353C Fig. 353. Seeds of Aster, Whiteweed and Horseweed. Fig.353D. A, Aster salicifolius. B, Daisy Fleabane or Whiteweed {Erigeron annuus). C, Horseweed (.Erigeron canadensis). D, Whiteweed (Erigeron ra/mosus). (A and B, drawings by Cliarlotte M. King; C and D, after Hillman ; C, Bull. Nev. Agr. Exp. Sta. ; D, Bull. Mich. Exp. Sta.) He found much variation in the trichomes of the genus. The hairs of A. drwmniondii are shorter. The trichomas of A. frad&sccmii and A. macrophyllus are longer and more slender than in A. drumi- vnondii. The duplex hairs of Aster laevis, A. ohlongifolius, A. novae- angliae and A. multiflorus are slender. Fig. 354A Pig. 354B Fig. 3540 Fig. 354D Fig. 354. Aehenial hairs of Asters. A. Aster novae-angliae. salicifolius. C. Aster tradescanti. D. Aster oblongifoUus. multiflorus. (Drawings by Mary A. Nichols and S. B. Fracker.) 31 Fig. 354E i. Aster I. Aster 482 WEED FLORA OF IOWA Daisy Fleabane {Erigeron annuus (L.) Pers.). Achenes pale straw color, smooth, shining, flattened, obovate; length 0.7-0.9 mm.; the apex bears a row of small straw-colored bristles. Horseweed {Erigeron canadensis L.). Achenes one-twenty-fourth to one-twentieth in. long, white or whitish, oblong lance-shaped, much flattened, one side often more convex than the other; scar of seed with small, whitish, raised Fig.-355A Fig 355B Fig. 3550 Fig. 355D Fig. 355. Achenial hairs of Asters and Bigelovia. A. Aster laevis. B. Aster macrophyllus. . C. Aster druminondii. D. Bigelovia nudata. (Drawings by Mary A. Nichols and S. B. Fracker.) border, pubescent; pappus small, of numerous, fragile, capillary bristles, usually breaking away. "With grass seeds and lawn mix- tures. Cup Plant {Silphium perfoliatimi L.). Achenes large, two-fifths in. in length, dorsally flattened, 2- winged, notched at apex, grayish or bronze-colored, margins thin. Marsh Elder {Iva xanthifolia Nutt.). Achenes obovoid, brown to black, with somewhat flattened longi- tudinal faces 1.5 to 2 mm. in length, longitudinally striate with fine markings. Small Ragweed (Ambrosia art emisiae folia L.). Involucre containing a single achene one-twelfth to one-sixth in. long, obovoid or globular, tipped by a tapering beak one-quarter length of involucre; ridges several (4-10), prominent, with pro- jecting tubercles, short, acute ; color grayish or brownish, pubescent; THE GENERAL CHARACTERS OP SEEDS 483 Pig. 356A Fig. 356B Fig. 356. Seeds of Small Ragweed and Cup Plant. A. Single achene of Cup Plant (.SilpMum perfoUatum). B. Achenes, various views of Small Ragweed (Ambrosia artemisiaefolia) ; A, five specimens having the outer covering, and showing the crown of teeth, or spines ; B, one having the covering partially broken away, exposing the achene ; C, achene, the covering persisting only at the base ; D, a sectional view of a fruit ; E, a group showing the natural size. (A, drawing by Ada Hayden ; B, after Hillman, Bull. Nev. Agr. Exp. Sta.) involucre reticulated, somewhat brittle, achene with thick, rather hard wall; cotyledons 5, large, thick, fleshy, oily; caulicle short. In clovers and alfalfa. L,ance-leaved Ragweed {Ambrosia hidentata Michx.). Involucre top-shaped (turbinate), closed, yellowish or brownish; length, exclusive of the spine, one-tenth to one-eighth in. ; 1 very prominent lobe and 6 or more prominent tubercles; surface of in- volucre rough and hispid, pubescent. Fig. 357A Fig. 357B Fig. 3570 Fig. 357. Seeds of some Ragweeds. A. Ambrosia bidentata. B. Ambrosia psilostachya. C. Ambrosia trifida. (Drawings, A, Charlotte M. IClng; B, Ada Hayden; C, after Hillman. Bull. Mich. Exp. Sta.) 484 WEED FLORA OF IOWA Western Ragweed {Ambrosia psilostachya DC.)- Bur teretish, one-eighth to one-fifth in. long, obovoid, with beak less prominent than in preceding species; tubercles when present, short ; ridges 4-5 ; color grayish ; pubescent ; involucre pitted, readily- removed leaving brown achenium, with short beak ; cotyledons large, fleshy, oily. In clover seed. Large Ragweed (Amhrosia trifida L.). Achene one-fifth to three-tenths in. in length, one-sixth in. across at widest portion near upper end, containing seed one-fifth to three- tenths in. long, or in extreme cases nearly one-half in. ; width at upper end 1.6 in., involucre obovate, narrow below, gradually widening toward top, tipped by tapering beak; fruit prominently Fig. 358A Pig. 358B Fig. 358. A. White-leaved Franseria (Franseria discolor). B. Franseria Hookeriana. A, bur enlarged ; B, natural size ; C, bur cut lengthwise. (A, drawings by Ada Hayden and Charlotte M. King; B, after Hillman, Bull. Nev. Agr. Exp. Sta.) ridged, forming rather long projecting tubercles, 4-10 in number, near upper end ; involucre pitted or marked by cross ridges ; color grayish or brownish ; pubescent or nearly smooth ; encloses a single achene, commonly called seed ; outer portions of achene blackish or brownish; embryo with large thick cotyledons; seed oily, caulicle thick, short. In uncleaned clover seed. THE GENERAL, CHARACTERS OF SEEDS 485 "WTiite-leaved Franseria {Franseria discolor Nutty) . Involucre with, burs from a little less than one-quarter in. to slightly more in length, with. 2 achenes, each in a separate cell, oblong, with 2 pointed spines usually incurved at apex 'and tapering base ; several prominent ridges ; 3 or more tubercles, furrowed ; light straw color, surface pubescent; achene slightly reticulated. Hooker's Franseria {Franseria hooTceriana Nutt.)- Involucre lanceolate or oval, two-fifths in. in length, with a promi- nent conical spine land numerous, straight or recurved rigid spines, variable in number, as long as the width of the bur ; surface wrin- kled ; involucre with one elongated achene ; color yellowish, slightly pubescent. Cocklebur (Xanthium canadense Mill.). Involucre containing 2 seeds; three-quarters to one in. or more long, each in a separate cell, the lower placed further down in the bur than the upper ; bur hard, woody, thick- walled, bearing numer- ous hispid recurved spines, the 2 spines at the end thicker, heavier, and incurved ; surface of achene blackish in color, thin-walled ; and embryo slender with 2 long cotyledons and a thick caulicle; each seed cavity connects with a channel, frequently may also show styles connecting with this channel; odor of seed strong. A B ^ Fig. 359A Pig. 359B Fig. 359. Burs of Cockleburs. A. Common Cocklebur (Xanthium canadense), with view of entire bur, and of cross section showing the pair of seeds in place. B. Spiny Clotbur or Cocklebur (Xanthium spinosum) . (After Hillman, Bull. Mich. Agr. Exp. Sta.) Cocklebur {Xaovthium spinosum Kearney) . Involucre one-third to one-half in. long, cylindraceous, obtuse, armed with short prickles, inconspicuous, 2-beaked, or pointless, occasionally a single straight spine ; bur oblong or somewhat flat- tened; surface sparingly covered with slender hooked prickles one- 486 WEED FLORA OF IOWA twelfth in. long; color dull; smooth or covered with yellowish hairs ; aehenes 2 in each bur. Cocklebur {Xanthium strumarium L.). Involucre one in. long; brownish in color; prominently bristly spines curved; aehenes 2 in each bur; closely resembles X'. can- adense. . Rough-Ox-eye {Heliopsis scabra Dunal). Aehenes thick, obtusely 3-4-angled, with truncate summit; one- eighth to one-seventh in. long; margins pubescent; blackish; apex somewhat depressed; scar at base light or straw-colored; pappus none. Pig. 360A Fig. 360A1 Fig. 360B Pig. 360C Fig. 360. Seeds of Heliopsis and Rudbeckia. A, Al, Ox-eye (Heliopsis scabra). B. Black-eyed Susan or Nigger-head (Rudbeckia Mrta) ; a, two views of aehenes, b, aehenes, natural size. C. Coneflower (Rudbeckia laciniata). (A, C, drawings by L. Collins; Al, Charlotte M. King; B, after Hillman, Bull. Mich. Agr. Exp. Sta.) Nigger-head {Iludbeckia Mrta L.). Achene purplish black, 1.5-1.8 mm. long, tapering slightly from base to apex ; a distinct ridge at each of the 4 angles of the achene ; each side with fine longitudinal strips; no pappus. Cone-flower (Rudbeckia laciniata h.) . Aehenes 4-angled, brownish, truncate, one-fifth in. long; min- utely roughened; upper end with projecting truncate point; apex with an inconspicuous scar. Gray-headed Cone-flower {Lepacliys pinnata Torr. & Gray). Aehene short, flattened or angular, one-tenth of an inch long, 2 slightly marginal wings, and 2 intermediate ones, or only 1, convex ; apex whitish, depressed with slight projecting scar; base with THE GENERAL CHARACTERS OF SEEDS 487 inconspicuous scar of nearly the same color as the rest of the achene. Sunflower (Helianthus annuus L.)- Achenes obovate, oblong, somewhat flattened, one-fifth to one- quarter of an inch long; with appressed pubescence (see figure) especially at upper end, grayish and mottled with brown ; marked by longitudinal lines; more prominent ridge in center; lower end of achene notched, containing the sear; the apical scar with a slightly elevated circular margin ; cotyledons large and fleshy. The achenes, according to Mr. Fracker, are long, slender, and duplex; H. tuberosus has simple and several-celled trichomes but not duplex. -H". occidentalis has short, thick, duplex hairs. Pig. 361A Fig. 361B Fiff. 3610 Pig. 861D Fig. 361. Seeds of Cone-flower and Sunflower. A. Coneflower (Lepachys pin- nata). B and C. Common Sunflower (Helianthus annuus). D. Meadow Sunflower (Helianthus grosse-serratus) . (A, drawing by Ada Hayden ; B and D, drawings by C. M. King ; C, after Hillman, Bull. Mich. Exp. Sta.) Saw-toothed Sunflower {Helianthus grosse-serratus Martens). Achenes oblong, narrowed at base and broad at apex, flattened, with 2 edges, and 1 prominent ridge, sometimes 2 on each side; one-sixth to one-fifth in. long ; pappus of 2 lanceolate awns ; smooth or slightly hairy; brownish or lighter color, mottled with brown; the scar at the end is in the form of a small notch; the remnant of a corolla tube at the apex; cotyledons fleshy. Prairie Sunflower {Helianthus petiolaris Nutt.). Achenes obovate-oblong, but slightly flattened, villous pubescent, (see figure), a prominent longitudinal ridge and several lines on each side ; grayish, mottled with brown ; scar in notch at the lower end; scar on upper end circular; cotyledons 2, large and fleshy. According to Mr. Fracker, the achenial hairs are long and slender and duplex. 488 WEED FLORA OF IOWA Fig. 362A Fig. 362B Fig. 362. Seeds of Sunflowers. A. Prairie Sunflower {Helianthus petiolaris). B. Wood Sunflower (Helianthus strumosus) . (Drawings by L. R. Collins.) Wild Sunflower {Helianthus strumosus L.). Achenes obovate, flattened, several fine lines and a longitudinal ridge on each side, one-sixth to one-fifth in. long, nearly glabrous: yellowish or light brown, finely mottled, except near apex and base which are lighter in color; lower end marked by small distinct soar, occurring in a notch; upper end bearing large circular scar; cotyledons 2, large, fleshy. Fig. 363A Fig. 363B Fig. 3630 Fig. 363D Fig. 363. Achenial hairs of Sunflower seeds. A. Artichoke {Helianthus tuber- osus). B. Prairie Sunflower {Helianthus occidentalis) . C. Common Sun- flower {Helianthus annuus). D. Prairie Sunflower {Helianthus petiolaris'). (Drawings by S. B. Fracker.) THE GENERAL. CHARACTERS OF SEEDS 489 Spanish. Needles (Bidens hipinnata L.). Aehenes exclusive of awns one-half to three-fifths in, long, linear, 4-angled, slightly pubescent; pappus consisting of usually 4 diver- gent downwardly barbed awns, lighter in color than the achene; base of seed with a lightish ringed border and a small depression. Pig. 364A Pig. 364B Fig. 364. A. Seeds of Spanish Needles, Pitchforks, or Bootjacks. Needle (Bidens frondosa), b, Bidens hipinnata.. B. Bidens discoidea. (Drawings by Charlotte M. King.) a, Spanish Small Stick-tight (Bidens discoidea (T. & Gr.) Britton). Aehenes sm.all, flat, narrowly acuminate, upwardly strigose; pappus of upwardly hispid, rarely downwardly barbed awns. Beggar-ticks (Bidens frondosa L.). Aehenes flattened, oval or obovate, three-tenths to two-fifths inch exclusive of the awns; slightly ciliate on the margins (see figure); awns generally diverging, downwardly barbed; corolla tube, whitish, with small opening in the center; basal portion of achene with a prominent depression with, a light border. The achenial hairs, according to Miss Mary A. Nichols and Mr. Fracker, are duplex. In B. cernua they are simple. The related species (B. aristosa) formerly called Coreopsis has duplex hairs, although some hairs are simple. 490 WEED FLORA OF IOWA Fig. 365A Fig. 3650 Fig. 365. Achenial hairs of Beggar-ticks. A. Bidens frondosa. B. Bidens cernua. C. Bidens aristosa. (Drawings by Mary A. Nichols.) Sneezeweed {Helenium auhcmoiale L.). Aclienes straw-colored, with several longitudinal ribs, length 1 mm., breadth 0.3 mm. at apex, toward which the achene widens; surface bears scattered appressed hairs; pappus several chaffy points on margin of truncate apex. Fetid Marigold (Dyssodia papposa (Vent.) Hitchc). Achene slender, 4-angled; length 3 mm., width at truncate apex .75 mm. ; black, with numerous, scattered, appressed black hairs ; pappus a row of chaffy scales, dividing into numerous, rough, bristly hairs ; 3 mm. long. According to Mr. Fracker, the achenial hairs are simple and duplex, the tip in duplex hairs deeply cleft. THE GENERAL CHARACTERS OF SEEDS 491 Fig. 366A Fig. 366B Fig. 366C Fig. 366. Seeds and achenial hairs of Sneezeweed and Fetid Marigold. ' A. Sneezeweed (Helenium autumnale) . B. Fetid Marigold {Dyssodia papposa). C. Achenial hairs of Fetid Marigold. (A and B, drawings by Charlotte M. King; C, from drawing by Mary A. Nichols.) Yarrow {Achillea millefolmm L..). Achenes one-twelfth to one-tenth in. long, oblong to obovate, somewhat compressed; light on the margin, the remainder some- what brownish ; sometimes slightly curved, base with prominent scar with slightly raised border; apex larger with a notch in the center and a projecting knob; surface of the achene marked with fine lines; pappus absent. Fig. 367A Fig. 367B Fig. 367. Seeds of Yarrow and Mayweed.' A, Yarrow (Achillea millefolium) ; a, seeds (achenes) in side view, the two at the left showing the minute, cir- • cular scar ; b, group showing the natural size. B. Mayweed (.Anthemis cotula) : a, a group of seeds showing the prevailing lorins ; h. a group showing the natural size. (Alter Hillman, Bull. Nev. Agr. Exp. Sta.) Mayweed (AntJiemis cotula L.). Achenes ore-twent'eth to one-sixteenth in. long, oblong with prominent tubercled ribs, or occasionally smoothish curved, the base tipped with smooth nipple-like projections; pappus absent; straw- colored to light brown ; bearing a projection sear; base with round, light-colored scar. Common in clover and grass seeds. 492 WEED FLORA OF IOWA Ox-eye Daisy {Chrysanthemum leucanthemum L.). Achenes flattened, club-shaped, straight or slightly curved, one- twentieth to one-tenth in. long, oblong; angles white, with brown interstices ; 5-10-ribbed ; small scar at basal end ; pappus wanting. Fig. 368. Seeds of Ox-eye Daisy {Chrysanthemum leucanthemum). A, pre- vailing forms of seeds (achenes) ; B, one in cross section ; C, a group showing the natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) Wormwood {Artemisia biennis Willd.). Achenes brown, smooth, from 3-4 flattened faces, angled between longitudinally; length .8 mm., width .3 mm., broader at apex than at base. ^■ \ 'h ^ Fig. 369B rig. 369A Fig. 369. Seeds of Wormwood and Fireweed. A. Wormwood {Artemisia Mennis) ; a, achenes, to, natural size. B. Fireweed {Erechtites hieracifoUa) ; a, achenes, to, natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) Fireweed {Erechtites hieracifoUa (L.) Raf.). Achene linear-oblong, straight, or curved, prominently striate, pubescent, beakless, one-sixth in. in length ; upper end with a white ring, within the ring a slight depression ; scar at the lower end with whitish ring, and a small depressed opening; pappus of numerous white soft, capillary bristles. THE GENERAL CHARACTERS OF SEEDS 493 Indian Plantain {Caoalia tuberosa Nutt.)- Achenes oblong, straight, or slightly curved, one-fifth in. in length; brown; prominently ribbed, the ribs minutely roughened; the apex of the seed with a slightly projecting rim or border to which the pappus is attached; the base with a circular ring; pappus with numerous fine, white, capillary bristles. Pig. 370A Fig. 370B Fig. 370. Seeds of Indian Plantain and Groundsel. A. Indian Plantain (Cacalia tuberosa). B. Groundsel (Senecio vulgaris). (Drawings by Charlotte M. King.) Groundsel {Senecio vulgaris L.). Achenes teretish or those of marginal flowers compressed, narrow, cylindrical; 5 or 10-ribbed, pubescent; one-half in. long; upper part expanded, extending beyond narrow portion of upper part of achene ; lower portion with a depression ; color reddish ; pappus of fine, white, capillary bristles. Burdock ( Arctium lappa L.). Achenes 3-5-ridged, upper portion truncate, one-fifth to one- fourth in. long, compressed or oblong, nearly straight to slightly curved, 3-angled; surface mottled in appearance, due to the small serrulate scales with projecting tips of ridges beyond the border; scar surrounded by a circular lighter colored area; scar at base lighter in color; pappus of numerous short scales. In commercial seeds, occasionally. 494 WEED FLORA OF IOWA ^. Fig. 371. Seeds of Burdock (Arctium lappa), a, a side view of one of the inner achenes of a bur ; b, showing the inner surface of a curved, outer achene, and exhibiting the character of the apex, both enlarged ; c, a group show- ing natural size. (After Hillman, Bull. Nev. Agr. Exp. Sta.) Tall Thistle {Cirsium altissimum "Willd.). Achenes laneeolate-obovate, tapering toward lower end, and some- what narrowed toward the apex, wider in the middle, one-eighth in. in length ; width one-twelfth in. ; dull brown or grayish excepting light colored ring at upper end; numerous fine ridges; apex con- cave, with the remnant of corolla tube projecting from the center; color uniform; not marked by light and dark areas as the bull thistle. i^ 'A Pig. 372 A Fig. 372. Seeds of Thistles. arvense). B. Bull Thistle (Cirsium lanceolatum) (Drawings by Charlotte M. King.) Fig. 373B A. Different views of Canada Thistle (.Cirsium Canr.da Thiit'e {Cirsium arvense (L.) Scop.). Afhene lancoolate, narrowed at lower end, tapering from some- what thitkened top, one-twelfth to one-eighth in. long; the cup- shajied top with a projecting conical portion, straight or slightly curved : markt'd with longitudinal dark lines or furrows; apex with a li.ulit colored border, giving appearance of a ring. Found in seed of small grains, clovers and grasses. THE GENERAL CHARACTERS OP SEEDS 495 Field Thistle (Cirsiitm discolor (Muhl.) Spreng.). Achenes obovate, inner edge nearly straight, outer curved, convex ; one-seventh to one-sixth in. long, tapering from narrowed base to apex, upper part longitudinally striated, slightly pigmented; Fig. 373. Seeds of Thistle. 3. Cirsium altissimum. 4. Cirsium discolor. 5. Cirsium undulatum. 6. Cirsium ioense. (Drawing by Charlotte M. King.) grayish, upper part yellowish for one-third length of the aehene. Found in seed of alfalfa and red clover. Iowa Thistle {Cirsium ioense (Pammel) Femald). Achenes obovate, lanceolate, one side of seed straight, outer side slightly convex, one-fifth to one-fourth in. long, one-twelfth to one- sixteenth in. in width, gradually tapering from lower end toward upper end, prominently widened just below the apex, marked by longitudinal striations and dark areas, upper part yellowish, promi- nent rim glossy; apex concave, with the prominent projecting rem- nant of flower center. Bull Thistle (Cirsium lanceolatum (L.) Hill). Aehene lanceolate, curved, tapering, in many oases somewhat angular, one-eighth to one-sixth in. long; brownish, not darkly striated, marked with definite grooves, upper part lighter, ringed, also showing at center of concave apex ; apex with projecting point. Found in red clover and in alfalfa seed. Wiavy-leaved Thistle {Cirsium undulatum (Nutt.) Spreng.). Aehene in general outline lanceolate, tapering from base, inner edge slightly convex, several prominent ridges, light brown, not pigmented; upper part yellowish; apex with prominent rim and prominent remnant of corolla tube; aehene slightly thicker than that of C. discolor. Found in seeds of red clover and alfalfa. 496 WEED FLORA OF IOWA Chicory {Cichorium intyhus L.). Achenes oblong, ribbed, 5-iaiigled, spotted, grayish or straw- colored, with darker spots, one-twelfth to one-eighth in. in length apex with the base of the pappus scales extending beyond the scar; Fig. 374. Chicory (.CicJiorium intyhus). A, B, two views of seeds; C, seeds, natural size. (After Hillman, Bull. Mich. Agr. Exp. Sta.) minutely, transversely roughened ; base of seed lighter in color, with small depressed scar ; achenes from the inner part of the flower more slender and straight than from outer part. Found with various commercial seeds. Corn-flower {CentoMrea cyanus L.). Achene oblong or obovoid, compressed, one-sixth to one-fifth in. long; smooth, shining; with inconspicuous veins or nerves; lower part of achene oblique ; ivory-white ; the elliptical or somewhat cir- cular scar at base with whitish rimmed border, depressed, made up of soft tissue; pappus of several series of scaly bristles; brownish in color. The achenial trichomes, according to Mr. Fracker, are long and simple. Bamaby's Thistle {Centcmrea solstitialis L.). Involucre ovoid, 1.5 cm. in diameter, with stout straw-colored spines, widely spreading ; achene cream or pale brown after matted ; length 2 mm., scar of attachment in a notch above rounded base; apex truncate, bearing tubercle in the center. THE GENERAL, CHARACTERS OF SEED'S 497 Fig. 375C Bamaby's Thistle or Fig. 375B Fig. 375. Seeds of Corn-flower and Knapweed. •Knapweed iCentaurea solstitialis) ; a, achene with pappus, c, pappus re- moved, b and d, achenes, natural size. B. Corn-flower (Centaurea cyanus). C. Achenial hairs of Corn-flower. (A, after Hillman, Bull, Nev. Agr. Exp. Sta. ; B, after Nobbe ; C, drawing by S. B. Fracker.) Bristly Ox-tongue (Picris echioides L.). Achene elliptical, narrowed fat base, with, projection at tip; one- tenth in. in length ; light brownish red ; wrinkled transversely, espe- cially toward apical end. Found in seed of alfalfa and clover. Oyster Plant, Salsify {Tragopogon porrifolius L.). Achenes linear, terete, beaked or long, covered with scalelike tubercles on the ribs, or merely roughened, light straw-colored or darker pappus of numerous plumose bristles; small scar at apex, whitish with a depression scar at base with an oval depression. Reported as a "weed of alfalfa meadows." Meadow Salsify {Tragopogon pratensis. L.) . Achenes linear, terete, one-half in. or little more long, exclusive of beak; scar at base, whitish, with an oval depression; beak one- third in. long; scar at end of beak whitish, Avith a depression, striate, smooth or slightly roughened, light straw-colored or darker ; pappus of numerous soft, brownish, plumose bristles. 32 498 WEED FLORA OF IOWA Fig. 376A Fig. 376A1 Fig. 376C Bristly Ox-tongue Fig. 376B Fig. 376. Seeds of Picris and Tragopogon. A and Al. (.Picris echioides) . B. Oyster Plant {Tragopogon porrif alius) ; a, achenes enlarged, b, achenes natural size. C. Meadow Salsify (Tragopogon pratensis) . (A, drawings by L. R. Collins ; B, after Hillman, Bull. Mich. Agr. Exp. Sta. ; C, drawing by C. M. King.) Dark-seeded Dandelion {Taraxacum erythrospermum Andrz.). Achenes one-sixth to one-fifth in. long; lance-shaped, or spindle- shaped, 5 longitudinal ridges, upper end with rough tubercles, per- sistent long beak about two-fifths in. long, brownish, somewhat pointed, prominently ribbed ; pappus of numerous capillary, fragile, white bristles ; color reddish ; toothed at apex ; beak and pappus both shorter; achenes more prominently tubercled than in T. officinale. B. Fig. 377B Fig. 377. Dandelion seeds. A. Red Seeded Dandelion (Taraxacum erythros- permum) ; a, seed enlarged, b and c, seed, natural size, c, with pappus. Common Dandelion (Taraxacum officinale). A, an enlarged view of one of the two similar faces of an achene, in which no attempt is made to show the minute surface-scales which are not evident under the ordinary lens. B, a group of seeds, natural size, b, one bearing the beak and pappus. C, a group showing common variation in the form of the achenes. (After Hillman: A, Bull. Mich. Agr. Exp. Sta.; B, Bull. Nev. Agr. Exp. Sta.) THE GENERAL CHARACTERS OP SEEDS 499 Dandelion {Taraxacum officinale Weber). Achenes two-fifths in. long including persistent beak, fusiform in shape, prominent ribs, and projecting teeth at ribs, especially at upper end ; beak four-fifths to one in. in length ; achenes light gray in color, otherwise like preceding; pappus capillary, whitish, fragile. "With grass seeds. Field Sow Thistle {Sonchus arvensis L.), Achenes dark reddish brown, dull, ends slightly truncate, length 2.5-3 mm., width 0.8 mm., somewhat flattened, with 4 strong ribs or angles, between which lie smaller ridges ; numerous transverse ridges on the ribs. e A Pig. 3780 Fig. 378. Seeds of Sow Thistles. A. Field or Perennial Sow Thistle (Sonchus arvensis) ; B, natural size, showing pappus on one achene. B. Sonchus oleraceus, different views of achenes. C. Sonchus aspcTj A and B, different views of aehen^s, C, achenes, natural size. (After Hillman, Bull. Mich. Agr. Exp. Sta.) Spiny Sow Thistle {SonclLus aspcr Vill.). Achenes broadly oblong or lance-shaped, similar faces, many- ribbed, one-tenth in. long, slightly pubescent, prominent ridges minutely roughened; base with a minute scar, brownish; the ap(^x: with projecting point and fine, capillary, white, bristles. Found with grass seeds. -.00 WEED FLORA OF IOWA Sow Thistle {Sonchus oleraceus L.). Aehenes light brown, flattened, ribbed, the prominent ribs rough- ened ; one-eighth in. long ; pappus of white capillary bristles, much like the preceding. "Apt to occur among grass seeds." Wild Lettuce {Lactuca canadensis L.). Achene three-twentieths in. in length, straight or curved, sides somewhat unequal, transversely wrinkled, blackish brown, beak one- twentieth in. long, shorter than in L. floHdana; one faint rib on each side of prominent midrib ; decidedly convex on each side of midrib to the flattened margin ; scar with whitish ring and small depression ; pappus white, capillary. Much like L. floridana, beak smaller and shorter. With commercial seed. Fig. 379. Fig. 379A Seeds of Lettuce, natural size. B. Lactuca floridana. (A, after Hillman, Bull. Mich. Agr. Exp. Sta. ; B, drawing by Charlotte M. King.) Fig. 379B A. Lactuca canadensis; a, enlarged achene, b, False Lettuce {Lactuca floridana (L.) Gra,ertn.). Achene brown, transversely wrinkled, three-twentieths to seven- fortieths in. in length, straight or slightly curved; beak light brown, about one-fifth in. long, generally persistent, convex ; ribs rather faint, 1 on each side of prominent midrib, strongly convex on each side of midrib, margin flattened; pappus white, capillary. Prickly Lettuce {Lactuca scariola var. integrata Gren. & Godr.). Aehenes brownish, margin somewhat lighter, surface roughened, one-ninth to one-sixth in. long ; beak one-tenth to one-eighth in. long, lance-shaped, straight or slightly curved, upper end tapering THE GENERAL CHARACTERS OF SEEDS 501 A Fig. 380A Fig. 380B Fig. 380. Lettuce Seeds. A. Lactuca scariola; A, side view of an achene, en- larged. B, a group of the same, natural size. C, an achene bearing its beak and fragile pappus. B. Prickly Lettuce (.Lactuca scariola var. integrata.) (A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; B, drawing by L. R. Collins.) toward the beak, somewhat flattened, on one side margined, faces convex, with 5-7 longitudinal nerves; scar circular, with a small depression. Rattlesnake Boot {Prenanthes alba L.). . Achene oblong or columnar, truncate, somewhat flattened, 4-5 angled, brownish; upper part with a projecting ring to which the bristles of pappus are attached ; scar at the base whitish, not prom- inent; one-eighth in. in length; pappus tawny. Fig. 381A Pig. 381B Fig. 381. Seeds of Rattlesnake Weed and False Calais. A. Rattlesnake "Weed {Prenanthes alba). B. False Calais (Agoseris cuspidata). (Drawings by Charlotte M. King.) 502 "WEED FLORA OF IOWA False Calais {Agoseris cuspidata (Pursh.) Steud.). Achenes fusiform, slightly contracted at the apex, with 10 prominent ribs; one-half in. long, or little longer; pappus of soft, white, capillary bristles ; scar at base, whitish, with a small opening. Orange Hawkweed {Hieracium aurantiacum L.). Achene oblong, columnar, one-tenth in. long; blackish or dark brown, marked with prominent longitudinal ridges, minutely roughened ; base of achene with small circular raised border, lighter than remainder of achene; pappus of numerous somewhat brown- ish bristles, frequently breaking away near the top of the achene, then showing short bristles. Fig. 382A Fig. 382A1 Fig. 382B Fig. 3 82. Seeds of Hawkweeds. A and Al, Orange Hawkweed {Hieracium aurantiacum). B, Hawkweed (.Hieracium canadense). (A, after Hillman, Bull. Mich. Agr. Exp. Sta. ; Al, drawing by L,. R. Collins; B, drawing by Charlotte M. King.) Hawkweed {Hieracium canadense Mx.). Achenes one-tenth to one-eighth in. long, oblong, cohunnar, 10-15-ribbed ; blackish or reddish ; base with prominent disklike area marked by circular ring; apex with somewhat fine tawny- colored capillary bristles; below point of attachment is an area bulging outward; capillary bristles have tendency to break. CHAPTER III. MICROSCOPIC STRUCTURE OF SOME WEED SEEDS By L. H. PAMMEL and CHARLOTTE M. KING CHAPTER J II. GRAMINEAE,* GRASS FAMILY. Smooth Crab Grass {Digitaria humifusa Pers.). A cross section of seed shows but slight development of the pericarp and testa. The epidermal cells of the former are smaller than the underlying rows of cells of the wall of the ovary. The testa is reduced to a single layer of cells, longer than broad. The aleurone layer is filled with protein grains. The starch cells of the endosperm are larger and densely packed with polygonal grains. Pig. 383. Structure of the grain fruits of some Grasses {, Gr amine ae) ■ I. "Wild Barley (Hordeum jubatum) . II. Timothy {Phleum pratense). III. Smooth Crab Grass (Digitaria humifusa). IV. Sandbur (Cenchrus tribu- loides). V. Millet (Setaria italica}. VI. Corn (.Zea mays). VII. Barn- yard Grass (EcMnochloa crusgalli). t=testa. al=aleurone. en=endosperm. n=nucellus. (Drawings by L. H. Pammel.) *The material for this family has been taken from the accounts by Pammel and Winton. 506 WEED FLORA OF IOWA Broomcorn Millet {Panicum miliaceum L.). The walls of the ovary are similar to those of Digitaria liumifusa except that they are wider. The testa is much compressed and consists of several layers of small cells. The cells of the aleurone layer are small, somewhat longer than broad. The cells of the starch layer are similar to those of D. liumifusa. Barnyard Grass {Echinochloa crusgalli (L.) Beauv.). The adherent glumes in this species consist of several rows of parenchyma cells, the inner portion, of one row of thick-walled sclerotic cells with pore canals. The cells of the pericarp and testa are much as in the other species, thin- walled and compressed. The protective features are preserved in the coriaceous glumes. The starch and aleurone layers are similar to those of Digitaria humifusa. Hungarian Grass or Millet {Setaria italica (L.) Beauv.). The colorless smooth pericarp is but slightly thickened and con- sists of three or four rows of elongated cells. These in colored seeds contain the pigment. The testa is but slightly developed. The cells of the aleurone layer are not much longer than broad, and are densely filled with protein grains. Green Foxta.il {Setaria viridis (L.) Beauv.). Dr. A. L. Winton describes the microscopic structure as follows: Empty Glumes and Glume of Sterile Flower. The lower empty glume is three-nerved and less than 1 mm. long; the upper empty glume and the glume of the staminate flower are five-nerved and 2 mm. long. In microscopic structure the three are practically identical. 1. Outer Epidermis. Characteristic of this layer are the elongated cells with sinuous side walls and longitudinal rows of pits so arranged that one pit occurs in each concave bend of the wall. On the middle portion of the mature glume each of these pits is so large that it fills completely the bend of the wall, and in addition has a thickened border, half of which coincides with the cell wall, thus giving the tissue a lacelike appearance. This structure is optically delusive, the pit borders often appearing to be the cell walls, but is resolved by careful focusing and comparison with the tissue in earlier stages of growth. In addition to these MICROSCOPIC STRUCTURE OP WEED SEEDS 507 Fig. 384. Green Foxtail (Setaria viridis). I, spikelet with ripe fruit, g^ lower empty glume ; g\ upper empty , glume ; gP-, glume, and p^, palet of the staminate flower ; gf^, glume, and p^ palet of fertile flower ; c, caryopsis ; b, bristles. II and III. caryopsis enclosed by flowering glume and palet. X 8. (After Winton, Conn. Agr. Exp. Sta.) elongated cells, pairs of short cells, one isodiametric, probably a hair-scar, the other more or less crescent-shaped, occur here and there, and less frequently stomata and thin-walled one to three- jointed hairs. 2. Mesophyl. Only about the nerves and the basal Pig. 385A Fig. 385B Fig. 385. Green Foxtail. A. Outer epidermis of the staminate flower; I, at the edge; II, in the middle. X 300. B. Outer epidermis of the glume of the fertile flower, showing the wrinkled central portion and the smooth edge. (After Winton, Conn. Agr. Exp. Sta.) 508 WEED FLORA OF IOWA portions of the glumes is this coat evident. It has no diagnostic importance. 3. The Inner Epidermis is composed of elongated cells with straight walls. Palet of Staminate Flower. Within the glume of the staminate flower is the palet, a hyaline scale only 1 mm. or less long with a notch at the end. In general structure, it is much the same as the other thin envelopes, but the cell waUs are thinner. 1. Outer Epidermis. The narrow, elongated cells are wavy in out- line, but pits are lacking or are indistinct. Isodiametric cells are thin-walled; jointed hairs also occur. 2. Inner Epidermis. Except at the base, where traces of mesophyl are sometimes evident, the inner epidermis immediately underlies the outer epidermis. Glumes and Palet of Perfect Flower. Both the glume and the palet of the fertile flower closely envelop the grain at maturity, the former being strongly convex, the latter flat except on the edges, which clasp about the caryopsis. At the time of flowering these envelopes are thin and of a green color, but at maturity they are coriaceous, silieified and of a brown or mottled color. Under the lens, numerous transverse wrinkles are evident on the glume and on the middle or flat portion of the palet, the lateral portions of the latter which clasp the caryopsis being smooth and shining. 1. Outer Epidermis. Throughout the glume and on the middle portion of the palet, the cells are isodiametric or moderately elon- gated and are arranged not only in longitudinal rows but also in irregular transverse rows, the wrinkles being formed by the out- bending of the cells at the end walls and the inward bending half way between. At the time of flowering, it may be seen that at the outer surface the end walls are sinuous and the side walls are compoundly sinuous, but farther inward the end walls are nearly straight and the side walls are simply, not compoundly sinuous. At the end of each cell nearest the apex of the envelope, a cuticular wart bearing a group of pits is usually evident, par- ticularly on the palet. About these warts the adjoining end walls are more or less curved and the side walls are not so deeply sinuous. At maturity the cell cavity beneath the wart is conspicuous (on the palet nearly circular), but at the other end of the cell is nar- row or not evident at all owing to the encroachment of the strongly thickened walls. The cell contents during the early stages of devel- opment are colorless, but later on usually become dark brown. The epidermal cells on the lateral or smooth portions of the palet which MICROSCOPIC STRUCTURE OF WEED SEEDS 509 F'iG. 386. Green Foxtail. Outer epidermis from the middle of the glume of the fertile flower. I, outer surface, and II, inner surface soon after blooming, III, outer surface when in fruit. X 300. (After Winton, Conn. Agr. Exp. Sta.) ■clasp about the caryopsis are longer, narrower, and less complex than those already described. At maturity the wrinkles are usually from 0.03 to 0.06 mm. apart. 2. The Hypodermal Fibers may be readily isolated by treatment on the slide with caustic alkali. They vary in length up to 0.6 mm. and are often toothed at margin. 3. Mesophyl. Rectangular parenchyma cells without intercellular spaces make up this layer. Numerous chlorophyl granules are present at the time of flowering. 4. The Inner Epidermis is com- 510 WEED FLORA OF IOWA posed of reetan^lar cells resembling those of the mesophyl. Both of these layers become more or less obliterated at maturity and are of no diagnostic importance. Pericarp. The ventral side is flat and has a darker colored spot, the remains of the hilum, near the base. Extending half way from the base to the apex on the dorsal side is a groove, which marks the position of the embryo. Vogl describes minutely the histology of the caryopsis of common millet {Pamcum miliaceum L.) and Fig. 387. Green Foxtail. Outer epidermis from the edge of the glume of the fertile flower. X 300. (After "Win ton, Conn. Agr. Exp. Sta.) states that German millet {Setaria panis Jessen) has practically the same structure. I find that his description applies also to the caryopsis of both green and yellow foxtail. 1. Epidermis. As in the outer epidermal layers of the floral envelopes the cells are elongated and wavy in outline. On the dark colored spot already referred to, the epidermal cells are more or less rectangiilar. 2. The Cross-Cells are similar to the tube-cells in form but are usually shorter, broader, and more irregular in shape. 3. Tuhe- Cells. These are 0.002 to 0.004 mm. wide and often reach the length of 0.3 mm. a. Nucellar or Hyaline Layer. After treatment with alkali, this layer is clearly seen in surface view. The cells are of large size and have beaded walls, h. Endosperm. 1. Aleurone Layer. The cells vary in diameter from 0.01 to 0.02 mm. MICROSCOPIC STRUCTURE OF WEED SEEDS 511 2. Starch-Cells. Polygonal starch granules with conspicuous hilums fill the parenchyma cells of the endosperm. In the outer layers they are from 0.004 to 0.008 mm. in diameter but farther inward they reach the maximum diameter of 0.018 mm. After dissolving the starch with potash, there remains a network of threads con- taining conspicuous granules. In this respect, however, this fruit cannot be distinguished from the fruits of S. glauca Beauv,, S. panis Jessen, Panicum miUaceum L. (see Vogl) and all the other species of Panicum which I have examined. Detection in Powder Form. The membranous glumes with pores in the bends of Fig. 388. Green Foxtail. Transverse section of caryopsis. F, pericarp con- sisting of the epidermis ep and the tube-cells sch ; N, nucellar layer ; E, endosperm consisting of the aleurone-cells al and the starch cells s. X 300. (After Winton, Conn. Agr. Exp. Sta.) the walls and the coriaceous, transversely wrinkled, more or less spotted, envelopes of the fertile flower with compoundly sinuous, thickened cell walls are highly characteristic of both green and yellow foxtail. These tissues are usually present in all stages of development. The fruit elements are like those of common millet and German millet. Treatment with caustic alkali brings out the structure of the fruit coats and nucellar layer, and serves to dis- tinguish this fruit from the common cereals. The starch is hardly distinguishable from the starch of bindweed. Dr. A. L. Winton describes the microscopic character of yellow foxtail {Setaria glauca Beauv.) as follows: The fruit of this species is larger than that of green foxtail, the envelopes are also proportionately larger (with the' exception of the upper empty glume which is but half the length of the 512 WEED FLORA OF IOWA spikelet) and the wrinkles on the glume of the fertile flower are more pronounced. In microscopic structure the fruits of the two species are identical. The floral envelopes are also much alike, the only distinction being in the distance apart of the wrinkles on the mature flowering glumes. In green foxtail this distance is usually from 0.03 to 0.06 mm., but in yellow foxtail it is often from 0.08 to 0.12 mm. Since this distinction does not apply to the mature glumes and since the wrinkles on the palets of the two species are practically the same, it is often difficult to identify the species in ground mixtures. Fortunately, identification of the genus is all that is usually required. sch Fig. 389. Green Foxtail. Caryopsis in surface view. Significance of letters- same as in Fig. 388. (After Winton, Conn. Agr. Exp. Sta.) Broom Corn {Andropogon sorghum var. tecliniciis Koern). Dr. A. L. "Winton describes the microscopic structure of the- pericarp and testa of broom corn as follows: Empty Glumes. — ^Both glumes are from 4 to 6 mm. long, equal- ing and closely enveloping the fruit. They vary in color from- yellow-brown to red-brown. The soft hairs, which nearly cover the outer surface, are loosely attached and most of them are re- moved during the threshing and cleaning of the seed, leaving the glumes smooth and shining. 1. The Outer Epidermis consists of strongly sclerenchymatized cells several times as long as they are broad, with wavy contour, interspersed here and there with iso- diametric hair-scars, each accompanied by a crescent-shaped cell MICROSCOPIC STRUCTURE OF WEED SEEDS 513 Fig. 390. Broom-corn. Fruit with chafE. r, two staminate spikelets ; g^ lower empty glume ; g^, upper empty glume ; g^, glume of rudimentary flower ; gf , flowering glume with awn ; p, palet ; c, caryopsis. X 4. (After "Winton, Conn. Agr. Exp. Sta.) with granular contents. The hairs, which are almost invariably detached in preparing the mount, if not in cleaning the seed, are often 1.0 mm. long and 0.012 mm. broad in the middle but taper toward both ends. Invariably the lumen is much broader than the walls. 2. The Hypoderm Fibers, of which there are several layers, have thick walls and narrow cavities. They vary in length Fig. 391. Broom-corn. Transverse section of caryopsis and an empty glume. Sp, empty glume, consisting of the outer epidermis aep, the fiber layer f, the spongy parenchyma p, and the inner epidermis iep ; g, bundle ; sto, stoma ; Fs, pericarp, consisting of the epidermis ep with the cuticle c, the hypoderm hy, the starchy mesocarp mes, the cross-cells q, and the tube-cells sell ; N, nucellar or hyaline layer with swollen inner walls s ; E, endosperm, consisting of the aleurone layer al and the starch-cells with starch granules st and proteid networli a. X 160. (After Winton, Conn. Agr. Exp. Sta.) 83 514 WEED FLORA OF IOWA up to 0.5 mm. or more. 3. Spongy Parenchyma. As seen in sur- face view, the cells of this layer are more or less rectangular with circular intercellular spaces and resemble those of rice and barley glumes. 4. Inner Epidermis. In cross section this layer is not readily studied since the radial walls are usually collapsed; but in surface preparations, the large elongated cells, often 0.15 mm. long and 0.05 mm. wide, interspersed with stomata and hairs, are clearly displayed. Tkim, Glume. — ^Within the lower or first glume and nearly equal- ing it in length, is the third or thin glume, the remnant of an abortive flower. This glume is exceedingly thin and membranous and bears numerous hairs, particularly in the margin. 1. Outer Epidermis. In general form the cells are similar to those of the outer epidermis of the thick glumes, but are narrower and much thinner-walled. The marginal hairs are long (often 0.5 mm.) single-celled and pointed; but on the surface shorter hairs, with two or three joints and blunt ends, also occur. Both of these Fig. 392A Fig. 392B Fia. 392. Broom-corn. A. aep, outer epidermis and f, fiber of an empty glume in surface view. X 300. B. p, spongy parenchyma and iep, inner epidermis of an empty glume in surface view ; sto, stoma ; h, hair. X 300. (After Winton, Conn. Agr. Exp. Sta.) MICROSCOPIC STRUCTURE OF WEED SEEDS 515 forms have exceedingly thin walls. 2. The Inner Epidermis is dis- tinguished from the outer by the straight walls and almost entire absence of hairs. Flowering Glume. — The fourth or flowering glume, situated be- tween the upper or second glume and the grain, is also mem- branous and bears lan upwardly barbed awn 5 to 7 mm. long. This awn, with the larger part of the flowering glume, being readily de- tached by threshing, it is seldom found in the grain on the market. Fig. 393. Broom-corn. Glume of rudimentary flower In surface view, aep, outer epidermis with h, one-celled hair and h. two-celled hair: lep, inner epidermis. X 300. (After Winton, Conn, Agr. Exp. Sta.) Palet. — This is membranous and hairy like the third or thin glume, but is much smaller. Pericarp. — The grain or caryopsis is about 5 mm. long and from 2 to 3 mm. wide, tapering to a blunt point at both ends. It varies in color from yellow-brown to red-brown. Harz, Hassack and particularly Mittlacher have described so fully the histological elements of the caryopsis, that only a brief description, essential for a clear understanding, need here be given. 1. Epidermis. The cells are longitudinally extended and have thick wavy side walls, with more or less distinct pores. Hassack has noted that the cuticle is of uneven thickness, due to minute granules or crystals, which may be seen in either section or sur- 516 WEED FLORA OF IOWA q sen. hy. mes. ^ Fig. 394. Broom-corn. Layers of the pericarp in surface view, of letters same as in Fig. 391. X 160. (After Winton, Conn. Agr. Exp. Sta.) Significance face view. 2. The Hypoderm consists of from one to three layers of cells, with walls somewhat thinner than those of the epidermis. 3. Starchy Mesocarp. Several layers of thin-walled parenchyma cells, filled usually with small round or rounded polygonal starch gTanules seldom over 0.006 mm. in diameter, make up this coat. In all the varieties here described the starch appears during the early stages of growth and persists until the fruit nearly or quite reaches full miaturity. As the earyopsis, even when nearly mature, is intensely green owing to chlorophyll grains in the outermost layers of the mesocarp,. it may be inferred that this starch is a direct product of photosynthesis in the pericarp. So far as I have observed, the presence or absence of a starchy mesocarp in the grain at the time of harvest is not a definite varietal peculiarity, but is dependent on the ripeness of the fruit or other conditions. Some kernels of the same variety may possess it, while others show only empty, obliterated cells. Whether or not the starch is present in a given seed may often be determined by careful scraping and observation with the naked eye. 4. Cross-Cells. These cells are usually long and narrow, being distinguished from the tube-cells only by their transverse arrangement. Near the extremities of the seed they are, however, shorter and of more irregular shape. 5. Tube-Cells (sch). The cells of this layer lie at right angles to the cross-cells. They are about 0.005 mm. wide and often reach a length of 0.20 mm. a. Nucellar or Hyaline Layer. This layer is frequently 0.05 mm. thick. The outer radial walls are thin, but the inner wall is greatly swollen. In surface view the large cells MICROSCOPIC STRUCTURE OF WEED SEEDS 517 are conspicuous, not only because of their size, but because of their yellow or brown color, h. Endosperm. 1. Aleurone Layer (al). The individual cells of this layer are characterized by their great variation in size (0.01 to 0.04 mm. in diameter) and form. 2. Starch^Cells (st). In the outer layers the starch granules, if present, are much smaller than in the interior of the seed, where they sometimes reach a diameter of 0.03 mm. They are usually sharply polygonal, with a distinct hilum and radiating fissures. The starch is surrounded by small protein granules, forming a network which is especially evident after removing the starch by reagents. In some specimens, one or more of the outer cell layers are filled with these protein granules to the complete exclusion of the starch. Sandbur {Cenchrus tribuloides L.). The pericarp is divided into two portions. The cells of the outer portion are thick-walled and short; of the inner portion, elongated, thick-walled and fusiform. The testa consists of one to two rows of thin-walled cells, much compressed. The aleurone cells are much larger than in Panicum and Setaria, thick-walled, densely filled with protein grains. "Walls of the starch cells thick- ened; starch grains larger and loosely arranged. Timothy {Phleum pratense L.). The testa and pericarp are dark colored. The epidermal cells are thin-walled, elongated, sometimes slightly irregular. The testa consists of several rows of thick-walled dark brown cells much longer than broad. The aleurone layer consists of a single row of cells relatively thin-walled, somewhat variable in size, solidly packed with aleurone grains. The nucellus is very evident as a remnant in some places. The cells of this layer are thick- walled, clear and colorless. The starch cells are much larger than the aleurone, and contain angular starch grains. Cheat or Chess {Bromus secalinus L.). Dr. A. L. Winton describes the microscopic structure as follows : Flowering Glume. — The structure throughout is much the same as in darnel, but the cells of the outer epidermis are much more conspicuously thick-walled, and the wavy-walled cells throughout much longer than broad. The circular cells also have wavy walls. The cells on the margins, interspersed with lance-shaped hairs, are the same as in darnel. 518 WEED FLORA OF IOWA Fig. 395. Chess (Bromus secalinus). Outer epidermis of flowering glume in surface view. X 160. (After Winton, Conn. Agr. Exp. Sta.) Palet. — The flowering glume and palet of chess are very similar in structure, but the outer epidermis of the latter is barbed on the keel, the stiff hairs often reaching 45i" in length. Pericarp (F). — The pericarp consists of two layers with rudi- ments of another layer in parts. 1. The Epidermal Cells (ep) are large, elongated-polygonal, and have thin, non-porous walls. 2. Mesocarp. As a rule, the cross-cells immediately underlie the q. al— Sf- FiG. 396. Chess. Transverse section of fruit. F, pericarp consisting of epidermis ep, and cross-cells q ; S, testa ; N, perisperm ; B, endosperm con- sisting of aleurone layer al, and starch-parenchyma st. X 160. (After Winton, Conn. Agr. Exp. Sta.) epidermis, but occasionally traces of the mesocarp are evident. 3. Cross-Cells (q). Whether this layer corresponds with the cross- cells of the tube-cells of other grasses, I have been unable to decide. MICROSCOPIC STRUCTURE OF WEED SEEDS 519 The tissue is made up of irre^lar spongj^'-parenehyina cells, usually transversely elongated with large, round or elongated inter- cellular spaces. The Testa (S). — Consists of one layer of elongated brown cells 10-20M wide. Perisperm (N) . — This layer is enormously developed. As may be seen in cross section, tlie cells are 40/" thick, but the walls are so swollen as to almost entirely obliterate the cavity. After soaking for some time in 1 per cent soda solution they are evident in sur- face view. Endosperm. — 1. The Aleurone Layer (al) is not of especial in- terest. 2. The Starch-Parenchyma (st) is remarkable for the thick- ness of the cell walls (often 10-" thick) and the elliptical starch grains 3-20/* in diameter. With proper illumination each grain may be seen to have an elliptical hilum. Fig. 397. Chess. Elements of fruit in surface view. Significance of letters same as in Fig. 396. (After Winton, Conn. Agr. Bxp. Sta.) Wild Barley or Squirrel-tail Grass {Hordeum jubatum L.). The grain is adherent to the palet. The epidermis consists of thick- walled, tangentially elongated cells, most of which are longer than broad. In part the cells are developed into short conical trichomes. The underlying cells are thick-walled with prominent pore canals. The remainder of the adhering palet consists of thin- walled cells much larger than broad. The pericarp as well as the 520 WEED FLORA OF IOWA testa is but slightly developed. In some eases the underlying parenchyma cells are not clearly defined. The blackish pigment is found in the internal part of the palet; some also occurs in peri- carps and the aleurone layer. The pericarp consists of one or two rows of rather thin-walled, tangentially elongated cells. The testa is reduced to a single layer of cells longer than broad. The nueellus is nearly absent except in the groove. It consists of a single row of thin-walled, colorless, compressed cells. In the groove several rows of cells occur. The aleurone in the specimens studied is made up of a single row of cells. The cells of the starch layer are larger than those of the aleurone. Darnel (Lolium temulentum L.). Dr. A. L. Winton describes its microscopic structure as follows: The Flowering Glume is 6-8 nun. long, equaling or exceeding the caryopsis. It is obscurely five-nerved, lobed at the end, and bears an upwardly barbed awn often 15 mm. long. Like the glumes of barley, oats, and other cereals, it consists of four coats, some of which, however, are lacking on the margins and at the end. 1. The Outer Epidermis differs greatly in structure in different parts of the glume. At the margins (as is clearly shown in Fig. 1 by Moeller*), it consists of straight-walled, elongated cells inter- spersed here and there with short lance-shaped hairs. On the greater part of the surface, however, the cells, as in barley and some other cereals, are of three kinds : first, cells of wavy outline, Fig. 398. Darnel (.Lolium temulentum). Margin of flowering lance-shaped hairs. X 300. (After Winton, Conn. Agr. Exp. Sta.) ?lume sliowing MICROSCOPIC STRUCTURE OF WEED SEEDS 521 into which the straight-walled cells at the margin pass; second, circular cells corresponding to the conical hair-cell of barley ; third, exceedingly short, more or less crescent-shaped cells. Near the margins and on the veins, where they alternate with stomata, the cells of wavy outline are elongated; but in other parts they are very short, often being broader than long. Although thick-walled, the walls are transparent, whereas the middle lamella is con- spicuous, giving the impression of thin-walled cells. Pores are few and inconspicuous. Near the margin the circular cells are small and are usually accompanied by crescent-shaped cells which often exceed them in size. On the greater part of the glume, however, the circular cells are much larger, often being 70-" in diameter. Numerous pores are conspicuous, both in the radial and tangential walls. Often one, sometimes two, crescent-shaped cells accompany a circular cell. Characteristic of this coat are the short, wavy Fig. 399. Darnel. Middle portion of flowering glume. X 160. (After Winton, Conn. Agr. Exp. Sta.) cells and the numerous circular cells, the latter frequently exceed- ing in area the former. 2. Hypoderm. The fibers in this layer are much the same as in cereals. Fibers of similar structure also make up the ground-tissue of the awn. 3. Spongy-Parenchyma. The elements are more or less rectangular in shape, like those of the corresponding layer of barley, and are readily distinguished from the star-shaped elements of oats. 4. Inner Epidermis. This layer is made up of thin-walled cells and stomata, and is of no diagnostic importance. 522 WEED FLORA OF IOWA Palet. — The two-keeled palet is about the same size as the flower- ing glume, but is of a thinner texture, owing to the absence of a well developed hypoderm layer. The Outer Epidermis is much the same as that of the flowering glume, except that it is barbed on the keels with rigid thomlike hairs 150i" or less in length, as is shown in Fig. 3 by Moeller. Fia. 400. Darnel. Keel of palet showing outer epidermis with hair h, and hypoderm fibers f. X ICO. (After Winton, Conn. Agr. Exp. Sta.) The Pericarp (F) . — Consists of four coats, of which only two, the epidermis and cross-cells, are fully developed. 1. Epidermis (ep). Cross sections of the mature seed show that this layer consists of collapsed, moderately thick-walled cells, which are best studied after heating with potash. Seen in surface view, the cells at the apex of the seed are nearly isodiametric, but at other parts are elongated. The walls are indistinctly beaded. 2. The Mesocarp (m) is not developed on all parts of the seed, but is conspicuous on the angles. The cells vary greatly in shape and size, some being ir- regularly isodiametric, others transversely elongated, resembling the cells of the next layer. 3. Cross-Cells, (q). Especially striking are the cells of this layer, which resemble the cross-cells of barley. As has been noted by Moeller, the radial walls appear indistinctly beaded, but this is evident only under favorable conditions. 4. Tuhe-Cells, spongy-parenchyma, and various intermediate forms, make up the interrupted inner layer of the pericarp. Testa (S). — The cells are for the most part elongated and are often diagonally arranged with reference to the axis of the fruit. In MICROSCOPIC STRUCTURE OF WEED SEEDS 523 Fig. 401. Darnel. Transverse section of fruit. F, pericarp consisting of epidermis ep, mesocarp m, cross-cells q, and tube-cells sch ; S, testa con- sisting of outer layer a. and . inner layer i ; N, perisperm ; f , fungus layer ; E, endosperm consisting of aleurone layer al, and starch-parenchyma st. X 160. (After Winton, Conn. Agr. Exp. Sta.) transverse sections this coat often separates from the pericarp on the one hand and the perisperm on the other. Examined in water, only one cell layer (the inner) is evident; but successive treat- ments with 5 per cent potash, dilute acetic acid and chlorzinc iodine, bring out two layers. 1. The Outer Layer (a) is made up of thin-walled cells with euticularized outer walls. Treated as above described, the cuticle is colored yellow-brown, the radial and inner walls, blue. 2. The Inner Layer (1) is not only thicker than the outer, but the cellsi are thicker-walled land, in addition, swell greatly with potash. These swollen walls are stained deep blue by chlorzinc iodine, thus differentiating them from the yellow-brown cuticle on the inner wall. Perisperm (N). — Characteristic of this seed is the nucellar-coat, consisting usually of two cell layers. In cross section these cells are rectangular with swollen walls ; in surface view, as may ■ be seen after soaking for a long time in dilute potash, they are. ir- regularly polygonal or more or less elongated. i •■ Fungus Layer (F) . — In most specimens a layer of fungus-threads 20m thick is present between the perisperm and the aleurone layer. So commonly is this fungus present in darnel grown in Europe, that it is of no little value in identifying the grain ; but it remains to be determined whether in California, where the plant is a pest 524 WEED FLORA OF IOWA in wheat fields, the fungus is also a common accompaniment. After treatment with potash this layer is stained bright yellow by zinc chloride of iodine. Endosperm. — 1. The Aleurone Cells (al) vary from less than 20 to 40i" in diameter. 2. Starch-Parenchyma (st). The thin-walled cells contain small polygonal grains 3 to If^ in diameter. The in- dividual starch grains are not distinguishable from the grains of rice and oats, and like the latter, often occur in aggregates of various sizes. Fig. 402. Darnel. Elements of fruit in surface view. Significance of letters same as in Fig. 401. X 160. (After Winton, Conn. Agr. Exp. Sta.) URTICACEAE, NETTLE FAMILY. Hemp {Cannahis sativa L.). The smooth crustaceous aehene consists of an outer epidermal layer of thick-walled cells with wavy outline, the thickness of the radial walls varying somewhat. This is followed by a layer of loosely arranged parenchyma cells, and a layer of cells with brown contents. A layer of small cells spoken of as the dwarf cells by Winton, may also be made out in some sections. The palisade Layer consists of thick-walled cells with pore canals, the walls having a wavy outline. The cell cavity is very much reduced. The testa is very thin and consists of thin-walled elongated paren- chyma cells, the second layer of spongy parenchyma. The com- MICROSCOPIC STRUCTURE OF WEED SEEDS 525 pressed nucellus follows. The endosperm consists mostly of a single layer of cells, the embryo of small epidermal cells and the elonga,ted palisade parenchyma on the upper face of the cotyledon ; cells of embryo and endosperm contain fat and protein. Nettle {TJrtica gracilis Ait.). The pericarp of the small achenes consists of an outer epidermal layer of rather large cells with exterior walls thickened, and underneath several layers of loosely arranged parenchyma cells. The testa and nucellus are compressed ; cells of the embryo squarish, containing fat and protein grains. Fig. 403. Microscopic structure of the seeds of the Nettle family. (^Urticaceae) . I. Hemp (Qannahis sativa). II. Common nettle (.TJrtica gracilis). ep= epidermis, thick-walled short cells, underneath followed by a pigment layer, thinner-walled parenchyma cells and a layer of thick-walled cells. pal= palisade cells. p=parenchyma cells with the pigment. t=testa. n= nucellus. em = embryo. (Drawings by L. H. Pammel and Charlotte M. King.) POLYGONACEAE,* BUCKWHEAT FAMILY. Miss E. Sirrine finds, "In the seed coats of the family, the palisade portion constitutes the outer part of the achenium ; this is followed in most cases by the testa consisting of several layers of cells varying, however, in some cases; they are quite regular in form and in some instances are of a dark color. In the mature palisade cell, the cavity is present; this varies greatly in the dif- ferent genera; in some cases occupying nearly the entire cell, in others small and irregular." *A study of the microscopic structure of the achenes is largely based on Miss Emma Sirrine's work and upon that of Dr. Winton. 526 WEED FLORA OF IOWA Sorrel or Sour Clover {Rumex acetosa L.). This species has very small palisade cells, rectangular in shape and with a small cell cavity which occupies only a small portion of the lower end of the palisade cell. No canals or irregularities of cell cavity. The cell is light in color while canal is darker. The sub-palisade portion is composed of small round cells of a variable number. The endosperm is composed of irregularly ar- ranged cells. Measurements: whole seed coats, 38.3m ; palisade cells, 23/*; sub-palisade, 13.2/*. Fig. 404. Microscopic structure of the seed of some Polygonaceous weeds. I. Buckwheat (Fagopyrum esculentum) . II. Curled Dock iRumex crispus). III. (Wild Buckwheat or Bindweed (.Polygonum convolvulus). IV. Smart- weed (Polygonum persicaria). V. Sorrel (Rumex acetosa). VT. Knotweed (Polygonum erectum). VII. Smartweed (Polygonum, hydropiper). e=epidermis. sd=sclerotic layer. t=testa. al=aleurone layer. p=parenchyma cells. (Drawings by L. H. Pammel.) MICROSCOPIC STRUCTURE OF WEED SEEDS 527 Curled Dock {Bumex crispus L.). The brownish achenes of this species consist of an epidermal layer of elongated cells with thick stratified walls, outer wall colorless and a thick cuticle. The underlying parenchyma cells of three rows are smaller, with thick, brownish walls; cells contain tannin. The testa consists of two layers of cells, one large, thin- walled with brownish walls, the other compressed. The endosperm cells are large, thin-walled, and contain simple starch grains. Lady's Thumb or Smartweed {Polygonum persicaria L.). In this species the palisade cells are long, narrow and truncate. The cell cavity extends the whole length of cell at the upper end, with prominent branching pore canals. The sub-palisade portion consists of four layers of small roundish cells, a small chainlike layer also between the sub-palisade and endosperm. The endosperm consists of large irregular cells. Measurements: 138. G^j palisade cells, 108. 9i"; sub-palisade, 29.7^". Knotweed (Polygonum erectum L.). In this species the ''palisade cells" are much broader than in the other species here described. The cells have irregular papillate projections as in P. dumetorumi var, scandens. The cell cavity is narrow with long canals extending from it ; cavity branches divide near the end of the cell. In P. erectum, the whole cell is of a light brown color while the cavity is colorless. The sub-palisade portion consists of two layers of isodiametric cells. The endosperm has long, narrow, regular cells. Measurements: whole seed coat, 82.5m ; palisade cell, 60^"; sub-palisade, 22.5/*; papillate projections, 3.3/*. Smartweed (Polygonum hydropiper L.). In this species the palisade cells are long and narrow, very irregular and truncate at end. The cell cavity is very narrow and extends nearly the whole length of the cell. The cavity has sinuate canals which extend out from sides of the cavity. The cell is colored light brown while the cavity is deeper in color. The palisade cells resemble very much those of P. virginianum. The sub-palisade cells, however, are much smaller with more numerous indistinct layers, there being at least six layers well defined. The endosperm cells also are small and quite irregular. IMeasurements : whole seed coat, 132/*; palisade cells, 92.4/*; sub-palisade, 39.6/*. 528 WEED FLORA OF IOWA Wild Buckwheat or Bindweed {Polygonum co7ivolvulus L.). Dr. A. L;. Winton describes its microscopic structure as follows: Pericarp (f). — The black hulls or shells of the grain should be studied in cross section and in surface preparations, the latter being freed from the black coloring matter by warming on the slide with caustic alkali, or better by boiling for half an hour with 1,25% sodium hydrate solution as in the determination of crude fiber. 1. Epicarp (epi). Cross sections show that the cells are about 0.10 mm. in radial diameter on the sides of the achenes and are still longer at the angles. The inner wall is thin, but the outer Fig. 405. Black Bindweed. (.Polygonum convolvulus) : Transverse section of the fruit. C, calyx ; Epi, epicarp ; Mes. mesocarp ; B, flbro-vascular bundle ; S, testa; E, endosperm; Em, embryo. X 16. (After Winton, Conn. Agr. Exp. Sta.) wall and the outer portions of the curiously wrinkled radial walls are strongly thickened. Proceeding from the inner wall outward, the radial walls increase in thickness until the much-branched cell cavity is almost obliterated. On the surface are numerous warts from 0.015 to 0.03 mm. in diameter, into each of which a narrow branch of the cell cavity passes. Surface preparations of the pericarp with the outer surface uppermost clearly show that the warts are arranged in irregular longitudinal rows, also that the epicarp cells at the surface are sinuous in outline, but gradually approach a circular form farther inward. As may be seen in preparations of the pericarp with the inner surface uppermost, the contour of the inner cell walls of the epicarp is, like the outer wall, sinuous in outline. 2. Hypoderm (hy). Beneath the epicarp is a layer of slightly elongated parenchyma cells somewhat larger than the cells of the mesocarp. 3. Mesocarp (p.) At the angles of the fruit this layer is somewhat thicker than on the sides. The cells of the ground tissue are thin-walled and isodiametric, those of the inner layers being more or less obliterated MICROSCOPIC STRUCTURE OF WEED SEEDS 529 "^ epi hy p' end ae 4 ie al Fig. 406. Black Bindweed. Transverse section of the fruit. C, calyx consist- ing of the outer epidermis aep, the mesophyll m and the inner epidermis iep ; F, pericarp consisting of the epicarp ei with cuticular warts w, the mesocarp p and the endocarp end ; S, testa consisting of the outer epidermis ae, the cross-cells q and the inner epidermis ie ; E, endosperm consisting of the aleurone-cells al and the starch-cells s. X 160. (After Winton, Conn. Agr. Exp. Sta.) in the ripe fruit. Six primary, sparingly branched vascular bundles pass longitudinally through the ground tissue of the mesocarp, one in each angle and one in each of the faces. 4. Endocarp (end). Like the inner mesocarp, the cells are usu- ally obliterated in the mature seed and are seldom evident either in cross section or in surface view. Testa (S). — Three coats, analogous to those of buckwheat, but differing in form, make up the testa. 1. Epidermis (ae). As in buckwheat, the epidermal cells are wavy in outline; but in bind- weed they are strongly elongated, whereas in buckwheat they are nearly isodiametric. 2. Cross-Cells (q). Most of the cells of 34 530 WEED FLORA OF IOWA this layer are elongated, resembling the tube-cells of cereals; but short cells of more irregular shape also occur, particularly near the base and apex. These are more or less separated from each other, but in no part do they form a spongy parenchyma with circular intercellular spaces like that of buckwheat. 3. Inner Epidermis (ie). This coat consists of thin-walled, elongated ele- ments. rig. 407A Fig. 407B Fio. 407. Black Bindweed. A. Epicarp in surface view. X 160. B. Tangential section of the epicarp. (After Winton, Conn. Agr. Exp. Sta.) Endosperm (E). — None of the elements are distinguishable from those of buckwheat, either in form or size. 1. Aleurooie Cells (al) are of variable size and irregular shape. 2. Starch-Cells (s). In the outer layers the cells are tangentially elongated; farther in- ward, they are radially elongated and of large size. The polygonal or rounded granules vary in diameter from 0.003 to 0.012 mm. Vogl has noted that after treating the starch aggregates of buck- wheat with caustic potash, there remains, a network corresponding to the outline of the starch granules, the threads of which are of homogeneous structure without granules. This phenomenon I have also observed in the fruits of P. convolvulus and other species of Polygonum as well as in a number of species of Biimex, and it is probably characteristic of the entire family. The Errtbryo, con- sisting of an elongated radicle and two oblong cotyledons, may be conveniently isolated by soaking the seed in 1.25 per cent, caustic soda solution for some hours until the starch is removed. MICROSCOPIC STRUCTURE OF WEED SEEDS 531 Pr- FiG. 408. Black Bindweed. Seed in surface view. Significance of letters same as in Fig. 406. (After Winton, Conn. Agr. Exp. Sta.) Detection in Powder Form. — Characteristic of this fruit are the papillae on the outer epidermis of the caljrx and the epicarp with sinuous cell walls and rows of warts. The outer epidermal cells of the testa are sinuous in outline, like those of buckwheat, but, unlike the latter, are commonly elongated. Although the cross- cells are morphologically the same as the spongy parenchyma of buckwheat, they resemble more nearly in structure the tube-cells of the cereals. The starch granules are not characteristic and the network obtained after treatment with caustic alkali serves merely as an indication that the seed belongs to a Polygonaceous plant. Buckwheat {Fagopyrum esculentum Moench.). The achenium consists of elongated epidermal cells with thick- ened walls, underneath similarly elongated thick-walled sclerotic parenchyma cells with pore canals. This layer contains the pig- ment. The testa follows the pericarp and is differentiated into an epidermal layer of yellowish brown walls, followed by smaller thin- walled, parenchyma cells. The testa is much compressed ; the albumen consists of an outer aleurone layer of small cells followed by larger cells. The albumen cells contain compound starch grains. 532 WEED FLORA OF IOWA Fig. 409. Black Bindweed. Surface view of the pericarp from below. X 160. Significance of letters same as in Fig. 406. (After Winton, Conn. Agr. Exp. Sta. ) CHENOPODIACEAE, GOOSEFOOT FAMILY. Goosefoot or Lamb's Quarters (Chenopodium allium L.). Harz has given an account of the structure of Beta and Spinacia. The structure of the seed of lamb's quarters is somewhat different. The thin utricle consists of an epidermal layer of somewhat wavy cells and an indistinct layer underneath. The testa contains the brownish pigment. The cells are thick-walled ; the nucellus is com- pressed. The cells of the endosperm are large and contain an abundance of small starch grains. Russian Thistle (Salsola kali (L.) var. tenuifolia G. W. F. Meyer). The seed is without endosperm ; the embryo fills the seed, and is coiled in a conical spiral. The seed coat consists of two parts, a layer of three rows of elongated cells followed by a layer of three rows of irregular parenchyma cells. One side of the seed coat is wider than the other and these cells contain an abundance of calcium oxalate crystals. The cells of the outer layer of the MICROSCOPIC STRUCTURE OP WEED SEEDS 533 embryo are somewhat elongated ; the remainder are nearly as broad as long; these contain no starch but albuminoids and fat. Fig. 410. Microscopic structure of seeds of the Chenopod family. (Chenopodia- ceae). I. Russian Thistle iSalsola kaU var. tenuifolia) . II. Lamb's Quar- ters (Chenopodium album). ep=epidermis. p=parenchyma cells. t=testa. n=nucellus. en=endosperm. (Drawings by L. H. Pammel and Charlotte M. King.) NYCTAGINACEAE, FOUR-O'CLOCK FAMILY, Wild Fonr-o 'clock or Umbrella Plant {Oxyhaphus nyctagineus (Mx.) Sweet). The nutlike fruit of the wild four-o'clock or umbrella plant is somewhat hairy; the outer portion of the pericarp is made up of thick black-brownish cells from 6 to 9 rows. The epidermal cells are smaller, some of the cells elongated into one-celled thick- walled trichomes. Adjacent to the testa are bundles of thick-walled, sclerotic cells, the outer layer of cells of the testa consisting of mucilaginous cells with colorless walls. This is followed by a second layer of thin- walled parenchyma cells. The nucellus con- sists of an indefinite granular mass, followed by the endosperm, and the thin-walled cells of the embryo. CARYOPHYLLACEAE, PINK FAMILY. Soapwort or Bouncing Bet {Saponaria officinalis L.). The kidney-shaped, black, roughish seeds consist of tangentially elongated, thick, black, rough cells, the outer layer being brownish colored, while the cell cavity is red or blackish brown. The inner walls of the testa are thinner, the cells are elongated and the inner seed coat is much compressed. The nucellus is indistinguishable from the inner seed coat. This is followed by the endosperm. 534 WEED FLORA OF IOWA Fig. 411. Wild Four-o'clock (Oxybaphus nyctagineus) . The sclerotic paren- chyma, parenchyma and epidermis belong to the pericarp. ep=epidermis. p=parenchyma. scl=sclerotic parenchyma. t=testa. t^=tri- chome. en=endosperm. r=ribs. (Drawing by L. H. Pammel and Charlotte M. King.) consisting of an outer tangential layer with, granular contents. The aleurone layer and remaining portion of the endosperm cells consist of large rather thin-walled cells with compound starch grains and protein. Slender Catchfly {Silene antirrhina L.). The small kidney-shaped seeds are rough and brownish, in color. The outer epidermal walls are thick, brownish black in color. The underlying parenchyma cells are tangentially elongated with near- ly colorless walls. This is followed by an indefinite layer con- MICROSCOPIC STRUCTURE OF WEED SEEDS 535 sisting of an inner seed coat and a nucellus. The endosperm con- sists of thin-walled parenchyma cells with granular contents con- sisting of starch grains and protein. Fig. 412. Microscopic structure of some seeds of the Pink family iCary- ophyllaceae) . I. Bouncing Bet (Saponaria officinalis). II. Catchfly (Silene antirrMna) . III. Virginia Catchfly (Silene virginica). ep=epidermis. p=parencliyma. n=nucellus. h=hypoderm cells. en=endo- sperm. (Drawings by L. H. Pammel.) The seeds of Virginia Catchfly {Silene virginica) are irregular. The outer walls are greatly thickened, irregular, the underlying parenchyma cells being slightly elongated. This layer is followed by the nucellus and the aleurone layer and remaining endosperm cells containing starch grains and protein material. Silene inflata is described and figured by Harz*. ♦Samenkunde 2 :10-79. 536 WEED FLORA OF IOWA RANUNCULACEAE, CROWFOOT FAMILY. Conunon Buttercup {Banunculus abortiims L.). The greenish achenes of the buttercup consist of three distinct layers. The outer epidermal is of elongated, thickish black cells. The cells containing the brown pigment are yellowish brown. The underlying layers of three or four rows of seeds are similar but larger and paler in color. This layer is followed by a thick- walled sclerotic layer containing three or four layers of thick- walled cells with pore canals. The testa consists of an outer layer of thin-walled parenchyma cells; the inner layer consisting of sclerotic parenchyma cells filled with pore canals. The endosperm cells are large or thin-walled and contain protein material. Harz has given an account of the structure of R. arvensis*. Fig. 413. Microscopic structure of the seed of Buttercup {Ranunculus aiorti- vus). ep=epidermis. p— parenchyma. scl=sclerotic parenchyma. en=€ndosperm. (Drawing by L. H. Pammel and Charlotte M. King.) PAPAVERACEAE, POPPY FAMILY. Ct)mmon Poppy {Papaver somniferum L.). Prof. A. L. Winton describes the seeds of this plant as follows : Testa (S). — Cross sections are prepared after soaking the seed in water that may be cleared with chloral or alkali. After soaking the whole seed for about twenty-four hours in 1 per cent sodium hydrate solution, the first four layers readily separate from the *Landw. Samekunde 3 :10-64. MICROSCOPIC STRUCTURE OF WEED SEEDS 537 fifth. Subsequent treatment with hydrochloric acid dissolves out the calcium oxalate, and staining with chlorzinc iodine or safranin renders the outer layers more distinct. 1. The Epidermal Cells (ep) are polygonal and of enormous size, corresponding to the net- work on the seed. As appears in cross section, the cells are col- lapsed except in the neighborhood of the radial walls. In surface view the radial walls are sinuous and thin, what are often con- sidered the thick dark walls of this layer being not the walls at all, but the ribs formed by the thickening of the second and third layers. This conclusion is consistent with Meyer's and Hanausek's figures of cross sections, also with Meyer's drawings and Mach's photomicrographs of surface preparations. The statement of Tschirch and Oesterle that the epidermis consists of elongated cells situated over the ribs, with large polygonal cells between, has since been corrected by the authors themselves. Doubtless they mistook some of the cells of the second layer for epidermis. Hanausek's surface view, on the other hand, might convey the impression that the ribs were the cell walls, but his description and cross section clearly show their true nature. 2. Crystal Layer (k). On the Fig. 414. Poppy Seed {Papaver somniferum) . Transverse section, s, testa consisting of epidermis ep, crystal layer k, fiber layer f, cross-cells q and netted-cells n ; e, endosperm containing aleurone grains al. X 160. (After VP'inton, Conn. Agr. Exp. Sta.) ribs, the cells of this layer are more or less tangentially elongated, but between the ribs are isodiametric and polygonal, the elongated cells having longer radial walls than the others, thus contributing to the formation of the ribs. They contain fine, granular crystals of calcium oxalate. Meyer has demonstrated that the blue color of the poppy seed is due, not to a blue pigment, but to the inter- ference of light by the crystals over the brown cells in the back- ground, and is the same phenomenon that causes the apparent blue color of the sky and the iris of the eye. As soon as these crystals are dissolved in hydrochloric acid, the seed appears brown. 538 WEED FLORA OF IOWA 3. Fiber Layer (f). The fibers of this layer are 15-40i" broad and are parallel to the curved axis of the seed. Seen in cross section, this layer is thickest in the ribs, the walls throughout being distinctly thickened and stratified. In surface view they are rendered more distinct by chlorzinc iodine. 4. Cross-Cells (q). The fourth layer consists of moderately thick-walled, transversely elongated, pointed cells arranged side by side in rows. The walls are impregnated with brown material. 5. Netted-Cells (n). Ow- ing to the netted-veined, colorless walls and the presence of deep brown contents, these cells are particularly striking. They are arranged transversely and often side by side in rows. The cell contents are insoluble in alkali and do not give the tannin re- action. Some authors designate the cells of this layer "Pigment cells," notwithstanding the fact that in the white poppy they do not contain pigment. Meyer, Tschirch and Oesterle, Vogl, and Hanausek describe an inner layer of thin-walled cells, but I am unable to find such a layer except in the vicinity of the hilum. Pig. 415. Poppy seed. Testa in surface view. Significance of letters same as in Fig 414. pig, pigment. X 160. (After Winton, Conn. Agr. Exp. Sta.) The Endosperm (E) contains aleurone grains up to 3m in the outer layers and 7-" in the inner layers, each grain containing several globoids and crystaloids. Emhryo. — In the cotyledons there is only one layer of palisade- cells and these cells are only slightly elongated. The aleurone grains are like those of the endosperm. MICROSCOPIC STRUCTURE OF WEED SEEDS Prickly Poppy {Argemone intermedia Sweet). 539 The blackish, pitted seeds are difficult to study. They consist of nearly colorless epidermal cells, with thick outer walls and cuticle. The cells of the underlying layer are thick-walled, walls and contents blackish, difficult to make out on account of dense Fig. 416. Rocky Mountain Poppy (.Argemone intermedia}. ep=epidermis with thick outer walls. pi=pigment layer, n=nucellus, en=en- do.sperm. (Drawing by L. H. Pammel and Charlotte M. King.) pigment. The nucellus is compressed, colorless. The endosperm of large cells contains oil in large amounts, and protein. The structure seems to differ in a marked degree from Papaver as described by Harz and G. Kraus.. CRUCIFERAE, MUSTARD FAMILY. Virginia Peppergrass (Lepidium virginioum L.). The seed coats consist of three well defined layers. The outer or epidermal cells are tabulated, somewhat compressed. The cuticle forms a continuous layer over these. On the addition of water the epidermal cells elongate and form a mucilaginous mass, showing stratified layers. These are not difficult to make out when the specimen is mounted in water. The cell cavity is very much re- duced ,• that portion of the cell wall in contact with the cell cavity is differentiated from the outer cell wall substance. Long con- tinued addition of water causes the cuticle to break and the exterior becomes very irregular. The second layer is colored brown, the cell walls are considerably thickened laterally and project upwardly in the shape of cones. A section made through the ends of these seeds shows that the second layer is considerably more developed and there are evidences 540 WEED FLQRA OF IOWA here of an indistinct .layer between the first and second. The layer following this consists of thin-walled parenchyma cells, in some cases considerably elongated but in others short. The third layer is followed by the endosperm which consists of a layer of rather thick-walled parenchyma cells. These carry granular protein grains. This is followed by one or more layers of elongated cells, in which the cell cavity is very much reduced. These cells reach their highest development between the folds of the caulicle and cotyledon. The cells of the first layer of the embryo are smaller, quite uni- form in size and filled with protein grains and oil. Small Peppergrass {Lepidium apetalum WiWd.) . The cuticle forms a continuous layer over the epidermal cells, which are larger than in L. virginicumv. On the addition of water the cell wall rapidly elongates, emitting a copious mucilage. The cell cavity is very much reduced but longer than in L. virginicum. It is surrounded by a denser, more or less difl:erentiated part of the cell wall which is more yellow in color than the remainder of the cell wall. The second layer is of a yellow straw color and consists of very minute cells with small cell cavities. The cell walls of the third layer are strongly thickened, brown, and serve the same purpose as in the other species. The endosperm consists of thick-walled parenchyma cells. In the first layer of cells, the cell walls are very much larger and packed with protein grains. The other layers of endosperm consist of small elongated thick-walled cells with a small cell cavity. These attain their greatest development between the caulicle and cotyledon. In the embryo, the cells of the first row are isodiametric filled with protein grains and oil. The outer cells are elongated larger, and also densely packed with the same material. Shepherd's Purse {Capsella hursa-pastoris (L.) Medic). The seed coats attain their maximum development in the region of the caulicle. Cuticle covers the epidermal cells, the latter tabular, compressed but in the addition of water elongating, be- coming mucilaginous and showing stratification. The second and third layers are brown with thick cell walls. Fourth layer consists of endosperm, one layer of isodiametric cells filled with protein grains, followed by thick-walled cells reaching MICROSCOPIC STRUCTURE OF WEED SEEDS 541 Fig. 417. Microscopic structure of seeds of Mustard family (Cruciferae). I. Hedge Mustard (. Sisymbrimn canescens) . II. Small Peppergrass (Lepidmm apetalum). To the right an enlarged epidermal cell with mucilaginous walls. ep=epidermis. p=parenchyma. em*=embryo. (Drawing by L. H. Pammel.) their greatest development between the cotyledon and caulicle. First row of cells of embryo . nearly isodiametric, filled with oil and protein grains. Others somewhat larger contain the same substances. Cotyledons incumbent. Central part of caulicle sepa- rated from the rest. Cells of caulicle very much larger than cells of cotyledons. Black Mustard (Brassica nigra Koch.). The cuticle covers the epidermal cells as a continuous layer; when mounted in alcohol the outer layer is very much 'compressed and shows very slight stratification; the cell walls expand and after it has been moist for a considerable time the cuticle breaks. Stratification is very evident on the addition of water. The second layer consists of rather thin-walled parenchyma. The cells of 542 WEED FLORA OF IOWA Fig. 418. Microscopic structure of some Cruciferous seeds (.Cruciferae). I. False Flax (Camelina sativa). II. Black Mustard (Brassica nigra). III. Common Mustard (B. arvense). IV. Winter Cress (.Barbarea vulgaris). V. Peppergrass (Lepidium virginicum). VI. Tumbling Mustard (.Sisym- brium altissimum) . VII. Shepherd's Purse (.Capsella bursa-pastoris) . t=testa. p=parenchyn:a cells. n=nucellus. em=embryo. I, II, III, and IV. Elongated palisade cells below the epidermal layer and parenchyma cells. To the right of I, epidermal cells after the addition of water. (Drawings by L. H. Pammel.) this layer differ greatly with, reference to their size, being scarcely at all developed in places, in others nearly as large as the cells of the outer layer. MICROSCOPIC STRUCTURE OF WEED SEEDS 543 The third layer consists of thiek-walled parenchyma cells, densely packed, radially elongated, sides presenting a cone-shaped appear- ance. Underneath this is a layer of thick-walled parenchyma cells which contain some coloring matter. The endosperm follows this layer. The first layer consists of thick-walled cells, densely packed with albuminous matter. The remaining cells vary in number, are much elongated, thick-walled with a small cavity; these cells extend down between the contiguous portions of the cotyledon or caulicle. The Embryo. — The cells of the first layer surrounding the cotyledon or caulicle are smaller, filled with fat and protein grains. The remaining cells are larger, also filled with fat and protein grains. The central part of the caulicle shows a differentiation of the embryonic vascular portion, consisting of small cells. Charlock or Common Mustard {Brassica arvensis (L.) Ktze.). The outer layer of cells is compressed, tabular, with stratification not evident, and cuticle well developed, and forms a continuous layer over the outer cells; on the addition of water, the cell walls become mucilaginous, elongate, stratification becomes evident, the cuticle breaks, and an irregular surface is formed. The second layer is but slightly developed, made up of thin-walled parenchyma cells. The cells of the third layer are elongated and thickened laterally. These cells are much longer than in B. nigra land brown in color. The fourth layer consists of one to two rows of rather thin-walled cells carrying pigment. Endosperm consists of several rows of cells; first row nearly isodiametric, filled with protein grains. The three or four layers of cells following are thick- walled with a small cell cavity. Embryo. — First layer of cells nearly isodiametric, those follow- ing somewhat larger, filled with protein and fat grains. Hedge Mustard {Sisymbrium- officinale Scop.). Cuticle covering the epidermal cells, the latter tabular, much compressed. On the addition of water the cell walls become mucilaginous with evident stratification. The cells of the second layer are brown and thin-walled, much compressed. On addition of choloral hydrate they expand. Third layer much darker than the second, thick-walled, followed by endosperm, cells elongated, filled with protein grains, followed by elongated thick-walled cells 544 WEED FLORA OF IOWA with a small cavity. These reach their highest development between cotyledons and caulicle. First row of cells of the embryo nearly isodiametrie, filled with protein grains and oil. Tumbling Mustard {Sisymbrium altissimum L.). On the addition of water the cell wall of the outer seed coat becomes mucilaginous. Outer epidermal layer covered with cuticle, cells elongated, on the addition of water, walls become mucilaginous and show stratification. Cell walls of second layer thick, light brown, followed by endosperm of two layers of cells, first elongated, thick-walled. Cells of embryo as in S. officinale. Hairy Hedge Mustard {Sisymhrium canescens Nutt.). The testa of the small brownish cells consists of an outer epidermal layer with thick walls. These cell walls become mucil- aginous on the addition of water. This is followed by a layer of several rows of brownish cells and a compressed layer, the nucellus. The cells of the outer row of the embryo are smaller than the underlying cells. Common Winter Cress or Yellow Eocket {Barharea vulgaris R. Br.) . First layer of outer seed coat not well developed, cells elongated in the direction of the seed. Cuticle covers the epidermal cells. On the addition of water a slight mucilaginous modification takes place. Second layer with thick lateral walls and quite large cell cavities, colored brown. Third layer of rather thick-walled parenchyma cells also colored brown, followed by endosperm as is usual in cruciferous seeds. False Flax {CameUna sativa (L.) Crantz.). Seed coats consisting of four layers. The outer epidermal cells not much longer than wide, on the addition of water become mucilaginous and well stratified. On the addition of chloral hydrate stratification is more evident. The cell walls are differentiated into several layers. The second layer is not always developed. Cells of third layer with thick walls and brown pigment, followed by a narrow layer of thick-walled brown cells. The first row of cells of endosperm, rather thick-walled, filled with protein grains, the other layers of unequal development, cells elongated, thick- walled ; followed by cells of embryo ; these contain protein grains and fat. MICROSCOPIC STRUCTURE OF WEED SEEDS 545 ROSACEAE, ROSE FAMILY. White Avens {Geum canadense Jaeq.). A greater part of the so-called seed is made up of the pericarp consisting of a layer of small epidermal cells with trichomes. The underlying parenchyma cells are large with numerous intercellular spaces. The testa is thin, consisting of an outer pigment layer followed by several rows of thick-walled, colorless cells. Fig. 419. Microscopic structure of fruit of Avens (Geum canadense). ep=epidermis. p= parenchyma. per=pericarp. t=trichome. t^=testa. (Drawing by L. H. Pammel and Charlotte M. King.) LEGUMINOSAE,* PULSE FAMILY. Rattlebox (Crotalaria sagittalis L.). The testa not strongly developed; endosperm 196-" in thickness. From Nadelmann's studies it appears that in Crotalaria verrucosa the horny endosperm is well developed, being four and one-half times as wide as the testa. The aleurone layer contains fat and aleurone grains. The cells of the embryo contain protein and fat but no starch. •The descriptions here given are taken for the most part from a paper by L. H. Pammel, Trans. Acad. Sci. St. Louis, 9. 35 546 WEED FLORA OF IOWA Malpighian. — The cells are prismatic in surface view, 9.8/* across, with five to six canals. In cross sections they are 84m long. The cuticle forms a continuous layer, with longitudinal canals pro- jecting into the cells; these extend down through the upper part of the cell wall and the cuticularized substance ; this layer is lighter in color than the rest of the cell wall, and separates from the re- mainder of the cell in the form of a band. The narrow light line occurs close under the cuticularized layer. The cell cavity is narrow and gradually tapers upward; it contains some protein matter. The cell wall consists of cellulose. Osteosclerid. — The walls are thickened. Cells wide in the lower part and narrowing upwards, with large intercellular spaces. Cells contain protein. Nutrient. — Consists of radially elongated cells, which are slightly compressed. Walls of medium thickness, slightly colored. Fig. 420. Microscopic structure of tlie testa of Rattle-box (Crotalaria sagittalis). ll=light line. m=malpighian cells. n=nutrient layer. o=osteosclerid. (Drawing by L. H. Pammel.) Endosperm. — Not strongly developed. The cells of the aleurone layer large, containing protein. Two layers follow this, the cells very much compressed, and somewhat radially elongated, of thick- walled cells. All of the cells contain protein and fat. Embryo. — Cells of outer row smaller; those adjoining the en- dosperm thicker walled, the inner part with thinner walls. The re- maining cells of the embryo larger. All of the cells tilled with protein. Starch is absent. Black Medick {Medicago lupulina L.). Testa and endosperm well developed, 245m in thickness on sides. More than half of this thickness consists of endosperm. MICROSCOPIC STRUCTURE OF WEED SEEDS 547 Maipighian. — Cells 40-42/" in length. Cuticle slightly irregular; underneath the cuticle a light colored area with conical projec- tions, as in Melilotus, but somewhat more prominent. With chlor- iodide of zinc this rapidly colors blue. It corresponds to the mucilaginous "membrana interna" of Mattirolo and Buscalioni, and, as shown by Schips, is chemically differentiated from the cuticle and remainder of the cell wall. The conical layer is highly refractive. The light line occurs below the conical layer and colors blue soon after the addition of chlor-iodide of zinc. The cell cavity is broadest at ^the base, gradually tapering upward. A large chromatophore occurs at the base or near the middle of the cell cavity. In colored seed some pigment occurs in the cavity as well as considerable amounts in the walls. Small pore-canals occur in the upper part of the cell wall. The cell walls color blue more slowly with ehlor-iodide of zinc than the cuticularized layer. Osteosclerid. — Cells broad at the base, with conspicuous longi- tudinal pores; intercellular spaces below the Maipighian cells tri- angular; walls colored brownish; cells containing pigment and tannin. Nutrient. — This layer is much compressed, and differentiated into two parts; cells elongated, rather thin-walled; those in the lower portion carry a great deal of pigment, and are much more compressed than the upper portion. Endosperm. — The endosperm is of unequal development, later- ally as much as ISOa* in thickness. Harz gives the thickness as 250/^. Cells of the aleurone layer rectangular, thick-walled, and filled with fat and protein grains. This layer is followed by re- serve cellulose. The primary wall persists when treated with weak solvents. The walls, except the primary, color blue with chlor- iodide of zinc. The inner portion of the endosperm consists of thick-walled, elongated cells. Embryo. — Cells of the first row smaller than those below; ex- terior walls thickened more than the lateral; all of the cell walls consist of cellulose. Cells contain fat and protein grains; starch grains do not occur, though Harz says they are usually abundant. In several specimens examined starch was not found even when potassium hydrate or weak sulphuric acid was used with the iodine. 548 WEED FLORA OP IOWA Fig. 421. Microscopic structures of seeds of some leguminous weeds. I. and V. Yellow Sweet Clover (MeUloUis officinalis). II. White Sweet Clover (Blelilotus alba). III. Black Medick {Medicago lupulina). IV. Bur Clover (Medicago denticxilata) . m=malpighian cells. ll=light line of the same. o = osteosclerid. em=embrya t=testa. en=endosperm. p=parenchyma. n=nucellus. (Drawings by L. H. Pammel.) MICROSCOPIC STRUCTURE OP WEED SEEDS 549 Bur Clover {Medicago denticulata Willd,). The seeds of this species agree with those of M. lupuUna. Malpighian cells 35-38/^ long; the narrow light line occurs be- low the conical layer; the chromatophores are absent. Osteosclerids 16-18/^ long; longitudinal striae well marked. Cross sections show beyond a doubt that these striae are canals. The nutrient layer is much compressed. Aleurone layer of endosperm as in M. lupuUna. The mucil- aginous reserve cellulose not so strongly developed as in the last species. Treatment with iodine gives no reaction for starch; nor do blue grains appear when treated with weak sulphuric acid and iodine, or potash and iodine. An abundance of fat and protein grains occurs in the cells. Walls of the reserve cellulose color light blue. Malpighian cells a darker blue. Sweet Clover {Melilotus alba Lam.). Testa and endosperm vary in thickness, average 75-". Malpighian cells as long as the thickness of the endosperm and remainder of testa. Malpighian. — Cuticle wavy and well developed ; the cuticularized layer below with small, conical projections, those of two adjoining cells meeting at the middle lamella of the lateral walls, giving the layer the appearance of consisting of conelike projections. These cones are also connected with the small pore-canals. This cuticular- ized layer is highly refractive. The light line consists of a nar- row but distinct refractive zone below the conical layer. The refractive zone colors blue with chlor-iodide of zinc. The whole upper part is more or less refractive. The remainder of the cell wall contains pigment and is colored blue with chlor-iodide of zinc; the cuticularized layer as well as the conical layer colors blue. Small canals project into the walls, and in some cases extend beyond the light line. The chromatophores are irregularly dis- tributed in the cell cavity, some near the base, others in the center, Ost&osclerid. — Cells with a broad base and a small triangular intercellular space above ; longitudinal pore-canals in the upper part of the cell, but these do not extend its entire length. Nutrient. — This layer is much compressed; consists of thin- walled cells, divided into two parts; cell walls of lower part thicker. Both layers contain pigment and tannin, the upper more than the lower. Cell walls consist of cellulose. 550 WEED FLORA OF IOWA Endosperm. — The aleurone layer is quite distinct; the cells are rectangular; cell walls made up of cellulose. The walls of the re- mainder of the endosperm, except where it joins the embryo, are thick, consisting of mucilaginous reserve cellulose. Cells of the internal layer of the endosperm thick-walled, elongated, containing some protein grains and fat. Ernbryo. — Cells of the exterior walls of first row thickened; smaller than those below. All of the cells contain fat, protein grains, and small starch grains. Proeambial vessels well developed. Yellow Sweet Clover {Melilotus officinalis Lam.). Testa with endosperm varying from 260-300-" in thickness. The Malpighian cells of this species are longer than in M. alba, and also more abundantly supplied with pigment. The conical pro- jections are longer. The osteosclerids are longer and nearly as wide above as below. The longitudinal canals are as conspicuous and well developed as in that species. Cells of the nutrient layer, especially in the lower part, are abundantly supplied with pig- ment and some tannin. The walls of the aleurone cells are thick; the mucilaginous reserve cellulose and the thick-walled, elongated cells are not essentially different from the last species. It also agrees with it with respect to the embryo. Hairy Prairie Clover (Dalea alopecuroides Willd.) {Parosela dalea (L.) Britt.). Testa and endosperm from 150-265/" in thickness. Variation is mostly due to endosperm, which reaches its greatest development laterally. Malpighian. — Cells are 36.4^ in length. Cuticle prominent; cuticularized layer not conspicuous; narrow light line near the cuticle; pores prominent, extending into the walls beyond the light line. Cell cavity broad at the base, containing protein grains. Osteosclerid. — Cells thick-walled, lighter in color than the Mal- pighian layer. They contain pigment, tannin and protein. Nutrient. — This layer is compressed and the cells are elongated. Walls color blue with chlor-iodide of zinc. Brown pigment abundant in the vascular region. Endosperm. — Aleurone cells nearly isodiametric, containing fat, and protein; most of the endosperm consisting of reserve cellulose MICROSCOPIC STRUCTURE OF WEED SEEDS gSl Fig. 422. Microscopic structure of legtiminous seeds (Leguminosae) . I. Silky Sophora (Sophora sericea). II. Parosela (Dalea alopecuroides) . III. Common Vetch (Vicia sativa). IV. Stemless Locoweed (Oxytropis lam- berti). V. Wild Liquorice (Glycyrrhiza lepidota). m=malpighian cells. ll=light line. em=embryo. o=osteosclerid. p=parenchy- ma. al=aleurone layer. en= endosperm, en = endosperm reserve cellulose cells. tr=tracheae. (Drawings by L. H. Pammel.) 552 WEED FLORA OF IOWA with prominent pore-canals ; the internal layer consisting of elongated thick-walled cells, with cell cavity much reduced. Embryo. — First row of cells of embryo smaller than underlying, with thickened outer walls. Cells below with small intercellular spaces. Reserve material consists of fat and protein grains; starch is absent. Stemless Loco Weed (Oxytropis lamberti Pursh.). Testa and endosperm 170-175/^. This, the so-called loco weed, is said to cause disturbances in animals, but alkaloids have not been found in the seed or any other part of the plant. Malpighian. — Cells 40-42^ long. Cuticle somewhat uneven; the narrow well marked cuticularized layer colors blue with chlor- iodide of zinc; the light line occurs below the cuticularized layer, and this also colors blue; the remainder of the cell wall takes on a darker blue color. Cells contain an abundance of pigment, tannin, and some plastic material. Osteosclerid. — Cell walls thickened, not prominently I-shaped, but with an elongated intercellular space. Nutrient. — Layer consists of thin-walled elongated cells from ten to twelve rows. Pigment more abundant in lower than in upper part. Walls color blue with chlor-iodide of zinc. Endosperm. — The aleurone layer consists of thick- walled cells; the underlying thick-w^alled 'cells of the reserA^e cellulose become mucilaginous on the addition of water. The internal part consists of thick-walled, elongated cells. The cells contain protein. Embryo. — Cells of the first row smaller, with thick exterior walls; cells below not so compact arid with thinner walls. Cell walls color blue with chlor-iodide of zinc. Starch is absent but cells contain fat and protein. Bush Clover (Lespedeza capitatai Mx.). Testa and endosperm 90-100^ thick. Light line occurs close under the cuticle. A large spherical chromatophore occurs in the pigmented Malphigian cells which is variable as to its position in the cell. The long pores extend to the middle of the cell. The os- teosclerids are short. The nutrient layer is compressed, containing much pigment. Endosperm as in L. stuvei; the aleurone cells are thick-walled, and the reserve cellulose is mucilaginous. Embryo as in the other species containing fat and protein but no starch. MICROSCOPIC STRUCTURE OF WEED SEEDS 553 Common Vetch {Vicia sativa L.). This species has been studied by Harz, Tschirch and Oesterle, Beck, and Sempolowski. Testa irregular, with small projections, 126m thick. Endosperm reduced to a single layer. The presence of endosperm has been indicated by the above writers. Beck speaks of an aleurone spot (Aleurone fleck) in the epidermal cells of the cotyledons of this and other species of the genus Vicia. Malpighian. — Cells 72-75/* long, pointed at the upper end; cuticle very irregular because of the projections; cuticularized layer most prominent in the depressions; pores project into the walls below the light line, and partly connect with the cell cavity; the upper part of the cell is not pigmented, or very little. The light line occurs just above the pigmented part of the cell. Cell cavity is large at the base, narrows upward, becoming much con- stricted below the light line, and above widens again. Small lateral projections or pores extend into the wall at right angles to the cavity. A large chromatophore, some pigment, and small granules occur in the cavity. The walls in lower part of cell are colored bluish brown. Osteosclerid. — Cells are thick-walled, 13-16. 8m long, longitudinally striated. Upper and lower cross-bars nearly equal; the inter- cellular spaces elongated. Tschirch and Oesterle state that this layer is not very strongly developed, but in specimens which I have examined it is well developed. These cells are more or less variable, as indicated by Harz, who states that they are from 11-13/" long. Nutrient. — This layer is differentiated into two parts ; the upper consists of thin-walled, elongated cells with a yellowish pigment; the cells of the lower part are larger, thin-walled and elongated, containing a brown pigment. Nucellus. — This consists of a narrow zone of compressed cells. Endosperm. — Occurs in the form of thick-walled elongated cells with a narrow cell cavity. Usually only one or two rows of cells. Embryo. — The outer row of cells of the cotyledon is continuous. The exterior walls are thickened; cells below are more loosely ar- ranged; small intercellular spaces in the angles of the cells; the epidermal cells contain fat and protein, the others in addition an abundance of spherical or elliptical starch grains measuring 25 x22.5m to 50x25m. Palisade cells wanting. 554 WEED FLORA OF IOWA Wild Liquorice {Glycyrrhiza lepidota (Nutt.) Pursh.). Testa and endosperm 490-500^ thick. Endosperm variable in different parts of the seed, but usually well developed. Malpighian. — Cells 70-75^ long. Cuticle somewhat irregular; the light colored cuticularized layer is followed by a narrow but sharply marked zone, the light line ; cell cavity is large at the base, gradually tapering upward. Pore-canals extend into wall beyond the light line. Cells contain pigment and some plastic material. Osteosclerid. — The I-shaped cells are thick-walled, with small projections somewhat similar to those shown for Ervum lens by Mattirolo and Buscalioni. The intercellular space is elongated. The cells attain their greatest development in the hilar region. All of the cells carry some pigment and plastic material. Nutrient. — This layer is much compressed and thin-walled; cells number from four to six rows. Pigment is most abundant in the lower part of the layer. Endosperm. — Aleurone layer consists of nearly isodiametric thick-walled cells. The mucilaginous reserve cellulose is variable in quantity. Cell walls differentiated into primary, secondary and tertiary. Internal part of the endosperm consists of thick-walled, elongated cells. All of the cells contain protein grains. Enibryo. — Cells of the outer row smaller than those within; ex- terior walls thickened, those below more loosely arranged than the epidermal; more compact and with thicker walls than those of Astragalus mexicanus. Cells contain fat and protein grains but no starch. LINACBAE, FLAX FAMILY. Common Flax {Linum usitatissimum L.). The shining, brownish seeds consist of an outer epidermal layer of thick-walled cells; walls colorless and stratified; these become mucilaginous on the addition of water. The cell cavity is very small, the underlymg layer consists of yellowish parenchyma cells. The third, called the fiber layer by Winton, consists of sclerotic parenchyma cells with pore-canals, the sclerotic parenchyma fol- lowed by a layer of colorless cross-cells with thin walls. The parenchyma cells of the pigment layer follow; these cells are squarish, pigment yellowish brown. The endosperm follows the MICROSCOPIC STRUCTURE OF WEED SEEDS 655 Fig. 423. Microscopic structure of the seed of common Flax (.Liitum usitatiS' aimum'). ep=epiderinis. p=parenchyma, underneath thick-walled sclerenchyma cells and the pigment layer. pi=pigment layer. en=endosperm. (Drawing by L. H. Pammel and Charlotte M. King.) pigment layer and consists of 2-6 layers of cells, the walls being thicker than those of the embryo, and containing fat and aleurone grains. The epidermal cells of the embryo are squarish, the cells underneath on the upper face of the cotyledon are palisade-like. All of the cells contain fat and protein. GERANIACEAE, GERANIUM FAMILY. Carolina Cranesbill {Geranium caroUnianum L.). The testa of the smooth small seeds consists of an outer epider- mal layer, the cell walls not greatly thickened; underlying it is a single row of elongated parenchyma cells followed by the Mal- phigian cells; the light line is narrow and occurs in the middle of the cell; this is followed by a layer of much larger cells with thick walls. The inner seed coat is much compressed and consists of several rows of small cells and a single row of large cells. The walls in both cases are not greatly thickened. The nucellus is much compressed. The cells of the endosperm are not much longer than broad. The cells of the outer row or the aleurone layer are much smaller than those of the second layer. 556 WEED FLORA OF IOWA Fig. 424. Microscopic structure of the seed of common Geranium (Geranium caroUnianum) . ep=epidermls. p=parenchyma, malpighian cells below. ll=light line of mal- pighian cells. pal=palisade cells. it=inner testa. n=nucellus. en=en- dosperm. (Drawing by L. H. Pammel and Charlotte M. King.) EUPHORBICBAB,* SPURGE FAMILY. Flowering Spurge {Euphorhia corollata L.). The outer layer of the seed coat is mucilaginous; the walls of the cells are, thickened and colorless; showing stratification upon addition of water; the cell contents are dark in color. The granu- lar layer beneath the mucilaginous cells is well developed ; the eon- tents give a blue reaction to iodine. Underneath the granular layer is a row of slightly elongated thin-walled parenchyma cells ; beneath these are the long palisade-like cells, in which are pores of less prominence than in E. mar gin at a and others. Next lie two compressed layers of thin-walled parenchyma cells. Spotted Spurge {Euphorbia preslii Guss.). The outer layer of cells are darkened; these cells are not mucilaginous. The palisade-like cells are present, as in all the species. *The descriptions here given are from a paper by L. H. Pammel, Trans. Acad. Sci. St. Louis. 5:543. The literature will be found in this paper. MICROSCOPIC STRUCTURE OF WEED SEEDS 557 Prostrate Spurge {Euphorhia maculata L.). The walls of the outer cells are dark in color; these cells are but slightly mucilaginous. The granular layer is not pronounced. The palisade-like cells resemble those of the other species. Fig. 425. Microscopic structure of the seeds of the Spurge family (,Euphor- biaceae). I. Cypress Spurge (.Euphorbia cyparissias) . II. Flowering Spurge (.Euphor- bia corollata). ep= epidermis, in figure II cell-walls mucilaginous. pal=palisade cells. p= parenchyma cells. (Drawing by L. H. Pammel.) Yellow Spurge {Euphorbia cyparissias L.). The seed shows the usual palisade-like cells with the overlying and underlying thin-walled parenchyma cells. MALVACEAE, MALLOW FAMILY. Velvet Weed, Butterprint {Ahutilon theophrasti Medic.).* The outer layer a, of the first integument is transformed into a strongly refractive layer. The second layer is composed of radially elongated cells. The seed hairs arise from a single cell and are large and conspicuous. The hairs are spindle-shaped and thin- walled; they occur mostly at the ends of the seed and are more or less pressed to it. There is little or no coloring matter in this in- *From Rolfs, P. H., Bot. Gaz. 1893 :33-39. 558 WEED FLORA OF IOWA tegument excepting in the base of the hair cells. The palisade cells, c, are narrow for their length. The cell cavity is not promi- nent and the nodosity is inconspicuous. The light line is narrow and occurs near the outer end of the palisade layer. The sub- palisade portion, d, is made up of two layers of light brown cells. They are symmetrical and elongated tangentially. Measurements, seed coats, 147/^; outer integument, 13m ; palisade layer, 96^"; subpalisade, 38/*. Shoo-fly {Hibiscus trionum L.). P. H. Eolfs has made a study of H. militaris, the microscopic structure of which species closely resembles that of H. trionum. The dark grayish seeds are roughened with tubercular processes, which contain the "seed hairs." The &eed hairs consist of cells somewhat longer than broad beginning with a broad base, ex- tending into a several-celled trichome, the terminal portion larger than remainder of cell. These hairs contain a yellow pigment. The Malpighian cells occupy about one-half the thickness of the testa, the cuticle isi well developed, the light line is near the upper portion of the cell. The cell cavity is spindle-shaped and near the middle of the cell. The remainder of the testa consists of a subpalisade portion of parenchyma cells carrying a brownish pig- ment; underneath it, larger thin-walled cells; walls brownish, a compressed marrow, brownish layer, the nucellus, n. This is fol- lowed by the squarish cells of the endosperm. Common Mallow {Malva sylvestris L.). The surface of M. sylvestris is rough in appearance. The second layer, b, of the outer integument, a, has been compressed into a thin layer and seems to have no definite arrangement. The outer layer, a, has been elongated radially. In places, these elongated cells have divided forming a double layer of cells. There is no brown coloring matter in this integument nor is there any between the integuments. The palisade cells, c, are clear; the walls thick. The cell cavity occupies about one-third the length of the cells, the lower end reaching to the middle. The nodosity is promi- nent. Below the cavity the cells are clear, almost transparent. The subpalisade portion, d, is usually made up of two layers, at some places only one, of large dark brown cells. MICROSCOPIC STRUCTURE OF WEED SEEDS 559 Measurements, seed coats, 122/*; outer integument, 27m ; outer layer of same, 22/*; inner layer of same, 5/*; palisade layer, 70/*; subpalisade, 25/*. (P. H. Rolfs.) -'^'O^^^^y- T Fig. 426. Microscopic structure of the seeds of some Malvaceous weeds. I. Siioo-fly (Hibiscus trionum). II. Indian Mallow or Butterprint iAhutilon theophrasti) . III. Mallow (Malva sylvestris). IV. Sida (Sida spinosa). V. Cheeses or common Mallow (Malva rotundifolia) . ep=epidermal cells. m=malpighian cells. ll=light line. pi=pigment layer. p= parenchyma cells. pal=palisade or malpighian cells. n=nucellus. en=en- dosperm. h=trichome. t=plant hair or trichome surface view (Drawings by P. H. Rolfs.) Cheeses or Mallow {Malva rotundifolia L.). The roughened, somewhat velvety, dark grayish seeds consist of an outer row of rather large, rather thick-walled cells, walls colorless. This layer is followed by the very long Malpighian cells, which are longer than the cells of the rest of the testa, light line near the upper part of the cell, lower portion of cell slightly yellowish. Cavity spindle-shaped near the middle. The dark 560 WEED FLORA OF IOWA brownish pigment cells of two or three rows. Adjacent to th& pigment layer is the colorless compressed nucellus and the squarish endosperm cells. Sida {Sida spinosa L.). The brownish seeds are minutely roughened. The Malpighian cells occupy more than one-half of the thickness of the testa, the cuticle is well developed, the light line occurs near the upper end of the cells. The cell cavity is spindle-shaped near the lower end of the cell. The subepidermal layer contains the brownish pig- ment, the walls of these cells are thickened; the parenchyma cells of the layer underneath are colorless, the walls are less thickened; a narrow pigment layer follows. The cells of the endosperm are thick-walled containing protein grains. ONAGRACEAE, EVENING PRIMROSE FAMILY. Evening Primrose {Oenothera 'biennis L.). The small, irregular, winged seeds are rough. Th^e epidermal cells, ep, of the testa are small, thick-walled with minute pore canals; the underlying parenchyma cells, p, are large, thick-walled and with small pore canals ; these cells reach their greatest develop- ment where the wings occur. The remaining portion of the testa consists of four or five layers of cells more or less rectangular. The nucellus and the endosperm much compressed, outer epidermal cells of the embryo, em, thin-walled, a little longer than wide. Fig. 427. Microscopic structure of the seed of Evening Primrose {Oenothera biennis). ep=epidermis of thick-walled cells. p= thick- walled parenchyma underneath thinner-walled parenchyma. n=nucellus and below a few layers of cells of the endosperm. (Drawing by Charlotte M. King and L. H. Pammel.) MICROSCOPIC STRUCTURE OP WEED SEEDS 561 UMBELLIPERAE, PARSLEY FAMILY. Sweet Cicely (Osmorrhiza longistylis (Torr.) D. C.)- The epidermal cells are longer than broad, the outer walls are thickened, five to six rows of thin-walled parenchyma cells occur underneath the epidermal layer ; the ribs contain the vascular ele- ments, thick-walled sclerenchyma cells; the testa consists of a layer of thin-walled parenchyma cells, p, followed by a layer tan- gentially elongated and another of large parenchyma cells, p^, and the compressed nucellus, n.^ The endosperm consists of large thin- walled cells. Fig. 428. Microscopic structure of some Umbelliferous weeds. I. Sweet Cicely {OsmorMza longistylis). II. Cow Parsnip (.Heracleum lana- tum). III. V^ild Carrot (Daucus carota). Underneath, parenchyma cells, thick-walled sclerotic parenchyma, sectional view to the right. a=nucellus. p=parenchyma. t=testa. en=endosperm. ep=epidermis. o=oil duct. (Drawings by L. H. Pammel.) 36 562 WEED FLORA OF IOWA "Wild Carrot {Daucus carota L.). The cremocarp consists of an outer epidermis of cells some- what longer than broad ; the underlying cells are of similar struc- ture except the cells near the inner epidermis, which are much longer than wide; a large oil duct occurs in each rib. The testa consists of a single layer of parenchyma cells and a few rows of compressed elements, probably the nucellus. The endosperm of thin-walled parenchyma cells contains protein. i Cow Parsnip {Heracleum lanatum). An outer epidermis with outer walls thickened. The underlying parenchyma cells similar, followed by a layer of thick-walled sclerenchyma cells. The testa of single layer of cells. The en- dosperm cells contain protein. ASCLEPIADACEAE, MILKWEED FAMILY. Milkweed {Asclepias syriaca L.). The flattened reddish brown seeds consist of an epidermis of isodiametric cells; the outer walls wavy, and thickened; each cell with a projecting point, outer walls colorless, contents brownish; the epidermis is followed by 10-14 rows of thin-walled parenchyma cells containing a brownish pigment. This layer is followed by e/n Fig. 429. Microscopic structure of the seed of Milkweed (Asclepias syriaca). ep=epidermis. p=parenchyma. n=nucellus. em=embryo. (Drawing by L. H. Pammel and Charlotte M. King.) MICROSCOPIC STRUCTURE OF WEED SEEDS 563 the compressed perisperm, brownish yellow in color. The endo- sperm consists of thickish-walled, colorless parenchyma cells, the outer row smaller than the underlying, the inner layer of smaller elongated cells. The contents consist of protein and fat. The inner epidermal cells of the embryo are smaller than the endo- sperm cells; they contain protein and fat. CONVOLVULACEAE, CONVOLVULUS FAMILY. European Bindweed {Convolvulus arvensis L.). The testa consists of an outer row of short or elongated cells p with thick walls and brownish contents. This is followed by a layer of small cells with colorless walls. Contents brownish. The Malphighian cells m are situated underneath. This is followed by a layer of parenchyma cells consisting of 8-12 rows of cells. The endosperm consists of thick-walled colorless cells. The walls in part mucilaginous. Fig. 430. Microscopic structure of the seeds of Convolvulaceae. I. Morning-glory {Convolvulus sepium). II. Cultivated Morning-glory (.Ipomoea purpurea). III. Dodder (Cuscuta epithymum). IV. Bindweed {Convol- vulus arvensis). ep=epidermis. m=malpighian cells. ll=light line. p=parenchyma. n=nucellus. en= endosperm. (Drawings by L,. H. Pammel and Charlotte M. King.) 564 WEED FLORA OF IOWA Wild Morning Glory {Convolvulus sepiwn L.). The testa of the seed of the common morning glory consists of an outer layer of elongated cells containing the blackish pigment followed by the Malpighian cells with small cell cavity and propii- nent light line. The colorless parenchyma cells are thick-walled followed by a compressed indistinct layer, the compressed nucellus and the endosperm cells. Cultivated Morning Glory {lpomoeesccns). ep=: epidermis. en=endosperm. pal=palisade cells. em=embryo. p=parenchyma. p^= elongated parenchyma cells. (Drawings by L. H. Pammel and C. M. King.) MICROSCOPIC STRUCTURE OF WEED SEEDS 569 Buffalo Bur or Spiny Nightshade {Solanum rostratum Dunal). The black seeds are irregular on the surface, which is mucil- aginous; the underlying layer consists of thick- walled cells with large cavities into which thickened processes extend; the third layer is also pigmented and consists of squarish cells or elongated, compressed elements. The endosperm is composed of thick-walled cells, the outer nearly square, the others elongated. Starch ab- sent; protein present. The cells of the embryo are smaller, thin- walled and contain protein and fat. Black Nightshade {Solammi nigrum L.). The surface of the yellowish seeds is slightly irregular. The superficial layers consist of mucilaginous, parenchyma cells, fol- lowed by large parenchyma cells with thickened folds. These cells are, however, variable as to structure and are sometimes short with folds not evident. The elongated, thick-walled portion of the testa contains the yellowish pigment. The cell cavity is tri- angular. The second layer of parenchyma cells is compressed. Jimson Weed {Datura stramonium L.). The blackish seeds are rough, surface irregular, cells and walls of epidermis ep thick; the underlying thinner-walled cells p are small, longer than broad, followed by an indistinct layer p\ whose walls are not clearly defined. The layer adjacput to the endosperm consists of somewhat larger cells also thin-walled. The endosperm cells e are large, containing protein. Ground Cherry (Physalis piibescens L.). The epidermal cells are thick-walled, the outer walls colorless. These cells contain the pigment. The parenchyma cells of the second layer are elongated; an indistinct compressed layer follows. The outer row of the endosperm cells are smaller, containing protein. A discussion of the seed coats of this family is to be found in Harz, Samen* kunde, 3 996-1025. 570 WEED FLORA OF IOWA SCROPHULARIACEAE, FIGWORT FAMILY. Mullein {Verhascum thapsus L.). The minute, roughened seeds are irregular. are dark colored, longer than broad and thick mal layer is followed by one or more layers more numerous in the micropilar region; an pressed layer with large intercellular spaces sponding to the irregularities on the surface, The epidermal cells -walled. The epider- of parenchyma cells, indistinct and com- follows, these corre- smaller intercellular Fig. 435. Microscopic structure of the seeds of the Figwort family (^Scrophul- ariaceae) . I Moth Mullein (Verbascum blattaria). II. Common Mullein (Verbascum thapsus). ep=epidermis. p=parenchyma. al=aleurone layer. en=endosperm. em=em- bryo. (Drawings by L. H. Pammel and Charlotte M. King.) spaces occurring between the larger. The nucellus is compressed, showing remnants of cell walls. The endosperm consists of an outer aleurone layer, the walls with pore canals; this is followed by cells of the same character. The cells of the embryo are smaller. The testa of Verhascum blattaria in an undeveloped seed consists of the epidermal cells with chlorophyll and the underlying much larger cells also with chlorophyll. MICROSCOPIC STRUCTURE OF WEED SEEDS 571 PLANTAGINACEAE, PLANTAIN FAMILY. Common Plantain {Plantago major L.). The small, yellowish brown seeds consist of an epidermal layer of thick black-brownish seeds. The walls on the addition of water become mucilaginous and expand. The cell cavity is small. The epidermal layer is followed by several layers and small parenchyma cells. These cells are usually somewhat compressed and brownish in color. The pigment layer and endosperm consist of an outer layer of aleurone cells smaller than the underlying cells. These cells contain protein grains and starch ; the walls have small pore canals. Fig. 436. Microscopic structure of the seeds of Plantain family. I. Bracted Plantain (Plcmtago aristata). II. Common Plantain (Plantago major). III. Buckhorn (Plantago lanceolata). l=epidermal cells showing stratification. c=cell cavity. ep=epidermis. pl=un- derlying parenchyma cells. 2=underlying parenchyma cells of the testa, em=embryo. n=nucellus. p=parenchyma cells. en=endosperm, (Drawings by L. H. Pammel and C. M. King.) 572 WEED FLORA OF IOWA Buckhom {Plantago lanceolata L.). The smooth, brownish, elongated seeds consist of epidermal cells with a small cavity and thick walls ; the outer walls become mucil- aginous on the addition of water. The underlying cells are thin, blackish, elongated, followed by a brown pigment layer as in the last species. The aleurone cells and remaining endosperm cells are of about the same shape and size; the walls are provided with small pore canals. Bracted Plantain (Plantago aristata Mx.). The seeds of this are similar in structure to those of P. lance- olata. The walls of the epidermal cells are mucilaginous. The underlying parenchyma cells and the underlying pigment layer are followed by the endosperm and embryo. The cells of the nucellus are narrow, elongated, and thick-walled. The cells of the embryo are isodiametric and are thin-walled. Several species of the genus have been studied by Harz*. Numerous earlier papers and references will be found in Pammel's article in Transactions St. Louis Academy of Science, 9 :91. RUBIACEAE, MADDER FAMILY. Bedstraw {Galium aparine L,). The dry fruit of the common bedstraAV is provided mth hooked prickles. The epidermal cells are somewhat elongated, brownish. The trichomes consist of single hooked cells with pitted walls. The underlying thin-walled parenchyma cells are elongated. Harz ob- served mucilaginous cells in this portion of the • pericarp. The testa is very much reduced, consisting of several layers of thin- walled cells with granular contents. The endosperm consists of an aleurone layer, thick-walled cells followed by a thick-walled irregular layer of cells with pore canals. Contents consist of pro- tein grains. *Samenkunde 2 ; 983. MICROSCOPIC STRUCTURE OP WEED SEEDS 573 Fig. 437. Microscopic structure of fruit of Bedstraw (.Galium, aparine). ep= epidermis. t=testa. t^ =trichome. en= endosperm. (Drawing by L. H. Pammel and Charlotte M. King.) CUCURBITACEAE, GOURD FAMILY. Wild Cucumber {Sicyos angulatus L.), The testa of the brownish seeds consists of elongated epidermal cells with narrow cell cavities; walls thickened, with pore canals. The underlying portion consists of a layer of one or two rows of cells with thin walls, and protein contents: the remaining portion of the testa is composed of thin-walled cells with large inter- cellular spaces. The related species, Echinocystis lohatai, contains a thick, pigment layer of brownish sclerotic parenchyma followed by a thinner layer of thick-walled cells with blackish brown pig- ment. In this species, as in Sicyos angulatus, frequently portions of the fruit adhere to the surface. The seed coats of this family have been described by Harz. 574 WEED FLORA OF IOWA Fig. 438. Microscopic structure of seeds of some cultivated weeds. I. Wild Cucumber or Wild Balsam Apple {Echinocystis loiata). II. Bur Cucumber (Sicyos angulatus). ep=epidermis. ll=light line. p=parenchyma. m=malpighian layer. scl=scler- otic cells. (Drawings by L. H. Pammel and C. M. King.) COMPOSITAE, COMPOSITE FAMILY. Large Ragweed {Ambrosia trifida L.). The so-called ' ' seed ' ' consists of an involucre of rather thick- walled sclerotic parenchyma cells, occurring underneath the epidermis; some of these cells are radially elongated, others are spherical in cross section, showing numerous pore canals. The internal layer of the involucre is composed of nearly isodiametric, thick-walled, sclerotic cells. The testa consists of a layer of brown- ish colored cells followed by a layer containing black pigment. Next within lies a layer of thick-walled, small, nearly colorless cells, then the compressed layer of the nucellus, followed by the nearly square cells of the embryo. MICROSCOPIC STRUCTURE OF WEED SEEDS 575 Conunon Sunflower {Helianthus annuus L.). The microscopic structure of the fruit and seed has been studied by Hanausek, Harz, Winton and Moeller. The obovoid achenes are more or less four-sided. The pericarp in some varieties is nearly black, in others it is striped with white and black. The pericarp consists of thin porous walls which are dark colored in the black seeded varieties, although in the varieties with striped seeds only a part of the cells are colored. Some of the cells are elongated, forming duplex hairs, which are attached to what Haniausek called the "foot cell." The underlying hypodermal cells of 4-6 rows of cells are thick-walled and porous, the cells ar- ranged in rows. These contain the blackish pigment, pitchlike in character. The third layer consists of thick-walled sclerotic parenchyma cells. These cells are more or less isodiametric. This layer contains the fibrovascular bundles which occur adjacent to the thin-walled parenchyma cells. Extending into the sclerotic parenchyma are radial rows of thinner-walled parenchyma cells. This layer is followed by large thin-walled parenchyma cells. The testa consists of thin-walled loose parenchyma cells. The outer or epidermal cells are roundish and have obscurely beaded walls; the spongy parenchyma follows and contains the fibrovascular bundles. The spongy parenchyma is followed by the rectangular cells of the inner epidermis. The endosperm consists of one or two rows of aleurone cells. The epidermal layer of the embryo consists of small, rather thin-walled cells of the cotyledons and underneath this on the upper surface are several rows of palisade cells. These cells contain irregular spherical aleurone grains larg- er than those in the epidermal cells. Crownbeard, (Verhesina Jielianthoides Mx.). The microscopic structure of the achene includes a series of small, rather thick-walled epidermal cells, followed by elongated or short, rather thick-walled parenchyma cells. The pigment layer is com- posed of thick-walled cells, whose walls contain a blackish pigment. The testa consists of two layers ; an outer of elongated, thick- walled cells and an inner layer of shorter cells also colorless. The cells of the embryo are much larger and contain protein grains. Boot-jack, Spanish Needle {Bidens discoidea (T, & G.) Britton). The pericarp consists of an outer epidermal layer underlaid by a similar layer of elongated, thick-walled cells; between which aire 576 WEED FLORA OF IOWA thinner-walled parenchyma cells. The outer layer of the testa is composed of nearly isodiametric cells, followed by larger thick- walled parenchyma cells ; cells of the lower portion compressed. The endosperm is much reduced, of elongated cells; embryo with row of outer cells longer than broad. Fig. 439A Fig. 439 B A. Fig. 439. Sunflower (Helianthus annuus) . Cross section of outer layers of pericarp, o, epicarp with h, hairs ; K, hypoderm ; H, fiber bundles separated by m, parenchyma ; p, parenchyma with g, fibro-vascular bundles. X 160. Epicarp with h, twin hairs, in surface view. After Winton. Burdock (Arctium lappa L.). The brownish mottled fruits consist of a thick-walled pericarp, the outer epidermal layer of thick-walled cells, walls colorless or but slightly colored; the underlying layer of six or eight rows of thick-walled cells, not as thick, however, as the epidermal cells. The first layer carries the brownish or blackish brown pigment. MICROSCOPIC STRUCTURE OF WEED SEEDS 577 '^. Fig. 439A. Miscroscopic structure of some weeds of the Sunflower family iCompositae). I. Small Ragweed (Ambrosia art emisiae folia). II. Verbesina (Verhesina hel- ianthoides) . III. Spanish Needle (Bidens discoidea). IV. Burdock (Arctium lappa). ep=epidermis. scl=sclerotic parenchyma. t=testa. n=nucellus. en=endosperm. em=embryo. pal=palisade cells. (Drawings by L. H. Pammel and Charlotte M. King.) The pigment layer is followed by elongated sclerotic parencliyma with a narrow cell cavity ; cells with granular contents. The testa is thin, cells! elongated, cell wall thickened slightly, tinged with yellow. The testa is followed by remnants of the nucellus. The parenchyma cells of embryo follow the nucellus. Wood or Field Thistle (Cirsmm discolor (Muhl.) Sprang.). The microscopic structure of the yellowish gray seeds shows a clear relationship to Arctium; the outer epidermal layer of the pericarp consists of thick-walled colorless cells, the walls bright and lustrous; the pigment layer underneath the walls, not nearly 37 578 WEED FLORA OF IOWA as thick-walled as the epidermal, pigment yellowish. The elong- ated sclerotic parenchyma cells are yellowish white or nearly color- less ; this layer is followed by the parenchyma cells of the testa and remnants of the nucellus. The parenchyma cells of the embryo ^vith numerous small intercellular spaces contain protein and fat. The fibrovascular bundles are located one at each end of the achene. Fig. 440. Microscopic structure of the seeds of Thistles {Cirsium). I. and II. Common "Wood Thistle {Cirsium discolor). III. Iowa Thistle (.Cir- sium ioense). ep=thick-walled epidermal cells. pi=pigment layer. scl=sclerotic palisade cells with narrow cell-cavity. p=parenchyma cells of testa. t=testa. n=nucellus. em=embryo. fv=fibro-vascular bundles. (Drawings by L. H. Pammel and Charlotte M. King.) Iowa Thistle {Cirsium ioense (Pammel) Fernald), The microscopic structure of the seeds is similar to that of pre- ceding, comprising a thick-walled epidermal layer with bright colored walls and underlying pigment layer, an elongated sclerotic parenchyma and the testa of small parenchyma cells. MICROSCOPIC STRUCTURE OF WEED SEEDS Chicory (Cichorium intyhus L.). 579 The microscopic structure of the pericarp and seed of chicory has been given by Harz and Lavialle. The pericarp consists of epidermal cells whose outer walls are irregular and cuticularized. This is followed by a variable number of rows, usually 10-15, of sclerotic parenchyma, some of the cells of which as observed by er en Fig. 441. Microscopic structure of the seed of Chicory {Cichorium intybus). ep= epidermis. scl=sclerotic parenchyma. per=pericarp. t=testa. al=aleu- rone layer. en=endosperm. (Drawing by Charlotte M. King and L. H. Pammel.) Kraus, contain crystals of calcium oxalate. Beneath are 6-8 rows of thin-walled, elongated parenchyma. The testa consists of a layer of large epidermal cells, followed by smaller thin-walled parenchy- ma, the inner portion much compressed. The aleurone layer is of elongated cells containing aleurone grains. Dandelion {Taraxacum officinale Weber). Harz has given an account of the structure of the pericarp and seed. The epidermal cells are irregular, many of the cells pro- longed into one-celled trichomes, the ribs forming tubercular processes. The underlying portion containing the thinner-walled parenchyma and the sclerotic parenchyma cells of the ribs. This is followed by several rows of compressed, elongated, thin-walled parenchyma cells. The testa consists of the epidermal layer of elongated, spirally thickened walls, followed by a compressed layer of parenchyma cells. The endosperm of one or two rows of aleurone cells. 580 "WEED FLORA OF IOWA Fig. 442. Dandelion (Taraxacum officinale). BIBLIOGRAPHY. ANATOMICAL STUDY OP SEED COATS. GENERAL. Buscaloni, L. Contribuzione alio studio della membrana cellulare. Malpighia 6 :3-40, 217-228 ; pi. 1-2. 7 :105-162 ; pi. 1-2. 8 :3-13 ; pi. 1-3. 1875. Dahmen, Max. Anatomiseh-plij'siologisch Untiersuchung iiber d. Funiculus d. Samen. Brings. Jalirb. f . wiss. Bot. 23 :441-478 ; pi. 20-22. Fluckiger, F. A., and Hanbury, D. Pharmacograpliia : a history of the principal drugs of vegetable origin met with in Great Britain and British India. Ed. 2, 803. London, 1879. Frank, A. B. Ueber die anatomische Bedeutung und die Entste- hung der vegetabilischen Schleime. Pringsh. Jhrb. f. wiss. Bot. 5:161; pi. 15-16. 1886. MICROSCOPIC STRUCTURE OF WEED SEEDS 581 Grodt'rin, H. Etude histologique sur les tegnments semineaux des angiosperms. Bull. Soc. des Sci. de Nancy. 5:109-219. Godfrin, J. Eeeherches sur ranaitomie comparee des cotyledons et de I'albumen. Ann. Sci. Nat. Bot. Soc. des Sci. de Nancy. 5 :109-219 ; pi. 1-5. 1880. Gruignard, L. Rechercbes sur le developpennent de la graine et en particulier du tegument seminal. Jour, de Bot. 7 :1-14, 21-34, 57-66, 97-106, 114-153, 205-214, 214-250, 282-296, 303-331. Hanausek, T. F. Die Nahrungs-und Genussmittel aus dem Pflanzenreiche. 485, 100 f. Harz, C. J). Landwirthschaftliche Samenkande. 1:552; /. 1-14. 2:553-1362; /. 15-201. Berlin, 1885. Verholzungen die holieren Pflanzen, speciell iiber das Vorkommen von Lignin in Samensckalen. Bot. Centrbl. 24:21-31, 59-61. 1885. Hofmeister, W. Ueber die zu G-allerte aufquellenden Zellem der Aussenflaelie von Samen und Perikarpien. Ber. d. Kon. Sachs Gesell. D. Wiss. Sitz. 18-37. Feb. 20, 1853. Jenkins, T. E. H., & Winton, A. F. American feeding stuffs. Bull. U. S. Dept. Agr., Off. Exp. Sta. 11:155. 1892. Joxe, A. Sur I'ouverture des fruits indehiscents a la germination. Ann. de Sci. Nat. IX. 15:257-375. Junowicz, E,. Die Lichtlinie in den Prisemnzellen der Samen- schalen. Sitzb. d. k. Akad. d. Wissensch. Wien. 76 :335-352 ; 2 pi. Mattirilo, 0. La linea lucida nelle cellule Malpighiane degli in- tegumente seminali. Mem. della R. Accad. delle Sci. II, 37 :30 ; 1 pi. 1885. Mattirilo, 0., and Buscalioni, L. Letture suUa funzione della linea lucida nelle cellule Malphigiane. Nota preventiva. Atti E-. Ace. delle Sci. di Torino. 25 :310-315. 1890. Moeller, Josef. Mikroskopie der Nahrungs-und Genuss-mittel aus dem Pflanzenreiche. 394; /. 308. Berlin, 1886. Pammel, L. H. Some methods in the study of mature seeds. Jour. Appl. Micro. 1 :37-39 ; 6 f. 1898. Sempolowski, A. Beitrage zur Kenntniss des Baues der Samen- schale. Inaug. Dis. Leipsig. 1874. 60; pi. 1-3. Ueber den Ban der schale landwirtschaftliche wichtiger Samen. Landw. Jahrb. 3 :824-866 ; pi. 7-8. Winton, A. L. Anatomy of weed seeds. Rept. Conn. Agr. Exp. Sta. 1902:345-358. 582 WEED FLORA OF IOWA AMARANTACEAE. Gravis, A., and Constantinesco, Mile. A. Contribution a I'anatomie des Amarantacees. Arch. Insi:. Bot. Univ. Liege. IV:1-146. Harz, C. D. See Landwirthscliaftliche Samenkunde. 2 :1101. ASCLEPIADACEAE. Harz, C. D. See Landwirthscliaftliclie Samenkunde. 2 :963-966. BERBERIDACEAE. Piammel, L. H., Burnip, J. R., and Thomas, H. Some studies on the seeds and fruits of Berberidaceae. Proc. la. Acad. Sei. 5 :ll-25. BORAGINACEAE. Harz, C. D. See Landwirthscliaftliche Samenkunde, 2:870. CARYOPHYLLAGEAE. Harz, C. D. See Landwirthschaftliche Samenkunde. 2 :1075-1089. Winton, A. L. Anatomy of Cockle seeds. Winton's Microscopy of vegetable products. 148 ; Cowherb, p. 151, Soapwort, p. 151. CHENOPODIAGEAE. Harz, C. D. See Landwirthschaftliche Samenkunde. 2 :1092-1039. Pammel, L. H. Bull. la. Agrl. Exp. Sta. 26:20. COMPOSITAE. Gerdts, C. L. Bau und Entwickelung der Kompositenfrucht mit besonderer Berucksichtigung der offizinellen arten. These Inaug. Leipzig, 1905. Goldflus, Mathilda. Sur la structure et les fonctions de I'assise epitheliale et des antipodes chez les Composees. Journ. de Bot. Morot. 1898-1899. Hanausek, T. F. Ueber das Perikarp und Perikarpsekret der Gattung Oarthamus. Ber. d. deutsch. Bot. Gesellsch. 29 :13-18 ; pi. 1. Zur entwickelungsgeschichte des Perikarps von Helianthus annuus. Ber. d. deutsch Bot. Gesellsch. 20 :449 ; pi. 21. Harz, C. D. See Landwirtschaftliche Samenkunde. 2 :841-866. Lavialle, P. Ovaire des Composees Ann. d. Sci. Nat. IX, 15 : (No. 2.) 65-149; 97 f. Nichols, Mary A. Achenial hairs of Compositae. Bot. Gaz. 18 :378 ; pi. 35. MICROSCOPIC STRUCTURE OF WEED SEEDS 583 Prister. Oelliefernde Compositernfruchte. Landw. Versuch. Stat. 43. E/Osenthaler and Stadler. Ein Beitrag zur Anatomie von Cnicus henedictus. Arch d. Pharm. 246 :436. Schwere. Zur Entmcklung'Sgeseliiehte der fracht von Taraxacum officinale. Fiona 82. 1896. Winton, A. L. Anatomy of the seed of the Sunflower {H. annuus). See Winton's Microscopy of vegetable products. 194-197. CONVOLVULAGEAE. Harz, CD. See Landwirthschaftiiche Samenkunde. 2 :751-767. Guttenberg, H. von. Ueher die anatomischen Unterscheidung der Samen einiger Cuscuta — Arten. Naturwiss. Zeitschs. Forst. u. Landw. 7:32-43. 1909. Abs. in Bot. Centr. 111:578. CRUGIFERAE. Burchard, 0. Ueber der Bau der Samenschale einiger Brassica — und Sinapis Arten. Journ. Fiir Landw. 42 :125 ; 44 :377. Cordemoy, J. de. Eecherches anatomiques sur les genres Brassica et Sinapis. 190; 45 f. Paris, 1907. Fournier, Eug. Recherches anatomiques et taxonomiques sur la ,famille des Cruciferes et particulierement sur le genre Sisym- brium. 154; pi 1-2. Paris. Harz, C. D. See Landwirthschaftiiche Samenkunde. 2:914-916. Pammel, L. H. On the seeds and testa of some Cruciferae. Cont. Bot. Dept. la. Agr. Coll. 6:25. Reprint from Am. Mo. Mic. Jour. Pieters, A. J., and Charles, V. K. The seed coats of certain species of the genus Brassica. Bull. U. S. Dept. Agr. 29 :19. Schroder. Untersuchung der Samen der Brassica — Arten und Varietaten. Landw. Versuchs^ — Station. 14. 1871. Uloth, "W, Ueber Pflanzenschleime und seine Entstehung in der Samen epidermis von Plantago maritima und Lepidium sativum. Flora. 58 :173-20O, 209-216 ; pi. 6. Winton, A. L. Anatomy of oil seeds among Cruciferae. Microscopy of vegetable products. 174-193. EUPHORBIACEAE. Harz, C. D. See Landwirthschaftiiche Samenkunde. 2:825-841. Pammel, L. H. On the seed coats of the genus Euphorbia. Contr. Shaw School of Bot. 8 :543-568. Trans. St. Louis Acad. Sci. 5 :543-568. 584 WEED FLORA OF IOWA GENTIANACEAE. Guerin, . Developpement et structure anatomique du tegument seminal des Gentianees. Compt. Ren. Acad, des Sci. de Paris, vi: 136. GRAMINEAE. Bessey, C. E. Structure of the wheat grain. Bull. Neb. Agr. Exp. Sta. 32 Hanausek, T. F. Vorlaufige Mittheilung liber der von Vogl. in der Frucht von Lolium temulentum entdeckten Pilz. Ber. Deutsch. Bot. Ges. 16 :203. 1898. Harz, C. D, See Landwirthschaftliche Samenkunde. 2 :1145-1349. Hillman, F. H. The seeds of fescue grass and chess. Bull. U. S. Dept. Agr., Bur. PI. Ind. 25 -A. Holm, Theo. A study of some anatomical characters of N. A. GraminefE. Bot. Gaz. 16 :166-171, 219-225, 275-281. 17 :358-363. 20 :362-365. 21 :357-360. 22 :403-406. Jumelle, Sur le constitution des fruit des Graminees. Compt. Rend. 107:285. 1888. Krutizky. On some peculiarities in the structure of the earyopsis of wheat. Just's Bot. Jahresb. 21: (Abt. I) 571. 1893. Moeller, J. Die Mikroskopie der Cerealien. Pharm. Centralh. 25: 507. 1884. Pammel, L. H. Comparative anatomy of the corn earyopsis. Trans. la. Acad. Sci. 1897. 5. The histology of the earyopsis and endosperm of some grasses. Trans. St. Louis Acad. Sci. 1898 :199-220. Pammel, L. H., Weems, J. B., and Lamson Scribner, F. The Grasses of Iowa. Bui. la. Geol. Survey. 1 :525. Winton, A. L. The anatomy and microscopic identification of the fruits of darnel and chess. Rept. Conn. Agr. Exp. Sta. 1903. 165-174. Anatomy of the seed of green foxtail. Rept. Conn. Agr. Exp. Sta. 1902. 352-358. Anatomy of seed of yellow foxtail. Ibid. 1902 : 358. Ueber amerikanische Weizenausreuter. Ztschr. Unters. Nahr-Genussm. 6 :433. LABIATAE. Harz, C. D. See Landwirthschaftliche Samenkunde. 2 :866-870. MICROSCOPIC STRUCTURE OF WEED SEEDS 585 LEGUMIN08AE. Beck, G. Die Samenkunde einiger Leguminosen. Sitzb. K. K. Akad. Zu. Wien. 1878. 79. Vergleichende Anatomie d. Samen von Vicia und Ervum. Sitz. d. k. Akad. d. Visseneh. Wien. 76 :335-352 ; 2 pi. Chalon, J, La graine des legumineuses. I. Cellule de la carapace. II. Albumen. Soc. des Arts, et des lettres du Hainaut. 1875. 66; pi. 1-3. Haberlandt, G. Ueber die Entwicklungsgeschiclite und den Ban d. Samenschule bei der Gattung Phaseolus. Sitz. d. k. Akad. d. Wissensch. Wien. 75 :33-47 ; 2 pi. 1877. Harz, C. D. See Landwirtbscliaftliche Samenkunde. 2; 562-736. Mattirolo, O. Ricerctie anatomo-Jfisiologisclie sui tegumenti seminali delle Papilianacee. Nota preventiva. Atti. R. Accad. delle sci. di Toniro. 24. 1889. Eicerche anatomo-fisiologiselie sui tegumenti seminali delle Papilionacee. I. Anatomia. II. Stor ia di sviluppo dei tegumenti seminali. III. Contribuzioni alio studio della fisiol- ogia del seminali. IV. Bibliographia. Reale Accad. delle Sci. di. Torino II, 42:223-318, 359, 445; pi. 1-5. 1892. Nadelmann, Hugo. Ueber d. Schleimendosperme d. Leguminosen. Brings. Jabrb. Wisenscb. Bot. 21 :609-691 ; pi. 16-78. 1890. Pammel, L. H. Anatomical character of seeds of Leguminosae. Trans. St. Louis Acad. Sci. 9:91-263; Tables A-G; pi. 7-35. The seed coats of Crotalaria sagitalis and Astragalus mollis- simus. Bienn. Kept. Ia. St. Agr. Coll. and Farm. 13 :17-24 ; pi. 52-53. On the structure of the testa of several leguminous seeds. Bull. Torr. Bot. Club. 13 :17-24 ; pi. 52-53. Schips, K. Ueber die Cuticula und die Auskleidung der Intercel- lularen in den Samenschalen der Papilionaeeen. Ber. Deutsche. Bot. Ges. 11:311. 1893. Schively, Adeline F. Contributions to the life history of AmpM- carpaea monoica. Cont. Bot. Lab. Univ. Penn. 1:270-363; pi. 19-36. Schleiden, M. J. Beitrage zur Entwiekelungsgeschichte d. Bluthen- theile bei d. Leguminosen. Nov.-Oct, K. Leopold-Carol. Akad, Naturf. 19:59-84; pi. 9-11. Winton, A. L. Anatomy of the seeds of Yicia sativa. Winton's Microscopy of vegetable products. 251-252. 586 WEED FLORA OF IOWA MALVACEAE. Harz, C. D. See Landwirthschaftliche Samenkunde. 2 :736-750. Rolfs, P. H. The seed coats of Malvaceoe. Bot. Gaz. 17 :33-39. ONAGRACEAE. Harz, C. D. See Landwirthschaftliche Samenkunde. 2 :875-878. PHYTOLACCACEAE. Harz, C. D. See Landwirthschaftliche Samenkunde. 2:1088-1031. PLANTAGINAGEAE. Harz, C. D. See Landwirthschaftliche Samenkunde. 2 :982-987. "Winton, A. L. Anatomy of plantain seeds. Microscopy of vegeta- ble products. 163. Uloth, W. Ueber Pflanzenschleime und seine Entstehung in der Samenepidermis von Plantago maritima und Lepidum sativum. Flora. 58 :193-200, 20-9-216 ; pi. 6. 1885. POLYGONACEAE. Harz, C. D. See Landwirthschaftliche Samenkunde. 2 :1101-1113. Sirrine, Emma. Structure of the seed coats of Polygonacese. Proc. la. Acad. Sci. 2:128-134; pi. 7-9. Winton, A. L. Anatomy of seed of black bindweed. Rept. Conn. Agr. Exp. Sta. 1902:340-352. Winton 's Microscopy of vege- table products. 157-158. RAlslVlsfCULACEAE. Harz, C. D. See Landwirthschaftliche Samenkunde. 2 :1063-1074. Winton, A. L. Anatomy of Banumculus arvensis. Microscopy of vegetable products. 152-154. 8APINDACEAE. Guerin, M. P. Developpement de la graine et in parti culier du tegumemt seminal de quelques Sapindace.es. Jour, de Bot. 15; 336-348. SCROPHULARIACEAE. Bachmann, E. Die Entwicklungsgeschichte und der Ban der Samenschalen der Scrophularineen. 179. Halle, 1880. Harz, C. D. See Landwirthschaftliche Samenkunde. 2 :966-973. SOLANANCEAE. Harz, C. D. See Landwirthschaftliche Samenkunde. 2:997-1025. MICROSCOPIC STRUCTURE OF WEED SEEDS 587 VMBELLIFERAE. Harz, C. D. See Landwirthscbaftliche Samenkunde. 2:1030-1063, Winton, A. L. Anatomy of the seeds of wild carrot. Microscopy of vegetable products. 158-159. URTICACEAE. Harz, C. D. See Landwirthschaftliche Samenkunde. 2:978-982. Winton, A. L. The anatomy of certain oil seeds with especial reference to the microscopic examination of cattle foods. Conn. Agr. Exp. Sta. 1903. 175-180. Microscopy of vegetable products. 212-217. CHAPTER IV. MORPHOLOGY OF LEAVES AND FLOWERS By J. N. MARTIN CHAPTER IV. LEAVES. INTRODUCTORY STATEMENT. Leaves are distinguishable into primary and secondary. The pri- mary leaves arise directly from the first cells produced by the division of the fertilized egg and in seed plants are called cotyle- dons. They are usually transient, and not rarely lare so distorted by acting as storage places for reserve food that they do not function as foliage leaves at all. The secondary leaves arise upon the sides of the stem and are the ordinary foliage leaves of the plant. They are very important organs in connection with the work of nutrition. PARTS OF A LEAF. In the typical foliage leaf there are three parts — the expanded portion which is called blade or lamina, the leaf stalk (petiole), and a pair of lappendages at the base of the petiole known as stipules. Fig. 443. Apple leaf; b, blade; p, petiole; s, stipules. (After Thome.) 592 WEED FLORA OF IOWA In some cases, as in the Hare's-ear mustard, {Conringia orient- alis) and in the upper leaves of Canada thistle {Cirsium arvense) the petiole is absent and the blade is directly attached to the stem. Such leaves are designated as sessile. Fig. 444. Sessile leaf of Thistle. (After Thomg.) The stipules are small leaf-like structures which appear at the place where the leaf is attached to the stem. They are very often absent but are conspicuous in the cinquefoils, vetches and other members of the rose and pulse families. VEINING. The blade of the leaf is traversed by a frame work of fibro- vascular bundles known as veins. In the leaves of grasses, sedges, and rushes, the veins run more or less parallel from the base to the tip of the leaf. These leaves are the parallel-veined type. In the leaves of most of our common weeds, the veins are branched so as to form a network. These are the neited-veined type. Palmate and pinnate veining. — Netted-veined leaves are palmately veined when the primary ribs radiate from the base of the petiole as in the great ragweed. If there is only one midrib from which smaller ribs extend both ways, as in dandelion, dock, goldenrod, etc., the veining is said to be pinnate (meaning featherlike) . LEAF ARRANGEMENT. Sometimes as in dandelion and evening primrose, the stem does not appear above ground or is late in appearing and the leaves at the surface of the ground are called radical leaves in distinction to the stem or cauline leaves. MORPHOLOGY OF LEAVES AND FLOWERS 593 Pig. 4451 Fig. 445II Fig. 445. I. Vetch. {Lathyrus aphaca), showing opposite leaves; r, tendril; b, flower ; f. fruit. Stipules performing the function of leaves. II. Grass type of leaf ; L, leaf blade ; G, leaf sheath ; Lig, ligule. (After Thome.) Leaves are usually arranged so as to secure the best exposure to the light. In the milkweed there is a pair of leaves at each node and the two leaves are on opposite sides of the stem. Here the leaves are said to be opposite. Fig. 4 4 6. 38 The clinging stem of the Bindweed, showing the alternate leaves. (After Thome.) 594 WEED FLORA OF IOWA In the asters, ironweed, goldenrods, lamb's quarter, etc., there- is only one leaf at each node, and they are spoken of as alternate^ In some cases several leaves appear at each node in a whorl. Such examples of whorled or vertieillate leaves are found in the bed- straws and Joe Pye weed. BRANCHING. The outline of a blade is extremely various. When the general outline is completely filled out and the margin represents an even line, the leaf is said to be entire. Examples of such leaves are found in water pepper {Polygormm hydropiper) , mild water pepper (P. liydropiperoides) , Pennsylvania smartweed (P. pennsylvani- cum), etc. Fig. 447. Leaf of the Privet plant showing entire margin. To designate the amount and character of the branching, the following terms are used: Pig. 4481 Fig. 448II Fig. 448'II Fig. 448IV Fig. 448. I. Triangular, lobed leaf of the Notch-weed. II. The reniform or kidney-shaped leaf of Ground Ivy, illustrating wavy margin. III. Arrow- shaped leaf of Bindweed. IV. Spear-shaped leaf of Sorrel. (After Thome.) MORPHOLOGY OF LEAVES AND FLOWERS 595 Wavy margin, when the margin forms a wavy line bending slightly inward and outward in succession, as in the bitter dock (Bumex obtusifolius). Pig. 449 I Fig. 449 II Pig. 449 III Pig. 449 IV Pig. 449 V Fig. 449. I. Leaf of Daisy, spatulate in shape with a serrate margin. ' II. Spiny-pointed, serrulate leaflet of alfalfa. III. Wavy-margined leaf of Pigweed (Amaranthus). IV. Ovate, dentate leaf of Snowball. V. Serrate leaf of Hen-bit. (After Thome.) Toothed or dentate, when the margin is cut into sharp teeth and the teeth point out, as in the lower leaves of the daisy fleabane (Erigeron annuus). Fig. 450. Cleft and pinnatifld leaves of Wild Lettuce. (After Thome.) 596 WEED FLORA OF IOWA Serrate, when the teeth point forward, as in the common sun- flower {Helianthus annuus). Serrulate, when the margin is finely serrate as in milk purslane (Euphorbia maculata). Crenate, when the teeth are broad and rounded as in the common mallow {Malva rotundifolia) . Fig. 451 1 451. Compound leaves. Fig. 451 II Fig. 451 III Fig. 451. Compound leaves. I. Leaf of Clover v^lth three leaflets. Pedately divided leaf of Dragon Root. 19 leaflets. (After Thome.) II. III. Pinnate leaf of Locust with Lohed, when the leaf is deeply cut, as in the great ragweed. The projecting portions are then called lobes. When the incisions are sharp the term cleft is often used; the leaf is pimva'tifid when the incision extends almost to the midrib, as in the prickly lettuce {Lactuca scariola) ; it is pinnate when the incisions have extended to the midrib and each separated portion takes the character of a leaf. Each of the smaller portions is a leaflet, and the leaf is now considered compound. The spotted cowbane (Cicuta maculaia), spring vetch (Vicia sativa) and cinquefoil {PotentUla monspelien- sis) are good examples. MORPHOLOGY OP LEAVES AND FLOWERS 597 Pig. 452 I Fig. 452 II Fig. 452. I. Wedge-shaped leaflet of Horse Chestnut. the "Wall Pellitory. (After Thome.) II. Pointed leaf of All of the iat)ove marginal characters may characterize the lobes of a simple leaf or the leaflets of a compound leaf. LEAF STRUCTURE. Before considering the work of the leaf it will be necessary to become acquainted with its structure. The leaf is covered with an epidermis which is composed of com- pact layers of cells, so modified as to protect the more delicate inner parts. The epidermis may be peeled off as a delicate trans- parent skin. A microscope shows that this transparent skin is made up of many cells, so closely fitted together as to make a contin- uous sheet or covering. Many slitlike openings between two cres- cent-shaped cells {guard cells) appear quite evenly distributed in the epidermis. The opening and guard cells constitute the stoma (plural stomata) which really means mouth. These numerous openings are passage ways into the interior of the leaf and per- mit interchange of gases between outside air and the air in the leaf interior. The guard cells can change their shape and so vary the size of the opening. In horizontal leaves the stomata are chiefly and sometimes exclusively on the lower surface, a fair average number being about 62,500 to the square inch. 59S WEED FLORA OF IOWA Fig. 453. I. A cross section of a leaf of Feppergrass (l,epidium) showing the upper epidermis (e), the lower epidermis (6), stoma (s), the chlor- enchyma (c) consisting of closely placed palisade cells (p) and more loosely placed spongy tissue (f), and a vascular or conductive tract (v) with bundle sheath (b), hadrome or xylem (h), and leptome or phloem (1). II. Surface view of stoma from Easter Lily ; g, the kidney-shaped guard cells en- closing the stomatal aperture (s) ; b, the subsidiary cells. III. Cross section of stoma; g, guard cell; s, central slit; o, outer slit ; i, inner vestibule ; c, stomatal cavity ; b, subsidiary cell. IV. Surface view of a grass stoma {Poa pratensis) showing the guard cells (g). with their dumb-bell-shaped lumina ; b, subsidiary cells with prominent nucellus (n). v. Median cross section and cross section through end of stoma of Poa annua; g, guard cell lumina ; b, lumina of subsidiary cells. VI. A cross section of a leaf of blue violet iViola cucullata) showing a single row of elongated palisade cells (p). and the loose spongy tissue (f). (Drawings after Cowles modified by Charlotte M. King.) A cross section of a leaf will show the interior filled with a mass of thin walled cells containing green bodies (cMoroplasts) . This inner mass of thin walled cells is called the mesophyll and is the food making tissue of the leaf. In the leaves of most weeds the cells just under the upper epidermis are much elongated and stand at right angles to the epidermis. These elongated cells are known as the palisade-cells. Between the palisade-cells and lower epi- dermis is the spongy tissue made up of irregularly shaped cells, so loosely joined as to form a system of intercellular spaces which permit the circulation of gases through the interior of the leaf. In the lower epidermis are seen the stomata with the air cham- bers beneath. Scattered through the mesophyll are the cross sec- tions of veins and veinlets which form the frame work of the leaf and conduct materials to and from the green working cells. MORPHOLOGY OP LEAVES AND FLOWERS 599 5te. Fig. 454. Section of leaf of Bromus mollis. Car, mid-nerve; L, leptome ; H, . hadrome ; B, bulliform cells ; Ste, stereome ; CB, chlorophyll bearing par- enchyma ; EC, epidermal cells ; Tri, trichone. ( Sirrine and King. ) FUNCTION OF LEAVES. Photosynthesis. This is the process by which sugar and starch are produced for the plant. It is really a process of food manufac- ture by which raw materials are made into plant food and is an exceedingly important one, for upon it depends the lives of all plants and animals. If an active leaf be submerged in water in the sunlight, bubbles will be seen continuously forming on the leaf surface and rising through the water. If light is excluded, the action will cease, and by increasing and decreasing the amount of light, it will be found that the process varies with the amount of light. An examination of this gas will show that it is oxygen. It has also been found that at the same time the oxygen is given off by the leaf, carbon dioxide (C0„) is taken in, and that the outgo of oxygen and intake of car- bon dioxide have a close relation. 600 WEED FLORA OF IOWA The formula for sugar shows that it is composed of three ele- ments, carbon, hydrogen, and oxygen. These elements are furnished by the carbon dioxide (CO,) which is taken in from the air, and the water (HoO) which is taken from the ground by the roots and conducted to the leaf tissue by the vascular bundles of the plant. Although CO2 and H2O furnish the necessary elements for sugar and starch, these are only the raw materials and some agent or fac- tory is needed to cause these elements to combine and to combine in the right proportions. These factories are the ehloroplasts, which give the green color to the entire leaf. The green pigment (chloro- phyll) is the active agent of the chloroplast in the manufacture of sugar. The process by which these raw materials are combined is not well understood, and it seems that several simpler products are formed before sugar is produced. We know that CO2 plus H2O forms carbonic acid (OH. COOH). The carbonic acid is prob- ably reduced to formaldehyde (H. COH). If six molecules of for- maldehyde were properly combined we would have one of the sim- ple sugars (HgCgOeHe) or better written (CeHiaOg). Two mole- cules of the simpler sugars combined with one molecule of water eliminated will give cane sugar — CJI^i^^Oe plus C6Hi206=Cane sugar C12H22O11 plus HgO. By a further synthesis starch is pro- duced. When formaldehyde is produced as described above, oxygen is eliminated and this forms the escaping bubbles from the submerged leaf. In this process of photosynthesis, the ehloroplasts constitute the factory, carbon dioxide and w^ater furnish the raw materials, sugar and starch. are the products, and sunlight is the necessary condition without which the machinery will not run. Respiration. Plant cells as well as animal cells have much work to do and in order to perform work, energy is needed. Plant cells transform materiaJ into cell walls, increase and repair protoplasm, divide and do many other things which require energy. This work never ceases as long as the plant lives. The external indication of it is the absorption of oxygen and the giving out of carbon dioxide. This exchange is spoken of as respiration. It will be noted at once that this is exactly the reverse of what takes place in photosynthe- sis. During the day both carbon dioxide and oxygen are being both absorbed and eliminated. Photosynthesis and respiration are independent processes and must not be confused. MORPHOLOGY OF LEAVES AND FLOWERS 601 Transpiration. "We are familiar with the fact that the air is continually taking up water in the form of vapor. A dish filled with water and exposed to the air in the laboratory or out of doors will soon become dry. We hang wet clothes upon the line so that the ladr will take up the water which they contain. When we look into the physics of this process, we find that the water is really the active agent, and that it is continually changing into vapor and passing into the air. This process of changing into vapor we call evaporation, and its rate depends upon temperature, the amount of moisture already present in the air, and atmospheric pressure. This same process of evaporation goes on in the leaf, for the air surrounds the leaf and fills the intercellular spaces within. This continuous loss of moisture from the leaves is called transpiration. As seen in photosynthesis, water must be present in the leaf cells in sufficient quantity or the process of food making will be hindered. Water is further needed for dissolving and transporting food ma- terials. It is evident that transpiration is continually diminishing this quantity of water which is so necessary and if the supply, which is furnished from the ground through the roots and stems, does not equal the loss, disaster will come to the plant. So far transpira- tion seems to be only a detriment to the plant. It is thought to be of use in that it increases the flow of the water from the soil and through the plant and thus increases the amount and better dis- tributes the salts secured from the soil. It is remarkable how well most weeds can thrive, when economic plants are suffering severely from transpiration. This may be due to protective modifications which cut down transpiration or to the ability to supply the loss through a more efficient root system. One of the harmful effects of weeds is the taking from the soil of the water which economic plants need. According to careful estimates a sunflower {Helianthus annuus) six feet high transpires on the average about 1 quart per day. A grass plant has been found to give off its own weight of water every twenty-four hours in hot, dry summer weather. This would make about 6% tons per acre or more than one thousand gallons every twenty-four hours for ordinary grass fields, or rather about 200 gallons for a plot about the size of a city lot. From the above figures we can form some notion of the immense loss of water from the soil through weeds, and see how weeds can retard the growth of economic plants. 602 WEED FLORA OF IOWA LEAF PROTECTION. Such an important organ as the leaf, with its delicate active tissue well displayed, is exposed to numerous dangers. Chief among these dangers are excessive transpiration and intense light. By regu- lating the opening in the stomata which are the chief passageways Pig. 455 I Fig. 455 II m Fig. 455 V Fig. 455 IV Fig. 455 III Fig. 455. Some protective structures of leaves and stems. I. One-celled hair of the Pelargonium. II. Multicellular hair of Geranium. III. Scale of Oleaster (Elaeagnus). IV. Prickle from common Hop. V. Stinging hair of Nettle. (After Thome.) MORPHOLOGY OF LEAVES AND FLOWERS 603 for the escaping moisture, the leaf is able to check transpiration. The various epidermal modifications which are quite common among the weeds afford protection. In some cases this consists of a waxy- layer on the outside of the epidermis as in some milkweeds and some species of wild lettuce. This layer of wax prevents the escape of moisture, and protects the chlorophyll-bearing tissue of the leaf from the intense light rays. Another very common protective structure upon the leaves is to be found in the great variety of hairs developed by the epidermis. In the muUein the hairs are so prominent that they form a felt- like covering. Among the cinquefoils and thistles, the hairs are usually not branched as in the mullein and the covering is not so dense. Fig. 456. Urticating hairs and cutting leaves, a, urticating hair of Nettle; b, bristle of Bugloss ; c, barbed margin of a leaf of Sedge ; d, barbed margin of a leaf of Grass. All stages from those in which the hairs are very small, giving the leaf a downy appearance, up to the extreme case in the mullein, can be found among the weeds. 604 WEED FLORA OF IOWA FLOWERS. A satisfactory definition of a flower has not yet been agreed upon by botanists. For this reason it seems better to describe a flower rather than attempt to define it. Fig. 457. Complete flower; cal, calyx; cor, corolla; p, pistil, and s, stamens. (After Thome.) A complete flower consists of four cycles or sets o'£ organs — sepals, petals, stamens land pistils. The sepals taken together constitute the calyx; the petals taken together constitute the corolla. Since the cells of the stem most active in forming new organs lie in the tip, it seems most natural that the organs appearing last, would be at the stem tip and that the age of organs would increase as their distance from the stem tip. According to this scheme, the succession of floral sets would be sepals, petals, stamens and pistils. This is probably the order of succession in many flowers, but many exceptions have been found. In shepherd's purse (Capsella) the petals are last to appear, while in the dandelion and other com- posites the sepals are last to appear. Fig. 458. Diagrammatic cross section of a perfect flower. St, ovary showing two cells ; S, stamens ; B, corolla ; K, calyx. (After Thome.) MORPHOLOGY OF LEAVES AND FLOWERS 605 Since the work of the flower is to produce seed, and seed forming is due to the co-operation of the stamens and pistils, these are known as the essential organs of the flower. A flower is a perfect flower if it contains both of the essential organs. The simplest Fig. 459. Essential organs of the flower of the Black Mustard, a, two short stamens ; b, four long stamens. Pistil is enclosed by the stamens ; the filiform body is the filament of the stamen ; the enlarged portion of the stamen is called the anther. (After Thome.) flower would have one stamen or one pistil and no corolla or calyx. Imperfect flowers are designated as staminate when they contain stamens, but no pistils; pistillate when they contain pistils but no stamens. The term "bisexual" is applied to the flower which con- tains both stamens and pistils. This is the most common type of flower. Fig. 460. Irregular flower of a leguminous plant, dissected so as to show the difference in shape and size of petals. (After Thome.) Plants, such as ragweed and corn, which have pistillate and staminate flowers (i. e., pistils and stamens in separate flowers but both kinds of flowers on the same plant) are monoecious (one house- hold) . Such plants as the red campion {Lychnis dioica) , mulberry, willows and poplars, which bear the pistillate flowers on one plant and staminate on another are dioecious (two households). A plant 606 WEED FLORA OF IOWA Fig. 461. II. Staminate flower of the Hazel showing the stamens and bracts, III. Pistillate flower showing pistils and enclosing bracts. IV. Style and two stigmas. Catkin at middle of stem containing the staminate flowers;. female flower at top of stem. The Hazel is a monoecious plant. (After Thome.) which bears some perfect flowers and some staminate or pistillate only, is polygamous. Fig. 462. Longitudinal section through the hypogynous flower of the Pink, show- ing the attachment of floral parts. (After Thome.) MORPHOLOGY OF LEAVES AND FLOWERS 607 :Fig. 463. I and III. Staminate and pistillate catkins of the Willow. II and IV. Staminate and pistillate flowers. V. Cross section of ovary showing the one cell, two placentae and ovules. VI and VII show opening of pod and character of the seed. Since the male and female catkins are borne on different trees, this plant is dioecious. (After Thome.) 608 fig. 464 I WEED FLORA OF IOWA Fig. 464 II Fig. 464 III Fig, 464 IV Fig. 464. Flowers with petals joined (gamopetalous). I. Globularia. II. Jasmine. III. Borage. IV. Ground Ivy. (After Thome.) Fig. 465. Gamosepalous and gamopetalous flower of Jamestown or Jimson Weed. (After Thom6.) MORPHOLOGY OF LEAVES AND FLOWERS 609 FLORAL ENVELOPES AND THEIR CHARACTERS. The sepals and petals constitute the two floral envelopes. The envelopes, taken together, are sometimes called the perianth. This is especially true in the lily family where the two envelopes do not differ much in shape and color. Floral envelopes are not es- sential and one or both may be absent. If only one is absent, it is the corolla, and the flower is apetalous. In the grasses and sedges there is no true perianth but the essential organs are enclosed by chaff-like bracts and glumes. Pig. 466 I Fig. 466. I. Flower of oats showing the grass type of floral envelopes. G, empty glume ; Pe, lemna bearing an awn A ; pi, palea ; F. S., sterile flower. Between lemna and palea are pistil and stamens. II. Flower with lemna removed, showing palea and the small bracts (lodicules) at the base of the pistil and stamens. (After Thome.) Stamens. — The stamens surround the pistils and their number is various. They may be opposite the petals or alternate with them. In the mustards and buttercups the stamens are inserted on the receptacle. When they are inserted on the corolla as in the morning- glory, they are epipetalous. Stamens are usually distinct or free from each other. When they are united by their filaments into one set, as in the malloAV family, lupines and lobelia, they are mona- delphous (one brotherhood). If united into two sets as in clover, they are diadelphous (two brotherhoods). More sets would be designated by tri-, tetra-, etc. 39 610 WEED FLORA OF IOWA Fig. 467 I Fig. 467 II Fig. 467 III Fig. 467 IV Fig. 467. I. Flower of Ground Ivy with stamens differing in lengtli. II. Mallow with monadelphous stamens. III. Orange with polydelphous stamens, rv. Clover with diadelphous stamens. (After Thome.) Relation of the attachment of floral envelopes and stamens to the pistil. — An examination of the floral sets in shepherd 's purse ( Cap- sella) or mustard {Brassica alba) will show that sepals, petals and stamens are inserted on the receptacle below the ovary. This flower is hypogynous (i. e., parts under the pistil). When the petals and stamens are joined to the calyx, the flower is perigynous (i. e., parts around the pistil). In such flowers as the evening primrose and those of the composites, the- calyx is adherent to the ovary and the corolla seems to arise from the top of the ovary. Such a flower is said to be epigynous (parts on the pistil). Fig. 468. Perigynous flower of the Rose. (After Thome.) Arrangement of flowers (inflorescence). — Flower arrangement is of three classes ; namely, indeterminate, when the flowers arise laterally and successively as the floral axis elongates; determinate, when the flowers arise from the terminal buds and thus check the elongation of the floral axis; and mixed, when these two are com- bined. MORPHOLOGY OP LEAVES AND FLOWERS 611 Fig. 469. Strap-shaped and tubular flowers from the head of Squaw Weed (Senecio). The corolla and calyx appear to arise from the top of the ovary. Such a flower is epigynous and the free portion of the calyx is called pappus. (After Thome.) Flowers may arise singly, as in silverweed {Potentilla anserina), and are then designated as solitary. If in the axils of ordinary leaves, they are axillary and solitary. A raceme is that indeterminate inflorescence in which the flowers are stalked and arranged along the sides of a floral axis. The shepherd's purse has the raceme type of inflorescence. New flowers are continuously arising at the top as the floral axis elongates. Fig. 470. Solitary, funnel-shaped flower of field Bindweed. (After Thome.) If the inflorescence is of the raceme type with the exception that the flowers have no stalks, as in the plantain, we ha,ve the spike. 612 WEED FLORA OF IOWA Fig. 471 I Fig. 471 II Fig. 471 III Fig. 471 IV Fig. 471. Types of inflorescence. I. Raceme of Currant. II. Umbel-like inflorescence of Cherry. III. Head of Clover. IV. Umbel of Parsley. If the lowest pedicels or flower stalks are elongated (or the upper ones remain short) so that the cluster is convex or nearly flat on top, we have the corymb type of inflorescence. In the wild carrot, common yarrow, and parsley family in gen- eral, the axis of the corymb is so much shortened that all pedicels seem to start from the same point and resemble the rays of an in- verted umbrella. This is the umbel. In the clover {Trifolium procumhens) the flower axis is short and the pedicels of the flowers are either short or absent. This causes the flowers to be crowded into a roundish cluster which is called a head. MORPHOLOGY OF LEAVES AND FLOWERS jn Fig. 472. Close head of a composite. (After Thome.) 613 Fig. 473. Close head of the Dandelion. (After Thomg.) 614 WEED FLORA OF IOWA The flower axis is so much shortened in the dandelion, sunflower and composites in general, that it may be a concave, flat, or conical surface. The flowers are crowded upon this surface, and the en- tire group is surrounded by one or more rows of leaf-like bracts which form the involucre. This is the close head or composite type of inflorescence. Fig. 474. Milkweed with flowers in umbels. In many cases, as in field sorrel and in five-finger {Potentilla norvegica) , the oldest flower of the floral axis is terminal and all later flowers must arise from axils below. This is the determinate type of inflorescence and this type of flower cluster is called a cyme. MORPHOLOGY OP LEAVES AND FLOWERS 615 Fig. 475 I , Pig. 475 II Fig. 475 III Fig. 475. Flower of Milkweed, showing the peculiar hooded and horned stamens, I. Flower. II. Stamen. IIL Pistil with adhering pollen masses. IV. Pollen masses or pollinia. (After Thome.) THE DEVELOPMENT OP A STAMEN AND ITS FUNCTION IN SEED PRODUCTION. Every one knows that the .pollen produced by the stamens has an important part to play in seed production. It is for this rea- son that the stamen is considered one of the essential organs of the flower. There is so little variation in the general development of stamens in the higher seed plants that the, history of a stamen from any weed will suffice for all. A mature stamen consists of a stalklike portion, the filament, and the pollen-bearing portion, the anther, which is borne on top of the filament. The filament may be variously modified or even wanting. Fig. 476. Cross section of anther showing pollen sacs. A. pm, pollen mother cells ; t, food cells. B. Pollen grains mature and being shed. (From Coulter, after Baillon & Luerssen.) An anther appears distinctly four lobed. If a cross section of a young anther be made, four distinct regions will be found, one in each lobe or a pair on each side of the axis. These four distinct 616 WEED FLORA OF IOWA regions are conspicuous because the cells contained are larger and have a denser content. Each of these cells will produce four pollen grains and for this reason are called pollen mother cells. Surrounding each group of pollen mother cells is usually one layer of cells whose content is quite dense. These are sacrificed as food material for the pollen mother cells and are designated as tapetal cells. After the pollen grains are formed, they lie loose in these cavities. Each cavity is considered as a case or angium and since a pollen grain is a spore, this case is called a sporangium. The partition between each pair of sporangia usually breaks down, and two spore-containing cavities are formed. These are generally called pollen sacs. The pollen sacs are now ready to open or dehisce as the process is called. This is due to especially modified cells, which produce such strains through the variation of moisture, that usually longitudinal slits or terminal pores are produced. Fig. 477. Thrift, ov, ovary ; s, style ; st, papillary stigmas. (After Thome.) The pollen is now either by wind, insects, or water carried to the stigma of the pistil where it begins the performance of its important function. This process of transference is pollination. An examination of a pollen grain at the time of pollination will usually show that it has two nuclei; one of these has to do with the production of a tube which traverses the tissues of the pistil and furnishes a passage way to the embryo sac which contains the MORPHOLOGY OF LEAVES AND FLOWERS 617 cells to be fertilized. The other nucleus of the pollen grain pro- duces two small nuclei which are called sperms. These sperms pass down the pollen tube to the embryo sac and fertilize the egg and endosperm nucleus. THE PISTIL AND ITS FUNCTION IN SEED PRODUCTION. A flower may have one or more pistils which occupy the center of the flower. They are the last to appear, since the order of development is usually sepals, petals, stamens, and pistil. Fig. 478. Iris with petal-like stigmas. (After Thome.) A complete pistil consists of three parts — ^the expanded base which bears the seed and is called ovary (or "egg-case") ; the ex- panded portion at the top, or the stigma ; the portion that connects the ovary and stigma, the style. The style is not an essential part of the pistil and may be absent without disturbing the function of the pistil. The stigma has on its surface many minute papillae which re- tain the pollen and excrete a sweetish, sticky fluid which serves as a nourishment and stimulant for the pollen grain. 618 WEED FLORA OF IOWA Fig. 479. Corn-poppy with a shield-shaped stigma capping the ovary. (After Thome.) If we cut a cross section of the ovary of the May apple, we find within, a cavity bearing on one side a projection to which are at- tached the small, somewhat globular bodies or ovules. This cavity Fig. 480. Pistil of Thistle. (After Thome.) within the ovule is usually called a cell by manuals, but a better term is loculus, since the term "cell" is universally used to desig- nate the unit of tissues. The thickened portion to which the ovules are attached is the placenta. The pistil of the May apple is a simple pistil and according to the older views concerning the pistil, it is a carpel. The older view was, that the carpel is a modified leaf. If one will imagine a leaf folded and the margins joined so as to enclose a loculus and then the outer part modified so as to form a style and stigma, the conception of a carpel will be clear. An examination of the pistil of oxalis will reveal five styles and stigmas, and one ovary with MORPHOLOGY OP LEAVES AND FLOWERS 619. Fig. 481. Cross section of the ovary of Gesneria showing one cell and two parietal placentae. (After Thome.) five loculi. This indicates that the pistil of oxalis consists of five carpels whose ovaries have united to form one with five loculi. This uniting may even extend to the styles and stigmas. A pistil that is made up of more than one carpel is compound. Fig. 482. I. Cross section of the compound pistil of Snapdragon, showing the two cells and the axillary placentae. II. Longitudinal section of an ovary with a free central placenta. (After Thomg.) Ovule. — The ovule is the most essential part of the pistil because it is the forerunner of the seed. The ovule consists of a central portion, the nucellus, which is enclosed by one or two jackets which are called the integuments. The integuments do not entirely close at the outer end of the nucellus and this small opening left is the micropyle through which the pollen tube usually passes. In the interior of the nucellus is a region which resembles a large cavity since it contains no cell walls. This is the embryo sac. At about the time the flower opens the embryo sac contains seven cells. The two which have an important future history are the egg and en- dosperm cells. 620 WEED FLORA OF IOWA FiGf. 483. Diagrammatic representation of fertilization of an ovule, i, inner coating of ovule ; o, outer coating of ovule ; p, pollen tube proceeding from one of the pollen grains on the stigma ; c, the place vt^here the two coats of the ovule bend. (The kind of ovule here shown is inverted, its opening m being at the bottom, and the stalk f adhering along one side of the ovule.) a to e, embryo sac, full of protoplasm; a, so-called antipodal cells of embryo sac ; n, central nucleus of the embryo sac ; e, nucleated cells, one of which, the egg cell, receives the male nucleus of the pollen tube ; f, funiculus or stalk of ovule ; m, micropyle or opening into the ovule. (After Luerssen.) The egg is in the end of the sac nearest the micropyle, in the most convenient position for the entering pollen tube. The en- dosperm cell is near the center of the embryo sac. The embryo sac is now mature and awaits the entrance of the pollen tube. Fertilization. — The pollen tube traverses the tissues of the stigma and style and finds its way to the micropyle. It passes through the micropyle, penetrates the tissues of the nueellus, and pierces the membrane of the embryo sac. The two sperms, which have had a rather long journey through the pollen tube, now enter the embryo sac. One finds its way to the egg and soon fuses with the egg nucleus. The other fuses with the nucleus of the endosperm MORPHOLOGY OF LEAVES AND FLOWERS 621 Fig 4*54 Pig. 485 Fig. 484. Embryo sac of Buttercup (Ranunculus multifldus). Near the center is the large endosperm nucleus. The egg is the inner one of the three cells at the upper end of the sac and lies between the inner ends of the two synergids. The three antipodals are shown closely crowded at the lower end of sac. (After Coulter.) Fig. 485. Fertilization in the Fleabane (Erigeron) ; pt, pollen tube with two densely staining bodies (x) ; a, male cell fusing with egg; b, male cell fusing with endosperm nucleus. (After Land.) cell. This process in which, the sperms or male nuclei fuse with the nuclei of the egg and endosperm cell is fertilization, and bothi fusions are designated as double fertilization. THE DEVELOPMENT OF THE EMBRYO AND SEED. When the fertilized egg germinates, a filament of cells, the suspensor, is usually found. At the end of the suspensor the embryo is developed which, when mature, is more or less sur- rounded by nourishing endosperm which has resulted from the growth and division of the endosperm nuclei. 622 WEED FLORA OF IOWA Fig. 486. Development of the ovule and embryo of the Shepherd's Purse (.Capsella). A, young ovule, showing origin of two integuments at base of nucellus, n. B, outer integument growing beyond the inner, and the ovule beginning to bend over ; es, embryo sac. C, diagram of a later stage with mature embryo sac. D, development of the suspensor s. E, early division of the terminal cell (embryo cell). F, later stage, showing the differentiation of an outer cell layer in the embryo, which is to be- come the epidermis. G, the two cotyledons c and the root region r now clearly defined. H, lengthwise section of an ovule, showing the position of an embryo in an embryo sac ; em, embryo ; s, suspensor ; e, endosperm ; li, inner integument ; oi, outer integument ; m, micropyle. (A, B. C, adapted after Campbell. Ginn & Co.) MORPHOLOGY OF LEAVES AND FLOWERS J623 The two groups of higher seed plants, or Angiosperms, differ widely in the structure of the embryo. In the group including the grasses, rushes, sedges and such plants as wild onion {Allium canadense) the globular embryo soon develops into an axis with the root tip at one end and one cotyledon at the other. The stem tip : arises from the side of the axis as a lateral member. This group of plants is designated as Monocotyledons (one cotyledon). Fig. 487. Fig. 4S Fig. 487 1 Pig. 487 II Fig. 488 I. Fruit of Squaw-weed (Senecio). II. Fruit of Dandelion. Bach is crowned with pappus which aids in distribution. (After Thome.) The fruit of the Winter Cherry (PhysaUs) with a portion of the inflated calyx removed to show the enclosed berry. (After Thome.) In the other group, to which a large number of the weeds be- long, the axis of the embryo develops a root tip at one end, a stem tip at the other, and a pair of cotyledons, one on each side of the stem tip. Since two is the prevailing number of cotyledons, the term Dicotyledons is applied to this group. Fig. 489 Fig. 490 Fio. 489. I. Fruit (pod) of Plantain with upper portion of pod breaking and falling off to allow seeds to escape. II. Pod of Poppy opening by a lid. (After Thomg.) Fio. 490. Fruit of Mallow which separates into as many one-seeded carpels as there are styles. -i :. (After Thom6.) 624 WEED FLORA OF IOWA Seed. — The seed is the matured ovule. It contains the young plant or embryo which is the essential part of the seed since it is through the later development of this young plant that new in- dividuals are produced. Accompanying this maturing of the ovule, various other changes take place which give distinguishing features to different seeds. Frequently the endosperm grows so extensively as to absorb and replace the cells of the nucellus and thus comes to occupy all the space within the coats of the integuments, :as in the morning-glory, onion, etc. The embryo may remain compara- tively small as in the morning-glory or onion, or it may in turn absorb and replace all the cells of the endosperm and so come to occupy the space within the integuments, as in the bean and clover. Sometimes some of the nucellus and endosperm remain. The in- teguments also undergo various changes during the formation of the seed, often becoming hard or papery or provided with hairs, hooks or spines, or becoming smooth or pitted. Fig. 491 I Pig. 491 II Pig. 492 Fig. 491. I. Immature pistils of Geranium. II. Mature pistil and carpels with their long styles are separating from the elongated axis. (After Thomg.) Pig. 492. Burry fruit of Jamestown or Jimson Weed (.Datura) showing method of dehiscing. (After Thome.) Fruit. — A fruit is a ripened ovary alone or a ripened ovary plus closely related parts such as calyx, involucre, and receptacle. In the beggar-ticks {Bidens) the ovary becomes tough and invests the MORPHOLOGY OF LEAVES AND FLOWERS 625 seed, while the awns which represent the calyx become barbed and aid in distribution. In the buttercups the ovary invests the seed while the style forms a hook. The involucre in the clotbur and ragweed remains around the pistils and becomes more or less spiny. In the nightshade {Solanum nigrum) the ovary becomes fleshy and the fruit is called a berry. 40 CHAPTER V. SCATTERING OF WEEDS ADA HAYDEN CHAPTER V. SCATTERING OF WEEDS. There is much to be observed as to how particular plants spread from one location to another, but from the hosts of observations that have been made the following means are recognized as agents of conveyance to the disseminules of plants to suitable habitats. Physical forces: Wind Water Snow and wind Animals : Man, furred animals and birds Mechanical adaptations : Explosive devices Hygroscopic movement Burial In comparing the amount of seed produced by a plant with the number of plants maturing from that seed, it is evident that rela- tively few plants reach locations favorable to existence. Wind transported fruits may be recognized by their appendages in the form of wings, comas of hair and bristly parachutes. Water carried fruits are characterized by lightness, inflated coverings and corky buoys. Seeds disseminated by animals are characterized by hooked and clawed appendages or spines which become attached to pelts or fabrics or have succulent portions which are edible. Scat- tering by mechanical devices is illustrated by the forcibly splitting pod, the twisted pod, the spearlike fruited grasses whose twisted awns aid in entering the earth and the cleistogamous flowered plant which buries its seeds in the earth. Birds destroy large quantities of weed seeds. Mr. H. W, Hen- shaw* states that a ring-necked pheasant's crop from Washington contained 8,000 seeds of chickweed and a dandelion head. Birds of the sparrow family, according to the same authority, feed largely on the seeds of weeds. The tree sparrow consumes one-fourth ounce of weed seeds per day. The tree sparrows on this basis annually consume 875 tons of weed seeds in Iowa. These birds save the farmers of the United States on this basis $89,260,000 annually. *Henry W. Henshaw. Fifty Common Birds of the Farm and Orchard. Farm- ers' Bull. U. S. Dept. Agr. No. 513. 630 WEED FLORA OF IOWA Fig. 493A Fig. 493B Fig. 4930 FiQ. 493. A. Seed of common Field Sorrel (Oxalis corniculata) with two cap- sules from which the seeds are shot out. B and C. Common Dock iRumex crispus). Fruit scattered by the water. The wings surrounding the fruit and tubercle make the fruit admirably adapted to floating on the water. Sec- tion of the fruit showing wings and tubercle shown in C. (Drawings by Ada Hayden.) Parts of the fruit which serve as disseminating mechanisms. — The stimulus of fertilization not only gives rise to the development of a seed but causes parts of the seed or seed-case to develop in many instances into a special contrivance for its dissemination. A fruit, botanically speaking, is a ripened ovary, including any closely attached parts, for example: the milkweed pod filled with seeds bearing tufts of hairs ; the dandelion fruit with its parachute- like pappus. Parts which serve as dissemination mechanisms : Ovary wall. a. Fleshy, often attractively colored — cherry, horse nettle, black nightshade. Bursting — ^touch-me-not. Inflated — sedge. Corky tubercles — dock. Winged — maple. b. c. d. e. Calyx, a. b. Capillary hairs — dandelion. Spined — buffalo bur. SCATTERING OF WEEDS 631 Pig. 494A Pig. 494B FiQ. 494. Scattering of seed by wind. A. The Iowa Tumble Weed (AmarantTms graecizans) . The weeds piled up against the fence; the Russian Thistle and other weeds are scattered in a similar way. B. Achene of Red-seeded Dandelion. (A, after Bergen's Botany — Ginn & Co. ; B, drawing by Ada Hayden.) Seed coat or its appendages. a. Coma of hairs^ — milkweed. b. Mucilaginous — peppergrass. c. Contractile seed coat — oxalis. Receptacle. a. Fleshy— rose. Bracts — ^basswood. Involucre. a. Spiny— burdock, cocklebur. 632 WEED FLORA OF IOWA The dissemination of weeds is not unlike that of other plants. "Weeds are commonly recognized as plants out of place, plants which are detrimental to the growth of crops or otherwise in- jurious. While ash or maple seeds are not usually placed in this category ; if, in their seedling stage they monopolize a piece of soil, for example a lawn newly planted with grass, absorbing the nutri- ment and crowding the plants desired in this location, these in- vaders have earned for themselves the title "weed." The epithet Fig. 495A P!g. 495B Fig. 495. Seeds and fruit scattered by the wind. A. Basswood (Tilia ameri- carta), a light bract to which is attached a stalk bearing the fruits. B. Milkweed (Asclepias syriaca) pod and seeds. (Drawings by Ada Hayden.) "weed" brings to mind the obnoxious characters of the plants so designated, yet weeds have just as respectable lineage as the palm, olive, lily or laurel, and in their systematic relationships they show by their structure that they are members of the first families of the plant kingdom. Thus the notable rose family, which serves the world with the apple, tlie plum, the cherry, the quince, the peach and the pear, claims among its numbers the aggressive little cinquef oil {Poientilla fruticosa) , an invader of pastures and tilled lands, the thorny prairie rose {Bosa pratincola) and the prickly black raspberry (Rtihus occidentalis) , which without invitation en- trench themselves upon the territory and contend with the agri- culturist as to what shall occupy the soil. Families such as the SCATTERING OF WEEDS 633 goosefoot (CJienopodiaceae) and the buckwheat (Polygonaceae) are recognized as cohorts of marauders thronging the highways, forging into fields, contesting with crops and contributing little beauty and few representatives of economic value. The great cos- mopolitan sunflower family {Gompositnie) contributes numerous species of economic reputation as well as a goodly number of widely recognized but combated species. A large number of plants may be identified with their families by their type of fruit structure only. Families which have little variation in fruit structure have few agents of dissemination, while families with considerable variation have usually several agents, as in the sunflower family in which the calyx is represented by bristles forming a parachute in the dandelion, lettuce or the Fig. 496A Pig. 496B Fig. 496. Fruit scattered by the wind and animals. A. To the right scattered by the wind: a, achene of Goldenrod {SoKdago rigida) ; b, Blue Flowered Lettuce (.Lactuca floridana), the bristly hairs called the pappus. To the left scattered by animals : a, an achene, commonly called a seed, of Bootjack or Beggar-ticks (Bidens frondosa) ; b, Spanish Needle (Bidens bipinnata) . B. Anemone {Anemone cylindrica). (Drawings by Charlotte M. King, la. Agr. Exp. Sta.) Canada thistle, or terminating in teeth as in Bidens or becoming a spiny involucre as in the cocklebur and the burdock. Some representatives of this family, for example the ragweed, have no special means of transportation and the seeds fall in great quan- tities near the mother plant where they germinate in large num- bers if not distributed by wind-driven snow or by chance inclusion with agricultural seeds. The seeds of the milkweed family 634 WEED FLORA OF IOWA Fig. 497A Fig. 497B A. Seeds of Catalpa {Catalpa Fig. 497. Seeds and fruits scattered by the wind speciosa) with winged appendages. B. Key fruits of Soft Maple {Acer saccharinum) are carried by the wind and in falling drop into the mud or soft grass of the lawn. (Drawings by Ada Hayden. ) (Asclepiadaceae) are provided with tufts of hair which serve to float the seeds in the air as they escape from the pods. The oxalis family (Oxalidaceae) have seeds whose outer seed coat separates from the seeds shooting them from the bursting pods. The gera- nium family (Geraniaceae) have contractile pods which shoot the seeds several feet from the plants. The mustard family (Cruciferae) have pods which burst but do not scatter the seeds far. Many species of this group have seeds with mucilaginous coats which, when in contact with damp surfaces, adhere to them. Peppergrass is a well known example. This family has also some SCATTERING OF WEEDS 635 Pig. 498A Fig. 498B Pig. 4980 Fig. 498. Weeds scattered by animals. A. Buffalo Bur (Solanum rostratum). B. Pitchforks (Bidens frondosa), the downwardly barbed points admirably suited for animal dissemination. C. Carrot {Daucus carota). (Drawings by Ada Hayden.) ■^ni^j] Fig. 499. Fig. 499A Fig. 499B Fig. 499C Cow with attached Burdock. B. Burdock enlarged. C. frey (Cynoglosaum) enlarged. Com- (A, after Bailey, Macmillan & Co. ; B, after Dewey, U. S. Dept. Agr.) 636 WEED FLORA OF IOWA Pig. 500A Pig. 500B Fig. 500. A. Weed seeds eaten by birds, a. Wild buckwheat {Polygonum, con- volvulus) ; b and d, Amaranth or Pigweed; c, Chickweed ; e. Spotted Spurge ; f, Ragweed ; g, Foxtail ; h, Dandelion. B. Seeds of sedges carried by water. (A, after Dewey, U. S. Dept. of Agr. ; B, drawing by Ada Hayden.) tumble weeds among which are several mustards like tumbling mustard. The seeds of the sedge family {Cyperaceae) are com- monly surrounded by inflated sacs or bear tubercles which enable them to be carried by water. Grasses {Gramineae) show consider- able variation in means of dissemination. Some grasses, for ex- ample Stipa, have sharp fruits with twisted awns a prominent factor. While dissemination is a prominent factor in the distribu- tion of plants, the factor of adaptation to habitat is no less im- portant for if a plant cannot adapt itself to the conditions in the habitat where the seed falls the transportation is of no avail so far as its development is concerned. Canada thistle produces some seed in northern Iowa, where habitat conditions are more favorable than in southern Iowa. SCATTERING OF WEEDS 637 Fig. 501. Birds scatter the seeds of the Wild Black Cherry (Prunus serotina). 1, flowering branch ; 2, fruit ; 3, fruiting branch ; 4, cross section of fruit ; 5, flower ; 6, branch with buds. (After Cheney in Green's Forestry of Minn.) From an ecological point of view weeds are plants which adapt themselves readily to ordinary agricultural conditions and since most crops are grown under mesophytic conditions, most weeds are mesophytes which adapt themselves to definite habitat con- ditions such as cultivated field or uncultivated field and are readily transferred with agricultural seeds, hence the association of certain weeds exclusively with certain crops, for example, among the com- mon clover field weeds are buckhorn, wild carrot and plantain. These are not found in corn fields where cocklebur, horse nettle, morning-glory and sandbur flourish. Many of the most obnoxious 638 WEED FLORA OF IOWA rig. 501A I . Fig. oOlA II Fig. 501-A. I. Chicadee carrying fruit. II. Berries of Horse Nettle ; carried by birds. J. I Fig. 502. Mixture of weed seeds commonly found in low grade Alsike Clover seed : a, Alsike Clover ; b, White Clover ; c, Red Clover ; d, Yellow Trefoil ; e, Canada Thistle ; f. Dock ; g, Sorrel ; h, Buckhorn ; i, Rat Tail Plantain ; k, Lamb's Quarters ; 1, Shepherd's Purse ; m, Mayweed ; n, Scentless Camomile ; o, White Campion ; p, Night-flowering Catchfly ; q, Ox-eye Daisy ; r, Small-fruited False Flax ; s, Cinquefoil ; t, two kinds of Peppergrass ; u, Catnip ; v, Timothy ; x, Chickweed ; y, Canada Blue Grass ; z, Clover Dodder ; 1, Mouse Ear ; 2, Knotgrass ; 3, Tumbling Amaranth ; 4, Rough Amaranth; 5, Heal-all; 6, Lady's Thumb (enlarged). (Hillman, U. S. Dept. Agr.) SCATTERING OF WEEDS 639 Fig. 503. Seeds of Poas with impurities. 1, Kentucky Blue Grass rubbed and unrubbed ; 2, Wood Meadow Grass (.Poa nemoralls) ; 3, Ergot, a fungus; 4, Texas Blue Grass (P. arachnifera) ; 5, Canadian Blue Grass (.Poa compressa) ; 6, Rough Stalked Meadow Grass {Poa trivialis) ; 7, Silky Bent Grass (Apera spica-venti) ; 8, Wood Hair Grass (Deschampsia flexuosa) ; 9, spine of Canada Thistle ; 10, Canada Thistle ; 11, caryopsis of Stink Grass (Eragrostis major). (U. S. Dept. Agr.) 640 WEED FLORA OF IOWA weeds have not prominent dissemination mechanisms but are trans- ferred with agricultural seeds, as carrot, buekhorn, dodder, sheep sorrel, yellow trefoil, quack grass and pigeon grass. The separation of impure seed from agricultural seed necessitates the recognition by their morphological characters of obnoxious seeds. An economic consideration of dissemination of weed seeds and their control involves (1) familiarity with the morphology of the fruit and seed; (2) the limitation of the habitat in which the weed is able to thrive; (3) recognition of the avenues and agents of dis- tribution. CHAPTER VI. ROOTS AND ROOT-STOCKS OF WEEDS. J. C. CUNNINGHAM 41 CHAPTER VI. ROOTS AND ROOT-STOCKS. The study of root systems is accompanied with more or less dif- ficulty and expense, and this, no doubt, accounts for the small amount of work done along this line. Two methods have been employed to obtain the complete root system of growing plants. That used by Ten Eyck is perhaps the most satisfactory, although tedious and expensive. It consists of excavating about a plant and enclosing the whole mass of earth containing the roots in a cage of wire netting. Steel rods are thrust through the cage horizontally to prevent the roots from breaking. The soil is then carefully washed away leaving the roots very nearly in their natural position. The other method, employed by a Russian investigator, Rot- minstror, has given quite satisfactory results. The plants are grown in soil made up of top- and subsoil. This is placed, the sub- soil below and the topsoil above, in boxes 1 in. wide, 20 to 40 in. deep and 20 to 40 in. long. These boxes are placed in the ground level with the surface. The plants are then grown in these boxes and removed when desired, the soil carefully washed away and the entire plant transferred to paper. Fig. 504. Root-stocks or rhizomes of Quack Grass (Agropyron repens). These root-stocks are sometimes more than four feet long. (Photographed by Stevens.) 644 WEED FLORA OF IOWA The pictures shown here are of plant roots obtained by the first method, the wire cages being omitted. The roots of weedy plants vary widely in form, structure, and in longevity. Their function is three- and sometimes fourfold: First, to absorb water and dissolved mineral matter; second, to anchor the plant in the soil; third, to act as a storehouse for re- serve food, and fourth, may serve to propagate the plant. E'iG. 505. Roots of White Sweet Clover (Melilotus alia). Plants with several strong branching roots. (Photographed by Stevens.) ROOT FORMS. E-oot forms may be divided into four general types : First, the primary; in this case a single, usually enlarged central root is de- veloped. From it grow the smaller lateral roots. The burdock (Arctium lappa), is of this class. Second, multiple primary, in which the embryonic root almost immediately breaks up into ROOTS AND ROOT-STOCKS OF WEEDS 645 many usually enlarged and fleshy roots. Sweet clover {Melilotus alba), Fig. 505, offers a good example of this type. Third, tuberous or those that develop an enlarged portion at the end of la some- what smaller one. Fourth, fibrous in which a mass of small roots develop usually just below the stem as in most of the grasses and in the plantains. Besides the forms already mentioned we find various types of aerial roots, or those that develop on the plant above ground. The aerial roots of the ivy become finger-like and cling to objects to assist the plant in climbing; those of the mistletoe and the dodder become parasitic by pushing their aerial roots into the tissues of the host plant and drawing nourishment from it. In performing the four functions mentioned 3,bove the roots of a single plant may occupy considerable area. Dr. Pammel has pre- pared the following table showing the depth and spread of the root system of a number of our noxious weeds. Weed Depth Spread Buckhorn Plantain Wild hemp Evening primrose Beggar ticks Dog fennel Nigger head Goldenrod White vervain Canadian lettuce Field thistle Burdock Black nightshade Pennsylvania smartweed Lady's thumb ^ Yellow oxalis Prickly lettuce Cocklebur Greater ragweed Rough pigweed Horseweed Tumbleweed Small ragweed Spanish dagger 24 sq. in. 30 " " The amount of reserve food stored within weed roots depends to a considerable extent upon the length of time they continue to live. 646 WEED FLORA OF IOWA Fig. 506. Roots of Common Milkweed (Asclepias syriaca) . These roots are sometimes more tlian 14 feet long. Buds are numerously produced on the root. More than 100 were found on the roots of this plant. (Photographed by Colburn.) ROOTS AND ROOT-STOCKS OP WEEDS 647 Boots may be classified according to their length of life, and this is, perhaps, the most practical knowledge to possess concerning weeds. Without this knowledge no intelligent or successful method of eradication can be adopted. First we have the annuals or those which complete their growth and mature their seed in one year. These plants produce an enormous amount of seed, sometimes as high as 50,000 to a single plant. The root system is simple, although it may extend to a con- siderable distance horizontally. Such plants are easily destroyed by cultivation unless they root from the joint as in the case of the crab grass (Digitaria sanguinalis) . Fig. 507. Roots of Curled Dock {Rumex crispus). (Photographed by Stevens.) Second are the winter annuals. These plants may begin their growth in the spring, in which case they become annuals. Many of the seeds, however, germinate in the fall and throw up a rosette 648 WEED FLORA OF IOWA of leaves and thus pass the winter stage. In the spring stems are thrown up from these leaves and seed is produced. Our com- mon shepherd's purse {Cwpsella lursa-pastoris) is an example. The third class is the biennials or those which expend their energy the first season in forming a root system, usually fleshy, and the second season in maturing seed. We have numerous examples among the garden crops, such as the beet, turnip, carrot, etc., while among the weedy plants we have the burdock {Arctium lappa), the sweet clover, figure 505, the wild parsnip and others. If these plants are prevented from forming seed the second year they perish. Fig. 508. Roots of Buckhorn {Plantago lanceolata). This perennial weed is easily destroyed by cultivation. (Photographed by Colburn.) In the fourth class belong the perennials which live year after year and for this reason become our most noxious weeds. When the roots once become well established it is very difficult to eradicate them, as is shown by the lawns, fields and pastures which are in- fested with such weeds as dandelions, quack grass, Canada thistle, ROOTS AND ROOT-STOCKS OP WEEDS 649 Fig. 509. Fibrous roots of Buckhorn. (Photographed by Gardner.) docks and wild morning-glory. These plants do not, as a rule, produce large quantities of seed but depend upon the roots or stems as a means of propagation. Thus if a field infested with quack grass or morning-glory is plowed or disked the roots or rhizomes are broken up and each piece may produce a new plant. Some roots which do not spread extensively through the soil but form new plants from offshoots from the crown, such as the docks and wild gourds, form heavier roots from year to year for the fol- lowing reason : The root growth is most active at the apex of the main roots. This resumption of growth starves many of the older roots, as we find few lateral on these older portions, and it thus extends the root system. In the annuals there is little need for a large amount of reserve food within the roots for the elaborated food is used up largely as it is manufactured. The life of the plant ceases when seed is produced. In the biennials, however, large quantities of reservt! 650 WEED FLORA OP IOWA ^^■KBi^^wr^ K ' IPF .^HH^^M^^fi^^^L ^^1 HiVh^^ ^% ^^^^^Mp^/jr ... ''r^tlr^^V^^^^Bfl HIP^^i^lSiH^ ^^H Hi I^^^D&tjSBKsl^ByK^^^^^lvi^s^v^HK \jSre- K^JE i^^KRw^ ^^M ■ /§:' '-^. /''l^ '}'''' *' ^II^^^I^^^^BL ■^^ ^^ll ■"^^ Fig. 510. Biennial root of Young Bull Thistle (Cirsium lanceolatum) after one year's growth. (Photographed by Charlotte M. King.) food are stored in the roots. The same is true of the perennials although to a less marked degree than of the biennials. By studying the root system in the late fall we may determine roughly whether the weed is an annual, a biennial or a perennial. That is to say, dead small fibrous or primary roots and seed produc- tion indicate an annual; large fleshy roots and no seed production a biennial; reserve food within the roots beside seed production a perennial. PROPAGATION OF WEEDS BY ROOTS AND STEMS. Prof. Hitchcock says that weeds may be propagated by seed and buds or by vegetative sprouts. The layman is inclined to call all parts of the plant below ground root. It may be, however, a stem called a root-stock or rhizome. Microscopical examination is often neeessiary to determine which is root and which is stem. ROOTS AND ROOT-STOCKS OF WEEDS 651 Fig. 511. Underground rhizomes of common Morning-glory sepium). (Photographed by Stevens.) {Convolvulus Roots. Adventitious buds are produced at indefinite points along the roots and from them stems and plants develop. A number of our noxious weeds are propagated by these running or creeping roots, such as: milkweed (Asclepias cornuti), bindweed {Convolvulus arvensis), sheep sorrel {Bumex acetosella), Indian hemp (Apocy- num ccmnabinum) , perennial ragweed {Amhrosia psilostachya) , pasture thistle {Cirsium undulatum). The weeds mentioned above are comparatively shallow rooted. A few weeds are propagated by buds which come from deep vertical roots. Among them we find the following : horse nettle {Solanum carolinense) , ground cherry (Physalis sp.), Canada thistle {Cirsium arvense). Undeegeotjnd Stems oe Rhizomes. These underground stems are usually found at a short distance beneath the surface. Along these stems are found nodes with leaf scales at definite intervals. From these nodes roots develop which penetrate the soil .and leafy stems which develop above ground. Some of the weeds so propagated are as follows: quack grass 652 WEED FLORA OF IOWA Fig. 512. Roots of Sour Dock (Rumex crispus). (Photographed by Stevens.) {Agropyron repens), morning-glory (Convolvulus sepium), smart- weed (Polygonum muhlenhergii) , poison ivy (Rhus toxicoden- dron), nettle (TJrtica gracilis), wild rose (Rosa arhansana) . Fig. 513. Rhizome of Solomon's Seal; a, leaf bud; b, old stem; c, d, old stem scars. (After Thome.) ROOTS AND ROOT-STOCKS OF WEEDS 653 Fig. 514. European Morning-glory or Bindweed (Convolvulus arvensis). In gar- dens and fields. (After Clark and Fletcher.) 654 WEED FLORA OP IOWA Ceowns oe Shoet Offshoots. A long list of weeds produce heavy crowns near tlie surface of the soil. Stems spring from these crowns year after year. Parts of the crown may become separated from the parent plant and thus form an independent plant. Among the weeds so propagated we find the dandelion {Taraxacum officinale) , white vervain {Ver- bena urticaefolia) , plantain {Plantago lanceolata) , catnip {Nepeta cat aria), curled dock {Bumex crispus), smooth dock {Rumex altissimus), rib grass {Plantago lanceolata), ox-eye daisy {Chrysan- themum leucanthemum) . CHAPTER VII. NUMBER AND KINDS OF WEEDS ON DIFFERENT SOILS. CHAPTER VII. NUMBER AND KINDS OF WEEDS IN DIFFERENT FIELDS. During the season of 1912 Mr. Robert H. Birlingmair counted the weeds appearing on various fields under different conditions, for this purpose four feet each way being measured off and the different weeds noted. The results were as follows: FIELD 1.* Weed Date Mar. 29 Apr. 6 Apr. 13 Apr. 20 Apr. 27 May 4 Peppergrass** _ _ 24 6 3 14 3 1 8 1 Dandelion Tall fiveflnger 2 1 Small ragweed _ 1 ai 3 10 Blue grass 20 10 1 51 24 Bracted vervain Mustard _ _ Daisy fleabane 8 1 Pigweed _ _ 1 Spotted spurge 282 4 4 2 460 Horseweed _ 6 Pennsylvania smartweed 1248 Ground cherry 2 Green foxtail _ _ _ _ 84 4 2 *On corn land that was in blue grass sod last j-ear. **A winter annual. FIELD 2.* Weed Date Mar. 29 Apr. 6 Apr. 13 Apr. 20 Apr. 27 May 4 Yellow foxtail 10 Daisy fleabane _ Horseweed** _ _ _ 143 65 '""32'" 1 34 72 Vervain Plantain 11 Pennsylvania smartweed 1 *On timothy meadow. **Winter annual. 42 658 WEED FLORA OF IOWA FIELD 3.* Weed Date Mar. 29 Apr. 6 Apr. 13 Apr. 20 Apr. 27 May 4 Small ragweed 1 1 2 Pennsylvania smartweed _ _ 1 Green foxtail 1 *On corn land that had been fall plowed. Field worked up and sowed to small grrain just before April 27. FIELD 4.* Weed Date Small ragweed _. Lamb's quarters- Pennsylvania smartweed Yellow foxtail _. Mar. 29 Apr. 6 Apr. 13 Apr. 20 Apr. 27 10 21 1 99 May 4 77 215 *On land sowed to winter wheat. FIELD 5.* Weed Date Mar. 29 Apr. 6 Apr. 13 Apr. 20 Apr. 27 May 4 Yellow foxtail 59D Green cfoxtail _ _ 718 Daisy fleabane 1 Bracted vervain 3 3 Peppergrass 3 4 40 Blue grass Pennsylvania smartweed 71 Spurge - _ _ _ 47 *On old corn land. Stalks harrowed down just previous to April 20. NUMBER AND KINDS OF WEEDS ON DIFFERENT SOILS 659 FIELD 6.* Weed Date Mar. 29 Apr. 6 Apr. 13 Apr. 20 Apr. 27 May 4 Small ragweed Yellow foxtail Green foxtail Lamb's quarters Pennsylvania smartweed Blue grass Dooryard knotweed Horseweed Spurge Hedge mustard 11 54 33 475 4a 3 3 3 39 71 *On fall plowed oats stubble. FIELD 7.* Weed Date Mar. 29 Apr. 6 Apr. 13 Apr. 20 Apr. 27 May 4 Dandelion 5 11 Veronica 1 Lamb's quarters 1 6 Small ragweed 9 Yellow foxtail _ 16 Shepherd's purse 75 +5 2 2 5 +4 7 1 1 7 or peppergrass Blue grass . 2 Hoary vervain _ Pennsylvania smartweed 1 Lady's sorrel +3 *On unplowed oats stubble. Field plowed previous to April 27. +Marks winter annuals. 660 WEED FLORA OF IOWA FIELD 8.* Weed Date Mar. 29 Apr. 6 Apr. 13 Apr. 20 Apr. 27 May 4 Small ragweed 33 169 46 ++37 10 8 ++5 7 ++4 49 Mexican dropseed ++16 ++18 Ijanib's quarters Morning glory ++6 ++7 Spurge Yellow foxtail Green foxtail 398 49 1785 Pennsylvania smartweed 15 23 38 65 Mustard Horseweed ++26 +4 2 9 10 11 Scribner's panic grass- Tansy mustard Nyctelea 3 Yellow dock +158 Large spotted spurge 129 Old witch grass 2 Wild four-o'clock +2 Self-heal 2 *In sheltered place on the south side of the railroad grade. Weeds were not all counted on April 27th, but there were hundreds of small ragweeds and smartweeds, and probably more than a thousand green foxtail plants. -H- Winter annual. -f Perennial. These tables reveal some interesting facts. The first weeds to appear in March were the winter annuals, like peppergrass and shepherd's purse, certain perennial weeds, and in one case horse- weed (Erigeron canadensis) in a timothy meadow. Two weeks later smartweed (Polygonum) was abundant. Spurge (Euphor- bia), an annual, was abundant in the latter part of April and early May. Foxtails in some cases surpassed all other weeds in abundance early in May. The smartweeds (Polygonum) and spurges increased enormously. These weeds were entirely removed from the plots. Fall plowing and clean cultivation certainly in- dicate a smaller number of weeds. Long, who measured off a square yard of ground in* Great Britain, roughly grouping its plant life therein into species, found on this square yard 1,050 seedlings or 5,082,000 per acre. There were 654 buttercup seedlings, 107 of annual meadow grass, 60 of dock, 26 of goosefoot, 25 of groundsel, 15 of shepherd's purse, 14 of *Trans. of Highland Agri. Sec. Scotland V. 23: 52. NUMBER AND KINDS OF WEEDS ON DIFFERENT SOILS 661 Fig. 515. A weedy cornfield, mostly Foxtail and Smartweeds. (Photographed by Colburn.) annual sow thistle, and 10 of chickweed, besides 139 of other species. He states that Korsmo's investigation revealed the pres- ence of an even larger number of seeds having the power of ger- mination, the seeds per square yard to a depth of 9.8 inches being as follows: Fallow field, 8,682 weed seeds (over 42,000,000 per acre) ; field for spring grain bearing the same crop for four suc- cessive years, 28,213 weed seeds (over 136,000,000 per acre) ; fallow field, 1,474 weed seeds (over 7,000,000 per acre). Mr. Long gives the following species of weeds found in Great Britain within an area 100 feet square : 662 WEED FLORA OF IOWA Fig. 516. Shepherd's Purse, a common winter annual. (After Vasey, U. S. Dept. Agr.) NUMBER AND KINDS OF WEEDS ON DIFFERENT SOILS 663 Fig. 517. A cornfield from which Quack Grass was removed by hoeing and cultivation. In adjacent check it formed a sod. The check was given the ordinarjr methods of cultivation. (Photographed by Colburn. ) ^Convolvulus arvensis (Euro- pean bindweed) ^Polygonum convolvulus (Black bindweed) * Polygonum aviculare (Knot- grass) *Rumex sp. (Dock) *Tussilago farfara '(Coltsfoot) * Mentha arvensis (Pepper- mint) ^Sinapis arvensis (Common mustard) ^Sonchus arvensis (Field sow thistle) ^Stellaria media (Chickweed) Papaver sp. (Poppy) * Ranunculus arvensis (Corn crowfoot) ^Viola sp. (Violet) Potentilla anserina (Silver weed) Aethusa cynapium (Fool's parsley) Scandix pecten-veneris (Ven- us' comb) Senecio vulgaris (Groundsel) ^Galium aparine (Cleavers) Vicia sativa (Vetch) 664 WEED FLORA OF IOWA ^Matricaria inodora (Wild *Agrostis sp. (Bent grass) chamomile) Agropyron repens (Quack Plantago major (Common grass) plantain) Poa annua (Low spear grass) Lychnis alia (White cam- "^Veronica sp. (Speedwell) pioii) Myosotis sp. (Forget-me-not) ^Euphorbia exigua (Spurge) Alchemilla arvensis (Parsley- ^Alopecurios agrestis (Foxtail piert) grass) Most of these species are troublesome weeds, and it may be added that those marked with * were abundant. For an Iowa cultivated field on June 2, 1903, the following weeds were found in one square rod. Name of weed. No. per sq. rod. Smartweed {Polygonum pennsylvanicum) Hedge mustard {Sisyiribrium officinale) Black beggar-ticks (Bidens frondosa) Prickly lettuce (Lactuoa scariola var. integrata) Pigweed (Chenopodium aWum) Horseweed (Erigeron canadensis) Dandelion ( Taraxacum, officinale) Foxtail ( 8etaria) 40,324 3,060 476 204 340 7,412 68 136,000 WEEDS AND CONTINUOUS CROPPING. Everyone has observed that continuous cropping increases the number of weeds; not only is this true for many. parts of Iowa but it is equally true for the older sections of the United States and of Europe. A. D. Hall who reported on the crops grown in grain land at Rothannstad* said: After continuous cropping for forty-seven years said weeds of all descriptions occupy considerably more space after continuous crop- ping than before. The relative proportion they bear to the grasses and clover has increased from year to year. Such weeds as barnet, hawkbit and black knapweed became abundant. Mr. Long gives the following list of worst weeds miade by four expert Scotch agriculturists : Arable Land. — Charlock, runch, chickweed, spurrey, docks, thistle, groundsel, coltsfoot, day nettle, red-shank, annual meadow grass, bulbous oat grass (pearl grass) , couch grass, fine bent grass or black couch, and wild oats. *Jour. Roy Agr. Soc. 64 :-83. NUMBER AND KINDS OF WEEDS ON DIFFERENT SOILS 665 Fig. 518. Green Foxtail (Setaria viridis). Common in gardens and fields. (Photographed by Colburn.) Grass Lcmd. — Buttercups, self-heal, docks, ragwort, daisy, thistles, ribwort, plantain, creeping soft grass, common bent grass, >york- shire fog or woolly soft grass, moss. There are, however, many other weeds which are given by him which are serious pests to the agriculturist of that country. Of the weeds of the arable land he lists buttercups, poppies, fumitory, charlock (Brassica arvensis), mnch (Baphanus raphanistriim) , shep- herd's purse, corn cockle, spurrey, silver weed, cleavers, thistle (Canada thistle), sow thistle, coltsfoot, groundsel, bindweeds {Poly- gonum convolvulus), {Convolvulus arvensis), dodder, buckhorn, plantain, broom rape, corn or field mint, hemp and dead nettle, smartweed, or red-shank {Plygonum persicaria), knotweed, docks, goosefoot, quack grass, fine bent grass, pearl grass {Arrenatherum avenaceum), slender foxtail {Alopecurus agrestis), wild oats and 666 WEED FLORA OF IOWA Fig. 519. Needle Grass (.Stipa spartea). In pastures. (Photographed by Charlotte M. King.) Fig. 520. Purple Cone Flower {Brauneria purpurea). (Photographed by Pammel.) In a prairie pasture. NUMBER AND KINDS OF WEEDS ON DIFFERENT SOILS 667 horsetail. Of grass land weeds there are listed {ColcMcum autum- nale), buttercups, leguminous weeds, gorse (JJlex) broom, rest har- row {Ononis spinosa), dyer's green weed {Genista tinctoria), wild carrot, burdock, knapweed {Centaurea nigra), thistles {Girsium arvense, G. acaule, G. lanceolatum, G. palustris), cotton thistle {Onoporduvn mcmtJiium) , daisy {Bellis perennis) , ox-eye daisy, rag- wort (Senecio jacohaea), plantains, yellow rattle, self-heal {Pru- nella vulgaris), docks, sorrel {Bumex acetosa, B. acetosella), sting- ing nettle {Urtica dioica) ; grasses: bent grass {Agrostis alba) tus- sock grass {Aira caespitosa), Yorkshire fog {Holcus lanatus), creeping soft grass {H. mollis), quaking grass {Briza media), bar- ley grass {Hordeum pratense), and the bracken {Pteris aquilina), horsetail, and mosses. Fig. 521. Common Porcupine or Needle Grass (Stipa spartea). A weed native to gravel soil, soon succumbs to cropping, a, single spikelet ; to, fruit with sharp pointed callus. (Lamson-Scribner, U. S. Dept. Agr.) CHAPTER VIII. INJURIOUSNESS OF WEEDS CHAPTER VIII. INJURIOUSNESS OF WEEDS. Weeds are injurious to man in the following ways : 1. They crowd out the growing crop. 2. They consume the moisture necessary for a crop. 3. They consume the mineral or other food elements essential to a crop. 4. They pull down the crop. 5. They are injurious because the seeds are difficult to remove. 6. They are injurious because they harbor insects. 7. They are injurious because they harbor parasitic fungi. 8. They prevent the proper cultivation of the soil. 9. They may cause conditions which breed disease. 10. They may poison the soil. 11. They stop drains. 12. They poison animals and man. 1. WEEDS CROWD OUT GROWING CROPS. When weeds are abundant they crowd out growing crops. Every plant requires a certain amount of space to bring forth a bountiful crop. Two plants cannot grow together in the same place; sooner or later, one plant will crowd out the other. If the weed is a more vigorous grower, like the greater ragweed, it will prevent the oat plant from maturing a crop. It prevents the proper amount of light coming to the plant, and so the food necessary for a crop can- not be made. 2. WEEDS CONSUME THE MOISTURE. To produce a crop all weeds need moisture, which should go to a more desirable crop. They transpire water just as cultivated plants do. Long, in "Common Weeds of the Farm and Garden," says: Weeds also absorb from the soil and "transpire," or pass off into the atmosphere, large quantities of moisture which would be of great service to the growing crop. For example, a maize plant has been observed to transpire in the 16 weeks between May 22d and September 4th as much as 36 times its own weight. A large oak 672 WEED FLORA OF IOWA Fig. 522. Ragweeds (.Atnbrosia trifida) consume an enormous amount of mois- ture. INJURIOUSNESS OF WEEDS 673 tree is also stated to transpire 10 to 20 gallons of water in a day; while barley, beans, and clover were found to transpire, during five months of their growth, over 200 times their dry weight of water. Experiments conducted at the agricultural experiment sta- tion of Cornell university showed that during the growth of a 60- bushel crop of maize the plants pumped from the soil, and tran- spired into the air through the leaves, upwards of 900 tons of water, A 25-bushel crop of wheat similarly disposed of 500 tons of water. "Weeds also transpire, and if the ground be covered with weeds it is certain that much of the moisture which would be of value to the crop will be lost in the manner indicated. Weeds are especially harmful in this way in a hot summer, and the loss is most felt by the cultivated crop on light sandy soils. 3. WEEDS CONSUME MINERAL AND FOOD ELEMENTS. A weed needs not only the carbon dioxide of the air to make food, but the nitrogenous and mineral elements of the soil to make plant food, all of which should go to the crop. Long gives the fol- lowing in his book, "Common Weeds of the Farm and Garden": Some analyses made at Konigsberg, and lately reported by Profes- sor Stutzer and L. Seidler, show that the amounts of nitrogen, phos- phoric acid, potash, and lime which are removed are deserving of serious consideration. A number of weeds without their roots were collected from oat fields, the soil of which was fairly heavy and poor in humus. In the case of the Wild Radish or White Char- lock the plants had .already formed many seed-pods, but the other weeds were in full bloom. The table following shows the percentage of ingredients in the dry matter. These figures indicate in a gen- eral way the amount of the chief plant foods required by weeds. The nitrogren in the Persicaria nearly equaled 20 per cent, and that in the Sow Thistle nearly 15 per cent of albuminoids in the dry mat- ter. Phosphoric acid was chiefly taken up by Spurrey and Persi- caria; potash by the Sow Thistle and Spurrey; and lime by Per- sicaria, Yarrow, and Cornflower. 43 674 WEED FLORA OF IOWA PEKCENTAGE CONTENTS OF DKY MATTER. 1Z< o o Si o S 3 5 '•5 o 02 4.77 1.94 2.16 1.94 3.13 1.07 4.21 1.52 1.91 1.30 1.81 0.71 3.12 4.93 2.53 3.15 3.84 1.17 3.08 2.86 1.59 Sow thistle (Sonchiis oler- aceus) Cornflower ( Gentaurea cy- anus ) Spurrey {Spergula arven- sis) Wild Radish (Raphanus raphanistrum) Persicaria or red-shank (Polygonum persicaria) . ' Yarrow (Achillea millefol- ium ) Average of six weeds 2.39 2.30 2.36 1.85 3.12 2.30 2.38 0.88 0.78 1.08 0.78 1.16 0.93 0.93 14.95 8.12 10.12 5.22 10.58 9.61 9.76 4. WEEDS PULL DOWN THE CROPS. Weeds like morning-glory, bindweed, wild buckwheat, and others, pull down a cultivated plant and then prevent the formation of a good crop. 5. WEEDS ARE INJURIOUS BECAUSE IT IS DIFFICULT TO RE- MOVE THE SEEDS. It is difficult in many cases to remove weed seeds from seed of various kinds. Buckhorn can be removed with difficulty from clover seed ; peppergrass with difficulty from timothy seed ; greater ragweed from wheat ; wild oats from oats ; quack grass from brome grass; cockle from wheat. These impurities often greatly reduce the quality of the grain or seed. 6. WEEDS HARBOR INSECTS. Long gives the following insects found on weeds : Fig. 523. Moming-glory pulls down the corn and other crops. (After Vasey, U. S. Dept. of Agriculture.) 676 WEED FLORA OF IOWA /J" Fig. 524. Impurities found in Red Clover: 1, Bull Thistle; 2, Canada Thistle; 3, Green Foxtail (Setaria viridis) ; 4, common Plantain (.Plantago rugelii) ; 5, Peppergrass (also found in Timothy); 6, Chicory; 7, Pigeon G-rass (Setaria glaivca) ; 8, Crabgrass (Digitaria sanguinalis) ; 9, Old Witch Grass; 10, Timothy; 11, Wild Carrot; 12, Pigweed (Amaranthus retroflexus) ; 13, Smartweed (Polygonum persicaria) ; 14, Lamb's quarters ; 15, Dropseed Gras^ (Muhlenbergia). (Drawings by Charlotte M. King.) Weed "host." Insect. Charlock {Sinapis arvensis) and similar Crucifers Goosefoot {Chenopodium aWum) Thistles (Cirsium sp) Sow Thistle iSonchus) Dandelion (Taraxacum) and appar- ently Docks (Rumex) Turnip Flea Beetle or "Ply" (Phyl. lotreta (Haltica) nemorum) Cabbage and Turnip Gall Weevil (GeutorhyncJius sulcicollis) Mangold Fly (Pegomyia hetae) INJURIOUSNESS OP WEEDS 677 Charlock and other Crucifers "1 Diamond-Back Moth {PlutelTa mac- Prickly saltwort {Salsola kali) j uUpennis) Thistles, and the Cotton Thistle "1 n^i„^„ w,, r a^s^-^ r,^„„„r^s\ iOnopordon AcantUum) | ^^^^^^ ^^^ ^^^^^^^ heraclet) Hops, Yorkshire Fog, Poa annua, Daisy, Shepherd's Purse, Spurrey, Buttercup, Cornflower, Sow This- tle, Black Bindweed (Poli/gonum Convolvulus) and Plantain Nightshades, Henbane, Hedge, Mus-'. Colorado Beetle (Dorypnora decern. tard. Thistles, Goosefoot, and y iA^a„+r,\ Stem Eelworm {TylencKus devas- tatrix) (not an insect) many other plants lineata) Shepherd's Purse, Winter Cress,"! Cabbage Root Fly {Phoriia bras- Hedge Mustard J sicae) Various Grasses | Frit Fly (Oscinis frit) Docks, Goosefoot, and some other "| _ ,■,,,.-,, . . ^ ^gg^g > Bean Aphis (Aphis ruimcis) } Ghost or Otter Moth (Hepialus lupuli) 7. WEEDS ARE INJURIOUS BECAUSE THEY HARBOR PARA- SITIC FUNGI. Long and Percival, in ''Common Weeds of the Farm and Gar- den," have the following table of fungus diseases that affect va- rious weeds : Weed "host." Disease. 1 Finger-and-toe of turnips {Plasmodia- Charlock and other Crucifers l pJiora brassicae Wor.) J Peronospora parasitica Be Bary 1 White Root-rot (Rosellinia necatrix . I Prill.) Many species ^ Sclerotium Disease (Sclerotinia scleroti- J orum Mass.) Wild Barley {Hordeum mur- 1 Blindness in Barley and Oats {Helmintho- inum) y sporium gramineum Erikss.) Shepherd's Purse and other "1 White Rust of Cabbages {Gystopus can- Crucifers j didus Lev.) Many species \ ^^^^^^ Root-rot (Rhisioctonia violacea Agrostis canina L., and other "> Reed-mace Fungus (Epichloe typMna grasses f Tul.) 678 Barberry Sedges (Carex) Goosefoot WEED FI.ORA OF IOWA [ Rust of wheat [Puccinia graminis Pers.) 1 Gooseberry-leaf Cluster - cup {Puccinia J pringsheimiana Kleb.) '■ Peronospora effusa Rab., on spinach. Docks, Sorrel, and many ] RoselUnia radiciperda Mass. A white others Hawkweed (Hieracium) }" Root-rot in New Zealand. Chrysanthemum Rust {Puccinia hieracii Mart.) Groundsel, Ragwort, and "1 Pine Cluster-cups {Peridermium pini other species of Senecio j Wallr.) Many wild grasses Fig. .525. Leaf rust of Wild Barley (Puccinia rubigo-vera) also occurs on wheat. (Drawing by Charlotte M. King.) These fiingus diseases are particularly noticeable in a number of plants of the mustard family. The Cystopus cnndidus common upon cabbages in Europe is very common on a large number of cruciferous plants, like mnctard, peppergrass, charlock, etc. At times it is very common upon the radish. A related fungus, downy mildew, of the mustard {Peronospora parasitica) is common and troublesome at times on some cultivated members of the mustard family. It is partif'ularly common upon peppergrass and shep- INJURIOUSNESS OF WEEDS 679 Fig. 526. Rusts of cereals also occur on weedy grasses, like Squirreltall Grass, Wild Oats, etc. Puccinia graminis : A, "winter" or teleutospore ; t, ger- minating, B, germ-tube (promycelium) with lateral sporidSa sp. C, epidermis of under surface of leaf of barberry showing crescent shaped cells of stoma and the germinating sporidium sp at i penetrating the epidermis. D, uredo spore germinating after being in water fourteen hours. E, Puccinia ruhigo-vera, the upper cell has germinated. C. D. E, magnified 390 times, the other somewhat more. (After DeBary.) F, Puccinia gram- inis^ Pars. ; both cells have germinated ; a^ a sporidium germinating, magni- fied 600 times. (After Bolley.) G, Puccinia coronata Cda. ; teleutospores of rust on leaves of oats, magnified about 600 times. (After Bolley.) 680 WEED FLORA OF IOWA Fig. 527. Barley Blight {Eelminthosporium gramineum) on Wild Barley, and b, hypha ; c, conidium. (Drawing by Charlotte M. King.) herd's purse. One of the very destructive diseases is the club-root of cabbage {Flasmodiophora hrassicae) which is eominon upon cab- bages in the eastern states, having now reached Illinois. This has been found on a large number of weeds of the mustard family, like mustard and charlock. A list of these was given by Dr. B. D. Halsted some years ago. Another most troublesome fungus dis- ease is rust of wheat {Puccinia graminis) which is abundant upon quack grass, red top and other grasses. This rust frequently spreads upon these weeds and then to our cultivated cereals. Some of the related rusts like Puccinia ruhigo-vera are common upon the leaves of squirrel-tail grass. A great many of the wild weedy grasses, like wild rye and quack grass, contain ergot {Claviceps purpurea). This is responsible in most cases for the conveying of this disease to cultivated cereals. We have a long list of root diseases found upon various weeds, like the scab of potato ( Oospora scahies, Ozonium o^mmvora) , etc. Certain species of Sclerotinia, one of which occurs upon sunflower, are transmitted from these weeds to cultivated plants. INJURIOUSNESS OF WEEDS 681 Fig. 528. White Rust (Albugo Candida). 1. Inflorescence of Shepherd's Purse with fungus. 2. Mycelium with haustoria (h) x 390. 3. Conidiophores and conidia (spores) in chains x 400. 4 and 5. Formation of zoospores in conidia x 400. 6. Germinating zoospore. 7. Oogonium (o) and anther- idium (a) attached, mycelium shown below. 8. Oospore with thick wall. 9. Germinating oospore forming a zoosporangium. 10. Zoospore 7-10 x 400. (After DeBary.) 8. WEEDS PREVENT THE PROPER CULTIVATION OF SOIL. Weeds of certain types, particularly the perennial weeds, often make it extremely difficult to cultivate a soil. This is especially true of weed^ like quack grass, which when present in the soil make it difficult not only to cultivate, but to plow and harrow, and also make the operation quite expensive. 9. WEEDS MAY CAUSE CONDITIONS WHICH BREED DISEASES. Dr. Evans says that tall weeds contribute to the breeding places of mosquitos, and he thinks that in this way the mosquitos will lead to malaria. It is a well-known fact that the pollen from weeds like ragweed and goldenrod cause hay fever and for this reason these weeds should always be removed. 10. WEEDS MAY POISON THE SOIL, There has long been a popular impression that weeds excrete poisonous substances which render the soil unfit for a succeeding crop. In regions where cockleburs are common, it is quite difficult to get a good stand of clover. Mr. E. B. Watson found that 682 WEED FLORA OF IOWA Fig. 529 Fig. 530 Fig. 529. Powdery Mildew of grasses (Erysiphe graminis). This is common on Wild Barley, occurs also on Wheat, a, mycelium and erect conidiophores ; b, c, conidla. Fig. 530. Cocklebur {Xanthium canadense) . There is a widespread belief that Cocklebur and other weeds may excrete a substance which is injurious to other crops. clover would not do as well in soil of this character, nor did the clover seed germinate as well, as in check soils. However, this subject has been investigated but little. Then there is the larger question of the actual antagonism betAveen roots in occupied soils that should be occupied by the roots of agricultural plants. 11. WEEDS STOP DRAINS. Drain tiles are frequently filled with a growth of the roots of weeds, causing stoppage and often much expense in removing the difficulty. INJURIOUSNESS OF WEEDS 683 12. POISONOUS WEEDS. There are many weeds which are injurious to man and to rnii- mals because they are poisonous. One of the best known illustra- tions is the cowbane, one of the most deadly poisonous plants in the state; then there are jimson weed, also poisonous; and poison ivy, which is poisonous to the touch. A large number of weeds, while not strongly poisonous, are in- jurious; some taint cow's milk; some are injurious because of spines and prickles and thorns. This subject has been treated in full in a large book by the writer, "A Manual of Poisonous Plants." Too little attention has been paid by the school teachers of the state to the subject of poisonous plants. Fig 531. Poison Ivy. Leaves poisonous to many people when they come in contact vpith the plant. CHAPTER IX. WEED MIGRATION CHAPTER IX. WEED MIGRATION. Geographical botany is that phase of botany which concerns itself with the distribution of plants over the earth 's surface. The study involves questions of geology, climatology, plant physiology, geog- raphy, paleobotany, ethnology, history, agriculture, horticulture and commerce. J. Burtt Davy says: "The facies of the world's flora is rapidly changing, and tends to become more uniform, within certain limits, under the influence of agriculture iand commerce." Before the advent of man the chief factors in weed immigration were the wind, water, snow, animals of various kinds, e. g., birds, mammals, reptiles, insects and gravity. Primitive man must have been an important factor in the distribution of plants. Many plants were no doubt widely scattered by the Indian. Some, like the persimmon, plum, pawpaw, maize, etc., were cultivated ; but many weeds also were scattered by the Indian, flnding a congenial environment near the wigwams. Commerce and the quest for new lands distributed many species far and wide. Lists of weedy plants of every civilized country, as indicated by Fernald, Davy, Gray and other botanists, show that a large percentage are foreigners. With the rapidity of modern transportation and with communica- tion with every part of the world, weed seeds have naturally been carried with the commercial products. Without exception, wherever agriculture has advanced in Iowa, I believe weeds have followed cultivation, generally making their appearance along the water courses where our agriculture was fostered earlier than in the in- terior of the state. For instance, such weeds as Jimson weed, Indian mallow, burdock, mayweed or dog fennel, cheeses, mullein, dock, black nightshade, smartweed, bull thistle, pigweed, lamb's quarticrs, and purslane, have been known in Iowa fbr more than sixty years. Some of these were abundant species in cities and on farms along the Mississippi long before central and northwestern Iowa became settled. There are regions in northwestern Iowa where some of the above weeds are still unknown. The mayweed, velvet weed and mullein were only infrequent weeds in central Iowa twenty-five years ago, though becoming more frequent from 688 WEED FLORA OF IOWA year to year. Commerce indeed has taken an important part in the migration of weeds. Wild carrot, chicory, black medick, quack grass, Canada thistle, shoo-fly and dodder are becoming more and more abundant in the fields of Iowa. Many weeds, moreover, first make their appearance in the vicinity of cultivated fields. In nearly every case wild parsnip, tansj^, shoo-fly, bouncing betty and butter and eggs show the influence of cultivation. W Pig. 531A I Fig. 531 A IV Pig. 531A V Pig. 531A VI Fig. 531-A. Seeds scattered with commercial seed. I. Quack Grass (Agropyroti repens). II. Corn Flower (Centaurea cyanus) ; scattered with flower seed, a frequent escape from cultivation. III. Corn cockle (Affj-ostemma githago) ; scattered with wheat, frequent in wheat fields. IV. Chicory iCichorium, intpbus) ; seed frequently found in alfalfa seed. It has been widely scattered in this way. V. Peppergrass iLepidium apetalum) ; wide- ly scattered with timothy seed. VI. Parsnip {Pastinaca sativa) ; a fre- quent escape from cultivation. (I and V, drawings, Charlotte M. King; II and IV, drawings, Ada Hayden ; III and VI, Hillman.) Every phytogeographer is confronted with the problem of placing weeds of the given area in their relation to other floras. Let us take as an illustration a virgin Iowa prairie covered with a close mat of such plants as the blue stems (Andropogon scopaHus and A. furcatus), vetch (Vicia aniericana), meadow rue (Thalictrum WEED MIGRATION 689 Fig. 532. Blue Stem (Andropogon scoparius). A plant common to the prairies of Iowa, a, spikelet ; b, c, first and second glumes ; d, third glume ; f, lodicules stamens and pistil. (Lamson-Scribner, U. S. Dept. Agr.) purpuras cens) , black-eyed Susan {Eudbeckicb hirta), Seribner's panic (Panicum scribnerianum) , PhiladelpMa lily (Lilium phila- delpMcum) , lobelia (Lobelia spicata), sorrel {Oxalis violacea), closed gentian (Gentiana andrewsii), goldenrods {Solidago viis- souriensis and S. rigida), aster (Aster laevis, A. azureus) and a host of other associates. Compare with this an area in the Wis- consin drift where such plants as blue vervain (Vertena stricta), coreopsis (Coreopsis palmata), side oats (Bouteloua curtipenddila) , needle-grass (SUpa spartea), perennial ragweed (Ambrosia psilo- stachya), sunflower (Helianthus Occident alis) , white aster (Aster 44 690 WEED FLORA OF IOWA -V ^A-r- FiG. 532-A. Prostrate Pigweed (Amaranthus ilitoides.) (Photographed by Hart.) multiflorus) , fragrant goldenrod (Solidago odora), and many others occupy the ground. What becomes of the flora when the sod and its flora have borne their own peculiar vegetation ? Comparatively few of the original inhabitants thereof remain as a part of the flora. The weeds most likely to appear here are such as have been partially adjusted to the open conditions. In such places it was not un- common in the early days to find that such weeds as the common Iowa tumble weed {Amaranthus graecizans), tickle-grass {Panicum capillare), creeping verbena {Verbena hracteosa), milk spurge or milk purslane (Enphorhia macula fa and E. geyeri), evening prim- rose (Oenothera hiennis), horseweed {Erigeron canadensis), blue vervain (Verbena striata), persisted for a few years, perhaps with a few other perennial weeds like flowering spurge (Euphorhia corol- lata), Helianthus occidentalis and Desmodium canescens, especially WEED MIGRATION 691 in a few places where tillage was not good; but in nearly every case these perennial weeds disappeared from the cultivated fields which thereupon became occupied by a large number of native annual weeds like the greater ragweed (Ambrosia trifida), Spanish needle (Bidens frondosa, B. discoidea) and smartweed {Polygonum sp.), a few hardy perennial weeds like milkweed {Asclepias syriaca), morning-glory (Convolvulus sepium), artichoke (Helian- thus tuberosus) and meadow sunflower (Helianthus grosseserratus) . Such annual or winter annual weeds as squirrel-tail grass (Hordeum juhatum), peppergrass (Lepidium apetalum) began to compete with a host of European and other exotic weeds like lamb's quarters {Chenopodium album), persicaria (Polygonum persicaria) , purslane (Portulaca oleracea), foxtail (Setaria glauca, S. viridis) and, later, crab grass (Digitaria sanguinalis and D. humifusa). In grain Fig. 533. Greater Ragweed (.Ambrosia trifida). This weed rapidly occupies cultivated ground. (Vasey, U. S. Dept. Agr.) 692 WEED FLORA OF IOWA fields or flax fields appeared the usual crop of weeds that are car- ried with grain, like com cockle, chess, cow-herb, mustard, penny- cress and darnel. Then came the weeds which were introduced with clover seed as buckhorn, dodder, evening catchfly, chicory, wild carrot, etc. Fig. 534. Small Peppergrass {Lepidiium apetalum). Rapidly occupies the vir- gin soil. (Drawing by Charlotte M. King.) As our agriculture shifted from a wheat country to one domi- nating in corn, the weed flora changed slightly. Corn cockle, chess and vetch {Vicia sativ-a), so common everywhere in a small grain country, disappeared over a large section of Iowa. They are again appearing where wheat is grown. Charlock, a relic of flax culture, remained to be distributed largely with oats seed. WEED MIGRATION 693 The fact, however, remains that a goodly number of our Iowa weeds are indigenous to this state. Many of these were plants capable of enduring sunshine and so did not have to readjust them- selves to new conditions. So we have received not only from Iowa but from the country to the west, as Nebraska and the Dakotas, such plants as the squirrel-tail grass, buffalo bur, winged pigweed, common sunflower {Helianthus annuus), and stinkweed {Cleome serrulaita) . The same thing has occurred in states to the west where many indigenous weeds are vying with the European weeds. To the north in Canada a pigweed {Monolepis nuttalliana) has become ex- tremely common, while such weeds as foxtail are troublesome to a limited extent only. The holy grass, a curiosity in many parts of Iowa, is a troublesome perennial weed of Manitoba. It would seem to me that it is not a question of self-fertilization or plasticity but one of tolerance of weeds for sunshine and ready means of dissemination either by natural agencies or by man. Kabsch, in a discussion of this problem, notes that precisely the same things have occurred in various parts of the world where the forests have been cleared. In Bolivia, Pteris, Anemia, Saururus, Lilicoya were followed later by small shrubs of the Eupatoriaceae and Malvaceae. In Brazil, Pteris caudata and Tristegis glutmosa make their appearance after the forest fire. In Teneriffe, in 1815, Pteris, in 1820, Erica arhorea, and in 1830 Laurus canariensis cov- ered the ground. Kabsch notes how suddenly the vegetation of a forest changes in Europe when sunshine is admitted after a forest fire or after the clearing of the forest. Plants like vetchling (O'rohus), four-leaved grass {Paris quadrifolia) , Arum, lovers of the shade, soon succumb, and in their places fireweed {Epilo'hium angustifolium) , bedstraw {Galium), thistle {Cirsium), wild mar- joram {Origanum) , foxglove {Digitalis), and others appear to be followed later by roses, brambles, hazel nut, birches, and grasses like reed bent grass {Calamagrostis epigeios), meadow grass {Poa), sweet vernal grass {Anthoxanthum odoratum), and bear moss {Po'lytrichum commune). Later shade-loving plants have a chance to grow. In the Pacific northwest the fireweed {Epilohium angusti folium) and common brake {Pteris aquilina) occupy the ground after a forest fire. Velvet grass {Holcus) and groundsel {Senecio) are followed by Spiraeas and the California blackberries {Eubus wsvnus and E. nutUanus) which in turn are succeeded by young 694 WEED FLORA OF IOWA Fig. 535. Common Brake (Pteris aquilina). A troublesome weed following fires in the northwest, also under similar conditions in some parts of northeastern Iowa. (Drawing by Charlotte M. King.) forests of Douglas fir. In places, the red cherry {Prunus emar- ginata) may occupy the soil for a long time. Cusick states that the "elkweed" of eastern Oregon, more commonly called fireweed, the only herbaceous plant to follow the fires, is followed in a year or so by the lodge pole pine {Pinus murrayana) and Oregon fir (Pseudotsuga taxifolia). In western Oregon it takes more time; the ground is covered with a thick growth of blackberry plants. In the Rocky mountains the conditions are somewhat different. The first year after a fire very few plants will grow; but among the first, mention may be made of fireweed (EpiloMum angusti- foliiim). thistle {Cirsium drunimondii and the variety acaulescens, C. eriocepliahim and foliosum), groundsel (Senecio comus), (and in moist places ;8'. triangularis) , painted cup (Castilleja integra), wild WEED MIGRATION 695 heliotrope (Phacelia sericea), stone crop {Sedum stenopetalum) , arnica {Arnica cordifolia) . During the first year the vegetation is frequently widely scattered, much depending on the source of the seed. The lodge pole pine may not reappear on the burnt area for a long time. Here again much depends on the distance from which the seed has to come. An Iowa forest, burned over, is covered by bull thistle {Cirsium lanceolatum) , fireweed {Erechiites hieracifolia) , horseweed {Erige- ron canadensis), whiteweed {Erigeron annuus), followed later by small perennials, as blue grass, goldenrods, asters and sunflowers; then hazel, coral berry, hawthorns, elms, poplars, maples and oaks. J. Burtt Davy* in an interesting account of alien plants spon- taneous in the Transvaal enumerates 141 species alien to that part of Africa; of these 15 are now so cosmopolitan that their original home is not known. Two w^ere unidentified. The origin of these Fig. 536. Lamb's Quarters (Chenopodium album). A common foreign weed. Native to Europe. •Rep. S. Afr. Ass. Adv. Sci. 1901 : 252-299. 696 WEED FLORA OF IOWA alien immigrants he gives as follows: Mediterranean region, 33 species ; tropical America and warm temperate regions, 13 ; tropical Africa, 16; Australia, 1; temperate North America, 1; temperate South America, 1; uncertain origin, 16. It is interesting to note that the following Iowa species are abundant and troublesome in the Transvaal (the exceptions being capitalized) : mayweed {Anthemis cotula), black mustard (Brassica nigra), hemp {Can- ndbis sativw), shepherd's purse (Capsella bursa-pastoris), goose- foot (Chenopodium album), wormseed {Chenopodium amhro- sioides), nut grass. (Cyperus escidentus), jimson weed (Datura stramonmm), wire grass (Eleusine indica), fleabane {Erigeron canadensis), shoo-fly {Hibiscus trionum), common morning-glory (Ipomoea purpurea) , toad flax (Linahia vulgaeis) , darnel {Lolium temulentum) , lady's sorrel {Oxalis corniculata) , ribgrass (Plantago lanceolata), common plantain {Plantago major), black bindweed (Polygonum convolvulus) , larger knotweed {Polygonum erectum) , purslane {Portulaca oleracea), jointed charlock {Baphanus rapha- nistrum), sheep sorrel {Bumex acetosella), yellow dock (Rumex CRiSPUs), smooth tobacco {NicoUana glauca), cow-herb (Saponaria vaccAria), bristly foxtail {Setaria verticillata) , lolack nightshade {Solanum nigrum), dandelion {Taraxacum officinale), chickweed {Stellaria media), sow thistle (Sonchus oleraceus), goat's beard (Tragopogon porrifolius) , vetch (Vicia sativa). In addition to the above plants, Davy lists quite a number which are common in the states to the south of Iowa and in California. Such' plants as castor-oil bean {Bicinus communis), zinnia {Zinnia pauciflorus) , marigold {Tagetes erecta), cosmos {Cosmos bipinnatus), cockscomb {Celosia crisfata), four-o'clock {Miraibilis jalapa), evening primrose {Oenothera grandiflora) , Xylopleurum tetrapterum, Mexican poppy {Argemone mexicana) are commonly cultivated in Iowa. Some, like Argemone, Oenothera and Cosmos, occasionally escape' in Iowa. In a classification of these weeds, Davy places the alien plants under the following heads: I. Colonists (species not yet showing signs of spreading) ; shepherd's purse {Capsella bursa-pastoris) , cat's-ear {Hypochaeris radicata), (one of the most common weeds on the Pacific coast and spreading in New England, not reported from Iowa), black bindweed {Polygonum convolvulus) (common every- where in Iowa), toad-flax {Linaria vulgaris) (common in the north). II. Adventive (occasional, but spreading); mayweed {Anthenvis cotida), Mexican poppy {Argemone mexicana). Cosmos bipinnatus, morning-glory {Ipomoea purpurea), darnel {Lolium WEED MIGRATION 'i, 697 ^-,.^,^^^^3^^-^^-^^ Fig. 537. Caster Oil plant. Cultivated as an ornamental plant in Iowa, but a troublesome weed in South Africa. (After Faguet.) temulentum), plantain {Plantago major)., ribgrass (Plant affo laficeolata) , sheep sorrel {Bumex acetosella), curled dock (Bumex crispus), black nightshade (Solanum nigrum), dandelion (Taraxa- cum officinale), cow-herb (Sapomaria vaccaria), vetch (Vicia sa^ iiva): III. Common; spiny amaranth (Amaranthus spinosus), goosefoot (Chenopodium album), hemp (Cannabis ioidica), nut grass (Cyperus esculentus), shoo-fly (Hibiscus trionum), lady's sorrel (Oxalis cornicidata) , purslane (Portulaca vleracea), castor- oil bean (Bicinus communis), and caltrop (Trihidus terrestris). IV. Abundant; (the most common species) purple amaranth (Amaranthus paniculatus) , sticktight (Bidens pilosa), jimson weed (Datura stramonium), purple thorn apple (Datura tatula), wire 698 WEED FLORA OF IOWA grass {Eleusine indica), Sida rhombifolia, spiny clotbur {Xanthium spinosiim), zinnia {Zinnia pauciflora). Fig. 538. Spiny Clotbur. An abundant and troublesome weed in South Africa, occasionally a weed in southeastern Iowa. (After Thurber.) As an example of the spread of American weeds in Europe sev- eral weeds may be cited. The small ragweed {Ambrosia artemisiae- folia), which is common throughout the United States, has accord- ing to Laubert, been widely spread with American grown clover seed*; though known in isolated places in Germany for forty years. It is now on the increase, perhaps because of the recent clover importation, yet its spread is somewhat limited because it blooms late. The plants are often only pistillate. In Stegiitz, Germany, it was associated with black bindweed {Polygonum convolvulus), fleabane {Erigeron canadense), wall barley {Hordeum murinum), ribgrass {Plantago la/nceolata) , common plantain {Plantago major), wild carrot {Daucus carota), yarrow {Achillea millefolium) and tumble Aveed {Corispermum hyssopifolium). *Landw. Jahrbucher. 35: 735-737. WEED MIGRATION 699 tfKTi Fig. 538A. Caltrop (Tribuhis terristris). (Photographed by Colburn.) Scherer and others record the occurrence of Solanum rostratum in Germany (1883) and in France. In Pflanzenleben, Kabsch says, "There are many illustrations of plant immigrations and spreading of plants in Europe, but so far as I know they have never occupied the soil to the same degree in Europe as in America. Most of our weeds of fields, like the cereals among which they grow, are of foreign origin, as star thistle {Centaurea cyanus), corn cockle {Agrostemma githago), charlock {Baphanus raphanistrum) , Myagrum, etc." There are many other weeds of grain fields that are of similar origin that are not men- tioned by Kabsch. Among them are the common mustard {Brassica arvensis), common vetch {Vicia sativa), darnel {Lolium temulen- tum), Russian thistle {Salsola kali var. tenuifoUa), pennycress 700 WEED FLORA OF IOWA Pig. 539. Corn Cockle (Agrostemma githago). An immigrant from western Asia. (After U. S. Dept. of Agr.) {Thlaspi arvense), false flax {Camelina sativa), Berteroa (Berteroa incana and B. mrutabilis). These weeds were undoubtedly spread with the cultivation of grain. Many, though by no means all, were brought to Europe with wheat during the early cultivation of grain in Europe. The crusaders undoubtedly were responsible for the spread of these small grain weeds in Europe. Other plants, of which the horseradish is an illustration, were no doubt brought into west Europe as cultivated plants. It may not be out of place to give the expression of some of the phytogeographical writers on the subject. WEED MIGRATIOlSr 701 Pig. 540A Fig- 540B Fig. 540. A. Charlock {Brassica arvensis). B. Black Mustard (B. nigra). Immigrants from western Asia brought to the United States by way of Europe ; early colonists. (Dewey, U. S. Dept. of Agr.) Warming and Vahl, in Oecology of Plants, speaking of the pam- pas in Soutli America and the European plants found there, say : The pampas occupy the vast, rockless, alluvial. South American plains that stretch from the Atlantic coast to the Andes, and from Patagonia to the forests of Paraguay and Brazil. The boundless, level or somewhat undulating, uniform, treeless surface is clothed with perennial grasses and herbs, like "a shoreless sea of grasses on whose horizon the eye finds no resting point, save where the sun rises and sinks". The genera represented are Melica, 8tipa, Aristida, Andropogon, Pappophorum, Panicum, and Paspalum. Between the grasses grow numbers of herbs belonging to various families; these include Verbena, Portulaca, Apocynaceae, Com- positae, Eryngium, and others. Curiously enough, there are very numerous European species, which have succeeded in exterminating the inland vegetation for miles and include not only such thistle- like Compositae as Cynara cardunctdus, 8ilyhum marianum and Lappa, but also Lolium perenne, Hordeum murinum, H. secalinum, 702 WEED FLORA OF IOWA Medicago denticulata, and Foenicidum capillaceum. In the flora of Buenos Ayres, according to Otto Kunze, at least three-quarters of the species are introduced, and largely Mediterranean in source. Roland M, Harper says: Every botanist who attempts to classify the vegetation of a populous region, such as the northeastern United States, is con- fronted at the outset with the problem of distinguishing the natural or undisturbed habitats from those which have been modified by civilization. Of course all our vegetation has felt the influence of civilization more or less, but it seems possible to draw a fairly sharp line between those habitats whose flora is essentially the same now as it was in prehistoric times and those where it has been so much altered that it is impossible to reconstruct the primeval conditions. In general it seems to be true — and the task of the phyto- geographer would be almost hopeless if it were otherwise — that external influences of slight amount or of short duration produce no permanent changes in vegetation. As an example of the first kind, when the pine trees are removed from an area of southern pine-barrens- the amount of sunlight reaching the ground is in- creased probably not more than ten per cent, and this seems to make no perceptible difference to the herbaceous vegetation. But if the ground is then plowed up and cultivated, the original vege- tation disappears,, most of it never to return. In the second place if a deciduous forest is destroyed by lumber- men or swept by fire it presents a very different appearance for a time, but if left undisturbed it will regain its former appearance and flora, or very nearly so, as soon as the trees have time to grow up again. But if the cutting or burning is repeated every few years the ground will gradually become covered with herbs and short-lived shrubs, among which it is difficult for trees to regain a foothold. M, L. Femald has said along the same line : The clearing of the forest lands and the letting in of the direct sunlight is the inevitable forerunner of the farm and the village, but it is as inevitably the death warrant of hundreds of native plants. As is now well understood, a majority of our woodland species have a root structure which allows them to grow only in the moist, spongy humus of the forest or the swamp, conditions as many of us know from practical experience, almost impossible of artificial attainment. Try as we will, most if not all of us have failed to imitate with sufficient skill permanently to satisfy the plant the exact conditions which please the stemless lady's slipper {Cypripedium acaule) , the trailing arbutus (Epigaea), the various species of Pyrola, the yellow wild foxgloves ( Gerardia) , the painted-cups {Castilleja), or the fringed gentian; though in their undisturbed haunts these plants bloom regularly and reproduce freely. WEED MIGRATION 703 In their own wild homes, likewise, these and scores of other species are almost as sensitive to change as when forced by man into an unappreciated state of culture. The simple cutting of the forest is to most of these plants disastrous, though such of them as are very hardy will often linger until fire has swept the cleared land and burned out the tinder-like humus. After the fire comes a complete change of vegetation, and, during the interval before the stumps are finally removed and the land turned by the plow, the clearing too often becomes a tangle of fire cherry {Prunus pennsylvanica) , aspens {Populus tremuloides and P. grandidenlata) and other quick-growing trees and shrubs with a liberal mixture of blackberry and raspberry bushes, fireweeds {Epilohium and Erechtites), rattlesnake-weeds (Prenanthes) , and other coarse plants which love the open and the direct sunshine. When the final planting of the farm crop comes, however, these sturdy plants of the burned land are quickly disposed of and rarely if ever do they make themselves troublesome in the cultivated field. E. W. Claypole, in speaking of the migration of weeds to America, says: Underneath the great wave of human emigration from the so- called Old to the so-called New World, underneath the noisy, busy surface tide that has swept westward from the shores of Europe to those of America during the last two hundred years, there has existed another and a less conspicuous wave, another and a less prominent tide of emigration. Westward in its direction, like the former, it has silently accomplished results that seldom strike the superficial eye, but yet are scarcely less in magnitude than those which have followed the advent of the white man to the shores of America. I allude to that slow and noiseless immigration of European plants which has been going on for many years, and which prob- ably commenced when the first European vessel touched our shores. Side by side with the displacement of the red man by the white man has gone on the displacement of the red man's vegetable com- panions by plants which accompanied the white man from his trans- Atlantic home. Not more completely have the children of the pilgrim fathers made themselves at home on the banks of the Charles and the Neponset, not more completely have the successors of Champlain and Jacques Cartier established themselves along the St. Lawrence, not more completely have the descendants of the aristocratic colonists of Maryland and Virginia appropriated the shores of the Chesapeake, than have the homely weeds of Eng- land and France made themselves at home in the New World: established themselves on its soil, appropriated its fields, its gar- dens and its waysides. Nor have the older states alone been seized by those European invaders. The stream has flowed beyond them, and as no village or hamlet in the west is without its population 704 WEED FLORA OF IOWA of European descent, so too it is never without its plant population of European weeds. Dr. Asa Gray, who discussed the subject of weeds from a phi- losophical standpoint, said: In the United States, and perhaps in most parts of the world, a large majority of the weeds are introduced plants, brought into the country directly or indirectly by man. Some, such as dande- lion, yarrow, and probably the common plantain and the common purslane, are importations as weeds, although the species naturally occupy some part of the country. "Why weeds are so pertinacious and aggressive is too large and loose a question; for any herb whatever when successfully ag- gressive becomes a weed ; and the reasons of predominance may be almost as diverse as the weeds themselves. But we may inquire whether weeds have any common characteristic which may give them advantage, and why the greater part of the weeds of the United States, and probably of similar temperate countries, should be foreigners. As to the second question, this is strikingly the case throughout the Atlantic side of temperate North America, in which the weeds have mainly come from Europe ; but it is not so, or hardly so, west of the Mississippi in the region of prairies and plains. So that the answer we are accustomed to give must be to a great extent the true one, namely, that, as the district here in which weeds from the Old World prevail was naturally forest-clad there were few of its native herbs which, if they could bear the exposure at all, were capable of competition on cleared land with emigrants from the Old World. It may be said that these same European weeds here prepotent had survived and adapted themselves to the change from forest to cleared land in Europe, and therefore our forest- bred herbs might have done the same thing here. But in the first place the change must have been far more sudden here than in Europe; and in the next place we suppose that most of the herbs in question never were indigenous to the originally forest- covered regions of the Old World; but rather, as western and northern Europe became agricultural and pastoral, these plants came with the husbandmen and the flocks, or followed them, from the woodless or sparsely wooded regions farther east where they originated. This, however, will not hold for some of them, such as dandelion, yarrow, and ox-eye daisy. It may be said that our weeds might have come to a considerable extent from the border- ing, more open districts on the west and south. But there was little opportunity until recently, as the settlement of the country began on the eastern border; yet a certain number of our weeds appear to have been thus derived; for instance, Mollugo vertioiU lata, Erigeron canadense, Xanthium, Ambrosia artemisiae folia, Verbena hastata, V. urticifolia, etc., Veronica peregrina, Solanum WEED MIGRATION 705 Pig. 541A Pig. 541B Fig. 541. A and B. Small Ragweed {A-mT^rosia artemisiaefolia) . An immigrant from the southern part of the United States. (Vasey, U. S. Dept. of Agr.) carolinense, various species of Amarantus and Euphorbia, Panicum capillare, etc. Of late, and in consequence of increased communi- cation with the Mississippi region and beyond — especially by rail- roads — other plants are coming into the eastern states as weeds, step by step, by somewhat rapid strides; such as Dysodia chrysan- themoides, Matricaria discoidea, and Artemisia biennis. Fifty years ago Budbeckia hirta, which flourished from the AUeghanies westward, was unknown farther east. Now, in tiwenty years, it has become an abundant and conspicuous weed in grass fields through- out the eastern states, having been aocidentally disseminated with red clover se;ed from the western states. There are also native American weeds, doubtless indigenous to the region, such as Asclepias cornuti, Antennaria margaritacea and A. plantagini folia, and in enriched soils Phytolacca decandra, which 45 706 WEED FLORA OF IOWA Fig. 542. Tickle Grass (Panicum capillare). A common grass, probably orig- inally found in clearings, has rapidly spread to cultivated ground. (Lamson-Scribner, U. S. Dept. of Agr.) have apparently become strongly aggressive under changed condi- tions. These are some of the instances which may show that pre- dominance is not in consequence of change of country and intrO' duction to new soil. In the interesting paper of Claypole the author argues that the abundance of European weeds in North America is because Euro- pean plants are more plastic than American plants. He says: But a weed possessing a plastic nature — one capable of being moulded by and to its , new surroundings — ere long adapts itself, if the change is not too great or sudden, to its new situation, takes a new lease of life, and continues in the strictest sense a weed. Is it not possible that some such cause as this may lie underneath the facts we detailed in the earlier part of this paper? The true and full explanation of the transfer of European species to America WEED MIGRATION 707 should at the same time explain the absence of American species from Europe. But the partial causes already alluded to fail to do this. There is a residual effect for which they do not account. May it not be true that the plants of the European flora possess more of this plasticity, are less unyielding in their constitution, can adapt themselves more readily to new surroundings, and thus secure their continuance in the New World ? And may it not be the lack of this plasticity in the American flora which incapacitates it for securing a foothold and obtaining a living in the different condi- tions of the New World 1 Under the care of the gardener they grow and embellish the gardens and conservatories of Europe, but without this care they speedily fail and die. Dr. Gray in a very friendly criticism of this paper remarked that, ' ' So far as we know, the greater plasticity of European as com- pared with American plants is purely hypothetical. More plastic, would mean of greater variability, which, if true, might be deter- mined by observation. Because Europe once had more species or types in common with North America than it now has, it does not seem to follow that the former has 'a younger plant-life,' or that its existing plants are more recent than those of the American flora. And as already intimated, so refined an hypothesis! is hardly neces- sary for the probable explanation of the predominance of Old World weeds in the Atlantic United States." It is interesting to note the large number of plants which are con- tinually being added to the flora of Europe. Bitter in his paper on the adventive flora of Bremen notes that out of the 2,492 plants listed by Garcke in his flora of Germany, 230 are adventive ; Hock, who published a paper on the plants of North Germany, lists 54 as weedy and ruderal. The region embraced in North Germany probably contains as many exotic weeds as Iowa. For our purpose let us compare foreign weeds of Iowa with the native plants. Hitchcock, in his catalogue of the plants of Ames and vicinity, lists 740 plants, of which 86 are introduced and of these about one-third have not become perma- nently established. Dr. Charles Mohr in his paper on Plant Life in Alabama, states that "fully one-sixth of the plants enumerated in the catalogue of the Alabama flora as growing without cultivation are immigrants from other regions, and but few of them are native in the more dis- tant parts of the continent north of Mexico. They are mostly from the warmer temperate, subtropical, and tropical regions of the Old World. Those of widest distribution and which have gained the 708 WEED FLORA OF IOWA firmest foothold are wanderers following civilized man in his con- quest of the wilderness. Originally children of the open plain, ex- posed to the extremes of heat, cold, drought, and excessive rain, these plants necessarily acquire the widest elasticity in adapting them- selves to new surroundings and possess the greatest power of re- sisting adverse conditions. ' ' THE DIRECTION OF WEED MIGRATION. Mr. L. H. Dewey, who made a study of 200 North American weeds and their migration, says: "A study of the origin of weeds now in this country will impress one with the largeness of the num- ber that have been introduced from Europe in comparison with the number of native species or of species received from other direc- tions." In the list of 200 weeds of the United States published in the Year Book for 1895, 108 species are of foreign origin, while 92 are native. Of the 108 introduced species, 64 are native in Europe and 30 are ascribed to the Old World in general, only 2 Asiatic species in the list having established themselves as weeds in this country without being first distributed in Europe. Africa and Australia are not represented among our weeds, while Central and South America have contributed only 12 or 15 important species, most of which are confined to the Gulf states. A list of the plants of Michigan published in 1892 contains 1,604 indigenous species, of which 22 are recognized as injurious weeds, and 142 species intro- duced from Europe, of which 57 have become troublesome weeds. A list of Kansas weeds enumerating 209 species contains 129 na- tive species, 42, introduced from Europe, and 38 from all other sources. Eighteen species native in the states east of the Mississippi river have been introduced into Kansas in opposition to the pre- vailing winds and the direction of the drainage, while only 3 species are mentioned which have come from the Rocky Mountain region with both of these natural forces in their favor. In an article on the weeds of California 110 species are mentioned as troublesome in that state. Of these, 53 are native, 43 are intro- duced from Europe, 5 are from the eastern United States, 3 from Central and South America, and only 2 from Asia. Even in the states bordering the Gulf of Mexico the number of weeds introduced from Europe in cultivated land equals or exceeds those from INIexico and South America. Canada thistle, bur clover, and skunkweed have been taken from California to Australia, where they quickly become naturalized and are now rapidly spreading. The weeds which have followed civilization in America are, shepherd's purse, dandelion, sow thistle, stinging nettle, mallow, plantain, chickweed, St. John's- wort, yarrow, toadflax and purs- lane. Manasseh Cutler, in 1783, reported 66 species, among them buttercup, chicory and daisy. Dr. Bigelow, in Florula Bostoniensis, WEED MIGRATION 709 Fig. 543. Jimson "Weed {Datura stramonium). An immigrant from India, reached United States by way of Europe. (After Cliesnut, U. S. Dept. of Agr.) 1814, records 83 introduced species and in the edition of 1840, lists 140 species. Dr. Fernald says : ' ' Gradually this list has increased until we are forced to number among the wild plants of New England more than 600 species which have been introduced through human agency since the first cutting of the forests." The causes for the appearance of these weeds into New England, the west. Pacific coast and elsewhere must be ascribed to the sowing of seed that contained the weed seeds. Wheat always contained the seed of cockle, mustard, vetch, etc., consequently we find that these weeds are found wherever cereals are cultivated. Many plants were, however, planted for medicinal purposes, among which were peppermint, black henbane, tansy, chamomile, caraway, poison hemlock, and a long list of other plants utilized by the Mor- mons which have become weedy wherever these people have settled. Even in Iowa we find that such plants as tansy, elecampane, jimson 710 WEED FLORA OF IOWA weed, European morning-glory, shoo-fly, and others have been spread from cultivation and have become weeds. In regard to the introduction of plants. Dr. Fernald has stated the case very well in the following paragraph : A review of the history and spread of this vagrant class of plants presents many aspects which are well worth consideration. John Josselyn, in 1672, stated that several species of European weeds had "sprung up since the English planted and kept cattle in New England", thus implying that these plants had come un- bidden or at least were not purposely brought to this country. He records no less than 40 European weeds introduced in this manner. According to a time-honored tradition, based perhaps on fact, the first weed to spring up in the track of the pioneer is plantain, and on this account it has been called by some primitive races "White-man's Foot", a name of more than fanciful appli- cation; for without question the plantain and many other roadside species are spread directly by the foot of man. For some years strange and outlandish weeds have been appearing along the river below Waterbury, Connecticut. These plants, upon careful study, prove to be vagrant species from geographically remote portions of the world, and their presence along the Naugatuck river has Fig. 544. Poison Hemlock {Conium macidaUim) . Common in Salt Lake Basin. (After Cliesnut, U. S. Dept. Agr.) WEED MIGRATION 711 been a mystery. Eventually, however, the whole matter was cleared when the source of these plants was traced to a factory which utilized old rubber shoes. These shoes were collected from every available source, and, before being melted for their rubber were stripped of the cloth linings which were thrown upon a rubbish heap. These linings naturally contained seeds of innumerable plants from the roadsides of every land, and the rains and spring freshets of the Naugatuck valley gave them every opportunity to scatter and to start life anew in Connecticut soil. In this or similar ways many of the plants mentioned by John Josselyn, M'anasseh Cutler, and Jacob Bigelow undoubtedly reached our shores; and these emigrants are being reinforced by almost every person who comes to us from foreign lands. Many weeds start in the proximity of woolen mills. Among these are, teasel, "buffalo bur, various borages, erodium, etc. Others are introduced with agricultural seeds. In recent years there Fig. 545. Chicory (Cichorium intybus). An immigrant from Europe, a, flower- ing branch ; b, single head ; c, single flower ; d and e achene ; e, cross section. (U. S. Dept. of Agr.) 712 WEED FLORA OF IOWA have been introduced into Iowa such weeds as wild carrot {Daucus carota), Silene noctiflora, S. dicliotoma, Cichorium intyhus, Conium maculatum, Centaurea solstitialis, Cirshom arvense, C. pi^atense, Cuscuia arvensis, C. epithymum, Eruca sativa, and others, largely with clover and alfalfa seed. Still another and frequent source of the introduction of weeds is through the cultivation of orna- mental plants which become weedy as: shoo-fly {Hibiscus trionum) during recent years, the bouncing bet {Saponaria officinalis L.), toad flax (Linaria vulgaris), EupJiorhia cyparissias, live forever {Sedum telephium) , snow-on-the-mountain (Euphorbia marginata) in many localities, pickerel weed {EicJiornia crassipes) in Florida, water chestnut (Trapa natans) in central New England. The or- ange hawkweed {Hieracium aurantiacum) , and others of this class are excellent illustrations of how ornamental plants become weedy. In some cases plants cultivated for food have become weedy, as in Iowa, the horse radish; in California, the beet (San Francisco Bay region) ; and in Utah and California, the spinach. Fig. 546. Snow-on-the-Mountain (Eiiphorbia marginata) . A western weed now common in some places in the east. (After Chesnut. U. S. Dept. Agr.) WEED MIGRATION 713 New introductions have come not only into western Europe from the United States, but from eastern Europe, Asia, and from the tropical world. The Berteroa incana, a recent introduction into Iowa, has been reported in Germany by Scherer. The spiny knapweed {Centaur ea solstitialis) , a recent Iowa introduction, has been reported from Germany by Lehmann, Bitter and Alpers. The Galinsoga parviflora, an introduction from South America into the United States, has been reported from northern France and southern Germany by Kieffer. The storksbill {Erodium mos- chatum), the butterprint {AJmtilon theophrasti) , the spiny clotbur {XantJiium spinosum) and the shoo-fly {Hibiscus trionum), are common plants of the tropical regions everywhere; these have ex- tended far northward. In recent years they have been reported in north Germany by Bitter. He has likewise reported as recent in- troductions the yellow sweet clover {Meliloius officinalis) , Matri- FiG. 547. Velvet Weed or Butterprint (.Ahutilon theophrasti) . A tropical weed now common in the north and spreading to Europe. (U. S. Dept. of Agr.) 714 WEED FLORA OF IOWA caria discoidea of Asia, Mexican fireweed ( Kochia scoparia), brome grass {Bronms tectorum) in the vicinity of Bremen; all being in- digenous to eastern Europe and western Asia. Dr. Fernald states that of the species of plants growing in the British Isles, at an altitude of 3,000 feet in the mountain country, where the primitive vegetation is but little disturbed, 68% are also native to the mountainous regions of New England, but of the species that occur everywhere at low altitudes and in thickly set- tled and closely farmed districts only 23% are native to New Eng- land while more than 50% haA^e become established in New England as weeds; and that barely 1% of the plants of temperate Europe have been imported from America, but every year adds to the new weeds introduced into Europe. Dr. Gray, in that interesting paper on the Pertinacity of Weeds, refers to the book by Mr. Henslow on the Self-Fertilization of Plants, in which the latter comes to the conclusion that weeds are intrusive and dominating plants of great emigrating capabilities, and have a longer ancestral life history than their more or less aggressive relatives. Furthermore, this dominance may be at- tributed to self-fertilization. In the list of weeds that Dr. Gray mentions in this paper as the most abundant in eastern North America and the southern United States, the rule evidently does not hold that this dominance is due to self-fertilization; in fact some of the most dominant of these plants are pollinated by in- sects. For the sake of convenience I shall here use a list prepared by Dr. Gray in 1879, adding to it weeds that are more or less pre- dominant in the state of Iowa at the present time ; the Iowa weeds are printed in small capitals. There is a slight rearrangement, according to present interpretation of taxonomists. Gramineae. DicjTARiA iTUMiFUSA, Smooth crab grass. D. SANGUiNALis, Crab grass. Panicum capillare. Old-witch grass. P. DiCHOTOMiFLORUM, Sprouting crab grass. Echinochloa crusgalli. Barnyard grass. Setaria glauca, Pigeon grass. S. viRiDis, Green foxtail. S. verticillata, Bristly foxtail. Cenchrus tribuloides, Sandbur. Anthoxanthimi odoratum, Sweet vernal grass. "WEED MIGRATION 715 MuHLENBERGiA MEXiCANA, Mexican drop-seed. M. RACEMOSA, Marsh nmhlenberg. M. ScHREBERi, Nimble Will. Sporobolus vaginiplorus. Sheathed rush grass. S. NEGLECTus, Small rush grass. Alopecurus pratensis, Meadow foxtail. A. GENicuLATUs^ Marsh foxtail. Phleum pratense, Timothy. Agrostis alba, Red top. AvENA PATUA, Wild oats. Eleusine indica^ Wire grass. Eragrostis pilosa. Southern spear grass. E. MEGASTACHTAj Candy grass. Dactylis glomerata, Orchard grass. Poa annua, Low spear grass. P. pratensis, Kentucky blue grass. P. trivialis, Bough-stalked meadow grass. P. COMPRESSA, Wire grass, Bromus secalinus. Chess. B. hordeaceus^ Soft chess. B. ABVENSis, Field brome grass. B. TECTORUM, Downy brome grass. Festuca pratensis, Meadow fescue. F. ovina^ Sheep's fescue. LoUum perenne, Common darnel. L. TEMULENTUM, Poisou darnel. Agropyron repens_, Quack grass. A. caninum, Awned wheat grass. A. Smithii, Western wheat grass. Hordeum jubatum, Squirel-tail grass. H. PUSiLLUM, Little barley. Gyperaceae. Cyperus esgulentus. Nut grass. Juncaceae. JuNCUs TENUIS, Slender rush. Liliaceae. Allium vineale, Wild garlic. Urticaceae. Cannabis sativa. Hemp, Urtica gracilis. Nettle. 716 WEED FLORA OP IOWA Polygonaceae. RuMEX CRisPUS, Curled dock. R. ALTissiMus^ Pale dock, R. SANGUINEUS^ Bloody dock. R. ACETOSELLA_, Sheep sorrel. Polygonum aviculare, Knotweed. P. erectuMj Larger knotweed. P. LAPATHiPOLiuM^ Slender smartweed. P. Muhlenbergii, Marsh smartweed. P. pennstlvanicum, Pennsylvania smartweed. P. ACRE, Water smartweed. P. PERSiCARiA, Lady's thumb. P. CONVOLVULUS, Black bindweed. Che^iopodiaceae. Chenopodium Botrys, Jerusalem oak. C. ALBUM, Goosefoot. C. HYBRiDUM, Maple-leaved goosefoot. Atriplex patula, Orach. Cycloma atriplicifolium. Winged pigweed. KocHiA scoparia, Mexican fireweed. Salsola kali var. tenuifolia, Russian thistle. Amaranthaceae. Amaranthus retroplexus, Green pigweed. A. graecizans. Tumble weed. A. BLiTOiDES, Prostrate pigweed. ACNIDA TUBERCULATA V. PROSTRATA, Water hcilip Nyetaginaceae. OXYBAPHUS NYCTAGINEUS, Wild four-0 'clock. Garyophyllaceae. Stellaria media. Chick weed. Ccrastium nutans, Mouse-ear chiekweed. Agrostemma githago, corn cockle (wheat sect it, n^' Lychnis alba. White campion. L. (Moica, Red campion. Silene latifolia, Bladder campion. S. noctiplora. Night-flowering catchfly.' S. ANTiRRHiNA, Sleepy catchfly. WEED MIGRATION 717 Saponaria officinalis, Bouncing Bet. S. VACCARIA^ soapwort (wheat sections). Portulacaceae. PoRTULACA OLERACEA, Purslane. Ranunculaceae. Eanunculus abortivus, Small-flowered crowfoot. B. 'buVbosus, Bulbous buttercup. E. acris, Tall buttercup. R. SEPTENTRioNALis^ Swamp buttercup. Cruciferae. Berteroa incana^ Alyssum. Thlaspi arvense, Frenchweed. Lepidium virginicum^ Large peppergrass. L. APETALUM, Small peppergrass. Capsella bursa-pastoriSj Shepherd's purse. Camelina sativa. False flax. Neslia panioulata. Ball mustard. Raphanus raphanistrum^ Jointed charlock (northeastern Iowa). Brassica arvensis^ English charlock. B. NIGRA, Black mustard. Sisymbrium officinale, Hedge mustard. S. altissimum. Tumbling mustard. Radicula nasturtium-aquaticum. Water cress. R. armoracia. Horseradish. Barbarea vulgaris. Winter cress. Capparidaceae. PoLANisiA GRAVEOLENS, Clammy weed. Cleome serrulata, Stinkweed. Resedaceae. Reseda lutea. Dyer's rocket. Rosaceae. Geum canadense. White avens. Rosa pratincola, Prairie rose. 718 WEED FLORA OF IOWA Leguminosae. Cassia chamaecrista, Partridge pea. Genista tinctorial Dyer's greenweed. Crotalaria sagittaliSj Rattle-box, Trifolium arvense, Stone clover. T. PROCUMBENS, Low hop clover. T. procumhenSj Low hop clover. T. repens, White clover. Melilotus officinalis. Yellow sweet clover. M. ALBA, White sweet clover. Medicago lupulina. Black medick. Dalea alopecuroides. Pink dalea. RoBiNiA pseudo-acacia, Falsc acacia. , Gltctrrhiza lepidota, Liquorice. ViciA SATivA, Vetch. Y. villosa, Hairy vetch. Strophostyles pauciplora, Wild bean. Oxalidaceae. OxALis CORNicuLATA, Lady's sorrel. Geraniaceae. Geranium maculatum. Wild eranesbill. EupJior'biaceae. AcALYPHA viRGiNiCA, Thrcc-seeded mercury. Euphorbia preslii, Large spotted spurge. E. MACULATA, Spotted spurge. E. COROLLATA, Flowcring spurge. E. CTPARissiAS, Cypress spurge. Malvaceae. Abutilon theophrasti, Butterprint. ;SiDA SPiNOSA, Prickly sida. Malva rotundifolia, Cheeses. Hibiscus trionum, Shoo-fly. Onagraceae. Oenothera biennis, Evening primrose. Gaura biennis. Biennial gaura. WEED MIGRATION 719 Umbelliferae. Conium maculatum, Poison hemlock. Carum carvi. Caraway. Pastinaca sativa, Wild parsnip. Daucus carota_, Wild carrot. Primulaceae. Anagallis arvensis, Pimpernel. Apocynaceae. Apocynum androsaemipolium. Spreading dogbane. A. CANNABINUM, Indian hemp. Asclepiadaceae. AscLEPiAs SPECiosA, Showy milkweed. A. SYRiACA, Milkweed. Convolvulaceae, Convolvulus sepium, Wild morning-glory. C. ARVENSIS, European bindweed. CuscuTA EPiTHYMUM, Clovcr dodder. C. ARVENSiSj Field dodder. Hydrophyllaccae. Ellisia nyctelea, Waterleaf. Boraginaceae. Cynoglossum officinale, Hound's tongue. Lappula echinata, Stickseed. ' ' Symphytum officinale, Comfrey. Echium vulgare, Blue weed. Yerhenaceae. Verbena bracteosa, Bracted vervain. V. HASTATA, Blue vcrvain. • V. STRiCTA^ Hoary vervain. Labiatae. Nepeta cataria. Catnip. N. hederacea. Ground ivy. Lamium amplexicaule, Dead nettle. 720 WEED FLORA OF JOWA Leanurus cardAaca, Motherwort. Mentha piperita, Peppermint. M. spicata, Spearmint. Satureja nepeta, Tbyme. S. VULGARIS, Basil. Marrubium vulgare, Hoarhound. Galeopsis tetrahit, Hemp nettle. SoLANUM NIGRUM^ Black nightshade. S. CAROLiNENSE, Horse nettle. S. ROSTRATUMj Buffalo bur. Datura stramonium, Jimson weed. D. TATULiA, Purple thorn apple. Verbascum thapsus, Mullein. V. hlattaria, Moth mullein. LiNARiA VULGARIS, Butter and eggs. Veronica peregrina. Speedwell. Plantago major. Common plantain. P. rugelh, Eugel's plantain. P. lanceolata, Ribgrass. P. aristata, Bracted plantain. Compositae. Erigeron annuus, Daisy fleabane. E. canadensis, Fleabane. E. RAMOsus, Whiteweed. Iva xanthipolia. Marsh elder. Ambrosia artemisiaefolia. Smaller ragweed. A. TRiFiDA, Greater ragweed. Xanthium canadense, Cocklebur. Gnaphalium uliginosum, Cudweed. Inula helenium, Elecampane. Heliopsis scabra. Ox-eye. KuDBECKiA HiRTA, Cone-flower. Helianthus annuus, Common sunflower, BiDENs PRONDOSA, Beggar-ticks. B. DiscoiDEA, Small beggar-ticks. Dyssodia papposa. Fetid marigold. Achillea millefolium, Yarrow. Anthemis cotula, Mayweed. Chrysanthemum leucanthemum, Ox-eye daisy. Tanacetum vulgare, Tansy. WEED MIGRATION 721 Artemisia biennis. Wormwood, Erechtites hieracifolia, Fireweed. Arctium lappa^ Burdock. CiRSIUM LANCEOLATUMj BuU thistle. C. ARVENSE^ Canada thistle. C. CANESCENS, Woollj thistle. CiCHORiuM iNTYBUS, Chicorj. Leontodon autumnalis, Hawkbit. Taraxacum officinale. Dandelion. T. erythrospermum, Red-seeded dandelion. SoNCHus ASPER, Spiny-leaved sow thistle. Lactuca scariola. Prickly lettuce. L. SCARIOLA VAR. INTEGRATA, Lydgodesmia juncea, Lygodesmia. SoLiDAGO canadensis, Goldeurod. Fig. 548. 46 Narrow Sneezeweed (Helenium tenuifoUum) . General aspect of plant and a single head enlarged. (After Chesnut, U. S. Dept. Agr.) 722 WEED FLORA OF IOWA Dr. Gray, in the above list mentioned 86 weeds which are more or less aggressive in the Atlantic United States. It would seem, however, that comparatively few of the aggressive weeds of the Gulf states are enumerated in the list. The more important gulf coast weeds are sneezeweed {Helenium tenuifolium) , Louisiana car- pet grass (Paspalum platycaule), Johnson grass {Sorghum liale- pense), beard grass {Andropogon virginicum) , buffalo bur {Sola- num r stratum) , prickly sida {Sida spinosa), southern nut grass (Cyperus rotundus), wild pansy (Viola arvensis) . Dr. Mohr gives the following list of weeds as the most conspicuous by their abundance all over the state of Alabama. Fig. 549. Johnson Grass (.Sorghum halepense). An African weed. Common in the Gulf states, and reported from southwestern Iowa. (Lamson-Scribner, U. S. Dept. Agr.) WEED MIGRATION 723 Leptochloa vmicronata, Yard grass. Manisurus granulans^ Manisurus. Cyperus rotundus, Southern nut grass. Amaranihus retroflexus, Green pigweed. Amaranthus hyhridus, Pigweed. Amarantkus spinosus, Spiny amaranth. Spergula arvensis, Corn spurrey. Portulaca oleracea, Purslane. Cassia occidentalis, Senna. Cassia tora, Low senna. Sida rJiombifolia, Rhombleaf sida. Sida spinosa, Prickly sida. Senebiera pinnatifida, Peppergrass. ■ Veronica peregrina, Neckweed. Veronica arvensis, Corn speedwell. Lamium amplexicaule, Dead nettle. Bichardia scabra, Mexican clover. Dr. W. A. and Mrs. Kellerman in a paper on the non-indigenous Flora of Ohio, state that out of 2,060 plants of the state 430 are not indigenous. Of the latter number 326 have come from Europe, 30 from Asia, 2 from Africa, 46 from Southern and Western United States and 21 from tropical or South America. When expressed in percentages the numbers are as follows: from Europe, 75.81%; from Asia, 6.99%; from Africa, 0.47%; from the United States, 10.70% ; and from tropical and South America, 4.81%. Comparing the Old World species with those from parts of the American continent we find the numbers to be 358 and 67 re- spectively. Therefore 83.25% of the introduced species have come from the eastern hemisphere and 15.58% from America. Expressed in percentages of the total number of introduced species they are as follows: waifs, 11.86%; occasionally escaped, 38.84% ; and thoroughly naturalized, 49.30%. The following list shows the families represented and the number of species in each. 1. Amaranthaceae, Amaranth Family 5 2. Aizoaceae, Carpet Weed Family 1 3. Apocynaceae, Dogbane Family 2 4. Berheridaceae, Barberry Family 1 5. Bignoniaceae, Bignonia Family 2 6. Boraginaceae, Borage Family 11 724 WEED FLORA OF IOWA 7. Cactaceae, Cactus Family 1 8. Campanulaceae, Bluebell Family 1 9. Capparidaceae, Caper Family 1 10. Caprifoliaceae, Honeysuckle Family . . . •. 4 11. Caryophyllaceae, Pink Family 23 12. Ghenopodiaceae, Goosef oot Family 11 13. Compositae, Thistle Family 88 14. Convolvulaceae, Morning-glory Family 8 15. Crassulaceae, Orpine Family 2 16. Cruciferae, Mustard Family 27 17. Cucurhitaceae, Gourd Family 6 18. Cyperaceae, Sedge Family 1 19. Dipsacaceae, Teasel Family 1 20. Elatmaceae, Waterwort Family 1 21. Euphorbiaceae, Spurge Family 7 22. Fumariaceae, Fumitory Family 1 23. Geraniaceae, Geranium Family 5 24. Gramineae, Grass Family 46 25. Hypericaceae, St. John's-wort Family 1 26. LaUatae, Mint Family 24 27. Leguminosae, Pulse Family 19 28. Liliaceae, Lily Family 7 29. Linaceae, Flax Family 1 30. Malvaceae, Mallow Family 9 31. Martyniaceae, Martynia Family 1 32. Nyctaginaceae, Four-o'clock Family 2 33. Oleaceae, Olive Family 2 34. Oxalidaceae, Oxalis Family 1 35. Onagraceae, Evening primrose Family 3 36. Papaveraceae, Poppy Family 5 37. Plantaginaceae, Plantain Family 4 38. Polygonaceae, Smartweed Family 14 39. Portulacaceae, Purslane Family 1 40. Primulaceae, Primrose Family 2 41. Ranunculaceae, Crowfoot Family 9 42. Resedaceae, Mignonette Family 3 43. Rhamnaceae, Buckthorn Family 1 44. Rosaceae, Rose Family 15 45. Rubiaceae, Madder Family 3 46. Salicaceae, "Willow Family 8 47. Saxifragaceae, Saxifrage Family 4 WEED MIGRATION 725 48. Scrophulariaceae, Figwort Family 14 49. Simarubaceae, Quassia Family 1 50. Solanaceae, Nightshade Family 9 51. Tlmhelliferae, Parsley Family 12 52. Urticaceae, Nettle Family 5 53. Valerianaceae, Valerian Family 1 54. Verhenaceae, Verbena Family 1 55. Violaceae, Viola Family 1 The weeds of the Pacific coast are somewhat different from those of the Atlantic coast. Eugene Hilgard, in a series of interesting articles in Garden and Forest, some years ago, S. B. Parish, J. Burtt Davy and other California botanists, have contributed notes on the introduction of these weeds of the coast. They enumerated the more important weeds, among which mention may be made of black mustard (Brassica nigra), catchfly (Silene gallica), storksbill (Erodium cicutarium), musk erodium {Erodium moschatum) , small-flowered mallow {Malva iorealis), black medick (Medicago Uipulina), bur clover (M. denticidata) , white sweet clover {Meli- lotus alia), and yellow sweet clover (M. officinalis), star thistle {Centaurea cyamis), knapweed (C. solstitialis) , brown knapweed (C. jacea) , black knapweed (0. nigra), wild carrot {Daucus car- ota) , heet (Beta vulgaris), spinach {Spinacia oleracea), lady's thistle {Silyhitm marianum), cotton thistle {Onopordon acanthium) , dodder (Cuscuta epithymum). The writer recently noted the following weeds in the San Fran- cisco Bay region, Oakland, and Sacramento, many of our eastern weeds being common among them: Hedge mustard (^Sisymbrium officinale), RapJianus sativus, Marrubium vulgar e, dock (Rumex crispus), cheeses {Malva- rotundifolia) , mallow (M. crispa), bull thistle (Cirsium lanceolatum) , sow thistle (Sonchus oleraceus), cat's-ear {Hypochaeris radicata), knotweed {Polygonum erectu/m), black medick (Medicago lupulina), Brassica campestris, lamb's quarters (Ghenopodium. album,), chickweed (Stellaria media), Poa annua, Alfilaria {Erodium cicutaria) , pineapple weed {Matricaria suaveolens), common groundsel {Senecio vulgaris), burdock {Arc- tium, lappa) , Silybum m^ariamim, Centaurea melitensis, prickly let- tuce {Lactuca scariola), mustard {Brassica campestris) , also such native weeds as Amsinchia and Escholtzia. 726 WEED FLORA OF IOWA / *■ H • F!g. 549A 1 Pig. 549A II Fig. 549A III Fig. 549-A. Seeds of weeds scattered with agricultural seeds. I. Dodder In clover and alfalfa seed. II. White Sweet Clover in alfalfa seed. III. Bitter Dock (Rumex ohtusifolius) in red clover seed. Many of these weeds have made their way into California by way of South America. Others are indigenous and widely scat- tered on the Pacfiic coast. The Pacific northwest has in common with the rest of the Pacific coast many European weeds, but also many that are indigenous to the country. Many years ago Cusick called attention to the predominance of the Northern fireweed {Epilohiuftn angustifolium) , which, after the removal of the forest and the burning of the slashings, comes up in great abundance. The -writer in another connection* discussed the weeds commonly *The Problem of Weeds in the West; Proc. la. Acad. Sc. 15: 34. WEED MIGRATION 727 Pig. 550. Curled iDock (Rumex crispus). A common European weed now occurring across the continent. (After Chesnut, U. S. Dept. Agr.) found in the northwest. A few of the abundant species may be mentioned. Russian thistle {Salsola kali var. tenuifolia) is abun- dant in the drier regions, especially east of the Cascades. In the Puget Sound country are found such common European weeds as Canada thistle {Cirsium arvense), bull thistle (C. lanceolatum) , batchelor's button {Centaur ea cyanus), chicory {Cichorium inty- bus), common mustard {Brassica arvensis), mullein (Verhascum thapsus) and also V. hlattaria, and toadflax (Linaria vulgaris). It is not uncommon to find in clearings of the forest the small Kenilworth ivy {Linaria cymhalaria) , the common pansy {Viola tricolor), the petunia {Petunia grandiflora) , the dead nettles {La- mium amplexicaule and L. album), ox-eye daisy {Chrysanthemum leucanthemum) , hemp nettle {Galeopsis tetrahit), foxglove {Digi- talis purpurea), European bindweed {Convolvulus arvensis). The 728 WEED FLORA OP IOWA cats '-ear {Hypochaeris radicata) is one of the most common weeds in lawns. There is a common belief that it was introduced from Chile. In the Great Basin country, especially in Utah, a large number of the weeds are of European origin. Of the most common of these mention may be made of the brome grasses (Bromus hrizae- formis and B. tedorum), bouncing Betty {Saponaria vaccaria), black medick {Medicago lupidina), dodders {Cuscuta arvevisis and C. epithymum), poison hemlock {Conium maculatum), moth mul- lein {Verh'ascum Mattaria), mint {Mentha viridis), Eussian thistle (Salsola kali var. tenuifolia), horehound {Marruhium vulgare), Fig. 551. Awned Brome Grass (Bromus tectonim). Common in the Great Basin country and California, occasionally in Iowa. WEED MIGRATION 729 prickly lettuce {Lactuca scariola) and storksbill {Erodium cicu- tariimi). There are also such native weeds as bee-plant {Cleome serrulata), wild liquorice {Glycyrrhiza lepidota), the squirrel-tail grasses {Hordeum jubatum and H. caespitosum) , prickly lettuce {Lactuca pulchella) , pine-apple weed {Matricaria suaveolens) and prickly poppy {Argemone plaiyceras). In the Rocky mountain re- gion, especially Colorado, many of the more recent introductions are from Europe. Among these are the sweet clovers {Melilotus alba and M. officinalis), black medick {Medicago denticulata), purslane {Portidaca oleracea), dodder {Cuscuta arvensis and G. Pig. 551A I ^ * Fig. 551A III Pig. 551A IV Fig. 551-A. Seeds scattered with agricultural seeds. I. Barnyard Grass (Echinochloa crusgalU). II. Medicago denticulata, common in alfalfa seed. II. Horehound (MarruMum vulgare), a weed commonly scattered with alfalfa seed. Common in the Great Basin country. IV. Wild Buck- wheat or Bindweed (Polygonum convolvulus), commonly scattered with grain seed. (All after Hillman.) epithymum), foxtail {Setaria viridis) , storksbill {Erodium cicu- tarivmi), Russian thistle {Salsola kali var. tenuifolia), vegetable oyster {Tragopogon porrifolius), goat's beard {T. pratensis) and lam^^b's quarters {Clienopodiuyn aUrum). A large number of native plants have become weedy, such as marsh elder {Iva xanthifolia) , 730 WEED FLORA OF IOWA (Franseria discolor), the two annual sunflowers (HeliantJius an- nuus, H. petiolaris) , small ragweed (Ambrosia artemisiae folia), buffalo bur (Solanum rostratum), Rocky Mountain bee plant (Cleome serrulata), gumweed {Grindelia squarrosa) and squirrel- tail grass (Hordetiftn juhatum). Pig. 551B I Pig. 551B II Pig. 551B III Pig. 551B IV Fig. 551-B. Seeds of immigrant weeds. I. Squirreltail {Hordeum jubatum) ; widely scattered with hay and stock trains from the western plains. II. Spinage (Spinacia oleracea) ; a common weed of the Great Basin country. Scattered from cultivated plants. III. Russian Thistle (Salsola kali var. tenuifolia) ; brought to Dakota with flax seed and grain seed ; now scat- tered in Iowa with alfalfa seed. IV. Winged Pigweed {Cycloma atri- plicifoUum) . (II, drawing, L. R. Collins; the others after Hillman.) Cosmopolitan Weeds. — A great many weeds, originally, bad a very wide distribution, although many of these so-called weeds were probably introduced by man. In many cases it is almost impossible to tell how . and whence they came to the places in which they occur. Who can trace the immigration of such weeds as common purs- lane, or charlock, or barnyard grass? In the first place, these WEED MIGRATION 731 plants immigrated when little was known about the species of plants. What was said about them by the early botanical writers was often very indefinite. In the second place, many of the early writers did not take pains to leave statistics concerning the intro- duction of the plants. The future records, however, will be more accurate as the adventive plants are being recorded by a host of botanical writers the world over. The notes in such floras as Britton's Manual, Robinson and Fernald-Gray's Manual, Bentham and Hooker's Handbook of the British Flora, Garcke's Flora of Germany, Acloque's Flora of France, Moore's Handbook of the Flora of New South Wales, Arcangeli 's Flora of Italy, Baron Fer- dinand von Mueller's Systematic Census of Australian Plants, Grisebach's Flora of the British West Indies, Millspaugh's Flora of Yucatan, Hemsley's Botany of Central America, Urban 's papers on the Flora of the West Indies give more or less detailed infor- mation on introduced weeds. Pig. 552. Crabgrass (Digitaria sanguinalis). A cosmopolitan weed. The following weeds are more or less cosmopolitan : crab grass {Digitaria sanguiTialis) , found in North and South America, Eu- rope, Asia, Africa, Australia and New Zealand; barnyard grass (EchiTwchloa crusgalli) , in Europe, Asia, Africa, North and South America and Australia; green foxtail (Setaria viridis), in Europe, 732 WEED FLORA OP IOWA Fig. 553. Foxtail Grass (Alopecurus geniculatus'). Widely distributed. Cos- mopolitan grass. (U. S. Dept. of Agr.) Asia, Africa, Australia, North and South America; pigeon grass {Setaria glauca), in Europe, Asia, Africa, North and South Amer- ica; whorled millet {Setaria verticillata) , in Europe, Asia, Africa, North and South America; Johnson grass {Sorghum halepense), in Europe, Asia, Australia and North America; foxtail grass {Alopecurus geniculatus) , in Asia, New Zealand, Australia, North America; hair grass {Agrostis liyemalis), in Australia, New Zealand, North America; Bermuda grass {Cynodon dactylon), a valuable forage plant, but, in cultivated fields, a weed, Europe, Asia, Africa, Australia, New Zealand, North and South America; southern spear grass {Eragrostis pilosa), Europe, Asia, Africa, Australia, New Zealand, North and South America ; crowfoot grass WEED MIGRATION 733 {Eleusine indica), Europe, Asia, Africa, Australia, New Zealand, North, and South. America; cheat {Bromus secalinus), Europe, Asia, North America, a weed; brome grass (Bromus tectorum), Europe, Asia, Africa, North America; soft chess {Bromus arven- sis), Europe, Asia, Africa, North America. . It is singular that only one species of Bromus is given by Moore and Ferdinand von Mueller, the Bromus arenarius. Reed {Phragmites communis), though not regarded as a weed in the United States, is a cosmo- politan plant ' found in Europe, Asia, Africa, Australia, New Zealand, Papua, North America (Canada, United States and Mexico). Fig. 554. Tumbling Mustard (Sisym'brium altissimum). in the Dakotas. (Dewey, U. S. Dept. Agr.) Introduced with grain Cress {Barl)area vulgaris) occurs in Europe, Asia, Australia, New Zealand and North America. None of the most common North American weeds among the remaining members of the mus- 734 WEED FLORA OF IOWA tard family occur in Australia or New Zealand, although shep- herd's purse {Capsella hursa-pastoris) , common mustard {Brassica arvensis), the hedge mustards {Sisymbrium officinale and S. altis- simum) and peppergrass {Lepiddum apetalum) are common in Europe and Asia. Of the pulse family the bird's-foot trefoil {Lotus corniculatus) occurs in Europe, Asia, Africa and Australia; the indigo plant {Indigofera hirsuta) in Africa, Australia, Papua and Asia. The absence of black medick {Medicago lupidina) and hop clover {Tri- folium agrarium) from Australia is striking. Of the geranium family the common European, African and Asiatic species of storksbill {Erodium cioutarium) are absent in Australia and New Zealand and the little yellow flowered sorrel {Oxalis corniculata) is the only representative in New Zealand, Australia and Papua. This species also occurs in Europe, Asia, Africa and America. The only malva^eeous weeds in Australia common also to the United States are sida {Sida spinosa) and butter-print {Ahutilon theophrasti) , both of tropical origin. The former occurs in Europe, Asia, Africa, North and South America, Australia and Papua. The pigweed {Amdranthus retroflexus) of southern North America is common in Europe but has not reached Australia. None of our troublesome weedy species of dock, which are cosmopolitan, occurs in Australia. Of the smartweeds there are two species, the water pepper {Polygonum hydropiper) (Europe, Asia, North and South America) and slender smartweed (P. lapathifolium) of Europe, Asia, North 'and South America. Silky cinquefoil {Potentilla anserina), of the rose family, is com- mon in the west and here and there in northern Iowa; it is found in Europe, Asia, Africa, Australia, New Zealand and North America. Feverfew {Agrimonia striata) is found in Europe, Africa and North America. None of our Oenotheras is cosmo- politan; however the primrose willow {Jussiaea suffruticosa) , a sub-tropical plant, is widely distributed in Asia, Africa, America and Papua. Very few of the Umbelliferae are cosmopolitan. Moore and Mueller record water parsnip {Sium latifolium) for New Zealand and Australia. The Mexican Ageratuin conyzoides of the sunflower family, found in Africa, Asia, Europe, North and South America, is often weedy. The Spanish needle {Bidens hipinnata) is found in Asia, Europe, North and South America. The small number of plants of this family found in Australia and New Zealand is remarkable. None WEED MIGRATION 735 of our plantains is of common occurrence. There is no morning- glory. It may be of interest to compare the noxious weeds of Ger- many with those of the United States. Dr. A. Thaer of the Uni- versity of Giessen in 1881 published a small book on the agricul- tural weeds of that country listing the following: (Those printed in small capitals are also weedy in Iowa.) Com poppy {Papaver rhoeas), mustard (Brassica arvensis), charlock (Raphanus raphanistrum), Canada thistle (Cirsium arvense), corn cockle (Agrostemma githago), chickweed (Stellaria media), sheep sorrel {Bumex acetosella), vetch {Vicia hirsuta), eolt's-foot {Tussilago farfara), com chamomile (Anthemis arvensis), corn marigold Fig. 555. Cypress Spurge (Euphorbia cyparissias) . Common in Europe and waste places in Iowa. In many cases started in the vicinity of cemeteries. (After Strasburger, Noll, Schenck and Karsten.) {Chrysanthemum segetum), groundsel {Senecio vernalis) , corn- flower (Centaurea cyanus), sow thistle (Sonchus oleraceus), small bindweed' (Convolvulus arvensis), clover dodder (Cuscuta epithymum), broom rape {Orohanche ramosa) , garden orach 736 WEED FLORA OF IOWA {Atriplex hortense), cock's comb (Bhinanthus crista-galli major and minor), smartweed (Polygonum persicaria), cypress spurge (Euphorbia cyparissias), meadow saffron ( Colchicum autumnale), silky bent-grass {Agrostis spica-venti) , wild oats (Ayena patua), c'hess (Bromur secatjntjs), quack grass (Agropyron repens), horse-tail (Equisetum arvense). L. Danger in his work on weeds and parasites of Germany, pub- lished in 1887, divides the weeds of Germany into two classes: A. Eoot weeds, B. Seed weeds. A. Root weeds. — Quack grass (Agropyron repens), reed grass (Phragmites com/munis), bindweed {Convolvulus arvensis), deadly nightshade {Atropa belladonna), goatweed {Aegopodium roda- graria), sheep sorrel {Rumex acetosella) , sour dock {R. crispus), meadow saffron Colchicum autumnale), marsh marigold {Caltha palustris), mint {Mentha arvensis), thistle {Cirsium arvense, C. alteraceum, C. acaule, C. heterophyllum, C. palustre, C. lan- ceolatum), {Carduus crispus, C. lanceolatus, C. natans), {Onopor- don acanthium), sow thistle {Sonchus arvensis, 8. palustre, S. o^per, 8. oleraceus), colt's-foot {Tussilago farfara, T. hyhrida, T. peta- sites), yarrow {Achillea millefolium), {Leontodon autumnalis) dandelion {Taraxacum officinale), plantain {Plantago coronspus, P. arenaria, P. major, P. media, P. maritima, P. lanceolata) , horse- tails {Equisetum arvense, E. palustre). B. Seed weeds. — Chess {Bromus secalinus), {Alopecurus agrestis), wild oats {Avena fatua), {Agrostis spica-venti) , darnel {Lolium temulentum) , black nightshade {Solanum nigrum), black henbane {Hyoscyamus niger), Jimson weed {Datura stramonium), fool's parsley {Aethusa cynapium), hemlock {Conium maculatum), cowbane {Cicuta virosa), Venus' comb {8candix pecten-veneris) , buckwheat {Fagopyrum esculentum), smartweed {Polygonum persicaria), dooryard knotweed {Polygonum aviculare), corn cockle {Agrostemma githago), buttercups {Ranunculus septentrionalis, R. flammula, R. arvensis), nettle {Lamitim), charlock {Raphanus raphanistrum) , foxglove {Digitalis purpurea), mustard {Brassica arvensis), mayweed {Anthemis arvensis and A. cotula) , groundsel {8enecio vidgaris), horseweed {Erigeron canadensis), field mari- gold {Chrysanthemum segetum), Frenohweed {Galinsoga parvi- flora), spurge {Euphorbia cyparissias), orach {Atriplex Jiortense), nettles {Urtica urens, U. dioica). WEED MIGRATION 737 AMERICAN WEEDS INTRODUCED INTO EUROPE. Every year more weeds are introduced into Europe from Amer- ica; however, it is very noticeable that the more abundant of these are from the warmer regions of America, rather than from the colder regions. A good many of these are weeds of the open country of North America. I have looked rather hastily through a few of the floras of Great Britain, Italy, Austria and Germany, in addition to a number of recent references on the adventive flora of Europe, from which these data have been compiled. Apple of Peru (Nicandra physaloides) Germany (Garcke). Aster (Aster nmn-helgii) Italy (Areangeli), Germiany (Garcke), France (Acloque). Aster {Aster parviflorus) Germany (Garcke). Aster (Aster salicifolius) Germany (Garcke). Bug seed (Corispermiim hyssopifoUum) Germany (Garcke), Italy (Areangeli). Bur cucumber (Sicyos angulatus) Germany (Garcke), Italy (Areangeli). Clotbur (Xanthium spinosum) Italy (Areangeli), Germany (Garcke, Bitter, Kiefer), Austria (Neilreich), France (Acloque). CoUomia (Collomia grandiflora) Germany (Garcke). Cone flower (Rudheckia kirta) Germany (Garcke). Cone flower (Rudheckia laciniata) Germany (Garcke, Bitter^ Lehmann). Cone flower (Lepachys pinnata) Germany (Bitter). Evening primrose (Oenothera sinuata) Germany (Bitter). Fleabane (Erigeron annuus) France (Acloque), Italy (Ar- eangeli) . Fleabane horseweed (Erigeron canadensis) France (Acloque), Austria (Neilreich), Germany (Garcke, Lehmann), England (Hooker), Italy (Areangeli). Galinsoga (Galinsoga parviflora) Italy (Areangeli), Germany (Garcke). Pigweed (Amaranthus retroflexus) Italy (Areangeli), Germany (Garcke, Alpers), France (Acloque), Austria (Neilreich). Goldenrod (Solidago canadensis) Germany (Garcke, Wegelin), Austria (Neilreich) . Goldenrod (Solidago lanceolata) Germany (Garcke), England (Hooker). 47 738 WEED FLORA OF IOWA Fig. 556. Goldenrod {Solidago rigida) . Common in Iowa. (Photographed by Gardner.) Goldenrod {Solidago serotina) Italy (Arcangeli), Germany (Garcke). Mexican tea {Chenopodium amhrosioides) Germany (Garcke, Alpers), Italy (Arcangeli). Nightshade, buffalo bur {Solanum rostratum) Germany (Garcke, Alpers) . Nightshade, buffalo bur {Solanum heterodoxum) Germany (Garcke). Nightshade, Three-flowered {Solanum triflorum) Germany (Garcke, Alpers). Pellitory {Parietaria pennsylvanica) Germany (Garcke). Peppergrass {Lepidium virginicum) Germany (Garcke), France (Tourlet). Phaeelia {Pliacelia tanacetifolia) Germany (Garcke). Pigweed, Tumbleweed {Amaranthus graecizans) Italy (Arcan- geli), Germany (Bitter). Pigweed {Amaranthus retroflexus) Italy (Arcangeli), Germany (Garcke, Alpers), France (Acloque), Austria (Neilreich). WEED MIGRATION 739 Fig. 557. Rice Cut Grass (Leersia orysoides). Common in low grounds, Iowa; not, however, regarded as a weed. Common in Italy. (Lamson-Scribner, U. S. Dept. of Agr.) 740 , WEED FLORA OF IOWA Pigweed, winged {Cycloloma platyphyllum) Italy (Arcangeli). Plantain {Plantago aristata) Germany (Bitter). Ragweed, small (Ambrosia art emisiif olio) Germany (Garcke, Laubert). Rice cut-grass {Leersia oryzoides) Italy (Arcangeli), Germany (Garcke, Buchenau), France (Acloque), Austria (Neilreich), England (Hooker). Sida (Sida spinosa) Germany (Alpers). Spanish needle (Bidens hipinnata) Italy (Arcangeli), Germany (Garcke, Boute), France (Acloque). Spanish needle (Bidens frondosa) Italy (Arcangeli). . Spanish needle (Bidens leucantJms) Germany (Garcke). Speargrass (Eragrostis pilosa) Italy (Arcangeli), Germany (Garcke), France (Acloque). Speedwell (Veronica peregrina) Italy (Arcangeli), Austria (Neilreich). Sunflower, artichoke (Helianthus tuherosus) Italy (Arcangeli), Germany (Garcke). Sunflower, common (Helianthus amiuus) Germany (Garcke), Austria (Neilreich). Tickle grass (Panicum capillare) Germany (Alpers, Garcke), France, Italy (Arcangeli), Austria (Neilreich). Tickseed (Coreopsis tinctoria) Germany (Bitter). Waterweed (Elodea canadensis) Germany (Garcke, Scherer, "Weshoff, Bitter), England (Hooker), France (Acloque). INDIGENOUS WEEDS COMMON TO THE NORTHERN HEMISPHERE. In all probability a few of the weeds here listed have been intro- duced, at any rate their origin is in doubt; some occur in Europe and North America only; those found in Asia are marked (As.). Achillea millefoliuim (yarrow) (As.). Alopecurus genicidatus (marsh foxtail). Anagallis arvensis (pimpernel) (As.). Anaphalis margaritacea (everlasting). Atriplex patida var. hastata (orach). Barharea vulgaris (yellow rocket). Bidens cernua (sticktight). Capsel'la hursa-pastoris (shepherd's purse). Cerastium arvense (mouse-ear chickweed). Convolvulus sepium (morning-glory) (As.). WEED MIGRATION 741 Fig. 558. Yarrow (Achillea millefolium). Common in the northern hemis- phere. (Drawing by Charlotte M. King.) Cyperus esculentus (northern nut grass) (As.). EpiloMum angustifolium (fireweed) (As.). Erigeron acris (fleabane). Erysimum cheiranthoides (treacle mustard). Galium trifidum (bedstraw) (As.). Galium aparine (cleavers) (As.). Gnaphalium, uliginosum (cudweed). Rierochloe horealis (holy grass). , J uncus tenuis (wire-grass). Lepidium apetalum (peppergrass). Mentha arvensis (mint) (As.). Myosurus minimus (mouse-tail). Oxalis corniculata (field sorrel). 742 WEED FLORA OF IOWA Plantago major (common plantain) (As.). Polygonum aviculare (dooryard knotweed) Polygonum hydropiper (smartweed). Polygonum lapathifolium (smartweed). Potentilla amserma (silvery cinquefoil). Potentilla monspeliensis (five-finger) (As.). (As.), Fig. 559. Holy or Vanilla Grass (Hierochloe borealis). Common in the northern hemisphere, mountain regions. In northern Iowa. (Lamson-Scribner, U. S. Dept. Agr.) Prunella vulgaris (self-heal). Badicula palustris (marsh cress) (As.). Banunculus cymhalaria (crowfoot). Ranunculus pennsylvanicus (crowfoot) (As. Banunculus repens (crowfoot). Bhinanthus crista-galli (yellow rattle"). WEED MIGRATION 743 Senecio palustris (ragwort). Stachys palustris (woundwort) (As.). Taraxacum officinale (dandelion). This species occurs every- where in the United States and Europe, even on the highest moun- tains. Fig. 560. Dandelion {Taraxacum officinale). Common in the northern hemis- phere, across the continent. INTRODUCTION OF SOME WEEDS INTO THE UNITED STATES AND INTO IOWA. CHENOPODIACEAE, GOOSEFOOT FAMILY. Russian Thistle (Salsola kali var. tenuifolia) . This plant has long been known as a troublesome weed. Henfrey, in his work, "The Vegetation of Europe, its Condition and Causes," published in 1852, notes its abundance in Russia, east of the Volga. (44 WEED FLORA OF IOWA Linnaeus, the Swedish botanist, seems to have known the plant as it occurred in eastern Europe. Prof. L. H. Dewey has given us a good account of the introduction of this weed in the United States.* It seems to have been first observed in Scotland, Bonhomme county, South Dakota, in 1873 or 1874, the seed having been brought in with flax seed. In 1877, it was reported from Yankton county; five years later in the counties to the north and west of Bonhomme. By 1888 it had infested many of the counties east of INIissouri river and two years later practically all of the counties of South Dakota and southern North Dakota. About the same time it invaded Pig. 561. Russian Thistle (Salsola kali var. tenuifolia). Common in eastern Europe. Introduced into the Dakotas, 1873 or 1874. Now common in northern United States, particularly in the west. (Drawing by Charlotte M. King.) ♦Bull. Div. of Bot., U. S. Dept. of Agr. 15:12. 1894. WEED MIGRATION 745 northwestern Iowa, northeastern Nebraska and western Minnesota. In 1898 it was reported from Colorado, Wisconsin, Illinois and other western states. In 1894 Pammel gave the following account of its distribution : Prof. Dewey's map indicates that the badly infested area extends from the east bank of the Missouri river at Bismarck to Jamestown and Moorehead in North Dakota ; south to Sioux City, in Iowa ; it also occurs in many isolated places in Minnesota, Wisconsin, Iowa, and at Denver, Colorado. The localities at which he found it in Iowa are Rock Rapids, Emmetsburg, Spencer and Avest to the Missouri river. Council Bluffs, and on the Missouri river opposite Nebraska City. To these we must add Edna, Ames, Little Rock (Ball), Calumet (Louthan), Missouri Valley, Mason City, Eagle Grove, and in all probability it occurs along our great trunk lines across the state. Last season Mr. G. W. Carver found a small specimen of what undoubtedly was Russian thistle along the Chi- cago & Northwestern railroad; the place was revisited this year, and an abundance of the weed was found. A few days later Messrs. Robt. Combs and C. B. Weaver found several localities between Ames and Ontario, and Mr. Sheldon reported it in the Ames stock yards. As to its probable early appearance in Iowa we have reliable data. Prof. A. S. Hitchcock, an excellent ob- server and collector, reported it from Woodbury county in 1888, and Mr. R. I. Cratty, of Emmetsburg, reported it from Emmet county in 1890 or 1891. It has also been sent to me from Ellsworth, in Nobles county, Minnesota, close to the Iowa line. Mr. G. W. Cairver found great quantities of it near Chicago, at Turner Junc- tion, and J. J. McMahon from Peatone, Illinois. It occurred as early as 1890 in Wisconsin. The writer, in re- cently looking over a collection of specimens made in the vicinity of Prairie Du Chien, in 1890, found a specimen of Russian thistle. The species was growing in considerable quantity along the sandy embankment of the river and railroad, not far from the railway station. It is not unlikely that it spread eastward along the Chi- cago, Milwaukee and St. Paul railroad for considerable distance. It now occurs in many Iowa counties, especially along railroads. It is one of the most abundant weeds in western Nebraska, Colo- rado, LTtah, Montana and Idaho. It is more or less sporadic in its appearance ; some years more abundant than others. It was espe- cially common at many points in Iowa in 1910 and 1911. Its dis- tribution in Iowa as reported from time to time is as follows : Post- ville, 1894 (Orr) ; Mason City and Eagle Grove, 1894 (Pammel) ; Muscatine, 1894 (Reppert) ; Boone, 1895 (Carver) ; Ames, 1895 (Rolfs) ; Hawarden, 1895 (Pammel) ; Missouri VaDey, 1897 (Pam- mel) ; Ledges, 1898 (Pammel) ; Armstrong, 1901 (Cratty) ; Ogden, 746 WEED FLORA OF IOWA 1901 (Pammel) ; Slater, 1902 (Fawcett, Tener and Reinbott) ; Mar- shalltown, 1902 (Pammel) ; Aurelia, 1912 (Summers) ; Sidney, 1912 (Graham). Winged Pigweed {Cydoloma platyplvyllum Moquin.). Not indigenous in Iowa. Des Moines, 1887 (A. S. Hitchcock) ; Hamburg (A. S. Hitchcock); Muscatine, 1890; Ontario, 1892 (Burgess) ; Des Moines, 1894 (Carver) ; Cedar Rapids, 1895 (Palmer), City Goosefoot {Chenopodium urhicum L.). Nevada, 1880 (A. S. Hitchcock) ; Iowa City, 1887 (A. S. Hitch- cock) ; Keokuk, 1887 (A. S. Hitchcock) ; Muscatine, 1890 (F. Reppert) ; Ames, 1891 (A. S. Hitchcock) ; Keokuk, 1891 (P. H. Rolfs). 0.ak-leaved Goosefoot {Chenopodium glaucum L.). Iowa City, 1889 (Hitchcock) ; Muscatine (F. Reppert). Jerusalem Oak {Chenopodium hotrys L.). Ames, 1883; Iowa City, 1887 (A. S. Hitchcock). Mexican Tea {Chenopodium amhrosioides L.). Keokuk (J. C. Arthur) ; Muscatine, 1890 (F. Reppert). Coast Elite {Chenopodium ruhrum). Keokuk, 1891 (P. H. Rolfs). Orach {Atriplex pafula L. var. hastatum Gray). Iowa City, 1887 (A. S. Hitchcock) ; Keokuk, 1891 (P. H. Rolfs) ; Ames, 1896, where it has now become well established; Boone, Ft. Dodge, 1912 (L. H. Pammel) ; Storm Lake, 1912 (L. H. Pammel). Var. Uttorale, Iowa City, 1887, (A. S. Hitchcock). Silvery Orach {Atriplex argenteum Nutt.). Ames, 1895 (G. W. Carver). Mexican Fireweed {Kochia scoparia (L.) Schrad.). Mexican fireweed is recorded as an adventive from Europe in the sixth edition of Gray's Manual of Botany, 1889, by Watson and WEED MIGRATION 747 Coulter, with the statement "sparingly introduced in Vermont, Ontario, and Illinois. " It is not recorded in the fifth edition of the same work by Dr. Gray in 1867. In the Britton Manual, 1901, the distribution is given as Ontario, Vermont, and northern New York, adventive from Europe, native also of Asia. According to the Robinson and Fernald Edition of Gray's Manual (7th. Ed.), 1908, it had become so common because of its cultivation and "lo- cally established as a weed" that the distribution was not given. The writer saw it in abundance as a weed in Denver and Ft. Collins, Colorado, and Salt Lake, in 1902, and in Chicago the same year. It has been spontaneous as a weed in Ames since the year 1900. It has been observed in Ames, Council Bluffs (1901), Sioux City (1902), Cedar Rapids (1905), LaCrosse, Wis. (1904). The fol- lowing catalogue of plants lists the species: Rydberg, Colorado, at Fort Collins. COMPOSITAE, SUNFLOWER FAMILY. Prickly Lettuce (Lactuoa scariola). This species was abundant in Utah in 1898 and was observed in many parts of California the same year, but was, however, far less common in the east. It was first observed in central Iowa, Ames, in 1909 and now occurs in Ft. Dodge, Boone and Des Moines, and is rapidly spreading. It is common in dry places in the Rocky mountains .and on the Pacific coast. Robinson and Fernald state, "Roadsides, railway ballast, etc.. New England to Oregon, N. W., and Kentucky, chiefly westward, but even then less common than the following variety (var. integrata) ." It is common in northern and central Ohio, Indiana and Illinois (DeKalb, Fox, Aurora, Geneva, Chicago and Wheaton). Prickly Lettuce (Lactuca scariola var. integrata) . Waste grounds, roadsides and fields from the Atlantic to the Pacific, especially northward. This is the form commonly referred to by botanists when speaking of the weed in the east. This variety was first reported by Dr. Gray. Specimens were collected by Mr. D. Murray in 1863 and 1864; some specimens were collected by M. S. Bebb at Rockford, Illinois, in 1879, and about the same time by Mr. Henry Eggert in St. Louis. In 1883 it was common in the vicinity of Madison but had not reached La Crosse, Wisconsin. In 1886 a few specimens were reported in the vicinity of Onalaska 748 WEED FLORA OF IOWA near La Crosse. It was abundant in Iowa in 1886, was reported from Eagle Grove in 1894 by Cratty, and by the same observer at lake Okoboji in 1901. The writer observed it abundantly in vairious places in Nebraska and eastern Colorado in 1894 and gave a more definite account of its distribution and spread in a paper in Proceedings Iowa Academy Sciences. In 1912 it was very abundant everywhere in Iowa. The seeds are easily scattered by the wind, which probably accounts for its wide distribution in a comparatively short time. Thistle {Cirsium palustre) . This European thistle is recorded as naturalized in woods. East Andover, New Hampshire, (Holt) by Robinson and Fernald in the 7th edition of Gray's Manual, 1908, and was reported from Iowa in 1911 and again in 1912. Canada Thistle {Cirsium arvense). This well known weed is common everywhere in Europe and is perhaps a weed of the open. Linnaeus in his Flora Lapponica (1837) notes that it is the greatest pest of our fields. It is dis- tributed from the Atlantic to the Pacific across the northern states and in Canada^. lu Iowa it is' found more particularly in the north half of the state. The earliest floras of the state (Arthur, Bessey, and Parry) note its occurrence in Iowa. It has occurred in Ames for forty years. In 1889 it was noticed in many counties. Cratty reports the species from Emmet county in 1892. At this time it had been reported also from Howard, Adair, Chickasaw, Johnson and Poweshiek counties'. In 1899 it was thoroughly es- tablished in a forest near Steamboat Rock in Hardin county. Plants from the early introduction seldom produced seed, but seed from the later introductions is not uncommon ; thus it has been matured in O'Brien county and in Cresco, 1892 (C. V. Johnson). It is spreading rapidly in northern Iowa., having become much more widely distributed in 1903 and 1C06 with clover seed. It has been reported from Johnson county, 1874 (0. G. Bab- cock) ; Lawler, 1890 (P. H. Rolfs) ; Greenfield, 1891 (F. C. Stewart) ; Corning, 1895 (A. B. Shaw) ; Taylor, 1895 (J. B. Matthews) ; Maple River Junction, 1895 (L. Bernholtz) ; Farragut, 1895 (C. Collman) ; Marcus, 1896 (Willey) ; Winterset, 1896; Barnes City, 1896 (J. W. Jones) ; Nevada, 1898 (G. C. White) ; Steamboat Rock, 1899; Rockwell, 1901 (J. H. Boom); Badger, WEED MIGRATION 749 1902 (Myrhe); Audubon, 10O5 (M. C. Griffith); Gmettiuger, 1906 (E. L. George) ; Clarion, 1909 (Melhus) ; also in Lorimer (Lochrie) ; Blairsburg (J. M. Hall) ; Oelwein (J. Thompson) ; Muscatine (F. Reppert) ; Reading (Dr. McClanahan) ; Griswold (R. E. Pierce) ; Randall (C. & G. R. Christianson) ; Hartley (H. R. Foblenkamp) ; Garrison (J. Grayson) ; Roland (E. N. W.augh) ; Kossuth (S. A. Merrill) ; Cedar Falls (C. E. Daily) ; and Wool- stock (A. P. Reynold). Woolly Thistle (Cirsium canescens). This plant has been reported from several states north and west of the Mississippi. In Iowa it occurs chiefly in the northern half of the state, having been reported by A. S. Hitchcock in 1889, as growing near Sioux City. Later it was reported from Sioux City by Pammel, 1895; Armstrong (Cratty), 1897; Webster City (McCoy), 1901; Onawa (Fletcher), 1902; Le Mars, 1902 (Wm. Long) ; Charter Oak, 1903 (C. N. Weed) ; Pisgah (L. H. Raymond), 1903; Rolfe (J. B. Jolliffe), 1908; Lu Verne (W. F. Blumer), Fia. 562. Woolly Thistle (Cirsium canescens). Originally along the Missouri and adjacent territory. Now spreading eastward. 1, head ; 5, single flower ; 6, achenium ; 7, stamens and style ; a, stigma enlarged ; 8, pollen grain. (Drawings by Charlotte M. King.) 750 WEED FLORA OF IOWA 1911 ; Harlan, Shelby county, Buena Vista county, and Clay county, 1912 (Pammel) ; Sac county, 1912 (Lee) ; Storm Lake, 1912 (Rehnstron) ; Dickens, 1912 (Evans) ; Smithland, 1912 (Bar- ber) ; Cartersville, 1912 (Connor). Hawkweed (Hieracium floribundum) . This weed, reported from Cutler, Maine, in 1902, now occurs in fields from New Brunswick to eastern Maine. Paint Brush {Hieracium aurantiacum) . Paint brush was cultivated as an ornamental plant in Maine in 1875 and became frequent in the New England states and New York in the early eighties. It is now distributed from eastern Quebec to Pennsylvania and occasionally in Iowa. Cat's-ear {Hypochaeris radicata) . According to Fernald this appeared in Penzance and Wareham, Massachusetts, in 1899 ; since then it has spread to other New England localities, as New Bedford and Dartsmouth. It had been, however, a very troublesome weed of lawns of the Pacific north- west for some time previously. It was abundant in Portland, Oregon, in 1906. Stinking Willie {Senecio jacoljaea). Fernald (1905) states that in the late 70 's a coarse yellow flowered plant {Senecio jacohaea) appeared as a waif on ballast at some points along Northumberland Strait in eastern New Bruns- wick. In 1884, it had begun to spread along the local railroads and now has reached Portland, Maine. The seventh edition of Gray's manual (1908) gives its distribution from Newfoundland to New Jersey. Barnaby's Thistle or Knapweed {Centaur ea solstitialis) . This weed was not reported in the sixth edition of Gray's manual (1889) nor in Britton's manual (1901). In the seventh edition of Gray's manual, Robinson and Fernald state, "Waste ground, eastern Massachusetts to Ontario and Iowa." It was re- ported from Iowa as early as 1903, and since, a few times each year, in alfalfa fields as follows : Paton, 1903 (Lundell) ; Maple- ton, 1904 (Perrin) ; Moville, 1905 (Morton) ; Des Moines, 1907 WEED MIGRATION 751 (Wallace). J. Burtt Davy reported it from central California in the nineties. Maxsh Elder {Iva xantMfolia) . Dr. G-ray in the fifth and sixth editions of the manual gave its distribution, "Northwest Wisconsin to Minnesota, Kansas and westward." Originally this must have been a local weed in Wis- consin and eastern Minnesota. Upham in 1890 mentions it as one of the most aggressive weeds of Red river, especially in waste places. Parry includes it in his list of plants collected in the upper Mississippi valley in 1848. It is not improbable that this plant was brought to eastern Minnesota and Wisconsin by the early voyagers, the Indians or the white settlers. It is a weed of the open and cultivated soil, especially near habitations. The early settlers in the Red river valley gave to it the name of "half breed weed" because so commonly found near the habitations of the half breeds who lived in that section of Minnesota, Manitoba and Dakota. There are early records of the weed, however. Hall mentions its occurrence near Athens, Illinois, in 1863. This was after Hall had returned from his trip to the Rocky mountains. He may have thrown away some of the seed, which germinated and produced plants. It was a common plant in the Rocky mountains, as reports of such botanists as Parry, Vasey, Hall, Fendler, M. E. Jones, Suksdorf, Cusick, Kelsey, Brandegee, Havard, Bigelow, (Camanche Plains, 1853) and others indicate its abundance. Though reported from Charles City by Arthur in 1871 it has not made much progress east of the Missouri river basin. Its dis- tribution and date of appearance. may be seen from the following: Boone, 1890 (Pammel) ; Keokuk, 1890 (Rolfs) ; Woodbine, Vale, Eagle Grove, Mason City, and Carroll, 1894 (Pammel) ; Armstrong, 1897 (Cratty) ; Ogden and Slater, 1896; Hanlontown and Ames, 1902 (Pammel) ; Decatur county, 1911 (Anderson). It was a fre- quent and abundant weed from Sioux City to Council Bluffs and probably south to Hamburg; reported at Independence, and, in 1876, at Humboldt, by Harvey. It had been reported from Emmet county as early as 1875, having been introduced with cattle. It has not spread very rapidly at any of these interior points. It was reported in St. Paul in 1861 (T. J. Hale) and it was abundant along the highway on a bank near La Crescent, Minnesota, in 1884. It now occurs in Hokah, Brownsville, and other points along the river (1910). In the early nineties it appeared in Onalaska, Wis- 752 WEED FLORA OF IOWA Fig. 563. Marsh Elder (Iva xanthiifolia) . Common in the Red River Valley, spreading ea.stward. WEED MIGRATION 753 consin (Pammel) ; Menominee Valley, 1888 (Runge) ; Kewaunee county, 1889 (Wheeler, Farwell) and in Seneca, New York. It is abundant throughout the country and common in the northwest to Washington. It is abundant in western Iowa and is rapidly spreading eastward, also becoming an aggressive weed from Ames north to the Minnesota line and westward. It was reported from Europe (Denmark, Ostenfeld) 1895. Perennial Sow Thistle (Sonchus arvensis). This thistle was reported by John Torrey in 1826 in the northern and middle states. Dr. Gray in 1848 in the first edition of the maoQual reported it from Massachusetts, Staten Island, and in New Jersey ; it did not occur in Pennsylvania, or at least was not men- tioned by Darlington. The 5th edition of Gray's manual, 1867, gives its distribution ''roadsides, etc., New England, New York, becoming more abundant;" the 7th edition (1908) says "from Newfoundland to the Eocky mountains northward." Britton (1901) places it in the same general region and west to Salt Lake, Utah. The weed is not common in Iowa nor in the surrounding states except northward in Minnesota and Dakota. It was re- ported from Grand Junction, Iowa, in 1898 by Tomson and from Ogden, Iowa, about 1900; the writer found it in Englewood, Il- linois, in 1886, and in northern Ohio in 1912. It has spread rapidly in recent years in Canada, North Dakota and Minnesota, as recorded in the agricultural press of the last two or three years. Galinsoga or Prenchweed {Galinsoga parviflora) . Danger has given several accounts of the introduction of this weed into Europe. The term Frenchweed seems to have been commonly applied to this weed in Germany shortly after the French soldiers occupied Hanover. One authority states that it was brought from France with horse feed; it is said to have been in- troduced into Germany about 1812. One authority states that the weed was distributed from the Berlin Botanical Garden in the year 1812, at any rate it was very common in Hanover in the year 1839 ; and has continued to spread. It may have spread from its first introduction near Paris to other places of France about the year 1800, although there is no definite date as to when it made its appearance in the vicinity of Paris. This plant is native to Peru where it was discovered by Ruiz and Pavon. about 1794, so 48 754 WEED FLORA OP IOWA it must have been introduced into Europe following their descrip- tion. In the United States the weed has become quite widely disseminated in recent years. The writer found it abundant in the vicinity of green-houses in the Missouri Botanical Garden in 1886, subsequently in 1896 he found it in similar situations in Ames and about 1898 or 1899 in La Crosse, Wisconsin. The writer has observed it at other points but always first in the vicinity of green-houses. This would lead to the assumption that it probably has been disseminated with flower seed. Horseweed {Erigeron canadensis). This widely distributed weed is common everywhere in North America and is said to have been introduced in the vicinity of Paris in 1635, although Leunis' Botany states "introduced in Europe in 1500." It is mentioned as one of the most common weeds of Germany ,and Switzerland by Ratzeburg (1859) . Treatises by Garcke, Koch, Ratzeburg and Acloque mention it as a common weed. Spiny Clotbur {Xantkium spinosum). According to Kabsch, this weed is said to have been introduced into Germany with wool brought from Hungary. Though it originated in tropical America it has become established as far north as Maine (Robinson and Pernald). Thurber in 1859 gave its distribution from Massachusetts to Georgia. In 1889, it reached Leavenworth, Kansas, and in the course of time will be found in Iowa. Hawkweed (Senecio vernalis). This weed was first mentioned by Rosenberg as occurring in Switzerland in 1882. It spread to Silesia; disappeared; was re- ported in West Prussia in 1824, in Breslau, 1835, Brandenburg, 1850, Stettin in 1860, first as a mere waif, then spread to cultivated fields generally. Chicory {Cichorium intyhus). Chicory was introduced into Dorchester, Massachusetts, in 1775. Torrey records it for the northern and middle states in 1826. Gray in 1848 stated "naturalized in the Atlantic States;" the 6th edition of Gray's Manual stated that it occurs from New England to Iowa and Minnesota ; the 7th edition adds Newfoundland and southward. It was common in Wisconsin in 1884 and was spreading; it oe- WEED MIGRATION 755 curred in Colorado in 1896. Gray reports it for Santa Barbara, California, in 1880, and since then it has become fairly common in that state. It was reported from several localities by Crandall and Rydberg in Colorado in 1906 ; reported by Webber in Nebraska. Mr. F. W. Paige states that this weed has been known in Ft. Dodge since 1887. In 1906 it was spreading in Pottawattamie, Story, Sac, Clay, and Kossuth counties, and has been reported from Westgate (Bruce Fink), 1893; Boone (Geo. W. Carver and Pammel), 1895; Des Moines, 1895; Corning, 1895 (Ellen Bettomer) ; well estab- lished in Midway, 1896; Jordan, 1906 (Harriette Kellogg). Vegetable Oyster (Tragopogon pratensis L.). This was reported from Ames, in meadow, 1894; Iowa City, 1889; Newton, 1889 (A. S. Hitchcock). Fetid Marigold {Dyssodia papposa (Vent.) Hitchc). Ackley, 1878 (B. E. Canavan) ; Boone, 1890; Keokuk, 1891 (P. H. Rolfs) ; Muscatine, 1891 (F. Reppert). This striking weed has been known for some time at Ames, and was said by Hitchcock to be frequent (Anth. Pteridophyta of Ames, p. 503). It is more or less sporadic in its appearance, being frequent in some years, in others not so common. It is, however, always abundant in western Iowa, which leads me to believe that the plant is not in- digenous to central Iowa, but introduced, although now occurring in timber and along river banks. Ox-eye Daisy {Chrysanthemum leucanthemum L.). For a long period of years occasional specimens of this weed have been found in the vicinity of the college, and it is an occa- sional introduction in meadows, but except in one place some four miles from Ames it shows no evidence of being naturalized. It has also been reported from Muscatine (Reppert) ; Atlantic (S. 0. Hamill) ; Ames, 1871 (C. E. Bessey) ; Ackley, 1878 (B. E. Cana- van) ; Sheldahl, 1885 (L. V. Harpel) ; Ames, 1891 (P. H. Rolfs) ; still occurs between Ames and Gilbert, 1911, but is not spreading. Mr. J. H. Lees reports this plant as having been introduced into the vicinity of Cedar Falls as early as 1890 and as occurring near LeMars in 1912. 756 WEED FLORA OF IOWA Gumweed (Grindelia squarrosa Dunal). Indigenous to western Iowa, rapidly spreading in contiguous territory, and reported from Boone and Moingona, as abundant in borders of woods along Chicago & North Western Railway in 1890 and still spreading in 1912 ; reported from Keokuk, 1891 (P. H. Rolfs) ; Battle Creek, 1895 (E. G. Preston) ; Osgood, 1895 (C. A. Wells) ; Carbonado, 1895 (John H. Smith) ; Smithland, 1896 (J. M. Wrapp). Eclipta {Eclipta alba Hassk.) . Keokuk, 1877 (Geo. E. Ehinger), 1891 (P. H. Rolfs). Sunflower {Ilelianthus annuus L.). Occasional in Ames and other parts of central Iowa, but in western Iowa indigenous and very abundant, becoming frequent as far as Carroll (Kelley) 1900; Denison and Boone. It was re- ported in Boone in 1871 (C. E. Bessey) ; Ames, 1882; Grinnell, 1891 (M. E. Jones) ; Keokuk, 1894 (P. H. Rolfs) ; Muscatine, 1891 (Reppert) ; and Marshalltown, 1891 (F. C. Stewart). It is not abundant except in a few localities in central Iowa. It is an in- troduced plant with us. CONVOLVULACEAE, MORNING-GLORY FAMILY. Bindweed {Convolvulus arvensis). This weed is of long standing in the United States. It is men- tioned by Torrey in his Compendium of "The Flora of the North- ern and Middle States" in 1826, and Dr. Gray in his first edition of hfs manual in 1848 gives the distribution from Massachusetts to Pennsylvania. Darlington, in 1853, states: "This foreigner has gradually extended itself among us — and will probably give our farmers much trouble if they do not carefully guard against it." This certainly has been realized in many of the central and eastern states. The statement in the seventh edition of Gray's manual would indicate quite general distribution in the region embraced in this work. Tlie fifth edition (1867) states, "fields near the coast; likely to become a troublesome weed." Britton gives its distribution from Nova Scotia to Kansas (1901) ; South Dakota, Parker (1903). It was abundant in St. Louis in 1886 and was reported at various times in Iowa as a troublesome weed WEED MIGRATION 757 befqre 1889. Since 1887 it has been well established in Ames; it was reported from Ladora, 1895 (John Hiltbrummer) ; Des Moines, 1896 (C. N. Page) ; Westgate, 1902 (P. H. Hinager) ; Fort Dodge, 1912 (F. W. Paige) ; and very likely occurs in other places. It was first introduced as a cultivated plant. This may become one of the most pestiferous of our perennial weeds. EUPHORBIACEAE, SPURGE FAMILY. Snow-on-the-Mountain (Euphorbia marginata Pursh.). Indigenous to western Iowa. Little Rock, Sioux City, Onawa, Council Bluffs and Hawarden. Naturalized east. Iowa City, 1887 (A. S. Hitchcock) ; Hamburg, 1888 (A. S. Hitchcock). Abundant at Denison, 1894; Woodbine, 1894; Vale, abundant, 1894; Missouri Valley, Carroll, 1895, abundant (W. Newell). GRAMINEAE, GRASS FAMILY. Squirrel-tail Grass or "Wild Barley {Hordeum jubahim L.). This plant was made known to science by Linnaeus, from speci- mens found in Canada. Dr. Asa Gray, in his Manual of Botany of Northern United States' in 1856, gives its distribution as "marshes and moist sands of the sea shore and the northern lakes." In 1868, its distribution was not extended, but Watson and Coulter, who revised the manual (1890), add to the above "and westward." In the seventh edition of Gray's manual the distribution is given as "coast Labrador to New Jersey prairie and waste ground, Ontario to Illinois, Kansas, and westward." It evidently is very generally distributed throughout the United States. At Ames, specimens have been received from Wyoming, Colorado, Nevada, New Mexico, Idaho, Utah, Montana, Yellowstone Park, Illinois, Ne- braska, the Dakotas, Minnesota, Kansas and from Argentine. It has also been reported from California, Wisconsin, Arkansas, Mis- souri, Michigan, Indiana, Ohio, New York, New Jersey, Massa- chusetts, Maine, Canada (in many parts), Europe (Russia), and Siberia in Asia. A truly cosmopolitan weed. We are without exact data in regard to its early appearance in Iowa, though it was probably native in portions of western and northwestern Iowa, especially where the soil was somewhat broken up. From answers received it would seem that this grass has been known in parts of Iowa for over fifty years, but it is only during the last twenty-five years that it has made much headway. Though 758 WEED FLORA OF IOWA Fig. 564. Wild Barley {Hordeum jubatum) . Originally common alonj shores of the Great Lakes, and alkali regions of the west. the possibly native, it is more than probable that this weedy grass has come into our state from the west as well as the east. It has be- come so thoroughly at home in many parts of Iowa that no one would be able to say, except for the records we have, that it has not always been indigenous. Forty years ago this weed was mentioned by Dr. Bessey as oc- curring in Iowa, "found along railroads, perhaps introduced," being noticed at Ames especially. It undoubtedly occurred in other parts of the state, but could not have been abundant or its presence would have been noted. Early in 1876 Dr. J. C. Arthur listed the plant from Iowa without locality. Prof. Halsted refers to the weed as common, but not excluding valuable plants. He considered it an introduced plant. One other botanist, Prof. A. S. Hitchcock, listed the plant from Ames, and remarks: "Waste places; common." The plant was certainly abundant about Ames in 1889, when I came here, but it has not spread quite so alarmingly as prickly lettuce {Lactuca scariola L.). In July, 1895, a circular was sent out to some correspondents in every county in the state WEED MIGRATION 759 inclosing a specimen and requesting information in regard to its introduction, weedy nature, diseases, etc. Replies were received from most of the correspondents. From this information it ap- pears that the plant has been in parts of the state many years, and several correspondents reported it as indigenous. It has been in Cedar Rapids for 57 years; in Carroll county, 33 years; Mason City, 45 years ; Hawkeye, 40 years ; Hampton, 37 years ; Jefferson, 40 years; Mount Pleasant, 36 years; Cresco, 35 years; Newton, 35 years; Unity, 35 years; Iowa City, 30 years; Shenandoah, 35 years; Neola, over 45 years; Fort Dodge, 50 years; Dedham, 35 years; Rossville, 45 years. It was not, however, generally distributed in the state. But it has shown wonderful aggressive powers and now occurs without doubt in every county in the state. It is more than likely that in Iowa, at least, the weed has spread from three sources: (1) Indigenous plants scattered in western and northwestern counties. (2) From the Great Lakes, where it is indigenous. (3) From the western plains, where it no doubt was indigenous. LABIATAE, MINT FAMILY. Lance-leaved Sage (Salvia lanceaefolia Poir.). Indigenous to western Iowa. Council Bluffs, Fremont county, Missouri Valley, Ames, 1890 (F. A. Sirrine) ; Muscatine, 1890 (F. Reppert) ; Des Moines, 1895, well established; Harlan, 1912 (Pam- mel). LEGUMINOSAE, PULSE FAMILY. Sweet Clover (Melilohts officinalis). Torrey, in 1826, gave the habitat of sweet clover as "wet mead- ows. ' ' Gray, in 1848, reports it for the east ; it apparently had not reached Pennsylvania, since it is not recorded by Darlington. This plant was observed in the vicinity of St. Louis, Missouri, in 1887, and in Humboldt, Iowa, in 1892. In 1894 it was abundant in eastern Colorado, Fort Collins, Denver, and other localities, indi- cating naturalization for a considerable length of time. As yet it is not common in central Iowa, though it was abundant in Sioux City and Council Bluffs as early as 1895. It had already been re- ported from Iowa City by Hitchcock in 1889, and from Muscatine by Reppert in 1891. L. H. Pammel found it in Dakota City in 1896, and R. I. Cratty reported it from Emmet county in 1903 ; it is rather abundant at present in Scott county. 760 WEED FLORA OF IOWA White Sweet Clover {Melilotus alba Lam.). This plant is not named by Torrey in 1826, but in 1840 its dis- tribution was given by Torrey and Gray as ' ' Rich soils, along rivers, New York and New England. Introduced." In Flora Cestrica, Darlington says that it appears in gardens and lots, having been naturalized from Europe. In 1853 he says that "this coarse hard stemmed plant has been partially cultivated hj some amateur farmers; but it is not likely to supersede the herbs now in general use as food for cattle." In the first edition of Gray's Manual its distribution is given as "adventitious from Europe." The same distribution is given in the sixth edition. In the seventh edition we read, "Roadsides, etc., common. (Nat. from Europe)." In Iowa, while it is found along the roadsides everywhere, the dates given with the following localities may indicate to some extent how it has spread: Vicinity of Ames, 1886; Iowa City, 1887 (A. S. Hitchcock) ; Emmet county, 1888 (Cratty) ; Ames, found frequent- ly, 1890 (J. F. Rolfs and F. C. Stewart) ; Muscatine, 1891 (Rep- pert) ; Turin and Onawa, 1894 (L. H. Pammel) ; Webster City and Postville, 1894; Alden, 1895 (Stevens) ; abundant in Moingona, Boone, Slater, Council Bluffs and Sioux City, 1895 (Pammel) ; Da- kota City, 1896 (Pammel) ; Kossuth county, 1897 (R. I. Cratty) ; Ogden, 1898; Carroll, 1898; Marshalltown and Des Moines, 1902 (Pammel). It was introduced into the vicinity of La Crosse, Wis- consin, as a forage plant in 1878 or 1879. Wild Liquorice (Glyci/rrJiiza lepidota Nutt.). This weed was reported from Grand Junction, 1872 (C. E. Bes- sey), and Harrison county, 1875 (Rev. Burgess); Ontario, 1886 (Hitchcock) ; Ames, 1889 (Hitchcock) ; Greenfield, 1891 (F. C. Stewart). Spreading near Greenfield, undoubtedly introduced, in- digenous to western and northwestern Iowa. It was spreading at Little Rock, 1893 (C. R. Ball) ; Hull, 1895 (W. Newell) ; Logan, 1895; Council Bluffs, LeMars, 1896 (W. J. Newell) ; Lenox, 1896 (J. L. H.). Stone Clover {Trifolium arvense L.). Collected by Professor Bessey in 1871, has not been found since. Hop Clover {Trifolium agrarium L.). Reported by Hitchock from Ames in 1886, has not been found since. WEED MIGRATION 761 Low Hop Clover {Trifolium procumhens L.). Ames, 1882 (Hitchcock) ; Iowa City, 1884 (Hitchcock). It is now frequent in Ames ; also in northeastern Iowa, in Waukon, Decorah and Dubuque, also in Clayton county. Dakota Vetch {Hosackia pursMana Benth.). Indigenous to the loess of Iowa along Missouri river. Sioux City, naturalized. Boone, 1895 (G. W. Carver). Black medick (Medicago lupulina) . Reported by Dr. John Torrey in 1826 as occurring in fields, also by Dr. Gray in 1848 and Dr. Darlington in 1853. In the fifth edition of Gray 's manual it was said to be ' ' adventitious from Eu- rope in waste places." Britton, in 1901, states, "In fields and waste places, common only throughout our area. ' ' It was found in Kossuth county, Iowa, in 1898; at Ames, 1871 (C..E. Bessey) ; 1898 (A. F. Sample and E. R. Hodson). Mr. F. W. Paige records having seen it in Fort Dodge about 1900. MALVACEAE, MALLOW FAMILY. Shoo-fly {Hibiscus trionum) . Reported in the first edition of Gray's manual in 1848. It is also mentioned by Darlington in 1853 as occurring in gardens and lots. The fifth edition of Gray's manual states, "advanced from Europe." The seventh edition gives "a wide distribution, culti- FiG. 565. Shoo-fly (.Hibiscus trionum) . This weed was widely distributed as an ornamental plant. (Drawing by Charlotte M. King.) 762 WEED FLORA OF IOWA vated and waste ground, rather local." This weed was common in Texas in 1888 and local in a good many counties in Iowa in 1909. In Iowa it has been reported as follows: Fayette, 1894 (Bruce Fink) ; Winterset, 1895 (G. W. Carver) ; Waterloo, 1904 (B. D. Roberts). Indian Mallow or Butterprint (Abutilon theophrasti) . This weed is not mentioned by Torrey, 1826, nor in the first edition of Gray's manual, 1848, but is recorded by Darlington in 1853. This foreign weed is becoming rather troublesome in culti- vated grounds in Iowa. It was more or less common in the vicinity of La Crosse in 1883; was abundant in Iowa in 1886. ONAGRACEAE, EVENING PRIMROSE FAMILY. Evening Primrose (Oenothera biennis). This American weed became a settler of Padua, Italy, in 1612. Since then it has spread to every country of Europe and is recog- nized as one of the most common weeds of the continent, although it does not have as good a means of dissemination as many other weeds, like the dandelion, thistle, bull thistle, etc. The small seeds of this plant may and perhaps frequently do cling to hoofs of animals and with mud may be carried by the feet of birds. PLANTAGINACEAE, PLANTAIN FAMILY. Buckhom {Plantago lanceolata) . This weed seems to have been pretty well established in the eastern states, when the first edition of Gray's manual was pub- lished in 1848, as it was reported as common. John Torrey, in a compendium of the Flora of the Northern and Middle States, pub- lished in 1826, describes the weed, indicating that it was evidently pretty well established. Darlington, in his Flora Cestrica, 1853, states, "this weed is extensively naturalized and more abundant than welcome in upland pastures." In the fifth edition of Gray's manual the distribution is given as ' ' dry fields, common eastward, ' ' 1867. The seventh edition indicates a wider distribution, and Britton in 1901 indicates a distribution from New Brunswick to northwest territory, Florida and Canada. It was observed in the vicinity of LaCrosse, "Wisconsin, in 1892, and as early as 1874 in Ames (C. E. Peterson). F. W. Paige records it from Fort Dodge WEED MIGRATION 763 in 1899. It is reported as quite common now in many counties of the state, being generally distributed with clover seed. It has also been reported in Ames, 1890 (F. A. Sirrine and L. H. Pammel) ; 1894 (G. W. Carver) ; Hartley, 1905 (W. B. Elliott) ; Audubon, 1906 (A. H. Edwards) ; Ames, 1909 (M. Clapper) ; Fayette (Bruce Fink) ; Maynard (A. F. Crawford) . PHYTOLACCACEAE, POKEWEED FAMILY. Pokeweed {Phytolacca decandra L.). Grinnell, 1889 (A. S. Hitchcock) ; Muscatine, 1891 (F. Reppert) ; Ames, 1894 (L. H. Pammel). A waif; not established. POLYGONACEAE, BUCKWHEAT FAMILY. Patience Dock {Bumex patientia L.). Boone (G. W. Carver). Established. Escaped from cultivation. Prince's Feather (Polygonum orientale L.). Muscatine, 1890 (F. Reppert); Onawa, 1894; Clinton, 1897 (Pammel) . PORTULACACEAE, PURSLANE FAMILY. Purslane {Porhdaca oleracea). Cultivated in Massachusetts in 1672 and since has spread to every part of the United States, appearing like an indigenous plant. It is likewise common in Germany, Holland, England, France and other European countries and in Australia. A cos- mopolitan weed. 764 WEED FI.ORA OF IOWA Fig. 566. Purslane {Portulaca oleracea). At first cultivated in • the United States for greens ; now appearing like an indigenous plant. (Vasey, U. S. Dept. Agr.) WEED MIGRATION 765 SOLANACEAE, POTATO FAMILY. Horse Nettle (Solanum caroUnense) . This weed is a most troublesome species in southern Iowa. It was reported in the southeastern part of the state as early as 1876 and has gradually moved northward until at present it is well scattered over the state. In Nebraska, Aughey had found it in 1875, and it was reported in Weeping Water by T. A. Will- iams in 1889 ; in Illinois it had been known for half a century near Peoria (Brendel) ; Port Byron, 1894 (Pammel) ; South Chicago (Higbee and Raddin) ; Delaware, Newcastle county, 1860 (Tat- nall) ; Pennsylvania, 1823 (Humphrey Marshall and Beck) ; West- chester, 1853 (Darlington) ; New Jersey, 1887 (Halsted and Brit- ton) ; New York, 1888; Buffalo, 1864 (Clinton); Cincinnati, Fig. 567. Horse Nettle (Solanum caroUnense). Originally a weed of the southern states ; rapidly spreading northward, a, general aspect of plant ; b, flower ; d, seeds ; c, seed enlarged. (After Dewey, U. S. Dept, Agr.) 766 WEED FLORA OF IOWA Ohio, 1889 (James) ; central and southern Ohio, 1860 (Newberry) ; Grand Rapids, Michigan, 1886 (Crozier) ; Topeka, Kansas, 1883 (Popenoe) ; Connecticut, Iowa, Illinois and Michigan. Within fifty years this perennial weed has extended its range northward in Iowa over 150 miles. This has been possible because of its deep roots. Darlington, in his Flora Cestrica, states that it was introduced by the late Humphrey Marshall into his botanical gar- den at Marshalltown. It was reported from Nashville, Tennessee, in 1877 by Giattinger ; St. Louis, 1879, by Eggert, and abundant in western Missouri in 1886 (S. M. Tracy) ; Rhode Island, 1887 (J. L. Bennett) ; Wiscon- sin, Watertown, 1887 (L. H. Pammel) ; Indiana, Dune Park, 1890 (Higbee and Raddin, Bolley, Arthur) ; Illinois, 1891 (Brendel), In Iowa it was reported from Emmet county, 1875 (Cratty) ; south- eastern Iowa, 1876 ; Fremont county and Council Bluffs, 1883 (Ar- thur) ; Ames, 1886 (Halsted) ; Agency, 1888 (Mrs. Richman) ; Car- roll county, 1890 (T. T. Rutledge) ; Grand Junction, 1890 (Pam- mel) ; Polk City and Mt. Pleasant, 1891 (L. H. Pammel and J. H. Mills) ; Fontanelle, 1892 ; Denison, 1893 (J. Rollins) ; Corning, 1893 (W. L. Abbey) ; Iowa City, 1893 (Fitzpatrick) ,• Springdale, 1894; Plattesville, 1894 (Studley) ; Postville, 1894 (Orr) ; Mt. Ayr, Guth- rie Center and Story county, 1894 (Sale, Ashton and Pammel) ; Des Moines, 1895 (Carver) ; Decatur county and Des Moines county, 1896 (Fitzpatrick) ; Webster City, 1897 (Garber) ; Shel- dahl, 1898 (Pammel); Yorkshire, 1899 (Stokes) ; Dallas Center, 1902 (C. B. Royer) ; Mondamin, 1903 (A. Spooner) ; Cooper, 1903 (Squires) ; Afton, 1904 (Geo. Williams) ; Audubon, 1905 (J. N. Eskech) ; Keota, 1905 (Klein) ; Lidderdale, 1907 (Mrs. Sander- son) ; Reinbeck, 1907 (Fred Wilcox) ; La Porte, 1908 (R. S. Meath) ; Algona, 1912 (A. Hutchinson) ; Collins, 1912 (J. Leon- ard) ; Brandon, 1912 (Roster) ; Whitten, 1912 (Parrish) ; Ontario, 1884 (Fletcher) ; Germany, Mulhausen, 1893 (Scherer Schorler) ; Denmark, 1895 (Ostenfeld). Buffalo Bur {Solanum rostratum). Has been reported frequently to me during the last few years. The number of specimens sent from Iowa correspondents during the season 1911 and 1912 was numerous, indicating a rapid spread in many different parts of the state. It has always been a native to the plains, finding a congenial home in the buffalo wallows. It was reported by Hartweg in 1837 as being seen north of the WEED MIGRATION 767 city of Mexico; by Bexar in Texas in 1828, in Rock Creek by Fendler in 1847, and in El Paso in 1849 ; and by Geyer from Pierre, South Dakota, in 1839. Nearly all of the early collectors, as Rothroek, Parry, Fendler, Geyer, Hayden, Brandegee, Palmer, mention this weed. It is generally believed to have become rapidly diffused in Texas after 1865. Jimson Weed {Datura stramonium). Found everywhere in Iowa and in many parts of the United States from the Atlantic to the Pacific. Common in eastern North America for more than seventy-five years. It is mentioned by Darlington, 1847, and Gray, 1848, states that it is a well known weed. The date of its appearance in Europe is not given by Ratze- burg, Kabsch notes that the thorn apple was introduced from India by gypsies. The plant is native to India where its poisonous prop- erties were long known. The 5th and 6th editions of Gray's Manual indicate a wide distribution in eastern North America. It was common in western "Wisconsin in 1881. Cratty states that it was rare in Emmet county, Iowa, in 1881. UMBELLIFERAE, CARROT FAMILY. Wild Carrot {Daucus carota L.). This was reported by Dr. Torrey as occurring in fields in the northern and middle states in 1826. Dr. Gray records it as common in 1848; Darlington, in 1857, states that ''this foreigner is ex- tensively naturalized and becoming more troublesome from the culpable negligence of our farmers. ' ' In his 5th edition. Dr. Gray, in 1867, states "advanced from Europe." In the 7th edition, 1908, Robinson and Fernald state "fields and waste places, a pernicious weed" indicating a general distribution. Britton, 1901, states "common throughout our area" and the writer knew this weed in western Wisconsin, in 1880. In some places it was pretty well naturalized. Occasional specimens were found by the writer in 1889, in Iowa. It had previously been reported by Halsted and Arthur. It began to spread quite rapidly in 1904. F. W. Paige reports it from Ft. Dodge in 1909. It is now reported quite fre- quently from different places in the state. The following are a few of the localities: Greenfield, 1891 (F. C. Stewart) ; Earlham, 1903 (J. Long) ; Carrolton, 1904 (E. C. Schreiber) ; Zearing, 1904 (E. E. Sparrow) ; Hawarden, 1905 (C. S. McCarty) ; Hartley, 1905 (W. B. Elliott) ; Panora, 1906 (L. J. Hooper) ; Marshall 768 WEED FLORA OF IOWA Fig. 568. Carrot {Daucus carota). Common in the east. Probably first spread from tl:e cultivated carrot. county, 1906 (W. R. Moninger) ; Whiting, 1907 (W. S. Whiting) Allerton, 1907 (J. H. Duncan); Lamoni, 1907 (T. L. Naftsger) Blackhawk county, 1907 (Pammel) ; Ames, 1909 (J. E. Campbell) Polk county, 1910 (Pammel) ; Rippey, 1910 (Osborn) ; Dumont, 1910 (Titus) ; Libertyville. 1911 (Armstrong) ; Bedford, 1911 (Spacht) ; Glidden, 1912 (Walters) ; Kelley and Ledges, 1912 (Pammel). Poison Hemlock {Conium maculatuni). This weed was reported by Dr. John Torrey in 1826 as occurring on roadsides. It is mentioned by Dr. Gray in 1848 as occurring in waste places. Britton in 1901 records it from Quebec to Michigan and Indiana, California, and Mexico. Robinson and Fernald in the 7th edition of Gray's Manual indicate "to Pennsylvania," the same distribution that Britton gives. It is not, however, common WEED MIGRATION 769 in the Mississippi valley. It was reported from Pottawattamie county, Iowa, in 1909 and it was abundant in Salt Lake City, Utah, in 1908 where it evidently had been naturalized for some time. It was abundant in places in the Sacramento Valley in 1912 indicating naturalization for some time. Brewer and Watson in Botany of California (1876) state "Sparingly naturalized." 49 CHAPTER X. MEDICINAL WEEDS OF IOWA HARRIBTTB S. KELLOGG CHAPTER X. MEDICINAL WEEDS OF IOWA. In the United States, the raising of drug plants has never re- ceived the commercial attention that has been devoted to this branch of agriculture abroad. As a result, we are importing regularly for the drug trade thousands of pounds of dried plants that might be raised in this country. Among them are many weeds, as, quack grass and mustard that, to us, are pests to be eradicated as quickly as possible. Not that it would be wise to devote good agricultural land to raising medicinal weeds but as by-products these are of value. The word "weed" is used ad- visedly; for, while many of our vegetable drugs come from plants which in this country are not weeds, it is undoubtedly true that many drug plants are noxious weeds in the country in which they were first applied medicinally. This is illustrated by such weeds as quack grass, the mustards, the docks, tansy, and dandelion, all of which are official in the U. S. P. As early as the days of Dioscorides the physician was the herbalist, and his knowledge of the active principles of plants was his stock in trade. Among semi-civilized and barbarous peoples the same thing is true today. While very many of the plants formerly considered medicinal are at present discredited, a sufficient number remains to make raising drug plants a profitable industry. The literature of medical botany, if we include the "Herballs" is quite voluminous. In Germany, in 1787, Schoepf published the "Materia medica americana, potissimum regni vegetabilis" in which he listed three hundred and sixty medicinal plants which he had collected among the American Indians; but he stated that there were actually over seven hundred in use. Between 1817 and 1821 Jacob Bigelow published three volumes of the "American Medical Botany; being a collection of the native medical plants of the U. S." in which he listed fifty plants, each illustrated by colored plates. William Barton, about the same time, published "Vegetable materia medica of the U. S. ; or medical botany contain- ing a botanical, general, and medical history of medicinal plants 774 WEED FLORA OF IOWA indigenous to the United States," in which fifty plants were de- scribed and illustrated. The high price of these books, however, necessarily limited their distribution. In Eafinesque's "Medical Flora," published in 1828 and 1830, one hundred and five plants are named as being native North American plants. Among those listed are such weeds as mayweed, butterfly weed, wormseed, wild hemlock, cowbane, thorn-apple, fleabane, boneset, Joe-Pye weed and mullein. The most complete work of recent years is Millspaugh 's American Medicinal Plants in which he describes and illustrates with colored plates 180 medicinal plants native in the United States and recog- nized by homeopathic physicians as of therapeutic value. He also adds to each description, the active principles of the plant in ques- tion, the method of preparation and the physiological action of the drugs derived therefrom. In addition to the one hundred and eighty plants fully described, he mentions hundreds of others that are known to the profession but are not native to the United States, making in 'all so satisfactory a treatise that for many years it must remain our most reliable source of information in this line. In Dr. Pammel's Manual of Poisonous Plants, many medicinal weeds not of a poisonous nature are listed among the economic plants. The United States Department of Agriculture has issued a num- ber of bulletins containing references to medicinal weeds, which are listed in the bibliography at the end of the volume. Many plants not listed as official in the United States Phar- macopoeia have, nevertheless, value as commercial products. Such, for instance, is true of the wormseed plant which, although not recognized in our Pharmacopoeia, brings from 6 to 8 cents per pound in the drug market. Quack grass {Agropyron repens) is the only weed of the grass family that is official in the U. S. P. A fluid extract from the rhizome of this plant sold under the name of dog grass or tritieum is a remedy in kidney and bladder troubles. The roots of various docks of the Iowa species are official. Bitter dock {Bumex obtusifolius) and yellow dock (E. crispus) are rated at 2 to 8 cents per pound and form the basis of various blood purifiers. The leaves of sheep sorrel (B. acetosella) while not official, are of market value. MEDICINAL WEEDS OF IOWA 775 Fig. 569. Quack Grass (Agropyron repens). The root-stock used for bladder trouble. (Drawing by Charlotte M. King.) The entire herb of water pepper (Polygonum hydropiper) when decanted with alcohol forms a valuable diuretic, but is not recog- nized in the Pharmacopoeia. The entire leafy part of the American wormseed (Chenopodium ambrosioides) is valued for its anthelmintic properties. Oil from the fruit is official and sells for $1.50 per pound. 776 WEED FLORA OF IOWA Of the Phytolaccaceae, pokeweed {Phytolacca decandra) has long been considered of medicinal value. The berries, collected when mature, are rated at 5 cents per pound; the roots at 2 to 5 cents; although not official they are the basis of remedies for various diseases of the skin and blood, especially in allaying rheumatism. In the order Caryophyllaceae is the corn-cockle {Agrostemma githago), the powdered seeds of which are the basis of a remedy used to cleanse the blood in certain skin diseases. Chickweed {Stellaria media) formerly had some reputation as an alterative but is now used very seldom. Among the Gruciferae are several weeds that are recognized as medicinal. The most important are the mustards, the seeds of which are official and sell at 3 to 6 cents per pound. Both the black mustard {Brassica nigra) and the white mustard {B. alba) are col- lected for this purpose and are used principally in making plasters and poultices but occasionally are administered in cases of dys- pepsia. They are emetic when given in large doses. The shepherd's purse {Capsella hursa-pastoris) is not official. At one time it was considered of value as a tonic, astringent, and antiscorbutic but has fallen into disuse except when occasionally applied as an astringent in hemorrhages. Among the Malvaceae is a dooryard weed, common mallow {Malva rotundifolia) , the whole plant of which is sometimes applied locally as a poultice or internally as a demulcent. A decoction of the dried plant of the evening primrose {Oenoth- era biennis), a member of the Onagraceae, is a remedy in cases of infantile eruptions, spasmodic asthma and bladder trouble. An introduced weed of the Leguminosae is noted; the yellow sweet clover {Melilotus officinalis), the seeds of which boiled with lard are sometimes made into a salve which is applied to ulcers and open indolent sores, the remedy proving efficacious. Among the Umbelliferae are the caraway {Carum carvi), the root of which is sometimes ground into a poultice and the fruit and leaves of M^hich are diuretic and stimulant; the poison hemlock {Conium maculatum) , the root of which is deadly poisonous, al- though the unripe fruit, dried and preserved, is official, selling at 8 cents per pound, and the leaves, though not official, are sometimes applied in cases of rheumatism, neuralgia or asthma to sooth the nerves; and the water hemlock {Cicuta maculata), sometimes sub- stituted for cowbane. MEDICINAL WEEDS OF IOWA 777 Two of the Milkweeds {Asclepias incarnata and A. syriaca) are listed as medicinal, an extract from the root alone being used. This is a diaphoretic and was formerly applied in acute pulmonary and bronchial affections and in rheumatism. Although at present it has fallen somewhat into disrepute, it is sometimes given in cases of dropsy. A tincture from the whole plant of bindweed (Convolvulus arvensis), of the family Convolvulaceae, is sometimes used as a diuretic or gentle laxative. The leaves and root of one of the Boraginaceae, hound's tongue {Cynoglossum officinale), are both medicinal, the latter being some- what narcotic. The leaves were at one time used as a styptic. Of the Yerhenaceae we find records of the use of the root and green parts of vervain {Yerhena Kastaia) which were substituted occasionally for boneset in fevers and agues. They are emetic and expectorant. The Labiate, self-heal {Prunella vulgaris), is an astringent but by no means is the universal curative agent that its name would suggest. Catnip {Nepeta cataria) no longer official, nevertheless is rated at 2 to 8 cents per pound for leaves and flowering tops, the coarse stems being rejected. A decoction from these parts is a mild stimu- lant and tonic, being rather quieting in effect. Motherwort {Leonurus cardHami) has similar properties. The family Solanaceae is very important medicinally, as it fur- nishes at least twenty drugs to the trade, of which the most im- portant is belladonna. Of the Iowa weeds Jimson {Datura stra- monium) is the best known. The leaves and seeds are official, the former being rated at 2y2 to 8 cents and the latter at 3 to 7 cents per pound. The leaves are applied in cases of asthma and the seeds in spasmodic diseases affecting the respiratory tract. Datura taiula is sometimes used in the same manner. The black nightshade {Solanum nigrum) is especially valuable as a resolvent but its use is no longer prevalent. In some parts of Iowa the bruised leaves are considered an unfailing remedy in cases of ivy poisoning. The root leaves and berries of horse nettle {S. carolinense) are mentioned by Alice Henkel as being medicinal though not official. Of the Scrophulariaceae, the cosmopolitan mullein weed {Yer- hascum thapsus) possesses considerable market value although it is not recognized by the U. S. P. as official. The dried leaves retail *?78 WEED FLORA. OF IOWA at 21/2 to 5 cents and the flowers at 25 to 75 cents per pound. A tincture from these is a recognized remedy in coughs and catarrh. It quiets nervous irritation and relieves inflammation. The uses of the plantains {Plant ago) are various. The fresh leaves are sometimes applied to wounds or chronic sores. The seeds steeped in milk form a remedy used in checking hemorrhages from mucous surfaces and in dysentery. Almost every part of the plant at some time has been recorded as medicinal. The fibers from the leaves were thought to be an unfailing remedy for toothache, the fiber, however, being placed in the ear on the side of the tooth affected rather than about the tooth itself. Plantain is also an antidote to snake bites. A decoction of the root was sometimes ad- ministered in cases of intermittent fever. In short it would seem possible for one to have quite a complete medical dispensary in his own dooryard without care or expense. The family Compositae undoubtedly contains a larger number of medicinal genera than any other plant family. A decoction made from the whole herb of yarrow (Achillea millefolium) is a bladder medicine and is administered sometimes in cases of hemorrhage or catarrh. The ragweed {Am,hrosia ar- temisiae folia) is used in similar cases. The mayweed {Anthemis cotula) furnishes a bitter stimulant and tonic in aid of digestion. From the leaves may be made a fermentation which relieves pain and inflammation, sprains and bruises ; none of the last three named is official. The burdock {Arctium lappa), however, is recognized in the U. S. P. Its fresh root gathered in autumn retails at 3 to 8 cents and seeds at 5 to 10 cents per pound. These are both useful in preparations against blood and skin diseases. The leaves are some- times applied externally as cooling poultices. An infusion of the root of chicory {Cichorium intyhus) is some- times offered to increase the appetite and to aid digestion. A decoc- tion from fireweed {Erecktites hieracifolia) is an alterative and is applied in cases of dysentery. The oil of horseweed {Erigeron canadense) is official, the herb being rated at 6 to 8 cents per pound. The plant has been known locally as "blood stanch" and, as the name implies, was used in arresting hemorrhages and bleeding from wounds. According to Millspaugh this use of the plants is practiced today among the North American Indians. The oil only is official. The various local names of Eupatorium perfoliatum, boneset, feverwort, MEDICINAL WEEDS OF IOWA 779 7 ^W'' \ Fig. 570. Burdock i Arctium lappa). Formerly used as blood purifier. (Vasey, U. S. Dept. Agr.) 780 WEED FLORA OF IOWA or agueweed, indicate the uses of the plant. It is tonic, diaphoretic, emetic, or cathartic according to the size of the dose administered; the root of the white snakeroot {E. urticaefoUum) is also of com- mercial importance, being rated at 2 to 8 cents per pound. The Joe-Pye weed {E. purpureum) has uses somewhat similar to the preceding but is also a diuretic and is valuable in cases of jaundice, dropsy, rheumatism or gout. The leaves and flowering tops of the scaly grindelia {Grindelia squarrosa) are the basis of a remedy against asthma and are also sometimes made into a poultice to apply in cases of ivy poisoning. The sneezeweed {Helenium aaitumnale) is a tonic and diaphoretic ; the powdered flowers are sometimes snuffed to relieve affections of the nasal passages. The wild lettuce {Lactuca canadensis), once considered a substitute for opium, is an anodyne, a diaphoretic, and a diuretic, and is applied principally in nervous complaints. Tansy {Tanacetum vulgare) is official in the U. S. P., the leaves and flowering tops being rated at 3 to 6 cents per pound. It is a well known but poisonous vermifuge. The root of the dandelion {Taraxacum officinale), collected in autumn, is official, selling at 4 to 6 cents per pound. A decoction from this is a tonic in cases of dyspepsia and diseases of the liver. A hair tonic is also made from it. Undoubtedly this list could be greatly extended were it possible to obtain information in regard to all cases of home use of native drug plants. Unfortunately few written records are obtainable and one is obliged to depend largely on tradition handed down by word of mouth. There is undeniably an opening in Iowa for raising and market- ing medicinal plants and a few words in this line may not be out of place at this point. For the profitable marketing of drug plants it is necessary that the plants be suitably prepared, that is, that they be thoroughly cleaned and well cured. To be cleaned they must be freed from all foreign substances, whether dirt, sand, insects, or fragments of other plants; when cured properly, they have been picked at the right season, and have been dried so as to retain so far as possible their characteristic color. If the leafy part is sought for the trade, the plant should be cut when in flower or before seeds have formed, thendrifedin gentle heat (not higher than 125° F.) so as to lose as little as possible of the volatile principle. In some plants, as cow- bane, the unripe fruit, well dried and preserved, has value officially. MEDICINAL WEEDS OF IOWA 781 Lut of mustard on the other hand, ripe seeds, only, are official. The dried leaves of the catnip have market value but no longer are recognized as official. The roots of the dandelion collected in the autumn are listed in the U. S. P. ; the rhizome of quack grass is marketable. In short, if one is to realize any financial profit from his fields of weeds, he must be able to recognize absolutely the weed in question, for poisonous herbs sometimes closely resemble innocuous weeds and a mistake in identification may result serious- ly ; he must also know what part of each plant is salable, when it must be collected, whether in the ripe or immature state, and in what form it is preferred by the trade. It is not an occupation to be followed by the careless or ignorant worker. Ignorance is no excuse for offering to the trade a deadly herb in mistake for its harmless relative. When the life of the patient is sacrificed as a result of such a mistake the old saying, that "if it kills it is poi- sonous, if it cures it is the right herb," will hardly suffice as an excuse. For the careful gardener, however, who is willing to wait for his herbs to mature one year, two years, or, as with ginseng, seven years, the occupation of growing drug plants offers many induce- ments. CHAPTER XI. PHENOLOGY OF WEEDS CHARLOTTE M. KING CHAPTER XL PHENOLOGY OF WEEDS. Several species of weedy plants bloom very early in tlie spring, responding promptly to a comparatively limited amount of light and warmth; others come to bloom after the growing season is more advanced ; while a number blossom throughout the season, or from spring until fall. The time of bloom is, in each species, related to its definite physiological constant of warmth, sunshine and moisture. "Warm, sunshiny weather in the early part of the season will hasten the time of bloom, as cold, cloudy weather will retard it. There is a difference of about two weeks between the blooming date of plants of northern and southern parts of Iowa. The season of a plant's activity is related in part to the hardiness it has developed, and to the climatic conditions of the geographical region selected by it, as most favorable to its existence. It is vigor and tenacity as well as wide seed distribution which contribute to the troublesome character of the plants which we call weeds. It is indicated by the accompanying table, as known also by com- mon experience, that the rain, warmth and sunshine received at the arrival of midsummer produce greatest bloom of weedy plants for the season in both number and kinds ; and since weeds quickly mature, it is apparent that the harvest of weed seeds steadily in- creases from that time until fall. The crucifers are among our earlier blooming weeds, as the winter annuals, shepherd's purse and peppergrass; the legumes and umbellifers are at their full growth about midsummer; the plantains begin in May, the polygonums in June; whilst com- posites are usually blooming throughout the latter part of the season. Grasses distribute their blossoming-time throughout the summer from May until October; vanilla grass and blue grass appear in May, orchard grass, quack grass, needle grass and timothy in June, crab grass, fescue grass, and rye grasses about July, Bouteloua in August, blue-stem and drop-seed grasses in September. 50 786 WEED FLORA OF IOWA Many plants, either annual or perennial, which have a recog- nized weedy character, have a prolonged period of bloom and seed- ing, thus maintaining a vigorous hold. Common cosmopolitan weeds, belonging to various orders, have often remarkable perennation, as in case of the dandelion, shep- herd's purse and chickweed; these weeds begin bloom in earliest spring and are also more resistant to frost than are other weeds. The period of time required for maturing fruit after blooming varies in different species; a comparatively short time is needed in case of most weeds, especially the late blooming ones. The dormant period required for a seed before germination will take place differs with varieties, and with individual seeds of the same variety. In seeds requiring a period of rest, this delay may be a matter of days, weeks, or years; therefore there is a distribu- tion for seeds through time as well as through space. Many seeds germinate immediately if conditions are favorable. Many young plants must be lost by this autumnal vegetating, in case of seed- lings overtaken by frost before they can bear seeds or establish roots; but the hardy habit of the winter annual, the biennial and perennial, protects for the most part such young plants after fall germination. Quack grass has a crop of seedlings of the same season as the ripiening of seed ; this is true also of wild carrot, burdock, thistles, horse nettle and ribgrass, all of which being biennial or perennial persist throughout the winter. The freezing and thawing of winter facilitates germination of weed seeds in the spring ; and very early one may note, in the loca- tion of the parent of last season, as soon as the soil grows warm enough, many flourishing young colonies of seedlings, such as spurge, oxalis, pigweed and smartweed crowding each other for foothold. The culturist is greatly influenced by considerations of blooming-time, seed-time, and time of seed-germination in his ef- forts to control and to exterminate weeds. PHENOLOGY OF WEEDS BLOOMING PERIOD OF COMMON WEEDS 787 Stellaria media A. Chickweed Capsella hursorpastoris A. Shepherd's purse Medioago lupulina A. Yellow trefoil Oxalis corniculata A. & P. Lady's sorrel Taraxacum officinale P. Dandelion Nepeta hederacea P. Ground ivy Barbarea vulgaris B. Yellow rocket Cynoglossum boreale B. Hound's tongue Plantago lanceolata P. Buckhom Ranunculus ahortivus B. Small-flowered buttercup. Ranunculus septentrionalis P. Buttercup Rumex altissimus P. Smooth dock Taraxacum, erythrospermum P. Small-flowered dan delion Allium oanadense A. & P. Wild garlic Asclepias speciosa P. Showy milkweed Brassica arvensis A. Wild mustard Bromus tectorum A. Downy brome grass Carum carvi B. Caraway Cerastium viscosum A. & P. Mouse-ear chickweed,. Convolvulus arvensis P. European morning-glory... Convolvulus sepium P. Wild morning-glory Datura tatula A. Purple thorn-apple Euphorbia marginata A. Snow-on-the-mountain Euphorbia preslii A. Spurge Glycyrrhiza levidota P. Wild liquorice Hierochloe odorata P. Vanilla grass Hordeum pusillum A. Small squirrel-tail grass Lepidium apetalum A. Apetalous peppergrass Lepidium virgimicum A. Wild peppergrass Lithospermum arvense A. Corn gromwell Lolium italicum B. or P. Italian rye-grass Malva rotundifolia P. Common mallow Oxybaphus nyotagineus P. Wild four-o'clock Plantago major P. Door-yard plantain Plantago purshii A. Pursh's plantain Potentilla anserina P. Silverweed Radicula palusfris A. or B. Marsh cress Rhus toxicodendron P. Poison ivy RudbecMa Mrta B. Black-eyed Susan Rumex acetosella P. Sheep sorrel Sisymbrium officinale A. Hedge mustard Solanum carolinense P. Horse nettle Solanum rostratum A. Buffalo-bur Sonchus oleraceus A. Sow thistle Trifolium procumbens A. Hop clover Yerbena bracteosa P. Bracted verbena Veronica peregrina A. Speedwell Yicia sativa A. Vetch Achillea millefolium P. Yarrow A. Annual. B. Biennial. P. Perennial. + + + + + + + + + + + + + 788 WEED FLORA OF IOWA BLOOMING PERIOD OF COMMON WEEDS— Continued. Acalj/pha virginica A. Three-seeded mercury Amaranthus graecizans A. Tumbleweed Amaranthus blitoides A. Spreading pigweed Anthemis cotvila A. Mayweed Apocynwm cannaMnum P. Dogbane Asclepias syriaca P. Milkweed. Berteroa incana A. or P. Berteroa Brassica nigra A. Black mustard Bromus seoalinus A. Cheat Camelina sativa A. False flax Carex vulpinoidea P. Sedge Cheno,p odium album A. Lamb's quarter Cicuta m,aculata P. Cowbane Cirsuim, arvense P. Canada thistle Cirsium undulatum B. Wavy-leaved thistle Crotalaria sagittalis A. Rattle-box Cycloloma atriplicifolium A. Winged pigweed Datura stramonium A. Jimson weed Daucus carota B. Wild carrot Erigeron annuus A. Fleabane Erigeron canadensis A. Horseweed Erigeron ramosus A. Branched fleabane Euphorbia maculata Spotted-leaved spurge Geum canadense P. Avens Helianthus petiolaris A. Petiolate sunflower Hordeum jubatum A. or B. Squirrel-tail Hypericum perforatum P. St. John's-wort Lactuca canadensis A. or B. Wild lettuce Lactuca pulchella P. Blue lettuce Lappula virginiana A. Beggar's lice Leonurus cardiaca P. Mother-wort Lygodesmia juncea P. Lygodesmia Melanthium virginicum P. Bunch flower Melilotus alba B. White sweet clover Oenothera biennis B. Evening primrose Parietaria pennsylvanica A. Pellitory Pastinaca sativa P. Parsnip Plantago rugelii P. Rugel's plantain Polanisia trachysperma A. Polanisia Polygonum aviculare A. Dooryard knotgrass Poi'.ygonum hydropiperoides P. Mild water pepper. . Polygonum lapathifoHum A. Slender smartweed. . . . Eleusine indica A. Gk)ose-grass Eragrostis megastachya A. Candy-grass Linaria vulgaris P. Toadflax Silene antirrhina A. Sleepy catchfly Thlaspi arvense A. Pennycress ; Vrtica gracilis P. Nettle Conringia orientalis A. Hare's-ear mustard Polygonum persicaria A. Lady's thumb Poriulaca oleracea A. Purslane Radicula armoracia P. Horseradish Raphanus sativus A. or B. Radish Rumex crispus P. Curled dock + + + + + + + + + + + + + + + + + + + + + + + + + + + + + -t- + + 1 + + + + + + + + -f + + + + PHENOLOGY OF WEEDS 789 BLOOMING PERIOD OF COMMON WEEDS— Continued. 03 o. OS a >> 3 +3 Q 0) o S < ^ i-s ^ <: ccjOJ + + + + + + + + + + + + + + + + + + + + + + + + + + f + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + -h + + + + + + + + + + + + + + + -f- -i- + + + + + + -r + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + -r + + + + + + + + + + + + - + + + Rumex ohtusifoHus P. Bitter dock Saponaria vaccaria A. Cow-herb Sida spinosa A. Prickly sida Siistf 171^7- ium aUissimum A. or B. Tall hedge mustard. Stachys palustris P. Woundwort Teucrium canadense P. Germander Trittulus terrestris A. Caltrop Verbascum thapsus B. Mullein Yeriena hastata P. Blue vervain Bromus hordeaceus A. Soft chess Agrostemma githago A. Corn cockle Yeriena stricta P. Hoary vervain Atriplex patula A. Orach. Acnida tuierculata A. Water hemp Avena fatua A. Wild oats .' AmWosia artemisiifoUa A. Small ragweed Amhrosia triflda A. Large ragweed Arotium lappa B. Burdock Bidens cernua A. Sticktight Bidens discoidea A. Sticktight Bidens frondosa A. Sticktight Ghenoip odium Tiy'bridwm A. Maple-leaved goosefoot. . Gvchorium intylyus P. Chicory Cirsium discolor B. Field thistle Cirsium ioense B. Iowa Thistle. Cirsium lanceolatum B. Bull thistle Cleome serrulata A. Stinking clover Cuscuta arvensis A. Field dodder Bigitaria humifusa A. Smooth crab grass Dyssodia pap-oosa A. Fetid marigold Eragrostis pilosa A. Pilose eragrostis Erechtites Meracifolia A. Fireweed Eupatoriiim urticae folium, P. White snakeroot Gaura Mennis B. Gaura Gonolodus laevis P. Angle-nod HeliantTius annuus A. (Wild) Sunflower Ipomoea hederacea A. Wild morning-glory Iva xantMfolia A. Poverty weed EocMa scoparia A. Kochia Lolivm perenne P. Rye grass Melilotus officinalis A. or B. Yellow sweet clover. . Mentha spicata P. Spearmint. Phy salts suiglahrata P. Smooth ish ground cherry. . Polygonum, convolvulus A. Black bindweed Polygonum erectum, A. Erect knotweed Polygonum hydropiver A. Water penper Polygonum tnulilenihergii P. Tanweed Polygonum, pennsylvanicum A. Pennsylvania smart- weed Polygonum raTnosissimum A. Branching knotweed . . Potentilla movspeHensis B. or P. Five-finger Salsola Tcali var. tenuifolia A. Russian thistle SfcroipJiularia maryMndica P. Simpson's honey plant. Setaria glauca A. Yellow foxtail. + -f- 790 WEED FLORA OF IOWA BLOOMING PERIOD OF COMMON WEEDS— Concluded. O 2J Setaria verticillata A. Whorled foxtail Setaria viridis A. Green foxtail Silene noctiflora A. Night-flowering catchfly Solanum nigrum A. Night-shade Sonchus arvensis P. Field thistle Saponaria officinalis P. Bouncing Bet Stipa spartea P. Needle grass StropJiostyles helvola A. "Wild pea Symphoricarpos orMculata P. Indian currant Tanacetum vulgare P. Tansy Lactuca scariola A. Prickly lettuce Hibiscus trionum A. Shoo-fly Urtica dioica P. Stinging nettle Vernonia fasciculata P. Iron-weed Abutilon theophrasti A. Velvet leaf Amaranthus retroflexus A. Tumhling pigweed.... Aristida dichotoma A. Poverty grass Artemisia biennis B. "Wormwood Artemisia ludoviciana P. "Western mugwort Aster multifloris A. Many-flowered aster Aster salicifo^dus A. "Willow-leaved aster Bidens aristosa A. or B. Sticktight Cenchrus tribuloides A. Sandbur Chenopodium, ambrosioides A. Mexican tea Cirsium altissimum B. Tall thistle Cirsium \canescens B. Woolly thistle Cyperus esculentus P. Northern nut grass Dalea alopecuroides A. Foxtail dalea Digitaria sanguinalis A. Crab grass Echinochloa crusgalli A. Barnyard grass Helianthus grosseserratus P. Wild prairie sunflower Helianthus maximiliani P. Maxmilian's sunflower. Helenium antumnale P. Sneezeweed Muhlenbergia mexicana P. Mexican dropseed Muhlenbergia racemosa P. Dropseed grass Solidago canadensis P. Canada goldenrod Solidago rigida P. Stiff goldenrod Solidago serotina P. Goldenrod Panicum capillare A. Hair grass Sporobolus neglectus A. Small rush grass Sporobulus vaginiflorus A. Sheathed rush grass. . . Xanthium canadense A. Cocklebur Xanthium spinosum A. Spined cocklebur Helianthus tuberosus P. Artichoke + -f + CHAPTER XII. WEED AND SEED LAWS L. H. PAMMEL CHAPTER XII. r PURE SEED AND WEED LAWS. Many states of the United States have weed and seed laws and similar laws are on the statute books of the principal agricultural countries of the world. Long, who in "Common Weeds of the Farm and Garden" has summarized the legislation, states, in Ap- pendix III, that the laws are quite stringent in Australia, and in the South African Colonies; that the only laws requiring the de- struction of weeds in the British Islands are in Ireland and the Isle of Man; that no laws or regulations are in force in Great Britain although there is an Adulteration and Seeds Act. Canada has a good general seed law; Manitoba has a noxious weed act passed in 1906 which included common wild mustard, Canada thistle, perennial sow thistle, wild oats, "stink-weed" or penny cress, and false flax. The law provides that owners and occupants of land shall be compelled to cut down, or destroy weeds, to prevent seeding. In Ontario the law provides that every occupier must cut down all Canada thistles, ox-eye daisies, wild oats, ragweed, burdock and all other noxious weeds to which the act may be extended by municipal law to prevent the ripening of seed, provided it does not destroy the growing grain. The law of the Northwest Territories is similar to that of Manitoba, excepting that inspectors are appointed who have the power to act in the case of the occupier's default. It is further provided that threshing machines shall be cleaned before being re- moved from one place to another. The law of Quebec includes daisies, wild endive, chicory, celan- dine and wild mustards as weeds. In Saskatchewan the Noxious Weed Ordinance schedules nine- teen species including six species of mustard and three of thistles. 'This province also provides for the appointment of weed inspectors. The province of Alberta, Act of 1907 amended in 1908, mentions 22 noxious weeds. Inspectors are also appointed. The sale of seed containing 5 per 1,000 noxious weed seeds is forbidden and the germinating power of all weed seed must be destroyed before 794 WEED FLORA OF IOWA test-'*'""'"" cleanings, etc., can be removed from any premises. Threshing ma- chines must be thoroughly cleaned before being removed to another place. WEED LEGISLATION. Various states have legislated in regard to certain weeds as follows: Arizona on cockleburs and sunflowers; California on Canada thistles and any and all weeds that are spread by the wind; Connecticut on Canada thistle and wild carrot; Delaware, Canada thistle; Illinois, Canada thistle on highways, cockleburs and all weeds before maturity; Iowa, Canada thistle, cocklebur, burdock, curled dock, smooth dock, wild parsnip, quack grass, vel- vet weed, horse nettle, Russian thistle and shoo-fly; Indiana, Can- ada thistle ; Kansas, on highways, cockleburs, Eocky Mountain sand- burs, burdocks, sunflower, and such other weeds as may be in- jurious to the best interests of the farming community ; Kentucky, Canada thistle; Maryland, Canada thistle; Michigan, to remove noxious weeds on highways, Canada thistle, milkweed {Asclepias syriaca) ; Minnesota, weeds, in three groups : first group, wild mus- tard, wild oats, cocklebur, burdock, tumble mustard, second group, Canada thistle, ox-eye daisy and quack grass, third group, French weed; a section prohibits the spread of weeds from empty freight cars ; the following weeds must be destroyed on highways : Russian thistle, Canada thistle or other thistles, burdock, ox-eye daisy, wild mustard, snap dragon or toad flax, cocklebur, sow thistle, sour dock, yellow dock and other noxious weeds ; Missouri, Canada thistle; Nebraska, Canada thistle; New Jersey, Canada thistle; New York, Canada thistle and other noxious weeds along canals; North Dakota, Canada thistle, cocklebur, mustard, wild oats, French weed, Russian thistle; Ohio, brush briers, thistles or other noxious weeds, Canada thistle, wild parsnip, sweet clover, wild carrots, teasel, burdock, cockleburs; Oregon, dagger cocklebur, Canada thistle; Pennsylvania, Canada thistle; South Dakota, Russian thistle, Canada thistle, and cocklebur ; Vermont, all thistles and noxious weeds ; Washington, Canada thistles ; in West Virginia, the county court may offer reasonable bounties or rewards for birds of prey or weeds; Wisconsin, Canada thistle, burdock, ox-eye daisy, toad flax, cocklebur, sow thistle, sour dock, and yellow dock, mustard, wild parsnip, sweet clover, and Russian thistle. Many states have passed supplementary legislation. Many other countries besides those mentioned here have rather stringent laws WEED AND SEED LAWS 795 on the extermination of weeds. There are laws in France and Germany but most of the European countries appear to have no legislation on the destruction of weeds. Denmark awards prizes to members of societies for weedless fields. In most countries and most states of the United States the laws are flagrantly violated. In the Canadian Provinces, where weed commissioners are appointed, they seem to have remedied this defect. A few years ago these laws were compiled by Dewey.* The present Iowa law is as follows : IOWA. SENATE FILE NO. 136. AN ACT TO PROVIDE FOR THE DESTRUCTION OF NOXIOUS WEEDS AND OTHER WEEDS UPON LANDS, HIGHWAYS AND OTHER PLACES; PRE- SCRIBING PENALTIES FOR THE VIOLATION THEREOF; ASSESSING THE COSTS AND EXPENSES OP THE DESTRUCTION OF THE SAME TO THE LANDS AND OWNERS THEREOF ; AND PROVIDING FUNDS WITH WHICH TO DESTROY THE SAME, AND REPEALING ALL OF CHAPTER NINETY- SIX (96) OF THE ACTS OP THE THIRTY-THIRD GENERAL ASSEMBLY RELATING TO WEEDS UPON LANDS AND HIGHWAYS. Be it Enacted iy the General Assembly of the State of Iowa: Section 1. It shall be the duty of each owner, occupant, person, company or corporation in control of any lands within the state of Iowa, whether the same shall consist of improved or unimproved lands, town or city lots, lands used for highways, railway right of way or depot grounds, lands in which the public has an easement for road, street or other right of way, or lands used for any other purpose whatsoever, to cut, burn, or otherwise entirely destroy all noxious weeds as defined in section two (2) hereof at such times in each year and in such manner as shall prevent the said weeds from blooming or coming to maturity, and to keep the said lands free from such growths of other weeds as shall render the streets or highways adjoining the same unsafe for public travel or shall in- terfere in any manner with the proper construction or repair of the said streets or highways, and shall cause to be cut, near the surface, all weeds on the streets or highways adjoining said lands between the fifteenth day of July and the fifteenth day of August of each year. But nothing herein shall prevent the land owner from har- *Bull. U. S. Dept. Agr. Div. Bot. 17 :60. 796 WEED FLORA OF IOWA vesting the grass grown upon the roads along his land in proper season. Sec. 2. The following weeds are hereby declared to be noxious weeds; namely, quack grass {Agropyron repens), Canada thistle (Cirmim arvense), cocklebur {Xanthmm canadense) , wild mustard (Brassica arvensis), sour or curled dock {Rumex cnspus), smooth dock (Rumex altissimus) , buckhorn or ribbed plantain (Plantago lanceolata) , mid parsnip (Pasiinaca sativa), horse nettle [Solanum carolinense), velvet weed or button weed (Ahutilon theophrasti) , burdock {Arctium lappa), shoo-fiy {Bihiscus trionum) , wild carrot {Daucus carota) and Russian thistle (Salsola kali L. var. tenui- folia) . Sec. 3. If any such owner, occupant, person, company or corpor- ation in control of any such land shall fail or neglect to do the things necessary to prevent the said noxious weeds on any such land from blooming or coming to maturity, or shall permit weeds thereon contrary to the provisions of section one (1) hereof, or if it shall appear that there is danger that any such noxious weeds on any such land may mature, then upon their own motion or upon com- plaint made to any member thereof, it shall be the duty of the board of trustees of the township in which such land lies or to which such land may be adjacent and within the same county, or of the town council or board of commissioners if within the limits of an incor- porated town or city, to make investigation of such condition or complaint, and if it appears that there is danger that any such nox- ious weeds may mature or that weeds thereon render or are about to render the streets or highways adjoining the land unsafe for pub- lic travel or interfere or are about to interfere in any manner with the proper construction or repair of the said streets or highways, the said board of trustees, town council or commissioners, as the case may be, shall make an order fixing the time within which the weeds shall be prevented from maturing seed or the said weeds shall be destroyed, prescribing the manner of their destruction, and shall forthwith give notice in writing of the said order personally to the owner of the land upon which the same exist if service of such notice can be made within the township in which such land is situated, and if it can not be so served, then by mailing said no- tice by registered mail to the owner at his last known address, and also by giving a copy of the notice to the person, company or cor- poration in the apparent control or occupancy of the said land, whose duty it shall also be to mail said notice to the owner, and WEED AND SEED LAWS 797 if the order so made is not substantially complied with by the time fixed in the order and after reasonable notice as herein provided, then it shall be the duty of the board of trustees, town council or commissioners, as the case may be, forthwith to cause said order to be fully performed, and the expense of the same, including the costs of serving said notice and the special meetings of the board of trustees, town council or commissioners, if any were required, shall be advanced out of the township road fund, or town or city general fund, as the case may be ; or if the said fund shall be in- sufficient therefor, the town council, commissioners, or the board of trustees may borrow the money necessary to advance the same by issuing warrants of a like amount upon the road fund, or upon the town or city general fund, and at any meeting of the board they shall assess all of the same against the said land and the owner thereof by a special tax which shall be certified and collected to- gether with interest and penalty after due in the same manner as road taxes unpaid and shall be collected by the county treasurer and when collected shall be paid into the fund upon which said warrants were drawn. Before making said assessment, ten days' notice shall be given such owner of the time and place of meeting of the trustees, council or commissioners, which notice shall also contain a statement of the work done and the expense thereof with costs, and shall be given in the same manner as originally given to owners as hereinbefore provided. At said time and place such owner may appear with the same rights given by law before boards of review upon increase in assessments. Sec. 4. It shall be the duty of the board of trustees of each town- ship to consider the conditions of all lands and highways within the township and outside of incorporated towns and cities as to noxious weeds, and the town councils and commissions shall have the same duties with reference to lands within their respective towns or cities, and on complaint made to them or on their own motion, when- ever it may appear that any of such lands within their jurisdiction are infested with noxious weeds or other weeds, whether about to bloom and mature or not, they shall order their destruction before a date to be fixed in the said notice and prescribe the manner in which the destruction shall be accomplished, notice of which order shall be .given as provided in section three (3) hereof, and if the said order shall not be complied with the board may proceed to cause the said order to be performed and shall certify the expense thereof and it shall be paid and assessed to the lands upon which 798 WEED FLORA OF IOWA the same shall have been destroyed and to the owners or owner thereof and be collected in the same manner as is provided for the expense of proceeding under section three (3) hereof. Sec. 5. It shall be the duty of all officers directly responsible for the care of public highways to make complaint to the proper town- ship trustees or town councils or commissions, as the case may be, whenever it shall appear that the provisions of section one (1) hereof may not be complied with in time to prevent the blooming and maturing of noxious weeds or the unlawful growth of weeds, whether in the streets or highways for which they are responsible or upon lands adjacent to the same. Sec. 6. All of the provisions of this section relating to the duty of the owner of the lands to prevent the blooming and maturing of noxious weeds thereon and to destroy such growths of other weeds thereon as may interfere with the use of highways shall apply also to cities and towns and the proper officers there as to all streets, highways and lands of any kind within their borders the fee of which shall rest in the public. Sec. 7. It shall be the duty of the township clerk between the first and fifteenth days of May of each year to post in two conspic- uous places in each school district of the township a notice calling attention to the weed law of the state of Iowa and giving a list of the noxious weeds contained therein and notifying the property owners to meet the requirements of the law. Sec. 8. It shall be the duty of the township clerk between the fifteenth and thirteenth days of October of each year to make a re- port to the board of supervisors of the county in which this town- ship is situated as to the presence and location of noxious weeds that have been reported or found within the township and the steps taken to bring about the destruction thereof, a copy of which report shall be forwarded to the board of supervisors to be kept on file and a copy of same to be forwarded by them to the secretary of the Iowa department of agriculture not later than the first day of De- cember following. Sec. 9. Any township trustee or road officer or other officer who neglects or fails to perform the duties incumbent upon him under the provisions of this act shall be guilty of a misdemeanor and shall be punished by a fine not exceeding one hundred dollars ($100.00). Sec. 10. Chapter ninety-six (96) of the acts of the Thirty-third General Assembly is hereby repealed. WEED AND SEED LAWS 799 Sec. 11. This act being deemed of immediate importance shall take effect and be in full force after its publication in the Register and Leader and the Des Moines Capital, newspapers published in Des Moines, Iowa.* Approved April 23, A. D. 1913, and became effective by publi- cation May 1, 1913. The law which was in force until repealed by the above act is as follows : Section 1. Land owners or tenants to destroy weeds — when. — It shall be the duty of every person, firm or corporation owning, occupying or controlling lands, town and city lots, land used as right of way, depot grounds or for other purposes to cut, burn or otherwise entirely destroy all weeds of the kinds mentioned in section two (2) hereof at such times in each year and in such manner as shall prevent the said weeds from blooming or coming to maturity. Section 3. Noxious weeds. — The following weeds are hereby declared to be noxious weeds, namely, quack grass (Agropyron repens), Canada thistle {Cirsium arvense), eocklebur {Xanthkim canadense), wild mustard {Brassica arvensis), sour or curled dock {Ewmex crispns), smooth dock {Bumex aitissimus), buckhorn or ribbed plantain (Plantago lanceolata) , and wild parsnip {Fastinaca sativa), horse nettle {Solanum oarolinense), and velvet weed or button weed {Abutilon theophrasti) and burdock {Arctium lappa). Section 3. Destruction on highways — neglect or refusal to de- stroy. — It shall be the duty of the township trustees or other officers responsible for the care of public highways in each town- ship or county in this state to destroy or cause to be destroyed all noxious weeds mentioned in section two (2) hereof or unnecessary brush on the highways in such a manner as to effectually prevent the production of their seeds or their propagation in any other manner, to warn out labor or to employ labor for this purpose in the same manner as for repairs to the highways, and for neglect or failure to perform this work they shall be subjected to the penalties in this act. If any occupant of lands adjacent to the public highways neglect or refuse to destroy the noxious weeds upon his land, or shall fail to prevent the said noxious weeds from blooming or coming to maturity, when such weeds are likely to be the means of infesting the public highway, or upon complaint of any land owner to the township trustees that his lands have been or are likely to be infested by weeds from the lands of an- 800 WEED FLORA OF IOWA other including railway right of way, the trustees shall make an investigation of such condition or complaint and if the same ap- pears to be well founded they shall make an order fixing the time within which the weeds shall be prevented from maturing seed, and an order that within one year such noxious weeds shall be permanently destroyed, and prescribing the manner of their de- struction and shall forthwith give notice to the occupant of the lands where the noxious weeds exist, and if he shall neglect to obey such order within the time so ordered the trustees may cause such noxious weeds to be prevented from maturing seeds or may cause such noxious weeds to be permanently destroyed and the cost of the work shall be recovered from the owner by a special tax to be certified by the township clerk in the same manner as other road tax not paid. Section 4. Road funds may de expended. — The destruction of noxious weeds in the public highway and other public places is hereby made a part of the road work of the township trustees and the county supervisors and they shall have authority to expend road funds for the destruction of weeds. Section 5. Property tax. — The law as it appears in section fifteen hundred and twenty-eight (1528) of the supplement to the code, 1907, is hereby amended as follows, namely: By inserting after the comma in the eighth line thereof the following words : ' ' and for the destruction of noxious weeds in public highways and other public places," and by striking out the word "four" in the tenth line of said section and inserting the word "six" in lieu thereof. Section 6. School of instruction. — Between November and the succeeding April of each year the county supervisors shall call a meeting of the township trustees and the road supervisors of the county to consider the best methods of road work and weed de- struction, and in the public interest may secure the services of experts to give instruction in road building and weed destruction. For such attendance the same compensation shall be allowed to the trustees and road supervisors and the county supervisors as is allowed by law for other services, to be paid as other expenses. The expenses of experts herein provided for may be paid from the county road fund. Section 7. Cutting of weeds on highways. — It shall be the duty of township trustees and other officers directly responsible for the care of public highways to cause to be cut near the surface all WEED AND SEED LAWS 801 weeds on the public highways in their respective districts at such times and in such manner as to prevent seeds from maturing. Section 8. Penalty. — Any person, firm or corporation violating any of the provisions of this act, or any township trustees, in- spector or other officer who neglects or fails to perform the duties incumbent on him under the provisions of this act, shall be gnilty of a misdemeanor and shall be punished by a fine not exceeding one hundred dollars ($100.00). Section 9. Repeal. — The law as it appears in sections fifteen hundred and sixty-two (1562), fifteen hundred sixty-two-a (1562-a) and fifteen hundred sixty-three (1563) of the supplement to the code, 1907, and sections fifteen hundred and sixty-four (1564) and fifteen hundred and sixty-five (1565) and section five thousand and twenty-four (5024) of the code are hereby repealed. Approved April 21, A. D. 1909. Hon. C. E. Brenton and the writer framed a bill with the aid of Eobert Hunter, an attorney in Des Moines, which would meet all requirement.' This provided for weed inspectors. The bill was in- troduced into the Senate by Mr. McColl and in the house by Mr. Brady; however this bill failed to pass. As the subject is so im- portant and is likely to come up again at a future session of the Legislature, I insert the bill. A BILL FOR AN ACT TO AMEND CHAPTER NINETY-SIX (96) OF THE ACTS OF THE THIRTY-THIRD (33) GENERAL ASSEMBLY, AND TO CREATE THE OFFICE OF COUNTY WEED COMMISSIONER, AND TO PROVIDE FOR HIS APPOINT- MENT AND DUTIES. Be it Enacted hy the General Assembly of the State of Iowa: That Section One (1) of said chapter be amended by adding thereto the following: Section 1-a. The office of County "Weed Commissioner is hereby created. It shall be the duty of the County Board of Supervisors, at a regular or special meeting of the Board, not later than the first day of April in each year, to appoint a County Weed Com- missioner whose term of office shall be from the first day of May after his appointment to the first day of November following. Section 1-b. The County Weed Commissioner shall devote his entire time to the duties of his office, and shall receive as full com- pensation for his services a salary not exceeding seventy-five dol- 51 802 WEED FLORA OF IOWA lars ($75.00) per month and his actual and necessary traveling ex- penses incurred while performing his official duties, payable in like manner as the salaries of other county officers. Section 1-c. The Board shall furnish such weed commissioner an office at the county seat, and all stationery, blanks and supplies necessary in the performance of his official duties. That Section Two (2) of said chapter be amended by changing the period at the end of said section to a comma, and adding im- mediately thereafter the following: And shoo-fly (Hibiscus Trionum), and wild carrot (Daucus Carota) . That all of Section Three (3) of said chapter following the words "in this act," in the ninth line thereof, be stricken out and the following enacted in lieu thereof : Section 3-a. It shall be the duty of the County Weed Commis- sioner during the first thirty (30) days of his term of office, to post in public places in each township of the county, at least fifteen (15) notices setting forth therein, in substance, the law of the State of Iowa in reference to noxious weeds and the destruction thereof; to inspect all lands, including highways and railway rights-of-way within the county, for noxious weeds, as defiined in Section Two (2) hereof, and give to the owners or occupants of said land, and to the officers responsible for the care of the high- ways on which any such noxious weeds be found, information in reference to the presence of such weeds and the manner of destruc- tion thereof. Section 3-b. If any occupant or owner of land, or any owner or operator of a railway right-of-way, neglect or refuse to destroy the noxious weeds upon his land or right-of-way or shall fail to prevent the said noxious weeds from blooming or coming to ma- turity, when such weeds are likely to be the means of infesting the public highways, or the lands of adjoining owners, the County Weed Commissioner shall cause such noxious weeds to be prevented from maturing seed, or shall cause such noxious weeds to be per- manently destroyed and the cost thereof, not exceeding (30) cents per hour for each man so employed, shall be recovered from the owner of the land, or owner or operator of such railway right-of- way by a special tax certified to the county auditor by the County Weed Commissioner to be paid by the owner or operator of the land or railway right-of-way as the ease might be, and collected by the county treasurer the same as other taxes. WEED' AND SEED LAWS 803 Section 3-c. If any townsliip trustee or other officer, or officers, responsible for the care of the public highways in each township or county in this state, neglect or refuse to destroy any noxious weeds upon such highway, or shall fail to prevent the said noxious weeds from blooming or coming to maturity, when such weeds are likely to be the means of infesting the land adjoining such high- ways, the County Weed Commissioner shall forthwith give written notice to such officer or officers, responsible for the care of such highways, to destroy such noxious weeds, and if such officer or officers shall neglect for ten (10) days after such notice to destroy such weeds, or to prevent the same from maturing seed, then such officer, or officers, shall be subject to the penalty provided in Sec- tion Eight (8.) of this chapter. Section 3-d. The County Weed Commissioner shall make a re- port of the work of his term to the Board of Supervisors, not later than the thirtieth (30th) day of October of the year for which he was appointed, such report to contain a statement in detail on the presence and location of Canada thistle, horse nettle and quack grass, and the board shall forward a copy of such statement to the Secretary of the Iowa Department of Agriculture not later than the first day of December following: Section 3-e. It shall be the duty of the Secretary of the Iowa Department of Agriculture to furnish to the Board of Supervisors of each county, the notices described in Section 3-a hereof, as well as all necessary blanks for reports to be made to said department, and to keep on file in his office all reports of such noxious weeds furnished him by County Boards of Supervisors, and include in his annual report a summary of the report furnished by such boards. This act being deemed of immediate importance shall take effect and be in force from and after its publication in the Eegister and Leader and the Des Moines Capital, newspapers published in Des Moines, Iowa. ILLINOIS. In Illinois the criminal code statutes provide a penalty of not less than $10.00 nor more than $100.00 for bringing Canada thistle in packing material or in grain, grass or vegetable seed on any land in this state ; nor shall it be permitted to go to seed. The same law also applies to railroads. This includes other noxious weeds growing on the right-of-way of other land operated by railways, but the fine is placed at not less than $50.00 nor more than $200.00. 804 WEED FLORA OF IOWA An Illinois statute provides for the appointment of a conunis- sioner of Canada thistles by the board of town auditors in counties under township organization and by the county commissioner in counties not under township organization for each township or election precinct and by the city council of any city or by the president and trustees of any town or village as the case may be, the former to hold his term of office for three years. Compensation $2.00 per day. The commissioner shall diligently enquire concern- ing the introduction and existence of Canada thistles in his town- ship or precinct. He shall take care that they do not go to seed, or otherwise spread. The commissioner shall advise with the owner of the land concerning treatment. The limit of money to be ex- pended by the commissioner shall not be more than $100 on any one infested tract. The commissioner shall make out a written re- port to the supervisor of the town or to the county commissioner. The report shall be read publicly at the annual town meeting, as to whether any thistles are growing; if growing, where; it shall contain a statement as to the treatment of the infested tract and shall make such other suggestions as may seem proper. He shall forward a copy to the secretary of the state Board of Agriculture. A land owner shall not deposit weeds or trash on the public road. The same chapter provides that the commissioners of high- ways in their respective towns shall enforce the law with reference to cocklebur, Canada thistle and Russian thistle. INDIANA. The Indiana law makes it a misdemeanor for any person or corporation, on property belonging to the person or corporation, to allow Canada thistles to grow until they become the length of 6 inches from the surface of the ground to the tip of the stem. The law makes it a misdemeanor for persons having charge of high- ways to allow Canada thistle to grow to the length of 6 inches or to mature. It makes it the duty of the road supervisor or of the president of the board of trustees, to notify the occupant of the land on which Canada thistle grows to cut said thistles below the surface of the ground within 5 days of notice. Penalty is attached for not complying with the notice. A penalty is also attached to non-performance of the duties of the supervisor, township trustee or mayor. WEED' AND SEED LAWS 805 KANSAS. The state of Kansas has several statutes in regard to the destruc- tion of weeds : one on Canada thistle and Russian thistle ; another on Johnson grass. Chapter 17 : 923, of the revised statutes, re- quires cities of the first class to enforce the cutting and destruc- tion of weeds on vacant lots, pieces of land, streets and alleys. A five days' written notice shall be given; if not removed the city may make a special assessment the same as for sidewalks. Chapter 16 gives cities of the first class the power to pass an ordinance on the removal of rank grass and weeds. Chapter 41 makes it the duty of the owner of real estate to cut the weeds along said real estate before they go to seed. The Canada thistle and Russian thistle laws make it the duty of every corporation, owner of land, or the occupier of lands where these weeds occur to remove the same at such times as the board and county commissioners may direct. When not removed, notice shall be published in one or more county papers not less than three weeks before the fixed time of destruction. The highway overseer of every township or county shall also cut or destroy all noxious weeds on the highway. The Johnson grass statute makes it unlawful to introduce into or sell or offer for sale within the state any seeds or roots of Johnson grass. It is made the duty of the county commissioner of each county within the state where Johnson grass occurs to prescribe the jurisdiction of each road overseer; each township to be in- cluded within the jurisdiction of some road-overseer. It is made the duty of the road overseer to prevent its spreading and if he receives written notice from any person in writing that the grass is seeding he shall investigate; if found to be the case he shall give .5 days' time in which to destroy it, if not destroyed he shall remove it and tax the costs against the land. If the owner of the land fails to notify tenant, on execution of lease, the owner shall be responsible for any damages. "Full tassel," as contained in law, shall mean seed. MINNESOTA. In regard to the suppression of noxious weeds in Minnesota the law is as follows: "Where the dean of the department of agri- culture of the university of Minnesota deems it necessary for the suppression of noxious weeds and for experimental purposes to sow timothy, clover, red top or other seeds on burned-over state lands, said department is hereby authorized to do so with seed purchased under this act." 806 WEED FLORA OF IOWA ''Any county commissioner who knowingly allows or aids in allowing to any such, applicant under this act any timothy, clover, red top or other seed, unless such applicant belongs to the class referred to, who is destitute of needed seeds, shall be guilty of a misdemeanor. ' ' MISSOURI. The revised statutes of Missouri make it the duty of the owner, lessee or other occupant of lands and every railroad company or corporation in the state to destroy Canada thistle and Scotch thistle, prevent the formation of seed, and prevent said thistles from spreading. A penalty of ten dollars is attached for every offence. Notice shall be given to the agent, overseer or other person having charge of the streets, roads or highways or places where such thistles occur. Cases of violation may be brought be- fore any justice of the peace of the county or city. Said fine when recovered shall be paid into the county school fund. Where such cutting is done on land by the overseer the cost is charged as a tax against the property and collected as other taxes. The law prohibits the throwing away of material with Canada thistle and Scotch thistle seed and provides for the burning of straw or grass packing containing thistle. NEBRASKA. In the state of Nebraska, there are two statutes concerning the destruction of weeds, one pertaining to the destroying of weeds in public roads, the main provisions in the law being as follows: It is the duty of land owners in the state to mow or otherwise destroy all weeds to the middle of all public roads running along their lands, at least once each year, namely, between the fifteenth day of July and the fifteenth of August. The overseer of roads has authority to cut the weeds when complaint is made ; expenses connected therewith shall be sent to the county clerk who shall make an assessment against the land. The usual penalty is also provided. In a second statute there is provision for the city of Omaha for the destruction of weeds and worthless vegetation upon vacant lots or land in the city of Omaha. NORTH DAKOTA. The state of North Dakota has a law which seeks to prevent the spread of noxious weeds by threshing machines. This act provides that any owner, or teamster employed in hauling grain, either WEED' AND SEED LAWS 807 threshed or unthreshed, shall upon completing any threshing en- gagement and before leaving the premises on which said work was done take all reasonable care to prevent the conveying and carry- ing away and scattering of noxious weeds which may have ac- cumulated in or on the machines. The law provides how this shall be done by operating the machine and sweeping. A printed copy of the law shall be kept posted on every machine operating in the state. A fine, or imprisonment, or both, is provided for violation of the law. I am told the law is not enforced. OHIO. The state of Ohio has several laws relative to the destruction of weeds, briers and brush. With reference to the destruction of these on toll, steam, and electric roads the law provides for the destruction of brush, briers, burs, Russian, Canada, or common thistle, wild lettuce, wild mustard, wild parsnip, ragweed, milk- weed, ironweed, and all other noxious weeds growing within the limits of any right of way whether in actual operation or not. If said weeds are not destroyed between the first and twentieth of June and between the first and twentieth of August and if neces- sary between the first and twentieth of September of each year, the tru^ees of the township through which such road passes shall cause it to be done and shall have right of action against such toll, steam, or electric road and one hundred per cent penalty; costs of action to be recovered before any justice of the peace of such county. The weed law as applied to the destruction of weeds on graveled or improved roads, turnpikes, county township roads, streets, etc., is essentially the same, putting the enforcement in the hands of pike superintendents and turnpike directors. The amount of money which can be collected is fixed at one dollar and a half per day to destroy these weeds. A street commissioner shall be paid for such services by the proper municipal authorities. The land owner or tenant is allowed to cut the noxious weeds along the highway abutting the property. The superintendent shall fix a reasonable compensation for the work. Another section provides that upon written information that Canada thistle, Russian thistle, wild lettuce or wild mustard is growing on land in a township and is about to spread or mature seeds between the first day of June and the fifteenth day of Oc- tober, the trustees of the township shall serve written notice upon the owner, lessee, agent or tenant that such weeds occur and that 808 WEED FLORA OF IOWA they must be destroyed within five days after the service of such notice. These laws are not enforced in Ohio. SOUTH DAKOTA. The South Dakota law specifies that every person or corporation shall destroy, on all land which he or it may occupy, all weeds of the following kinds: Russian thistle, Canada thistle and cockle- bur. The enforcement of the law is in the hands of the board of supervisors. If the weeds are not destroyed a notice for three weeks shall be published in the papers. After such notice the weeds shall be destroyed. Owners must also destroy weeds on highways abutting their property. These weed laws are not en- forced. WISCONSIN. The state of Wisconsin has a law requiring that every person or corporation shall destroy, on land which he or it shall own, occupy, or control, all weeds known as Canada thistle (Cirsium arvense) , ox-eye daisy {Chrysanthemum leucanthemum) snap dragon (Linaria vulgaris), sow thistle {Sonchus arvensis), sour dock and yellow dock (Eumex crispus), mustard {Brassiea ar- vensis), wild parsnip {Thaspium, hardinode), burdock (Lappa officinalis), Russian thistle {Salsola kali) and wild barley (Hor- deum juhatutm) , at such times and in such manner as shall ef- fectually prevent them from bearing seed. The above weeds shall be destroyed to the middle of the highways by the commissioner of noxious weeds. The corporation or party shall be given notice and if weeds are not removed within 6 days a $5.00 fine is im- posed every day thereafter during which such neglect shall con- tinue. The weeds shall be specified ; also on what land they occur. The commissioner or commissioners of weeds shall be appointed by the chairman of each town board, the president of each village, or the mayor of each city. The commissioner of weeds shall hold the office for one year. He shall give notice if the weeds are not removed. Then the commissioner shall remove the same. The city of Milwaukee is exempt from these provisions. SEED LEGISLATION. Numerous states of the Union and various European countries as well as Canada and other British countries have legislated on the subject of seeds and seed adulteration. Two classes of laws are in vogue in the United States. One requires a guaranty of WEED AND SEED LAWS 809 the seed sold and may be called the Maine idea. The other gives standards of purity and vitality and is the Iowa idea. This law- has been passed in many states, among them, Wisconsin, "Wash- ington and Wyoming. The Iowa law is as follows : Section 1. Every lot in bulk, bag, pail, parcel or package of concentrated commercial feeding stuffs as defined in section three (3) of this act; and every parcel, package or lot of agricultural seeds as defined in section nine (9) of this act, and containing one pound or more, offered or exposed for sale in the state of Iowa, for use within this state, shall have affixed thereto, in a conspicuous place on the outside thereof, distinctly printed in the English language, in legible type not smaller than eight point heavy gothic caps, or plainly written, a statement certifying: In the case of agricultural seeds: First. The name of the seed. Second. Pull name and address of the seedsman, importer, dealer or agent. Third. A statement of the purity of the seed contained, specify- ing the kind and percentage of the impurities as defined in sec- tions eleven (11) and twelve (12) hereof, provided that said seeds are below the standards fixed in this act. Fourth. Locality where said seed was grown, when known. Section 6. The state food and dairy commissioner shall cause to be made analyses of all agricultural seeds sold or offered for sale in this state. Said state food and dairy commissioner is here- by authorized, in person or by deputy, to take for analysis a sam- ple from any lot or package of agricultural seeds not exceeding four ounces in weight ; but said sample shall be drawn or taken in the presence of the party or parties in interest, or their repre- sentative, and shall be taken from a parcel, lot or number of par- cels which shall not be less than five per cent of the whole lot in- spected and shall be thoroughly mixed and divided into two sam- ples and placed in glass or metal vessels carefully sealed and a label placed on each, stating the name or brand of the agricultural seeds or material sampled, the name of the party from whose stock the sample is drawn, and the date and place of taking such sample, and said label shall be signed by the state food and dairy commissioner, or his authorized agent; or said sample may be taken in the presence of two disinterested witnesses; one of said duplicate samples shall be left on the premises of the party whose stock was sampled and the other retained by the state food and 810 WEED FLORA OF IOWA dairy commissioner, for analysis and comparison with the certified statements required by sections one (1) and four (4) of this act. The result of the analysis of the sample, together with additional information shall be published from time to time in bulletins issued by the state food and daiiy commissioner upon approval of the executive council. Section 7. Any person purchasing any agricultural seeds in this state for his own use, may submit fair samples of said seeds to the state food and dairy commissioner, who, upon receipt of an analysis fee of fifty cents (50c) for each sample of agricultural seeds shall cause an analysis of the same to be made. Section 8. No person shall sell in ground form, wheat or rye screenings containing cockle or other poisonous or deleterious sub- stances. Section 9. The term, agricultural seeds, as used in this act, shall include the seeds of the red clover, white clover, alsike clo- ver, alfalfa, Kentucky blue grass, timothy, brome grass, orchard grass, red top, meadow fescue, oat grass, rye grass and other grasses and forage plants, flax, rape and other cereals. Section 10. No person shall sell, offer, or expose for sale, or distribution in this state, for the purpose of seeding, any of the agricultural seeds as defined in section nine (9) of this act, unless the said seeds are free from the seeds of the following weeds: Wild mustard, or charlock {Brassic€D sinapistruni) , quack grass (Agropyron repens) , Canada thistle {Cnicus arvensis), wild oats {Avena fatua), clover and alfalfa dodder (Cuscuta epithymum), field dodder {Cuscuta arvensis), and corn cockle {Lychnis githago). Section 11. The seeds of the following weeds shall be consid- ered as impurities in the agricultural seeds as defined in section nine (9) of this act, sold, offered, or exposed for sale, within the state for the purpose of seeding : Wliite cockle {Lychnis vesper- Una) , night-flowering eatchfly {Silene noctiflora) , curled dock {Rumex crispus), smooth dock {Rumex altissimus) , sheep sorrel {Rumex acetoseUa) , yellow trefoil {Medicago' lupulina) , burr clover {Medicago denticulata) , sweet clover {MeUlotus alba and officinalis) , black mustard {Brassica nigra), plantain, buckhorn {Plantago lanceolata) , bracted plantain {Plantago aristata), bindweed {Con- volv'idus sepium) , smooth crab grass {Panicum glabrum), common chickweed {.SteUaria media). AA^hen such impurities or any of tliem are present in quantity exceeding a total of two per cent of the weight of said agricultural seeds, the approximate percentage of WEED' AND SEED LAWS 811 each shall be plainly indicated in statement specified in section one ^1) ,0 Distribution 691, 705, 719, 794, m. 2i0 INDEX 875 Root system 651, f. GJ,6 Seed 462, 562-563, f. J,63, 563, 032 tuberosa Seed 463 f. i63 verticillata Seed 46 3, f. Ji63 Ash 6, 632 Ashton, T\^ M. 766 Asia, TVeeds of 731, 732, 733, 734 Asparagus 6 Aspens 703 Aster azureus 689 drummondii 4 81 Trichomes f. J/SZ laevis 481, 689 Trichomes f. ^82 macrophyllus 481 Tricliomes f. Ji82 Many-flowered 317-318, 790, f. 317 Distribution 689, m. 318 multiflorus 317-318, 790, f. 318 Distribution 690, m. 318 Trichomes f. iSl novae-angliae, Trichomes f. JfSl novi-belgii, Distribution 737 oblongifolius, Tricliomes f. ^81 paniculatus f. 320 parviflorus Distribution 737 salicifolius 319-320, 790, f. 320 Distribution 737, m. 320 Seed 481, f. m Tricliomes f. ^Sl sp. 594 tradescanti 320 Trichomes f. 781 White. See Many-flowered Willow-leaved 319-320, 790, f. 319 Distribution m. 320 Seed 4 81, f. m Astragahis canadensis 193, f. lO.'t inexicanus 554 Atriplex hortense Distribution 736 patula V. hastata 109-110, f. 110 Distribution 716, 740, 789, m. 110 Seed 433, f. m Atropa belladonna Distribution 736 Aughey 765 Auricle 862 Australia, Flora of 696, 731, 732, 733, 734. 763 Seed investigations 837 AVeefl legislation 793 Weeds 839 Australian Burr 849 Avena fatua 40-41. 789, f. !fi Distribution 71'^. 736, in. 'fl Seed 415-416, 810, 829, f. U6 glabrata Seed 829 sativa Seed 813 Avens, Seed 449. 7 88, f. .','i9 White sviK Stick!='eecl Awn 609, 862, f. 609 Awned Brome grass syn. Downy Brome Gross Wheat grass 7i5 Awnless Brcme Grass 812 Axil 862 Axillarv flowers 610 Placenta f. fii9 Axis, Floral, 611 Babcock, O. G. 74 8 Bachelor's Button Distribution 727 Bachmann, E. 58fi Bailev, B. H. S. 837 Bailey, F. j^t. 8'"J Bailey, L. H. 847, 860 Baldwin's Ironweed 309-310, f. 310 Distribution m. 310 Seed 477, f. J,77 Ball, C. R. 745, 760, 834, 855 Ball, O. M. 834, 855 Ball Mustard 163, 717, 814 Balsam Apple 573, f. 57 J/ Bamber, M. K. 847 Barbarea vulgaris 170, 787, f. 170 Distribution 717, 733, 740, in. 171 Seed 447-448, 544, /'. U7, 5J,2 Barber, C. J. 750 Barberry, 678 Family, Distribution 723 Barley 8 Blight f. 6S0 Blindness of 677 Grass 667 Little 61-63, f. 62 Chemical composition 61, 63 Distribution 715, m. 62 Seed f. m Seed 812 Transpiration 673 Wild syn. Squirrel-tail Grass Barnaby's Thistle syn. Knapweed Barnet, 664 Barnyard Grass 16, 790, f. 16, 330 Chemical composition 17 Distribution 731. in. 16 Seed 411-412, 506, f. J,12, 505, 729 Base 862 Bartlett, J. M. 85 3 Barton, L. W. 833 Barton, W. M. C. 773, 853 Basil 2 86 Distribution 720 Bas.swood seed 631, f. 632 Beach, C. L. 855 Beach, D. L. 834 Beal, W. J. XI, XIII, 24, 824, 830, 838, 855 Bean 67, 180, 621 Aphis 677 Castor-oil 205 Distribution 696 Coffee 180 Trailing wild Distribution 718 Transpiration 673 Wild 199-200 Distribution 718, m. 200 Seed 455, f. .',55 Beard Grass 862 Distribution 722 Beard-tongue 845 Bebb, M. S. 747 Beck 765 Beck, G. 5 53. 585 Beck, L. C. 838 Bedford, S. A. 57 Bedstraw 572. 594. 663. 665, f. 573 Distribution 693, 741 Seed 47 fi, f. m Bee-plant, Rocky Mountain 173-175, f. 17 Jf, 175 Distribution 729, 730, m. 17J, Seed 44 8, f. US Beet 99 Distribution 712, 725 Root system 648 Sugar 99 Beetle. Colorado 677 Flv 676 Turnin Flea 676 Beggar's Lice 259-260, 788, f. 259 Distribution 821 Seed 466, f. 1,67 Bea-gar-ticks 351-352, 624, 664, 789, 822, f. 351 Distribution 6'^'7. 720, 740. m. 352 Root system 645 INDEX Seed 489, f. JfS9, 633, 635 Black syn. Beggar-ticks Small Distribution 720 Sp. Seed f. J,S9 Bellis perennis 667 Bennett, J. L. 766 Bent Grass 667 Fine 664, 665 Reed, Distribution 736 Silky, Seed f. 639 Bentham, G. 731, 838 Berberidaceae, Bibliography 5 82 Distribution 723 Bermuda Grass, Distribution 732 Bergen, J. W. 838 Bergen and Davis XII Berlin Botanical Garden, weeds dis- tributed by, 753 Bernholtz, L. 748 Berry 625 Bersch, W. 847 Berteroa incana 147-149, 788, f. US Distribution 700, 713, 717, m. llfi mutabilis Distribution 700 Bessey, C. E. 288, 584, 748, 755, 756, 758, 760, 761, 825, 847 Bessey, E. A. XII, 831, 855 Beta 532 vulgaris 725 Bettomer, Ellen 755 Bexar 767 Bibliography Anatomical study of seed coats 580-587 Chemical composition of weeds 837 Distribution of weeds 837-846 Eradication of weeds 846-853 Medical plants 853-855 Weed laws 860 Weed seeds 855-860 Bidens 624, 633, 789 aristosa 352-354, 489, 790, f. 353 Distribution m. 35^ Trichome f. 1,90 bipinnata. Distribution 696, 734 Seed 489, f. 1,S9, 633 cernua 489, 789 Distribution 740 Trichome f. Ji90 discoidea 349-351, 789, f. 350 Distribution 691, 720, m. 350 Seed 4 89, f. iS9, 577 frondosa 351-352, 664, f. 351 Distribution 691, 720, 740, m. 352 Seed 489, f. J,S9. 633, 635 leucanthus. Distribution 740 pilosa 697 Biennial Gaura 718 Wormwood 367-368, 790 Biennials 648, 786, 862 Bigelovia nudata, Trichomes f. JiS2 Bigelow, Jacob 708, 711, 751, 773, 853 Bignonia Family Distribution 723 BiGNONIACEAB Distribution 723 Bindweed, Black 97-99, 663, 677, 789, f. 98 Distribution 696, 698, 716, 829, m. 99 Seed 429, 528-531, f. iS9, 526j 528, 529, 530 531 European 248-250. 663, 665, 777, 787, 844, f. 2J,9, 593, 59.'i Distribution 719, 727, 735, m. 21,9 Root system 651, f. 653 Seed 463, 563. f. m Hedge 245-248, 848, f. 2^6 Distribution in. 2i6 ^mall syn. European Wild syn. Black Birch sp. Distribution 673 Birds destroy seeds 629, f. 636 distribute seeds 629, 636, 859, f. 637, 63S Bird's-foot Trefoil 734 Seed 815 Birkett 824 Birlingmair, R. H. XII, 657 Bisexual flowers 605 Bishop, J. J. 336-337 Bitter, Dr. 707, 713, 737, 738, 740 Bitter Dock, 78-79, 428, 595, 726, 774, 789 Black Beggar-ticks syn. Beggar-ticks Bindweed 97-99, 429, 526, 528-531, 677, 696, 698, 716, 789, 829 Cherry, Wild 637 Couch Grass syn. Fine Bent Grass Henbane 277, 709. 736 Knapweed 664, 725 Medic 190-191, 453, 546-549, 688,718, 725, 728. 729, 734, 761 Mustard 142, 157-159, 445-446. 541- 543, 605, 696, 701, 717, 725, 776, 788, 810, 811. 814 Nightshade 281-283. 471-472, 568- 569, 625, 630, 645. 687, 696, 697, 720, 736, 777, 790 Blackberry. California 175, 694, 703 Distribution 693 Black-eyed Susan 339-340, 689, 787, f. 339 Distribution m. SiO Root system 645 Seed 486, f. i86 Bladder Campion 436, 716, f. 1/36 Ketmia syn. Shoo-fly Blade 591. 592, 594, f. 593 Blankinship, J. W. 838, 853 Blatchley, W. S. XIII, 824, 838 Blazing-star, Seed 478, f. Ji79 Bleakley, J. L. Ill Elite, Coast. Distribution 746 Bloody Dock 716 Blooming time of plants 786-790 Blue Field Morning- Glory 243-245 Grass 6. 8. 58, 657, 658. 659 Distribution 695. 785 Seeds 830, 832, 857 Canada 811-812, f. 638-639 Kentucky 418, 715, 810, 811, 812, f. 639 Texas f 639 Lettuce 402-403. 404, 633, 788 Sage 277-279. 759 Vervain 263-264, 469, 689, 690, 719, 777, 789 Bluebell Family Distribution 724 Blue-stem 688. 785. f. 689 Blue-weed 256, 719 Blumer, W. F. 749 Bo.gue. E. E. 838 Bohmer. G. R. 838 Bolivia. "Weeds of 693 Bollev, H. L. XII. XIII. 766. 824, 825, 826. 834, 839, 847, 860 Boneset 778, f. 313 False Seed 478, f. J,79 Boom. J. H. 748 Boot-jack svn. Beggar-ticks Boot-jack, Tall 349-351, f. 350 Distribution m. 350 Seed 575-576, f. 577 Borage 256. f. 60S Familv 256-263 Distribution 723. 841 Seed 466-468, 564-566 sp. 711 INDEX 877 BORAGINACEAE 4, 256-263, 777 Bibliography 5S2 Distribution 723 Seed 466-468, 564-566 Boss, Andrew 844, 848 Botanical Gazette XII Botany, Geographical 687 Bouncing Bet 134, 136, 790, f. 1S5, ISG Distribution 688, 710, 717, 728, m. 136 Seed 533-534, f. 535 Boute 740 Bouteloua 785 curtipendula 689 Bo wen- Jones, J. 860 Bowman, J. G. Ill Boy ton, M. F. 855 Bracken syn. Brake Bract 862 Bracted Plantain 305-^07, 474, 571, 572, 720, 740, 810, 814 Verbena sijn. Bracted Vervain Vervain 657, 658, 719, 787 Bracts as seed disseminators 681 Brake 5, 667, f. 6% Distribution 693 Brambles, Distribution 693 Brandegee, T. S. 751, 767 Branched Fleabane 788 Branching Knotweed 789 Brandenberg weeds 845 Brassica alba 444, 776, f. iU arvensis 155-157, 663, 665, 676, 787, 796, 799, 808, f. 156, 101 Chemical composition 157 Distribution 699, 717, 727, 734, 735, 736, m. 159 Seed 444, 445, 543, 810, 811, f. JM, 51,2 campestris Distribution 725 Seed 445, f. US hirsuta 842 juncea Seed 446, f. U6 napus 445, f. U5 nigra 157-159, 776, 788, f. 158, 101 Distribution 696, 717, 725, m. 15S Seed 445-446, 541-543, 776, 810, 811, f. U5, 5i2 rapa seed 811, 813 sinapistrum syn. B. arvensis Brauneria purpurea f. 666 Breeder's Gazette 288, 826 Bremen, Flora of 707, 713-714 Brenchley, W. B. 860 Brendel 765, 766 Brenton, C. R. 801 Brewer, W. H. 769 Briers 794-807 Bristle 863 Bristly Foxtail 22-24, 714, 732 Ox-tongue 497, 498 British Isles, Flora 714, 731, 838 Britton, N. L. 731, 747, 756, 762, 765, 767, 768 Briza media 667 Broad-leaved Dock syn. Bitter Dock Giim-plant syn. Giimweed Broken seed 811 Brome Grass Annual syn. Soft Chess Awned syn. Downy Awnless. Seed 812 Downy 50-52, 787, 819, f. 51, 128 Distribution 714, 715, m. 51 Seed 420, f. J,20 Field Distribution 715 Hairv Seed 828 Hungarian Seed 419, f. m Impurities in 674 Smooth syn. Hungarian sp. 728, 810 Bromus arenarius Distribution 733 arvensis 715 Distribution 733 brizaeformis. Distribution 728 hirsuta 842 hordeaceus 46-48, 789, f. H Chemical composition 46, 48 Distribution 715, m. 57 Seed 419, f. 1,19 inermis 842 Seed 419, 812, f. m mollis f. 599 secalinus 48-50, 788, 819, f. i9 Chemical composition 48, 50 Distribution 715, 733, 736, in. 50 Seed 420, 517, f. J,19 tectorum 50-51, f. 128 Distribution 714, 715, 787, 728, 733, 819, m. 51 Seed 420, f. m Broom 667 Corn Seed 411, 512-517, f. 512, 513, 5U,515 Corn Millet, Seed 506 Rape 665, 827, 848 Distribution 735 Brown, Edgar 832, 835, 836. 855, 857 Brown Knapweed 725 Bruce, TV. 848 Bruckner, W. 848 Bruhl, P. 839 Brush on liighways 794, 807 Buchanan, F. 740, 839 Buchanan, R. E. 834, 858 Buckhorn 301, 303, 637, 665, 786, 787, 796, 799, f. 302 Chemical composition 303 Distribution 692, 696, 697, 698, 720, 762, 843, m. 302 Root system 645, 654, f. 6^8, 6Ji9 Seed 473, 572, 640, 674, 810, 814, 830, 832, 833, 834, 836, f. Jt15, 511, 638 Buckhout, 'W. A. 839 Buckthorn Family, Distribution 824 Buckwheat 74 Distribution 736 Seed 531, 812, f. 526 Family 74-99, 633 Seed 425-431, 525-532 Wild 97-99, 674, f. 9S Distribution m. 99 Seed 429, 528-532, 814, f. i29, 526, 528. 529, 530, 531, 636 Budd, J. L. 839 Buds, Adventitious 651 Buenos Ayres, Flora 702 Buettner, R. 839 Buffalo Berry 310 Buffalo Bur 284, 286-288, 787, 826, f. Distribution 693, 711, 720, 722, 730, 738, 766, 767, on. 286 Seed 471, 569, f. Ifl2, 568, 635 Bug-seed, Distribution 737 Bu gloss 256, f. 603 Viper's 468, f. i68 Bulb 863 Bulbous Buttercup 717 Oat Grass 664 Bull, C. P. 839 Bull Thistle 372-373, 494, 495, 650, 687, 695, 721, 725, 789 Bulliform cell f. 599 Bunch Flower 66, 788 Common 66, f. 66 Distribution 66, 67 878 INDEX Bur Clover 452, 453, 548, 549. 70S, 810, 811, 815, 832, 834 Cucumber 737 Bur Seed stjn. Stinkseed Burchard, 6. 5 83, 827, 855 Burdock 370-371, 631, 644, 667, 778, 786, 789, 793, 794, 796, 799, f. 370, 779 Distribution 687, 721, 725, 838, m. 371 Root system, 645, f. GJ/S Seed 493, 576, 577, f. m. 577. 635 Tricliomes f. 371 Burgess, Rev. 746, 760 Burned-over land 805 Burnut, Ground syn. Caltrop Burrill, T. J. 826, 848 Burs 707 Burtt-Davy, J. 687, 695, 696, 725, 751, 839. 860 Burweed 839 Buscalioni, L. 547, 554, 580-581 Bush Clover 454, 55 3 Honeysuckle 307 Bushy Knotweed 85-86, 431 Bussey Institution 107, 138, 389 Butter and Eggs syn. Toadflax Buttercup, Bulbous 717 Celery-leaved 849 Common syn. Small-flowered Crow- foot Creeping syn. Swamp Buttercup Family 139-142 Distribution 724 Seed 438, 440 Small-flowered 787 sp. 625, 660, 665, 667, 677, 736, f.6tl Swamp 140-141, 787, f. 1J,1 Distribution 717, m. 11,1 Tall, Distribution 717 Seed 440, f. J,J,1 Butterfly Weed Seed 462, f. J,63 Butterprint -215-218, 718, 790, 799, 850, f. 216 Distribution 718, 734, 762, m. 559 Seed 567-558, f. 5-59 Bnttontveed svn. Butterprint Butz, G. C. 831, 856 Cabbag-e 142 Club root 680 Gall Weevil 676 Root Fly 677 White Rust 677 Cacalia tuberosa 493, f. Ji93 Cactaceae^ Distribution 724 Cactus Family, Distribution 724 "Caesar Weed" 861 Calais, False, Seed 502, f. 501 Calamagrostis epigeios, Distribution 693 California Blackberry 693 Flora 845, 853 "Weed legislation 794 Weeds 708, 712, 725, 755, 757 Callus 863 Caltha palustris. Distribution 736 Caltrop 203-205, 789, 844, f. 20i Distribution 697, m. 205 Familv 203-205 Calyx 604, 863 As seed disseminator 630 Camelina sativa 149-151, 788, f. 150 Distribution 700, 717, m. 151 Seed 443, 544, f. US, 5^2 sp. 853 CampanulacbaEj Distribution 724 Campbell, J. R. 768 Campion, Bladder Distribution 716 Seed 436, f. >i36 Red 605 Distribution 716 White 126-128, 664, f. 127 Distribution 716, m. 128 Seed 810, 814, f. 638 Canada (Canadian) Blue Grass 638, 639, 811, 812 Goldenrod 313-314, 479, 480, 721, 790. Lettuce s^jn. Wild Lettuce Seed investigation 836-837 Seed laboratory XII Seed legislation 808, 814 Saskatchewan 713 Thistle 67, 379-382, 494, 592, 633, 636, 638, 639, 648, 651, 665, 688, 708, 748-749, 788, 793, 794, 796, 803, 804, 805, 806, 807, 808, 810. 814, 819, 826, 833, 834, 844, 847, 848, 852 Weeds 693, 733, 753, 757, 762, 766, 825, 839 Canaigre 74 Canavan, B. E. 755 Candy Grass 43-44, 788, f. U Distribution 715, to. H Seed 417, f. 1,16 Cannabis indica 697 sativa 70-72, f. 71 Distribution 696, 715, m. 71 Seed 425, 524-525, f. 1,26, 525 Caper Family 171-174 Distribution 724 Seed 448 Capparidaceae 4, 171-174 Distribution 717, 724 Seed 448 Capripoliaceae 307 Distribution 724 Capsella bursa-pastoris 151-153, 604, 776, 787, 819, f. 152, 153, 622 Distribution 696, 717, 734, 740, TO. 153 Root system 648 Seed 443, 540-541, f. ^1,3, 5^2 Trichomes f. 153 Capsule 863 Caragana 180 Carawav 224, 226-227, 776, 787, f. 226 Distribution 709, 719, m. 227 Carbon dioxid 599-600 Carbonic acid 600 Card, F. W. 857 Carduus crispus Distribution 736 lanceolatus syn. Cirsium lanceolatum natans Distribution 736 Carex sp. 678, f. m vulpinoidea 788, f. 1,07 Seed 407, f. 1,07 Carnation 120 Carolina Cranesbill 555, f. 556 Carpel 618. 863 Carpenter Weed 270-271, f. S7i Distribution m. 271 Carpet Grass, Louisiana, Distribution 722 Carpet "^''eed Family, Distribution 723 Carrier, L. 85 6 Carrot Family 224-234 Distribution 725 Seed 460-462, 561-562 Root System 648 "Wild 227-228, 637, 667, 786, 788, 796, 802, 819, f. 227, 768 Distribution 688, 6?>2, 698, 712, 719, 725, 767-768, 794, to. 228 Seed 461, 562, 640, 833, f. 1,62, 561, 635. 565 Carruthers, Wm. 848, 860 Carum carvi 226-227, 776, 787, f. 226 Distribution 719, m. 227 INDEX 879 Carver, G. W. 745, 746, 753, 762, 763, Cartophyllaceae 4, 120-134, 776 Bibliography 582 Distribution 716-717, 724 Seed 435-438, 533-535 Caryopsis 516, 863 Cassia chamaecrista Distribution 718 occidentalis Distribution 723 tora Distribution 723 Cassidy, J. 837 Castilleja integra Distribution 694 sp. 702 Castor-oil Bean 205, 697, f. 697 Distribution 696 Catalpa speciosa. Seed, f. 63i Catchfly Evening' I 437, f. i37 II 437, f. 4S7 Distribution 692 Forked 128-130, f. 1S9 Distribution m. 130 Seed 436, f. J,37 Night-flowering 130-132, 790, f. 131 Distribution 716, m. 132 Seed 437, 810, 814, f. ^37, 638 Sleepy 788 Distribution 716 Slender, Seed 534-535, f. 535 Small-flowered (S. gallica) Distribution 725 "Virginia, Seed 535, f. 535 Gates, J. S. 839, 852, 861 Catkin f. 606 Catnip 268, 273-274, 777 Chemical composition 273 Distribution 719, in. 274 Root system 654 Seed 469, 566-567, f. J,70, 567, 638 Cat's-ear 696 Distribution 725-728 Cattle foods, weed seeds in 833, 855, 856, 858 Caulicle 863 Cauliflower 142 Cauline leaves 592 Cazaux, L. 848 Cedar, Red 6 Celandine 793 Celery 224 Flv 677 Cell Aleurone 524, 530, f. 523, 529 Bulliform f. 599 Chlorophyll f. 599 Cross 510, 516, 518, 522, 529, 538, f. 513. 516. 518. 523, 537 Epidermal 514, 5l8, f. 516, 518, 51,1, 565, 599 Guard 597, f. 598 Malpighian 547, 549, 553, 554, 564, 567, f. 5^6, 551, 555, 556, 558, 567 Netted 538, f. 537 Palisade 527, 59 8, f. 5k2, 556, 557, 577, 578. 598 Parenchyma 527, 5 36, f. 536, 557, 558, 561, 566, 568, 571, 578 Sclerenchyma f. 555 Sclerotic f. 571,. 578 Starch 511, 517, 530, f. 513, 529, 51,2 Tapetal 616. 871, f. 615 Tube 516, 522, f. 513, 523 Cellulose 863 Celosia cristata Distribution 696 Cenchrus tribuloides 25-26, 790, f. 26 Distribution 714, m. 26 Seed 412, 517, f. 1,12, 505 Centaurea cyanus Chemical composition 673, 674 Distribution 699, 725, 727 Seed 496, 735, f. 1,97, 688 jacea. Distribution 725 melitensis. Distribution 725 nigra 667 Distribution 725 repens. Seed 834 solstitialis 383-384, f. 381, Distribution 712, 713, 725, 750, m. Seed 496, f. 1,97 Central America, Flora 731 Placenta f. 619 Cerastium arvense. Distribution 740 nutans 122-123, f. 123 Distribution 716, m. 122 viscosum 122, 787 Distribution 124 vulgatum 122, /. 12^ Cereal Gra,sses, Sale 814 Cereals 814 Ceutorhynchus sulcicollis 676 Chaff 863 Chalaza 863 Chalon, J. 5 85 Chamomile, Corn Distribution 735 Scentless, Seed f. 638 Wild 664 Distribution 709 Chapman, G. H. 833, 851, 856, 859 Charles, V. K. 583 Charlock 845, 848, 851 English 155-157, 676, f. 156, 159, 701 Chemical composition 157 Distribution 717, 734, 735, m. 157 Seed 444, 543, f. m, 51,2 Jointed 153-155, 853, f. 151, Chemical composition 674 Distribution 696, 699, 717, 735, 736, m. 155 sp. 664, 668 Diseases 678, 680 Seed 814 White syn. Jointed Charlock Cheat syn. Chess Cheeses 219-221, f. 210 Distribution 687, 718, 725, m. 221 Seed 558-559, f. 558 Chemical composition 837 Barley, Little 61, 63 Barnyard Grass 17 Catnip 273 Charlock, English 157 Charlock, Jointed 674 Chiess 48, 50 Chess, Soft 46, 48 Clover, Sweet 188, 190 Corn-flower 673, 674 Crab Grass 10 Crowfoot Grass 43 Dock, Curled 75 Dropseed Grass 34-35 Foxtail 19 Foxtail, Green 21-22 Lamb's Quarters 109 Medic, Black 190 Mustard, Hedge 165 Mustard, Wild 157 Nettle. Stinsi-ing 70 Persicaria 674 Pigeon Grass 19 Pigweed 109 Plantain, Common 299 Purslane 138 Quack Gra.=s 57 Sheep Sorrel 82 Sow Thistle 674 Spurrey 674 Squirrel-tail Grass 60-61 880 INDEX Vetch 199 Yarrow 674 Wild Radish 674 Wire Grass 43 Chemical sprays 847, 84 8, 849, 850, 851, 852 Chenopodiaceae 3, 99-113, 633 Bibliography 582 Distribution 716, 724, 743, 747 Seed 431-433, 532-533 Chenopodium album 107-109, 664, 676, 697, f. lOS. 095 Chemical composition 109 Di"tribution 691, 696, 716, 729, <'95, 829, TO. JOB Seed 432, 532, f. m, 5S2 ambrosioides 103-104, 775, 790, f.lOi Distribution 696, 738, 746 anthelminticum 103 botrys f. 105 Distribution 716, 746 glaucmn. Distribution 746 hybridum 105-107, 789, f. 106 Distribution 716, m. 107 Seed 432, f. 1,32 murale. Seed f. Jf32 rubrum. Distribution 746 urbicum. Distribution 746 Cherry, Black, Wild f. 637 Fire 703 Ground 277, 279-280, 657, 789, f. 280 Distribution m. 2S0 Root 651 Seed 569 Red, Distribution 694, f. 568 sp. 630, 632, f. 612 Winter f. 623 Chesnut, V. K. 853 .Chess 48-50, 788, 819, f. ^9 Chemical composition 48, 50 Distribution 692, 715, 733, 736, in. 50 Seed 420, 517, 814, f. 1,19 Soft 46-48, 789, f. 1,7 Chemical composition 46, 48 Distribution 715, 733, m. 17 Seed 419, f. ^19 Chestnut, Horse f. 597 Water, Distribution 712 Chickweed 121-122, 629, 661, 663, 786 787, f. 121 Distribution 696, 708, 716, 725, 735, TO. 122 Seed 435, 810, f. 1,35. 635, 638 Mouse-ear 122, 787, f. 123 Distribution 716, 740 Larger, Distribution 124 Nodding 122-123, f. 123 Distribution 122 Cliicory 384-386, 778, 789, 793, f. 386 Distribution 688, 692, 708, 721, 727, 754, TO. 3S6 Seed 496, 579, 814, 836, f. 1,96, 579, 676, 6S8, 711 Chile, Seeds 836 Weeds 728 Chilean Dodder 464, 465, 828, 836 Chives 66 Chlorophyll 600, 863 cell f. 599 Chloroplast 59 8 Christianson, C. & G. R. 749 Chromatophore 863 Chrysanthemum leucanthemum v. pin- natifidum 362-364, f. 363 Distribution 720, 727, 755, SOS, m. 363 Root system 654 Seed 492, f. Ji92 rust 678 segetum Distribution 735, 736 Chufas 63 Cichorium intj'bus 384-386, 778, 789, f. 385 Distribution 712, 721, 727, m. 386 Seed 496, 579, 754, f. 1,98, 579, 688, 711 Cicuta maculata 230-233, 596, 776, 788, f. 201, 232, 233 Distribution to. 231 Seed 460, f. 1,61 virosa Distribution 736 Cieslar, Ad 830, 856 Cinquefoil 175-176, 592, 596, 614, 632, 789, f. 176, 638 Distribution 742, to. 176 Seed 448, 449, f. W Shrubby 842, 849 Silky, Distribution 734 Silvery syn. Silverweed Cirsium acaule 667 Distribution 736 alteraceum. Distribution 736 altissimum 790 Seed 494, f. 1,95 arvense 379-382, 592, 667, 788. 796, 799, 808, 819, f. 380, 381. 592 Distribution 712, 721, 727, 735, 736, 748-749, to. 381 Root 651 Seed 494, 810, f. m canescens 374-476. 790. f. 37!,, 375,71,9 Distribution 721. 749-750, m. 375 discolor 376-377, 789, f. 376, 377 Distribution m. 377 drummondii. Distribution 694 drummondii v. acaulescens. Distri- bution 694 eriocephalum. Distribution 694 foliosum, Distribution 694 heterophyllum, Distribution 736 loense 377-379, 7S9, f. 37S Distribution m. 378 Seed 495, 578, f. Ifio. 578 lanceolatum 372-373, 667, 789, f. 373 Distribution 695, 721, 725, 727, 736, TO. 373 Root system f. 650 Seed 495, f. m palustre 667 Distribution 736, 748 pratense. Distribution 712 sp. 676, 693 undulatum Root 651 Seed 495, f. 1,95 City Goosefoot, Distribution 746 Clammy Weed f. 172 Distribution 717 Clapper, M. 763 Clark, G. H. 24, 57, 59, 76, 80, 97, 111, 126, 130, 132, 138, 147, 149, 151, 250, 251, 294, 297, 301, 328, 360, 362, 382, 384. 390, 391, 394, 399, 825, 826, 827, 836, 839, S60 Clarke, G. W. IV, V Claviceps purpurea 678, 680 Clay soils. Weeds of 819 Claypole, E. W. 703, 706, 839 Cleat^ers syn. Bedstraw Cleistogamous flowers 629 Cleome serrulata 173-175, 789, f. 174- 175 Distribution 693, 717, 729, 730, m. m Seed 448. f. US Climbing Milkweed 241, 242, 243 Clinton 765 Clinton, G. P. 826, 839 Clotbur 625 Spiny 334, f. 336 Distribution 698, 713, 737. 754, 821 Seed 485-486, f.. 1,85 INDEX 881 Clothier, G. L. 842 Clover Alsike, Seed 450, 810, 812, 830, f. J,51, GSS Impurities S31, f. 63S Bokhara syn. Sweet Clover Bur, Distribution 708 Seed 452, 549, 810, 811, 815, 832, 834, f. 453, 5i8 Busli, Seed 454, 552, f. m Crimson Seed 812, 831 Dodder 250-253, f. 63S Distribution 719, 735 Seed 465, 810, 828, 835, f. i65 Fields, Weeds of 637 Hop 787, f. m Distribution 734, 760 Low 183, 184, 185. f. 185 Distribution 718, 734, 761, in. 185 Seed 451, f. m Japan, Seed 831 June, Seed 812 Meadows, Weeds of 846 Mexican, Distribution 723 Peavine, Seed 812 Prairie, Hairy Seed 550, 552, f. 551 Red, Seed 451, 810, 811, 812, 828, 830, 831, 832, 833, 836, 855, 857, f. J,51, 638 Impurities in, 78, 130, 149, 175, 360, 674, 692, 698, 705, 712, 830, 831, 835, 836, 855, 856, 857, 858, 859, f. 67 i, 726 Mammoth, Seed 811, 812 Medium, Seed 811. 830 Small, Seed 812 Sapling, Seed 812 Sour, Seed 526, f. 526 sp. 6, 67, 180, 624, f. 596, 605, 612 Seed 805, 806, 812, 814, 827, 828, .'='30, 831, 833, 836 Stinking syn. Rocky Mountain Bee- Plcifit Stone, Distribution 718, 760 Sweet sp. Seed 794, 815, 834 White 187-190, 788, 794, f. 188 Chemical composition 188-189 Distribution 718, 725, 729, 760, m. 189 Root system 645, 648, f. 6U Seed 451, 549, 550, 810, 811, 831, 832, f. m, 5J,8, 726 Yellow 186-187, 776, 789, f. 186 Distribution 713, 718, 725, 729, 759, m. 187 Seed 452, 810, 813, f. 1(52, 5i8 White (T. repens) Distribution 718 Seed 830, 831, f. 1,51, 638 White (T. agrarium) syn. Yellow Clover Yellow, Seed 183-184, 450, f. 1,51 Club-root of Cabbag-e 680 Ckister-cup, Gooseberry-leaf 678 Pine 678 Cnicv.s arvensis syn. Cirsiuin arvense Coast Elite, Distribution 746 Cockerel, T. D. A. 839 Cockle, Corn 125-126, 665, 776, 789, 819, 829, f. 700 Distribution 692, 699, 709, 716, in. 126 Seed 436, 674, 735, 736, 810, 829, 838, f. i36, 688 Cow, Seed 814 Purple, Seed 814 White, Seed 810, 814 Cocklebur 334-337, 631, 637, 681, 790, 794, 795, 799, 808, 822. 839, 850, f. 335, 682 Distribution 720, m. 335 Root System 645 , Seed 485, /. 1,85 Dagger 794 Spined syn. Clotbur ' , Cockscomb Distribution 696, 736 Coit, J. B. 839 Colburn, F. E. XII Colchicum 66 autumnale 667 Distribution 736 Collman, C. 748 CoUomia grandiflora. Distribution 737 Colonists, Plant 696 .\ ,„, Colorado Beetle 667 :' . J.'^' Grassss 837 j' - Weeds 745, 747, 748, 755, 757, 759 Coltsfoot 663, 664, 665 Distribution 735, 736 Coma 629, 631, 864 Combs, Robert 745 Comfrey, Common 256, f. 635 Distribution 719 Wild (Cynoglossum boreale) Seed 466, f. i66 Wild (C. virginianum) 258-259, f. 259 Distribution m. 259 Seed 564-565, f. 565 Commerce aids in scattering seeds 687- 688, f. 688 Common alien plants 697-698 Complete flower 604, f. 601, CoMPOSiTAE 4, 307, 404, 633, 701, 788, 785 Bibliography 582, 583 Distribution 720-721, 724, 747-756 Inflorescence 614, f. 613 Seeds 477-502, 574-580 Composite Family syn. Sunflower Family Cone-flower Distribution 720, 737 Seed 486, f. 1,86 Gray-headed, Seed 486-487, f. 487 Purple f. 666 Connecticut Experiment Station XII Legislation 794 Seed investigations 830 Weeds 766 Conium maculatum^ 709, 776, f. 710 Distribution 712, 719, 728, 736, 768-769. Conringla orientalis 160-162, 592, 788, f. 161, 162 Distribution m. 162 Seed 446, f. m Constantinesco, A. 582 CONVOLVULACEAE 4, 241, 254 Bibliography 5 83 Distribution 719, 724, 756-757 Seed 463-465, 563-564 Convolvulus arvensis 248-250, 663, 665, 777, 787, f. 249 Distribution 719, 727, 735, 736, 756-757, m. 249 Root svstem 651, f. 653 Seed 463, 563, f. 46L 563 Family 241-254 Seed 463-465, 563-564 sepium 245-248, 787, f. 246 Distribution 691, 719, 740, m. 246 Root system 652, f. 651 Seed 464, 564, 810, f. 4U. 563 Cook, L. C. 840 Coral Honeysuckle 307 Coralierry syn. Indian Currant Cordemoy, J. de. 583 Coreopsis 307, 489, 689 Distribution 838 883 INDEX palrnata 689 tinctoria Distribution 740, 844 Corispermum hyssopifolium 698 Distribution 737 Corn 368, f. 505 Seed 813 Broom 512 Seed 514, f. 513, 516 Cliamomile, Distribution 735 Cocl^Ie 125-126, 665, 776, 789, 819, 829, f. 125, 700 Distribution 692, 699, 709, 716, 735, 736, 829, 838, m. 126 Seed 436, 810, f. i36, 688 Crowfoot 663 Fields, Weeds of 692, 845, f. 2h 661, 663 Gromwell 262-263, 787, f. 262 Seed 467, f. J,68 Kaffir 8 Marigold, Distribution 735, 736 Mint 665 Poppy 7 35, f. 61S Speedwell 723 Spurrey, Distribution 813 Sweet, Seed 813 Cornell University 673 Corn-flower 677 Chemical composition 673, 674 Distribution 735 Seed 496, 814, f. 1,91, 688 Trichomes f. .^97 Corolla 604, 864 Corymb 612, 864 Cosmopolitan weeds 695, 736, 757, 763, 777, 786 Cosmos 307 bipinnatus, Distribution 69 6 Cotta, H. 840 Cotton 213 Thistle 667 Distribution 725 Cotyledons 623, 864 Couch Grass 851 Black 664 Coulter, J. C. 747, 757 Coverdale, F. 187 Coville, F. V. 840 Cow Cockle 814 Parsnip 234, f. 231, Seed f. 561. 562 Cowbane 230-233, 683, 776, 788, f. 231, 232, 233 Distribution 736, m. 231 Seed 4 60, f. J,61 Spotted 596 Cow-herb 132-134, 789, f. 133 Distribution 692, 696, 697, m. 13.', Seed 438, f. 1,38 Cowpea 180 Cox, H. R. 839, 848, 861 Crab Grass, Common 8-10, 731, 785, 790, f. 9 Chemical composition 10 Distribution 714. 731, m. 9 . Root system 647 Seel 409, f. 1,09, 676 Smooth 10-12, f. 11 Distribution 714, m. 12 Seed 408-409, 810. f. 1,09 Sprouting 14-15. f. 15 Distribution 691, 714, m. 15 Seed 410, f. 1,10 Craig, M. S40 Cranberry marshes. Weeds of 846 Crandall, C. S. 755, 826 Crane. O. B. 84 8 Cranesbill, Carolina 555, f. 556 Wild, Distribution 718 Crassulaceae, Distribution 724 Craty, R. I. XI, 745, 748, 749, 751, 759, 760, 766, 767 Crawford, A. F. 763 Creeping Buttercup 141 Charley syn. Ground Ivy Soft Grass 665, 667 Spurge 208, 209, 458 Verbena syn. Prostrate Vervain Cremocarp 864 Cress, Marsh 167-168, 787, f. 167 Distribution 742, m. 168 Seed 447, f. 1,1,7 Seed 441, f. 1,1,1 Water 142 Distribution 717 Winter 170, 677, f. 170 Distribution 717, 733, 740, m. 171 Seed 447-448, f. 1,1,7, 51,2, 51,1, Crimson Clover 812, 831 Crocker. Wm. 829, 856 Cropping, continuous. Effect of 684 Cross cell, see Cell, Gross Crosby, J. C. 840 Crosby, M. L. 836 Crotalaria sagittalis 182-183, 788, f. 182 Distribution 718, m. 183 Seed 545-546, f. 51,6 Crowfoot. Distribution 742 Corn 663 Family svn. Buttercup Family Grass 41-43, f. 1,2 Chemical composition 43 Distribution 732, m. 1,2 Seed 416, f. 1,16 Small-flowered 139, f. 139 Distribution 717, m. 11,0 Seed 440, 536, f. 1,1,0, 536 Crown 654 Crownbeard, Seed 575. f. 577 Crozier, A. A. 766, 825 Crucifer 677, 785, f. 606 Cruciferae 4, 142, 170, 634, 776, 819 Bibliography 583 Distribution 717, 724 Seed 441-448, 539, 544 Crusaders distributed weeds 700 Cryer, J. 840 Cucumber, Bur. Distribution 737 T^^ild 573. f. 57i CucuRBiTACEAE, Distribution 724 Seed 573 Cudwee'i. Distribution 720, 741 Culm 864 Crvstalloids 864 Cunningham. J. C. VII, XII. 641 Pup Plant. Seed 482, f. 1,83 Curled Dock 74-76, 426-427, 630, 647, 65''., 654, 660, 696, 617, 716, 725, 727, 736, 774, 788. 794, 796, 799, 805. 810, 814, 834 Currant f. 612 Indian 307, 790, f. 308 Distribution m. SOS PurtiP, C. F. V. Cuscuta arvensis 252-254, 789, f. 25S Distribution 712, 719, 729, m. 252 Seed 810 chi'ensi.s. Seed 465, f. 1,65 epilinum f. 953 epithymum 250-253, f. 251, 253 Distribution 712, 719, 725, 729, 735, m. 251 Seed 4 65. 564, 810, f. 1,65. 56i euronaea 852 sp. 850 Seed 828. 829 Cusick, M^m. 6^4, 726, 751, 840 Cutler. Mana?seh 708, 711 Cvclachaena xanthifolia 332 Cycloloma atriplicifolium 99-101, 788, f. 100 INDEX 883 Distribution 716, 740, m. 100 Seed 431, f. m, TSO platyphyllnm syn. C. atriplicifoliiwi Cyme 614, 864 Cynara cardunculus 701 Cynodon daetylon Distribution 732 Cynog-lossuni boreale 787 Seed 466, f. 466 officinale 256-257, 777, f. 257 Distribution 719, m. 257 Seed 466, f. 1,66 virginianum 258-259, f. 259 Distribution m. 259 Seed 564-565, f. 565 sp. f. 635 Ctpbraceae 3, 63, 407-408, 636 Distribution 715, 724 Cj'perus esculentus 63, 790, f. 64 Distribution 696, 697, 715, in. 6i rotundus 63 Distribution 722, 723 Cypress Spurge 718, f. 735 Distribution 736 Cypripedium acaule 702 Cystopus candidus 677, 678 Dactylis glomerata Distribution 715 Seed 417, 811, 813, f. m Dagger Coeklebur 794 Spanish, Root system 645 Dalimen, Max 580 Daily, C. B. 749 Daisv 362, 665, 667, 677 Fleabane 322-324, 657, 658 Distribution 720 Seed 482, f. 1,81 Trichomes f. 1,82 Ox-eye 362-364, 667, 793, 794, f. 363 Distribution 704, 720, 727 Root system 654 Seed 492, f. 1,92, 638 sp. f. 595 Dakota Vetch 761 Dakota North, Flora 839 Seed investigation 834 "Weed legislation 794, 806-807 Weeds 744, 757 South ^Veed legislation 794, 805 Weeds 744, 756, 757, 767 Vetch 761 Weeds 693 753 Dalea alopec'uroides 192-193, 790, f. 192 Distribution 718. 790, m. 193 Seed 453, 550, 552, f. m. 551 Foxtail syn. Dalea laxiflora Seed 454, f. m Distribution f. 1,51, Pink, Seed 454, f. 1,51, Dandelion 386-389, 592, 604, .629, 633, 657, 659, 664, 676, 773, 780. 786, 787, 814, 819, 843. 850, f. 18, 386, 387, 388, 389, 623, 71,3 Chemical composition 389 ' Distribution 630, 696, 697, 704, 708, 721, 743, 838, m. 387 Root svstem 648, 654 Seed 490, 579, f. 1,98, 580 Dark-seeded syn. of Red-seeded 390-391, 787, f. 396 Distribution 721 Seed 498, f. 498, 631 Small-flotoered syn. Red-seeded Dan- delion Danger, L. 736, 753, 819, 848 Danish Seed Control Station 828 Dark-seeded Dandelion syn. Red-seeded Dandelion Darlington, Wm. 756, 760, 761, 762, 767, 820, 822, 826, 840 Darnel, Distribution 692, 699, 715 Poison 52-53, f. 52 Distribution 696, 699, 715, 736, m. 53 Seed 522-524, f. 520, 521, 523, 524 Datura stramonium 288-291, 777, 788, f. 290, 709 Distribution 696, 720, 736, 767, m. 290 Seed 471, 569, f. 472, 568, 621, tatula 288-291, 777, 787, f. 289 Distribution 697, 720, m. 289 Daucus carota 227-228, 7 88, 796, f. 227, 768 Distribution 698, 712, 719, 725, 767-768, 796, 802, 819, m. 228 Seed 461, 562, f. 462, 561, 635 Davis Weed 218 Day Nettle 664 Dead Nettle 665, 719, 723, 727, 822 Deadly Nightshade 736 Delaware Weed legislation 794 Weeds 765 De Loach, G. B. 856 Delphinium consolida Seed 439, f. 4-19 penardi 142, f. 11,2 Seed 439, f. 1,39 ' Denmark Weeds 753, 766, 795, 844 Seed investigations 828 Deschampsia flexuosa Seed f. 639 Desmodium canescens 690 Des Moines Capital 803 Determinate inflorescence 610-614 Devol, W. S. 831, 85 6 Dewey, L. H. 396, 708, 744, 745, 795, 825, 826, 840, 848, 856, 860, 861 Diamond-back Moth 677 Dibble, W. 851 DICOTYDEDONBA:^; 3, 67-404 Dlcotvledons 623, 864 Dicots 67-404 Didlake, M. L. 857, 860 Digitalis Distribution 693 purpurea Distribution 227. 736 Digitaria humifusa 10-12, 789, f. 11 Distribution 691, 714, m. 12 Seed 408-409, 505, 810, f. 409, 505 sangLiinalis 8-10, 790, f. 9, 11, 731 Chemical composition 10 Distribution 691. 714, 731, m. 9 Root system 647 Seed 409, f. 409. 676 Dioecious plants 605 Dioscorides 773 DiPSACBAE Distribution 724 Dissemination, Burs 256 bv woollen mills 203 Dock, Bitter 78-79, 595, 789, f. 79 Distribution in. 79 Seed 427, 726, f. 427 Bloodv, Distribution 716 Broad-leaved syn. Bloody Dock • Curled 74-76, 660, 774, 788, 794, 796, 799, 808, f. 74. 76, 630, 727 Chemical composition 75 Distribution 652, 696, 697, 716, 725, m. 75, 736 Root svstem 652, 654, f. 647 Seed 426-427, 810, 814, 834, f. 426, 638 Pale, Distribution 716 Patience, Distribution 763 Peach-leaved sijn. Smooth Dock Red-veined syn. Bitter Dock 884 INDEX Smooth 76-78, 787, 794, 796, 799, f. 77, 78 Root system 654 Distribution in. 77 Seed 427, f. V?.l Sour syn. Curled Dock sp. 592, 630, 649, 660, 665, 667, 67b, 678, 687. 734, 773, 774 Seed 832 Tall. See Curled Doch Yellow. See Curled Dock Dodder 645, 665, 688, 838, 839, 850, 852 Alfalfa 252 Seed 810 Chilean Seed 465, 828, 836, f. Jt65 Clover 250-252, f. 251, 253 Distribution 719, 725, 729, in. 251 Seed 465, 564, 810, 828, 835, f. J,65, 663, 638, 726 Lesser f. 2')3 Field 252-254, f. 253 Distribution 719, 729, m. 25i Seed 464, 810, f. m Flax f. 253 Perennial 843 sp. 645, 692 Seed 640, 814, 833, 834, 856, 857 Thyme f. 253 Dodson, W. R. 840 Dog- Grass 774 Doa Fennel svn. Mayweed Dogbane Family 234-237 Distribution 723 Spreading- 235, 237 Distribution 719, m. 235 Dooryard Knotgrass syn. Knotiveed Knotweed 84-85, 428, €59, 716, 736, 742 Plantain syn. Common Plantain Dooryard weeds f. 25 Dormant period 786 Dorph-Petersen, K. 828, 856 Doryphora decemlineata 677 Do-wny Brome Grass 50-52, 420, 714, 715, 728, 819 Dragon Root f. 596 Drains clogged by weeds 682 Dropseed Grass 785, 790, 850 Seed 834, f. 616 Mexican 32-34, 660, f. 33 Chemical composition 34-35 Distribution 715, m. 33 Seed 413-414, f. !,U Drug plants 853 Preparing for market 780-781 Raising 773. 780-781, 854, 855 Drugs, Root 85 3 Drysdale, J. 851 Duggar, J. F. 853 Duncan, J. H. 768 Duvel, J. W. T. 835, 856 Dyer's Green "Weed 667 Distribution 718 Dyssodia chrysanthemoides syn. of papposa 356-358, 789. f. 357. 358 Distribution 705, 720, 755, m. 357 Seed 490-491, f. 1,91 JTrichomes f. pi Barnshaw, G. T. 851 Eaton, A. J. 84 8 Echinochloa crusgalli 16-17, 790, f. 16 Chemical comnosition 17 Distribution 714, 731, in. 16 Seed 411-412, 506, f. J,ll, 505, 729 Echinocystis lobata. Seed f. 57Jf Echinospermnm lappula syn. Lappula echinata Echium vulgare 468, f. ^68 Distribution 719 Eclipta alba. Distribution 756 Economic plants 853 Edson, H. A. 848 Edwards, A. H. 763 Eelworm, Stem. 677 Egg, 620, f. 621 Egg-case 617 Eggert, Henry 747, 766 Ehinger, G. E. 756 Ehrhart, F. 840 Eichornia crassipes. Distribution 712 Elatinaceae Distribution 724 Eleagnus f. 602 Elder, Marsh 332-334, f. 333. 752 Distribution 720, 729, 751-753. m. 333 Seed 482, 814 Elecampane Distribution 709, 720 Eleocharis palustris. Seed 407-408, f. 1,07 Eleusine indica 41-43, 788, f. 42 Chemical composition 43 Distribution 696, 698, 715, 733 Seed 416, t il6 Elliott, W. B. 763, 767 Elkweed Distribution 694. 840 Ellisia, Common 255-256. f. 255 nyctelea 255-256, f. 255 Distribution 719, m. 256 Elm 69 Distribution 695 Elodea canadensis Distribution 740 Embryo 621-623. 624, 864, f. 622 Sac 620, f. 630. 621 Endive, Wild 793 Endosperm 865 England, Weeds of 763 English Charlock 155-157, 444, 542, 543, 701, 717, 735 Plantain syn. Buckhorn Rye Grass syn. Perennial Rye Grass Envelopes, Floral 609, f. 609 Epicarp 865 Epichloe typhina 677 Epiderm 865 Epidermal cell. See Cell, Epidermal Epidermis 597, f. 59S Epigaea, sp. 702 Epig-T,'nous flowers 610, f. 611 Epilobium angustifolium Distribution 693, 694, 726, 741 hirsutum Seed 829 roseum Seed 829 sp. 703 spicatum Distribution 840 Equisetaceae 3, 6 Equisetum arvense 5, 6, f. 5, 6 Distribution 736, m. 5 palustre 849 Distribution 736 Eradication, of weeds 846-853 Also see species Eragrostis pilosa 45-46, 789, f. i5 Distribution 715, 732, m. ^6 Seed 417, 740, f. 1,16 Pilose syn. Spear Grass Erechtites hieracifolia 368-369, 778, 789. f. 369 Distribution 6'15, 721, m. 369 Seed 492, f. 1,92 sp. 703 Erect Knotweed 8'', 83, 429, 526, 696, 716, 725, 789 Ergot 680, 814, 815, f. 639 Rye 678 INDEX 885 Erica arborea, Distribution 693 Brigeron acris Distribution 741 annuus 321-322, 595, 788, f. S21, 621 Distribution 695, 720, 737, in. SZB Seed 482, f. m canadensis 322-326, 660, 664, 778, 788 Distribution 690, 695, 696, 698, 704, 720, 736, 737, 754, 819, m. S26 Seed 482, f. m ramosus 321, 322-324, 788, f. S2S Distribution 720, in. SSi Seed f. m sp. f. 621 Erodium cicutarium i57, f. i57 Distribution 725, 729, 734 .moschatum Distribution 713, 725 Muslv Distribution 713, 725 sp. 711 Eruca sativa 159-160, f. 159 Distribution 712, m. 160 Ervum lens 554 Eryngium sp. Distribution 701 Erysimum cheiranthoides. Distribution 741 Erysiplie graminis f. 6S2 Escholtzia, Distribution 725 Eskech, J. N. 766 Esparcette 831 Essential organs 605, 615 EUPATOEIACEAB 693 Eupatorium perfoliatum 778 purpureum 780 Seed 477, f. ps Trichomes, f. i78 urticaefolium 312-313, 780, 789, f. 312 Distribution m. 313 Seed 477, f. 47S Trichomes f. i78 villosum 477 Trichomes f. i78 Euphorbia corollata 210, f. 211 Distribution 690, 718, f. 211 cyparissias 212-213, 819, f. 212, 735 Distribution 712, 718, 736, in. 213 Seed f. 557 exigua 664 geyeri, Distribution 690 maculata 208-209, 586, 788, f. 209 Distribution 690, 718, m. 209 Seed 458, 557, f. h57 marginata 210-211, 7 87, f. 210, 712 Distribution 712, in. 211 Seed 458, f. Jf5S peplus 819 preslii 207-208, 787, f. 207 Distribution 718, m. 208 Seed 458, 556-557, f. i58 sp. 660 Distribution 705 Euphorbia CEAE 3, 205-213 Bibliography 583-584 Distribution 718, 724, 757 Seeds 457-458, 556-557 European Bindweed 248-250, 563, 653, 663, 665, 710, 719, 727, 735, 736, 777, 787, 822, 844 Morning Glorii syn. Bindweed Weeds 703, 704, 706, 713, 731, 732, 733, 734, 748 European weeds from America 737-740 Evans, Dr. 681 Evans, Ed. 750. Evans. J. R. 853 Evans, M. W. 836 Evening Catchfly I 437 Catchfly II 437 Primrose 224, 225, 460, 560, 592, 645, 690, 696, 718, 737. 762, 776, 788, 819 Family 224-225, 460, 724 Ewart, A. J. 187, 829, 837, 840, 856 Everlasting, Distribution 740 Explosive seeds 629, 631. 634 Fagopyrum esculentum Distribution 736 Seed 531, f. 526 Fahlenkamp, H. R. 749 Fallow field. Weeds of 661 False Acacia 718 Boneset 47 8, 479 Calais, 501, 502 Flax 149-151, 443, 542, 544, 700, 717, 788, 793, 815 Small-fruited 638 Lettuce 500 Strawberry 175-176 Farmer's Review 188, 250. 826 Farwell 753 Fawcett, H. S. 746, 835, 856 Fendler 751, 767 Fern, Boston 5 Maidenhair 5 Shield 5 Fernald, M. L. XI, 687, 702, 709, 710, 714, 731, 750, 754, 767, 768, 840. Ferns 5-6 Fertilization 620-621, f. 620. 621 Double 621 Fescue Grass 785 Seed 827 Meadow Distribution 715 Seed 418, 810, 811, 813, f. il8 Sheep's Distribution 715 Festuca elatior 418, f. ilS elatior pratensis Distribution 715 Seed 811, 813 ovina Distribution 715 pratensis syn. F. elatior pratensis Fetid Marigold 356-358, 490-491, 755, 789 Feverfew, Distribution 734 Feverwort 778 Fiber plant 861 Fibrovascular bundle 865 Field Brome Grass 715 Dodder 252-254, 464, 719, 729, 789, 810 Larkspur 439 Marigold syn. Corn Marigold Mint 665 Pennycress 143, 814 Sorrel 202-203, 630, 734, 741 Soio Thistle syn. Perennial Sow Thistle Thistle syn. Prairie Thistle Pig 69 Figwort Family syn. Mullein Family Filament 615 Fine Bent Grass 664, 665 Fiiiqer Grass Syn. Crab Grass Fink, Bruce 755, 762, 763 Fir, Douglas, Distribution 694 Oregon, Distribution 694 Fire, Flora following 69 3-695, 702, 703 Fireweed 368-369, 703, 778, 789, f. 369 Distribution 695, 721, m. 569 Seed 492, f. m Mexican 101-103, f. 102 Distribution 714, 716, 746, m. 103 Seed f. 433 Northern 694, 703 Distribution 726, 741 Fitzpatrick, F. J. 766 • .; 886 INDEX Five-finger syn. Cinquefoil Tall 657 .Flax, Common Seed 456, 554-555, 810, 813, f. -',5C, 5i>5 Impurities in 692, 744, 839 Dodder f. 253 False 149-151, 788, 793, f. LW Distribution 700, 717, m. 131 Seed 443, 544, 815, f. W, 5^2 Small-fruited, Seed f. 63S Family, Distribution 724 Mustard 155 Fleabane 321-322, 788, f. 3.21 Distribution 695, 720, 737, in. 322 Seed 482, f. W Branched syn. Dais\] Fleabane Daisy 322-324, 657, '658 Distribution 720 Seed 482, f. J,S1 sp. 741, f. 621 Fletcher 749 Fletcher, James 24, 57, 59, 76, 80, 97, 111, 126, 130, 132, 138, 147, 149, 151, 250-251, 294, 297, 301, 328, 360, 362, 382, 384, 390, 391, 394, 766, 825, 826, 839 Flora Cestrica 766 Floras Australia 696, 731, 733, 734, 763 Boston 708-709 Bremen 707, 713-714 British Isles 714, 731, 838 Buenos Ayres 702 California 845, 853 Central America 731 France 713, 731, 837, 846 Germany 731, 841 Italy 731, 838 Missouri 854 Montana 838, 853 Nebraska 845 New England 709, 714 New South AVales 731 North Carolina 854 North Dakota 839 Ohio 723 Oklahoma 838 Oregon 694 Pampas 701 Plymouth 845 Tennessee 853 Vienna 843 Westchester, Pa. 766 ^''est Indies 731 Wisconsin drift 689-692 Yucatan 731 Floral axis 611 envelopes 609, 610, f. 609 Florida, Weeds 762 Florula Bostoniensis 708-709 Flowering plants 6-404 Spurge 210, 211, 556, 557, 690, 718 Flowers 604-625 Apetalous 609 Axillary 611 Bisexual 605 Complete 604, f. 60.'t Epigynous 610, f. 611 Funnel-shaped f. 611 Gamopetalous f. 608 Hypogynous 610, f. 606 Imperfect 605 Irregular f. 605 Morphology of 604-625 Perfect 605, f. 60i Perigynous f. 610 Pistillate 605, f. 606, 607 Solitary 611. f. 611 Staminate 605, f. 606, 601 Sterile f. 607 . Strap-shaped f. 611 Tubular f. 611 Fluckiger, F. A. 5 80 Ply Beetle 676 Cabbage-root 677 Celery 677 Frit 677 Mangold 676 Foeniculum capillaceum 702 Fogel, Estella D. 861 Food plants become weeds 712 Fool's Parsley 663, 736 Forest vegetation 693 Forget-me-not 664 Forgrave, Caroline 824 Formaldehyde 600 Foultes, P. H. 848 Four-leaved Grass 693 Fournier, Eug. 583 Four-o'clock Distribution 696 Family 119-120, 533 Wild 119-120, 660, 787, f. tW Distribution 716, m. 120 Seed 533, /. 53Jf Foxglove Distribution 693, 727, 736 Wild Yellow 702 Foxtail Bristly 22-24, 790, f. 22, 23 Distribution 714, 732 Grass syn. Marsh Foxtail Green 20-22, 506-511, 657, 790, f. 21, 507, 509, 510, 665 Chemical composition 21-22 Distribution 691, 714, 729, 731 Seed 412-413, 834, f. 412, 511, 512, 676 Marsh, Distribution 715, 732, 740, f. 732 Meadow, Distribution 715 Slender 665 sp. 664, 732, 850, f. 217, 661 'VChorled sun. Bristly Yellow 17-20, 22, 657, 658, 659, 660, 789, f. IS, 19 Chemical composition 19 Distribution 691, 714, m. 19 Seed 22, 413, 511, 512, 616, f. 1,13, 676 Fracker, S. B. 478, 479, 481, 487, 489 Fragrant Goldenrod 690 France, Flora 713, 731, 837, 846 Weed legislation 795 Weeds 753, 754, 763 Frank, A. B. 580, 820 Franseria discolor. Distribution 730 Seed 485, f. m Hookeriana 485, f. 484 Hooker's 485, f. m "White-leaved 485, f. iSi Freeman, G. F. 831, 859 Freight cars, Weeds distributed by 794 French, C. 841 French, G. T. 833, 834, 859 Frenchweed (Thlaspi) 794 Distribution 717 (Galinsoga) Distribution 736, 753 Fringed Gentian 702 Frit Fly 677 "^ruit 624-625, 865 Fruwirth, C. 820, 856 FUMARIACEAE Distribution 724 Fumitory 665 Family, Distribution 724 Fungi destructive to weeds 852 harbored by weeds 677-678 ■^unicle 865 Funnel-shaped flowers*/'. 611 Galeopsis tetrahit. Distribution 720, 727 Galinsoga par^aflora Distribution 713, 736, 737, 753-754 INDEX 887 Galium aparine 572, 663, f. STS Distribution 741 Seed 476, f. Ifl6 sp. 693 trifidum Distribution 741 Gall TVeevil, Cabbage 676 Turnip 676 Galloway, B. T. 838 Gamopetalous flowers f. 60S Garber 766 Garcke, A. 707, 731, 737, 738, 740, 754, 841 Garden OTach 735 Pink 120 Garden and Forest 725 Gardens, Weeds of 58-59, 93 Garlic 66 Wild 67, 787 Garman, H. 832, 848, 857, 860 Gattinger, A. 766, 853 Gaura, Biennial, Distribution 718 biennis 783 Distribution 718 Genista tinctoria 667 Distribution 718 Gentian, Closed 689 Fringed 702 Gentiana andrewsii 689 George, E. L. 749 Georgia 'Weeds 754 Geraniaceae 634 Distribution 718, 724 Seed 457, 555-556, 634 Geranium f. 602, 62^ carolinianum 555, f. 556 Family 457 Distribution 724, 734 maculatum, Distribution 718 Gerardia, sp. 702 Gerdts, C. L. 5 82 Germander, American 272-273, 789, f. S73 Distribution in. 273 Seed 469, f. J,70 Germany, Flora 731, 841 Weed legislation 795 Weeds 713, 735, 736, 753, 766, 820, 841, 845 Germination of Seeds 24, 99, 856, 857, 858 Standards 835 Te=t=; 835, 837, 855, 856, 857, 858, 859 Gesneria f. 619 Geum canadense 180, 788, f. 181 Distribution 717, m. 181 Seed 449, 545, f. W, 5Jf5 Geyer, C. A. 374, 767 Ghost Moth 677 Giant Hyssop, Seed 567, f. 567 Gibbons, W. P. 853 Gilia squarrosa 840 Gillanders, F. 851 Ginseno- 7 81, 854 Gland 865 Gleditsch, J. G. 841 Globoids 865 Glossary 862-872 Glover, G. H. 848 Glume S65 Glycvrrhiza lepidota 196-197, 787, f. 1% Distribution 718, 729, 760, m. 197 Seed 554, f. 551 Gmelin, J. F. 841, 848 Gnaphalium uligiriosum, Distribution 720, 741 Goat Weed, Distribution 736 Goat's Beard. Distribution 696, 729 Godfrin, H. 5 81 r^oessman. C. A. 837 Goff. E. S. 371, 824, 825, 826, 841 Golden Seal 854 Goldenrod, Canadian 313-314, 790, f. 3U Distribution 721, 737, m. SV, Seed 479, f. m Fra^^rant 690 Large Yellow-flowered 316-317, 689, 790, f. 317, 633 Distribution 73 8, m. 317 Seed 480, f. m Late syn. Smooth Goldenrod Smooth 315, 316, f. 315 Distribution m. 316 Seed 480, f. 480 sp. 6, 307, 592, 594, 645, 681, 689, 737, 738 Stiff syn. Large Yellow-floivered Goldenrod Goldflus, M. 582 Gonolobus laevis 241, 242-243, 789, f. Distribution f. 2J,3 Goodspeed, C. M. 854 Goose Grass sini. Crowfoot Grass Gooseberry-leaf Cluster-cup 678 Goosefoot, City, Distribution 746 Family 99-113, 633 Distribution 724, 743-747 Seed 431-433, 532-533 Maple-leaved 105-107, 789, f. 106 Distribution 716, m. 107 Seed 432, f. 1,32 Oak-leaved Distribution 746 Gorse 667 Gourd Family, Distribution 724 Graham, C. H. 746 Grain fields, weeds of 699-700 Gramineae 3, 7-63 Bibliography 5 84 Distribution 714-715, 724, 757-759 Seeds 407-424, 506-524 Grass Annual Brome, syn. Soft chess Annual Meadow 660, 664 Aioned Brome, syn. Doivny Brome Grass Awned Wheat 715 Awnless Brome 812 Barley 667 Barnyard 16, 17, 330, 412, 505, 506, 729. 731 Beard 722, 862 Bent 664, 667 Bermuda 732 Black Couch Grass syn. Fine Bent Blue 6, 8, 58, 638, 639, 657, 658, 659, 695, 715, 785, 811, 812, 830, 832, 857 Blue-stem 688, 689, 785 Bristly Foxtail 22-24, 714, 732, 790 Brome sp. 728, 819 Bulbous Oat Sim. Pearl Grass Candy 43-44, 416, 417, 715, 788 Carpet 722 Cheat sun. Chess Chess 48-50. 419, 517, 692, 715, 733, 736, 788, 819 Couch 851 Crab 8-10, 409, 647, 676, 714, 731, 785, 790 Creeping Soft 665 Crowfoot 41-43, 416, 732, 788 Dog 774 Downy Brome 50-52, 420, 714, 715, 728, 819 Dropseed 676, 785, 790, 834, 850 English Rye 811 Family 7-63, 407-424, 506-524, 584, 623, 636, 645, 677, 714-715, 724,. 757-759, 785 Fescue 785, 827 Field Brome 715 INDEX Fine Bent 664, 665 Fincjer syn. Crab Grass Four-leaved 693 Foxtail syn. Marsh Foxtail Grass Goose syn. Crowfoot Grass Green Foxtail 20-22/ 412, 413, 510, 511, 512, 657, 665, 676, 691, 714, 729, 731, 790 Hair 790 Hairy Brome 828 Holy 27-28, 693, 741, 787, 814 Hungarian 506 Hungarian Brome 419, 420 Italian Rye 421, 787, 811, 813 Johnson 7-8, 722, 805, 853 Land, Weeds of 665-667 Little Barley 61-63, 424, 715, 812 Long-awned Poverty 29-30 Low Spear 664, 715 Marsh Foxtail 715, 732, 740 Marsh Muhlenberg 35-37, 413 Meadow 660, 693 Meadow Fescue 418, 715, 810, 811, S13 Meadow Foxtail 715 Mexican Dropseed 32-35, 413-414, 660 Needle 666-667, 689, 790 Nimble Will 30-33, 735 Nut, Northern 63, 64, 696, 697, 715, 741, 790 Southern 63, 722, 723 Oat 810, 813 Old-Witch 12-14, 410, 660, 676, 706, 714, 740 Onion Couch 851 Orchard 417, 715, 810, 811. 813, 828, 832, 857 Pampas 8 Pearl 664, 665 Perennial Rye 420, 421, 789, 811, 813 Pigeon 17-20, 22, 413, 640, 676, 714, 732, 814 Porcupine syn. Needle Grass Poverty 28-29, 790 Powdery Mildew on 682 Quack 8, 27, 53-58, 241, 273, 421- 423, 640, 643, 648, 651, 664, 665, 674, 680, 688, 715, 736, 773, 774, 781, 786, 794, 796, 810, 819, 822, 844, 847, 848, 850 Quaking 667 Quick syn. Quack Grass Red Top 415, 680, 715, 805, 806, 810, 811, 813 Reed 733, 736 Reed Bent 693, 736 Rib syn. Buckhorn Ribbon 8 Rice Cut 739, 740 Rough-stalked Meadow 639, 715 Rye 785, 789, 810 Sandbur 25-26, 412, 517, 637, 714, 790 Scribner's Panic 660, 689 Scutch syn. Quack Grass Seed Impurities 832, 834, 855, 856, 857, 858, 859 Sheathed Rush 37-38, 715, 790 Sheep's Fescue 715 Side Oats 689 Silky Bent 639 Skunk-tail syn. Squirrel-tail Slender Foxtail 665 Slender Wheat 53, 57, 422, 423 Small Squirrel-tail 787 Small Rush 38-39, 715, 790 Smooth Brome syn. Hungarian Brome Grass Smooth Crab 10-12, 408-409, 505, 714, 789, 810 Soft Chess 46-48, 419, 715, 733, 789 Southern Spear 45-46, 416, 417, 715, 732, 740 Sprouting Crab 14-15, 410, 691, 714 Squirrel-tail 58-61, 678, 679, 680, 691, 693, 715, 729, 730, 788 Stink syn. Candy Grass Sweet Vernal 693, 714 Switch 6, 410, 411 Tickle syn. Old Witch Grass Timotliy 414-415, 517, 638, 676, 715, 785, 805, 806, 810, 813, 827, 832, 833 Tussock 667 Twitch 851 Vanilla syn. Holy Grass Velvet 693 Wall Barley 69 8 Western Wheat 53, 56, 423, 715 Wild Barley syn. Squirrel-tail Grass Wild Oats 40-41, 415-416, 664, 665, 674, 679, 715, 736, 789, 793, 810, 814, 829 Wire 41-43, 418, 697, 715, 741 "Wood Hair Grass 639 Woolly Soft 665 Yard syn. Croiofoot Grass Yellow Foxtail 17-20, 22, 413, 511, 512, 657, 658, 659, 660, 676, 691, 714, 789 Yorkshire Fog 665, 667 Grasses of Cornfields 17 Gravelly Soils, Weeds of 819 Gravis, A. 582 Gray, Asa 687, 704, 707, 714, 722, 747, 751, 753, 754, 755, 756, 757, 759, 760, 761, 762, 767, 768, 820, 841 Gray-headed Cone-flower 486-487 Grayson, J. 749 Great Britain, Weeds of 660, 663-664 Greater Ragweed 326-327, 645, 691, 720, 789, 814 Green Foxtail 20-22, 412-413, 506-511, 512, 657, 658, 659, 660, 665, 676, 691, 714, 729, 731, 790 Greene, E. L. 841 Greene, L. C. 247 Greene, M. L. 848 Greenish, H. G. 853 Greif, O. 841 Griffith, M. C. 749 Griffiths, D. 848 Grind elia 307 Scaly 780 squarrosa 780 Distribution 730, 756 Seed 479, f. J,SO Grisdale 836 Grisebach, A. H. R. 731 Gromwell, American Seed 467, f. J,67 Corn 262-263, 787, f. S62 Distribution 262-263 Seed 467, f. J,GS Ground Burnut syn. Caltrop Cherry 277, 279-280, 568, 569, 657 Virginia 279, 281 Ivy 275, 276, 594, 608, 719 Groundsel 660, 663, 678 Distribution 693, 725, 735, 736 Seed 493, f. ^93 sp. Distribution 694 Guard cell f. 598 Guerin, M. P. 584, 586 Guignard, L. 5 81 Gulf States, T^^eeds of 722 Gum-plant svn. Gumiveed Gumweed 307 Broad-leaved Distribution 730, 756 Seed 479 Giissow, H. T. 849 Guttenberg, H. V. 583, 828 INDEX GYMNOSPERMAE 3, 6, 404 Gymnosperms 6-404 Haberlandt, G. 585 Hackberry 69 Hadrome f. 59S Hag-lund, E. 841, 849 Hair Grass 79 Distribution 732 Plant 603 Hairy Brome Grass 828 Hedg-e Mustard 544 Prairie Clover 550, 551. 552 Vetch 455, 718 Hale, T. J. 751 TIalfhreed Weed syn. Marsh Elder Hall 751 Hall, A. D. 664 Hall, J. M. 749 Halsted, B. D. 80, 680, 758, 765, 766, 767, 826, 841, 849, 861 Haltica syn. Phyllotreta Hamburg Seed Control Station 827, 856 Hamill, S. O. 755 Hammond, R. F. 832 Hanausek 538, 575, 581, 584 Hanbury, D. 580 Hanover Weeds 753 Hansborough, Senator 826 Hare's-ear Mustard 161-162, 592, 788 Seed 446, 814, 815, f. W Harpel, L,. V. 755 Harper, R. M. 702, 841 Harrington, G. T. 834, 857 Harrison, F. C. 841 Hart, G. T. XII Hartig, Th. 841 Hartweg 766 Harvey 751 Harvey, P. L. 826, 832, 841, 857 Harz-, C. D. 533, 535, 539, 547, 553, 575, 581, 582, 583, 584, 585, 586, 587, 827, 830, 857 Havard, V. 751 Hawkbit 66< Distribution 721 Hawkweed 678, 840, 843, 845 (Hieracium), Distribution 750 Seed 502, f. 502 (Senecio), Distribution 754 Orange 842, 846, 849 Distribution 712, 750 Seed 502, 814, f. 502 sp. 846 Hawthorn, Distribution 695 Hay fever caused by pollen 681 Hayden 767 Hayden, Ada VII, XII, 627 Hayne, F. G. 853 Hays, W. M. 825, 842 Hazel f. 606 Distribution 693, 695 Heal-all syn. Self-heal Hedge Bindweed 245-248, 848 Mustard 164-165, 446-447, 543-544, 659, 664, 677, 717, 725, 787 Heileman, W. H. 837 Helenium autumnale 354-356, 780, 790, f. 255, S56 Distribution m. S55 Seed 490, f. J,91 tenuifolium f. 721 Distribution 722 Helianthus annuus 340-342, 596, 601, 789, f. 31,1, Sm Distribution 693, 730, 740, 756, m. Sil Seed 487, 575, f. JfST, 576 Trichomes f. iSS grosseserratus 344-346, 790, f. 3U, Si5 Distribution 691, m. 3^5 maximiliani 348-349, 790, f. 3^8 Distribution m. 3^8 occidentalis. Distribution 689, 690 Trichomes 478, f. J/SS petiolaris 342-343, 788, f. SiS Distribution 730, ?n. 343 Seed 487, f. JfS8 Trichomes f. 4S8 strumosus. Seed 488, f. 488 tuberosus 346-348, f. 3i6, 3^7 Distribution 740, m. 347 Trichomes 487, f. 4SS Heliopsis scabra 338-339, f. 338 Distribution 720, m. S39 Seed 486, f. J,86 Heliotrope, Wild, Distribution 695 Helminthosporium gramineum 677, f. 6S0 Hemlock 6 Poison 709, 776, f. 710 Distribution 719, 728, 768-769 Water syn. Cowbane Hemp 69, 70-72, 665, f. 71 Distribution 696, 697, 715, m. 71 Seed 425, 524-525, f. Jfi5, 525 Indian 235-237, f. 236 Distribution 719, m. 237 Root 651 Nettle, Distribution 720, 727 Water 118-119, 789, f. 118 Distribution 716, m. 119 Seed 435, f. 1,35 Wild, Root system 645 Hemsley, W. B. 731 Henbane 677 Black 277, 709 Distribution 736 Hen-bit f. 595 Henderson, L. P. 826, 842 Henfrey, A. 743, 861 Henkel, Alice 777, 853, 854 Henry, W. A. 826 Henshaw, H. W. 629 Henslow, J. S. 714 Hensman, R. 829, 857 Hepialus luperli 677 Hepner, F. B. 61, 188, 837 Heracleum lanatum 234, f. 231, Seed 562, f. 561 Herb 865 "Herball" 773 Hermaphrodite 866 Herr, Bertha XII Hexham Scent 843 Hibiscus trionum 221, 222, 790, 796, 802, f. 222, 761 Distribution 696, 697, 712, 713, 718, 761-762, m. 222, Seed 460 Hicks, F. H. 857 Hicks, J. F. 831, 859 Hieracium aurantiacum. Distribution 750 Seed 502, f. 502 canadense. Seed 502, f. 502 floribundum. Distribution 750 sp. 678 Hierochloe borealis 27-28, 787, /. 27, 71,2 Distribution 741, m. 27 odorata syn. H. borealis Higbee 765, 766 Highways, Weeds on 799-800, 805, 806, 807. 808 Hilgard, Eugene 725 Hill, E. J. 842 Hillman, F. H. XII, 464, 584, 826, 831, 836, 842. 855, 857 Hiltbrummer. John 757 Hiltner, L. 828 Hilum 865 Hinager, P. H. 757 Hitchcock, A. S. 250, 650, 707, 745, 746, 749, 756, 757, 759, 760, 761, 763, 826, 842 890 INDEX Hitier, H. 849 Hoarhound s\jn. Horehound Hoarv Alyssum 147-149 Vervain 264-266, 469, 659, 719, 789 Hock 707 Hodge 824 Hodson, E. R. 761 Hofmeister, W. 581 Hogenson, J. C. 849 Hogioeed syn. Smaller Ragweed Helens lanatus 667 mollis 667 sp., Distribiition 693 Holland Weeds 763 Hollyhock 213 Holm, Th. 584, 854 Holt, P. L. 861 Holy Grass 27-28, 787, f. S7, 7^2 Distribution 693, 741, m. 27 Seed 814 Honey Locust 180 Honeysuckle, Bush 307 Coral 307 Family, Distribution 724 Hooker, J. D. 731, 737, 740 Hooker's Franseria 485, f. 48-4 Hooper, L. J. 767 Hop Clover 787, f. 181, Distribution 734, 760 Low 183, 184-185, f. 185 Distribution 718, 745, 761, m. 185 Seed 451, f. J,51 Hops 69, f. 602 Hordeuni caespitosum. Distribution 729 jubatum 58-61, 788, 808, f. 59, 60,758 Chemical composition 60, 61 Distribution 691, 715, 729, 730, 757, 759, m. 60 Seed 423, 519-520, f. m, 505 murinum 677, 698, .701 pratense 667 pusillum 61-63, 787, f. 62 Chemical composition 61, 63 Distribution 715, m. 62 Seed 424, f. m secalinum 701 Horehound, distribution 720, 728 Seed 470, f. 1^0. 729 Horse Chestnut f. 597 Nettle 67, 247, 283-285, 637, 777, 786, 787, 796, 799, 823, 833, 850, f. 285, 638, 765 Distribution 720, 765-766, 844, m. 285 Root 651 Seed 471, 568, 630, f. i72, 568 Sorrel siin. Sheep Sorrel Horseradish 168-169, 788, f. 169 Distribution 700, 712, 717, m. 169 Horsetail 667, 819, f. 5. Distribution 736, m. 5. Familv 6 sp. 736 Horseweed 324-326, 657, 659, 660, 664, 778 819 Distribution 324, 690, 695, 736, 737, 754, m. 326 Root system 645 Seed f. m Horton, H. E. 842 Hosackia purshiana. Distribution 761 Hound's Tongue 256-257, 777, 787, f. 257 Distribution 719, in. 257 Seed 466, f. .1,66 Howitt, .T. E. 826, 842 Humus Soils, "Weeds of 819 Hundeshagen, J. G. 842 Hungarian Brome Grass 419, 420 Grass 506 Hungary, Weeds of 754, 843 Hunter, Robert 801 Hutcheson, T. B. 856 Hutchinson, A. 766 Hutton, G. 850 Hyacinth 66 Hyaline layer 516 Hyams, C. W. 854 Hydrophtllaceae 4, 254-256 Distribution 719 Hygroscopic movement in seeds 629, 636 Hyoscyamus niger, Distribution 736 Hypericaceae 4, 221, 223-224 Distribution 724 Hypericum perforatum 223-224, f. 223 Distribution 788, 841, m. 221, Hypochaeris radicata 696 Distribution 725, 72 8 Hypoderm 516, 865 Hypogynous flowers 610, f. 605 Hyssop, Giant, Seed 567, f. J,70, 567 Idaho Weeds 745, 757, 842, 844 Illinois weed legislation 794, 803-804 Weeds 745, 751, 757, 765, 766 Immigrant weeds 743-769 Imperfect flowers 605 Indeterminate inflorescence 610, 866 India Weeds 767 India-rubber tree 69 Indian Currant 307, 308, 790 Hemp 235-237, 651, 719 Mallow 215-218, 557-558, 559, 687, 713, 762, 790, 822 Mustard 44 6 Plantain 49 3 Indiana weed legislation 804 AVeeds 747, 757, 766, 768, 838 Indians, Plants disseminated by 687 Indigo Plant, Distribution 734 Indigofera hirsuta. Distribution 734 Inflorescence 610-614, 866 Catkin f. 606 Composite 614, f. 613 Corymb 612, 864 Cyme 614, 864 Determinate 610, 614, 864 Head 612, f. 612. 613 Indeterminate 610, 866 Mixed 610 Raceme 611, 869, f. 612 Spike 611, 870 Umbel 612, 871, /. 613, 611, Insects and weeds 674, 676-677 Integuments 619, 624, 866 Internoc;e 866 Inula helenium. Distribution 720 Involucre 614, 866 as seed disseminator 631, 633 Iowa Homestead 284, 288, 334, 335, 391. 826 Seed investigations 834-835 Seed legislation 809-814 Thistle 377-379, 495, 578, 789 Tumbleweed 116, 631 Weed legislation 794-801 Proposed law 801-803 T^^eeds 840, 841, 844, 845, 851 Ipomoea hederacea 243-245, 789, f. 2',S Distribution m. 2^5 purpurea f. 2^. 2^5 Distribution 696, in. 2J,5 Seed 463, 564, f. m, 563 Ireland, T^''eed laws 79 Weeds of 846 Iris f. 617 Ironweed 309-310, f. 309 Distribution in. 310 Seed 477, f. J,77 T^^estern 310-311, 594, 790, f. 311 Distribution m. 311 Seed 477, f. ^77 sp. 807 Irregular flowers f. 605 Isle-of-man, Weed laws 793 INDEX 891 Italian Tiye Grass 421, 787, Sll, 813 Italy, Flora of 731, 838 Iva xanthifolia 332-334, 789, f. 333, 755 Distribution 332, 720, 729, 751- 753, 844, m. 333 Seed 482 Ivy 645 Ground 275-276, 787, f. 27.^, 59.',, 60S Distribution 719, m. 276 Kenilworth Distribution 727 Poison 213,. 214, 683, 787, 843, f. ZU 215, 6S3 Distribution in. 214 Root system 652 Poisoning- 780, Antidote 780 Jag-ger, Mary G. 830 James, B. 766 Jamestoion Weed syn. Jimson Weed Japan Clover 831 Jasmine f. 60S Jenkins, E. H. 21, 43, 70, 107, 138, 190, 299, 303, 364, 389, 581, 830, 837, 842, 857 Jerusalem Oak, Distribution 716, 746 Jimson Weed 277, 288-291, 471, 683 709, 777, 788, f. 2S9, m, G08, 6U, 709 Distribution 687, 696, 720, 736, 767, m. 290 Seed 569, f. 568 Joe Pye Weed 594 Seed 477, f. 47S Trichomes f. 47S Johnson, A. G. 849 Johnson, C. V. 748 Johnson, P. 829 Johnson, L. 854 Johnson, T. 857 Johnson Grass 7, 8, 805, 853, f. 722 Distribution 722, 732, m 722 Jointed Charlock 153-155, 673, 674, 699, 717, 735 Jolliffe, J. B. 749 Jones, J. W. 74'o Jones, L. R, 833, 842, 849, 857 Jones, M. E. 751 Josselyn, John 710, 711 Joxe, A. 581 Juhlin-Dannflet, H. 849 Jumelle 584 JUNCACEAE 3, 63, 65 Distribution 715 Juncus balticus 820 tenuis 63, 65, f. 65 Distribution 715, 741, m. 65 June Clover 812 Junowicz, R. 5 81 Jussiaea suffruticosa. Distribution 734 Kabsch, W. 693, 699, 754, 767, 842 Kalter, G. M. 842 Kansas Seed investigations 831. 832 "Weed legislation 794, 805 Weeds 70S, 751, 754, 756, 757, 766, 837, 842 Kav, G. F. Ill, V Keel 866 Kellerman, W. A. 723 Kellerman, W. A. Mrs. 723 Kelloga-, Harriette, VII, XII, 755, 771, 817, 824. 854 Kelsey, J. A. 751, 849 K'enjlworth Ivy, Distribution 727 Kentucky Blue Grass *418, 639, 715, 810, 811, 812 P«=ed investigations 832-833, 857 "^''eed legislation 794 "Weeds 747 Ketmia. Bladder svn. Shoo-fly Kev for families 3-4 Key, Sothoron 835. 857 Khaki Bush 846 Kieffer, 713, 737 Kienitz, M. 828, 858 King, Charlotte, VII, XII, 406, 782, 817, 824, 834, 835, 845, 850, S5S King Islands Melilot syn. Yellow Siveet Clover Kinghead 847 Kinzel, W. 828, 858 Kirk, T. W. 849 Klein, F. A. 760 Klugh, G. F. 854 Knapweed 383-384, 667, f. 3S3 Distribution 699, 713, 725, 750, m. SS3 Seed 496, f. 1,97 Black 664 Distribution 725 Brown Distribution 725 Spiny syn. Knapioeed Knight, H. G. 61, 188, 837 Knotgrass 663 Seed f. 63S Dooryard 7 88 Knotweed, Branching 789 Bushy 85-86 Distribution m. S6 Seed 431, f. .1,31 Dooryard 84-85 Distribution 659, 716, 736, 742, m. SJ, Seed 42 8, f. 428 Erect 82-83, 789, f. S3 Distribution 696, 716, 725, f. 82 Seed 429, f. 1,29, 526 Face syn. Bushy sp. 665 Larger syn. Erect Knotweed Knowlton, C. H. 842 Koch, G. D. J. 754 Kochia scoparia 101-103, 789, f. 102 Distribution 714, 716, 746, 844, m. 103 Seed f. J,33 Kolkwitz, R. 858 Konigsberg, Experiments at 673 Korsmo, E. 661, 658 Korsoms, E. 849 Kraemer. H. 854 Krafft, G. 827, 842 Kraus, G. 539 Kraus, O. 849 Krutizky 584 Kuhnia eupatorioides Seed 478, f. 1,79 Trichomes f. 1,79 Kunze, Otto 702 Kuntze, R. E. 858 Labiatae 4, 268-278, 777 Bibliography 5 84 Distribution 719-720, 724, 759 Seed 469-570, 566-567 Lactuca canaclensis 399, 401, 780, 788, f. 1,00, 1,01 Distribution m. 1,01 Seed 500. f. 500 floridana, Seed 500. f. 500, 633 pulchella 402-403, 788, f. 1,03 Distribution 729 scariola 396, 596, 664, 790, 819 Distribution 721, 725, 729, 747, 75 8, m. 398 scariola integrata 396-399, 721, 747. f. .397 Distribution m. 398 Seed 500, f. 501 Dady Slipper, Stemless 702 Lady's Sorrel 659, 787 Distribution 6^6, 697, 718 Seed 456, f. .',57 Thistle, Distribution 725 892 INDEX Thumb 93-95, 664, 665, 736, 788, f. H Chemical composition 677 Distribution 691, 716, m. 95 Seed 430, 527, f. J,30, 526 Lambert 740 Lamb's Quarters 107-109, 594, 658, 659, 660, 676, 697, 788, f. lOS, 695 Chemical composition 107, 109 Distribution 687, 691, 696, 716, 725, 729, m. 109 Seed 432, 532, f. J,32, 53S, 638, 676 Western, Seed f. m Lamella 866 Lamina 866 Lamium album, distribution 727 amplexicaule, distribution 719, 723, 727 sp. 736 Lamson-Scribner, F. 842 Lance-leaved Ragweed 4 83 Salvia 277, 278, 279, 759 Lang-ethal, C. E. 842 Lappa sijn. Arctiutn Lappa officinalis syn. Arctium lappa Lappula echlnata 260-262, f. S61 Distribution 719, m. 262 Seed 466, 565-566, f. J,6T, 566 virginlana 259-260, 788, f. 259 Seed 466, f. Jf67 Large Peppergrass 143, 144-145, 442, 539-540, 542, 717, 738, 787 Ragiveed syn. Greater Ragweed Spotted Spurge 660, 718 Large-Jjracted Vervain syn. Prostrate Vervain Larger Knotioeed syn. Erect Knotweed Mouse-ear Chlckweed 124 Larkspur, Field, Seed 439, f. JfS9 Prairie 142, f. 11,2 Seed 439, f. i39 Larsen, O. H. 849 Laschke, W. 858 Late Goldenrod syn. Smooth Goldenrod Lathy rus aphaca f. 593 Laubert, R. 69 8, 849 Laurus canariensis, Distribution 693 Lavialle, P. 582 Lazenby, "VV. R. 843, 857 Leaf, Alternate 594, f. 593 Arrangement 592-594 Arrow-shaped f. 59^ Branching 594-597 Caullne 592 Cleft 596, f. 595 Compound 596 Crenate 59 6, f. 596 Dentate 595, f. 595 Entire 594 Function 599-601 Kidney-shaped f. 59i Lotaed 596, f. 5Si, 59i Morphology 591-598 Netted-veined 592 Opposite 593, f. 593 Ovate f. 595 Parallel-veined 592 Parts 591-592, f. 593 Pinnate f. 596 Pinnatlfid 596, f. 595 Primary 591 Protection 602-603 Radical 592 Renlform f. 59^ Secondary 591 Sessile 592. f. 592 Serrate 596, f. 595 Serrulate 596, f. 595 Spear-shaped f. 59i Spiny-pointed f. 595 Toothed 595 Transpiration 601-602 Triangular f. 59Jf Veining 592 Wavy 594, f. 595 Lee, L. V. 750 Leek 66 Leersia oryzoldes f. 739 Distribution 740 Lees, J. H. XII, 755 Legislation, Weed 794-808 Leguminosae 4, 180-199, 776, 819 Bibliography 585-586 Distribution 718, 724. 759-761 Seed 450-455, 545-554, f. 551 Leguminous weeds 667, 785 Lehmann, B. 713, 737, 858 Leonard, J. 766 Leontodon autumnalis. Distribution 736 Leonurus cardlaca 276-277, 777, 788, f. 276 Distribution 720, m. 277 Seed 470, f. if^l Lepachys pinnata 486-487, f. 4S7 Distribution 737 Lepldium apetalum 146-147, 787, f. 1^6 Distribution 692, 717, 734, 741, m. W Seed 441, 540, f. m, 5J,1, 688 Sativum 441, f. Ul sp. f. 59S virglnlcum 144-145, 787, f. U5 Distribution 717, 738, 844, m. US Seed 442, 539-540, f. U2, 51,2 Leptochloa mucronata, Distribution 723 Leptome f. 598 Lesage, P. 829 Lespedeza capitata. Seed 545, 552, f.i5i sp. 850 stuvei 552 Lettuce 307, 633 Blue 402-403, 788, f. 1,03, 633 Distribution 729, m. 1,01, Canadian syn. Wild Lettuce False, Seed 500, f. 500 Prickly 396-399, 596, 645, 664, 790, 819, 826, 838, 840, f. 398 Distribution 721, 725, 747, 758, 840, m. 398 Root system 645 Seed 500-501, f. 501 Prickly (integrata) 396-399, f. 397 Distribution 721, 747, m. 398 Seed 500, f. 501 Wild 399-401, 780, 788, 807, f. 1,00, 1,01 . 595 Distribution 838, 810, 846, «!-. 398 Root system 645 Seed 500, f. 501 Leunls, Johannes 754 Liatris gracilis 478 punctata. Seed 478, f. 1,79 Trichomes f. 1,79 Light, Effect on germination 829 Ligule 867 LiLIACEAE 3, 66-67 Distribution 715, 724 Llllcoya 693 Lilv 6, 66 Easter f. 698 Family 66-67 Distribution 724 of-the-valley 66 Philadelphia 689 Lllium philadelphicum 689 Limy Soils, Weeds of 819 LiNACEAE, Distribution 724 Seed 456. 554-555 Linaria cymbalaria. Distribution 727 vulgaris 292-294, 808. f. 293 Distribution 696, 712, 720, 727, 788, m. 291, Seed 473, f. 1,73 Linnaeus, see Linne Linne, C. V. 744, 748, 826 INDEX 893 Linum usitatissimum 554-555, f. 555 Seed 456, 813, f. J,56 Liquorice, Wild 196-197, 787, f. 196 Distribution 718, 729, 760, to. 197 Seed 554, f. 551 Lithospermum angxistifolium, seed 467, f. 467 arvense 262-263, 787, f. S62 Seed 467-468, f. m latifolium, Seed 467, f. i67 Little Barley 61-63, 424, 715, 812 Live-forever 712 Lloyd, F. E. 843 Loamy Soils, Weeds of 819 Lobe 867 Lobelia 689 spicata 689 Lochrie, G. R. 749 Lockhead, W. 841 Loco Weed, Purple 194-195, f. 195 Distribution 838, 845, m. 195 Seed 454, 552, f. J,5J,, 551 Stemless svn. Purple Loco Weed Locule 618-619, 867 Locust f. 596 Honey 180 Lodg-e-pole Pine 694, 695 Lolium italicum 421, 787, f. ^21 Seed 811, 813 perenne 52, 701, 789 Distribution 715 Seed 420, 811, 813, f. m temulentum 52-53, 520, f. 52 Distribution 696, 699, 715, 736, m. 53 Seed 522-524, f. 520^ 521, 522, 523, 52^ Long, H. C. 660, 661, 671, 673, 674, 677, 793, 825, 843, 850 Long, J. 767 Long, Wm. 749 Long-awned Poverty Grass 29-30 Long-fruited Anemone 439 Lotus corniculatus. Distribution 734 Louisiana Carpet-Grass, Distribution 722 Weeds 840 Louthan 745 Lovsr Hop-Clover 184-185, 451, 718, 761 Senna 723 Spear Grass 464, 715 Lucerne syn. Alfalfa Luhn 827 Lumen 867 Lummis, G. M. 22, 858 Lundell, J. 750 Lupine 180 Lychnis alba 126-128, 664, f. isr Distribution 716, m. 128 Seed 810, f. J,S7 dioica 126, 605 Distribution 716 ffithago syn. Agrostemma githago vespertina syn. L. alba Lygodesmia juncea 403-404, f. 404 Distribution 721, 788, m. W Rushlike 403-404, f. m Distribution m. 404 McAlpine, A. N. 850 McCarthy, Gerald 830, 832, 858 McCarty, C. S. 767 McClanahan, Dr. 749 McCoy 749 McCready, A. B. 837, 843, 850 McKee, Roland 836 McMahon, J. J. 745 McNair, A. D. 850 Madder Family, Distribution 724 Maiden, J. H. 843 Maine seed investia:ation 832 Seed legislation 809, 814, 860 Weeds 750, 754, 757, 841 Maize 687 Transpiration of 671, 673 Mallow, , Common (M. rotundifolia) 219-221, 596, 787, 822, f. 220 Distribution 708, 718, 725, to. 221 Seed 460, 559-560. f. 559 Common (sylvestris). Seed 558-559, f 559 Family 213, 215-222 Seed 459-460, 557-560 Indian 215-218, 790, 822, f. 216, 217, 713 Distribution 687, 713, to. 216 Seed 557-55 8, f. 559 Small-flowered, Distribution 725 sp. 725 Malpighian Cell. See Cell Malpighian Malva borealis. Distribution 725 crispa, Distribution 725, 776, 787 rotundifolia 219-221, 596, f. 220 Distribution 708, 718, 725, m. 221 Seed 460, 559-560, f. 559 sylvestris. Seed 55 8, f. 559 Malvacear 4, 213, 215-222 Bibliography 5 86 Distribution 693, 718, 724, 734, 761-762 Seed 459-460, 557-560 Malzew, A. 829, 843 Mammoth Red Clover 811, 812 Man, Seed disseminated by 629, 687 Mangold Fly 676 Manilla substitute 216 ' Manisurus granularis, Distribution 723 Manitoba weed law 793 Weeds 693 Manure, Weed seeds in 833 Many-flowered Aster 317-318, 689, 790 Maple 6, 630, 632 Distribution 695 Soft, Seed f. 63^ Maple-leaved Goosefoot 105-107, 432, 715, 789 Marigold, Common, Distribution 696 Corn, Distribution 735, 736 Fetid 356-358, 789, f. 357, 358 Distribution 720, 755, m. 357 Seed 490-491, f. 1,91 Field syn. Corn Marigold Marsh, Distribution 736 Marjoram, Wild, Distribution 693 Marl Soils, Weeds of 819 Marre, B. 850 Marrubium vulgare. Distribution 720, 725, 728 Seed 470, f. 1,70, 729 Marsh Cress 167-168, 447, 742, 787 Elder 332-334, 482, 720, 751-753 Foxtail 715, 732, 740 Marigold 736 Muhlenberg 35-37, 413 Marshall, Humphrey 765, 766 Martin, J. N. VII, XII, 589 Maryland seed investigation 833 Weed legislation 794 Weeds 833, 844 Martynia Family, Distribution 724 Martyniaceae, Distribution 724 Massachusetts seed investigations 833 Weeds 750, 754, 757, 763, 842 Matthews, J. B. 748 Matricaria discoidea syn. M. suaveolens inodora 664 suaveolens, Distribution 705, 714, 725, 729 Mattirolo, O. 547, 554, 581, 585 May Apple 618 Mayne 824 Mayweed 360-362, 778, 788, f. 361 Distribution 687, 696, 736, to. S62 Root system 645 Seed 491, f. 1,91, 638 Meadow Fescue 418, 715, 810, 811, 813 Foxtail syn. MarsJi Foxtail 894 INDEX Grass 660, 693 Annual 664 Roush-stalked 639, 715 Rue 438-439, 688 Saffron 736 Salsify 497, 498 Sunflower 344-346, 487 Meath, R. S. 766 Mechanical devices as aids to seed scattering- 629, 630, 631,7- 630, 631, 632, r,33 Medic, Black 190-191, f. 191 Chemical composition 190 Distribution 688, 718, 725, 728, 729, 734, 761, m. 191 Seed 453, 546-549, f. Ji-jS, 518 Medicago denticulata 549, 702 Distribution 725, 729 Seed 549, 811, 832, f. 51,9, 729 hispida. Seed 452, f. 543 lupulina 190-191, 787, f. 191 Chemical composition 190 Distribution 718, 725-728, 734, 761, m. 191 Seed 453, 546-547, 549, 810, 811, 831, f. ko3, SJfS sativa, Seed 811, 812 Medicinal Plants 307, 773-789, 853-855 Absinth 307 Agueweed 780 Bindweed 777 Boneset 774, 778 Burdock 778, 779 Butterfly Weed 774 Caraway 709, 776 Catnip 777 Chamomile 709 Chickweed 776 Chicory 778 Corn-Cockle 776 Cowbane 774, 776' Dandelion 773, 780 Docks 774 Elecampane 709 Evening Primrose 776 Feverwort 778 Fireweed 778 Fleabane 778 Golden Seal 854 Grindelia 790 Hemlock, Poison 709, 776 Water 776 Wild 774 Henbane, Black 709 Horse Nettle 777 Horseweed 778 Hound' s-tongue 777 Jimson ^^eed 709, 777 Joe-Pye Weed 774, 790 Lettuce, Wild 780 Mallow 776 Mayweed 774, 778 Milkweeds 777 Motherwort 777 Mullein 774, 777 Mustard, Black 776 sp. 773 White 776 Nightshade, Black 777 Peppermint 709 Plantains 778 Pokeweed 776 Quack Grass 773, 774, 775 Ragweed 778 Self-heal 777 Sheep Sorrel 774 Snakeroot 780 Sneezeweed 790 Sweet Clove. Ye'low '^7fi Tansv 307. 70^. 773, 780 T'l-'orn Apnle 774 Vervain 777 Water Pepper 775 Wormseed 774, 775 Yarrow 778 Mediterranean Weeds 696 Medium Red Clover Seed 812, 830 Melanthium virginicum 66-67, 788, f. 66 Distribution m. 67 Melhus, J. 749 Melica, Distribution 701 Melilot, King Islands syn. Yellow Sweet Clover Melilotus alba 187-190, 788. f. 188 Chemical composition 188, 190 Distribution 718, 725, 729, 760, m. 189 Root system 645, f. 6U Seed 451, 549-550, 810, 811, 832, f. 1,52, 51,8 officinalis 186-187, f. 187 Distribution 713, 718, 725, 729, 759, TO. 187 Seed 452, 550, 776, 810, 811, f. i52, 51,8 parviflorus syn. M. officinalis sp. 853 Menault, E. 843 Mentha arvensis 268, 663 Distribution 736, 741 a.r\'ensis v. canadensis 268-269, f. 269 Distribution m. 269 piperita 268, f. 270 Distribution 720 spicata 268, 789 Distribution 720 viridis. Distribution 72 8 Mercury, Three-seeded 205-207, 788, f. 206 Distribution 718, m. 207 Seed 457, f. 1,57 Merrill, S. A. 749 Mesocarp 518, 528, 867, f. 523, 528, 529 Starchy 516, f. 513 Mesophyil 578, 867, f. 519 Mexican Clover 723 Drop-seed Grass 32-34, 413-414, 660, 715, 790 T^ireweed 101-103, 433, 714, 716, 746 Poppv 839 Tea 103-104, 738, 746, 790 Mexico, AVeeds of 733, 767-768 Mever 538 Michel XII Michigan seed investigations 830 T^^eed legislation 794 Weeds 70S, 757, 766, 768, 824-825, 830-831, 838, 855 Micropyle 867 Mignonette Family, Distribution 724 Migration of Weeds 687-769, 837-846 Mikania scandens 847 Mildew, Downy 678 TVliite 85 Milk Purslane syn. Creeping Spurge Spurge syn. Creeping Spurge tainted by weeds 683 Vetch 193-194 Milkweed, Climbing 241, 242-243, f. 2^3 Distribution m. 21,3 Common 239-241. 788. 794, f. 239, SiO Distribution 691, 719, to. 2i0 Root svstem 651. f. 6.',6 Seed 462. 562-563, f. 1,63, 562, 632 Family 237-241, 633 Seed 462-463, 562-563 Showy 237-238, 787, f. 238 Distribution 719, m. 238 sp. 631, 777, 807, 850 Swamp, Seed 462, f. 1,63 Whorled, Seed 463, f. 463 Millet, Broom Corn, Seed 506 Common, Seed 411, 506, 813, f. 1,11, 505 Hog. Seed 813 Pearl, Seed 813 INDEX 895 Whorled, Distribution 732 Seed 413, f. m Mills, J. H. 766 Millspaugli, C. F. 731, 774, 778, 843, 850, 854 Milwaulsee weed legislation 808 Minnesota medicinal plants 855 • Weed legislation 794, 805-806 Weeds 745, 751, 753, 757, 844, 845, 848 Mint 268-269, f. 269 Distribution 736, 741, vi. S69 Corn 665 Family 268-278 Distribution 724, 759 Field 665 sp. 72 8 Mirabilis jalapa, Distribution 696 Mississippi Valley weeds 751, 769 Missouri Flora 854 Medicinal plants 854 Weed legislation 794, 806 Weeds 754, 757, 759, 766 Mistletoe 645 Mixed inflorescence 610 Moeller, J. 520, 522, 575, 581, 584 Moesz, G. 843 Mohr, Dr. Charles 707, 722 MoUugo verticillata, Distribution 704 Moninger, W. R. 768 Monocotyledon 867 MONOCOTYLEDONEAB 3, 6-67 Monocotyledons 623 Monocots 6-67 Monoecious plants 605 Monolepis nuttalliana, Distribution 693 Montana Flora 838, 853 Weeds 757, 838 Moore, C. 731, 733, 734 Moore, G. T. 834 Moore, R. A. XII, 382, 850 Morning Glory, Annual 245-24 8, f. 2U Distribution 696, m. 2^5 Seed 463, 564; f. m, 563 Blue Field 243-245, f. 2^3 Distribution m. ZJ/S European 248-250, 787, 822, 850, f. 2.!i9 Distribution 710, 740, m. 2^9 Root f. 653 Family 241-254 Distribution 724, 756-757 Seed 563-564 Perennial 250 Wild 241,, 245-248, 624, 649, 660, 674, 787, 789, 848, f. 2J,6, 67Jt Distribution 691, 719, m. 2J,6 Root system 649, 652, f. 651 Seed 464, 564, 810, 814, f. J,6Ji, 563 Morrow, G. E. 826 Morse, ^^r. J. 842, 849 Morton, J. 750 Mosquitos harbored by weeds 681 Moss 665, 667 Bear 693 Rose 134 Moth, Diamond-back 677 Ghost 677 Mullein 292, 472, 473, 570, 720, 728 Otter 677 Mother Cell 616, 867, f. 616 Motherwort 276-277. 777, 788, f. 276 Distribution 720, m. 277 Seed 470, f. 1,71 Mouse-ear Chickweed 122, f. 12i Larger 122. 787 Distribution m. 12i sp. 740 Mouse-tail, Distribution 741 Mueller, Ferdinand V. 731, 733, 734 Mugwort, ^Vestern 366-367, 790, f. 366 Distribution m. 367 Muhlenberg, Marsh 35-37, f. 35, 36 Distribution 714, m. 36 Seed 414, f. J,l!i Muhlenbergia mexicana 32-34, 790, f. 33, 31, Chemical composition 34-35 Distribution 715, m. 33 Seed 413-414, f. m racemosa 35-37. 790, f. 35, 36 Distribution 715, m. 36 Seed 414, f. m Schreberi 30-32, f. 31 Distribution 715 Seed 414, f. J,1J, sp. f. 676 Muhlenberg's Smartweed 88-90 Mullbery 605 Mullein 291-292, 310, 777, f. 291 Distribution 687, 720, m. 292 Seed 72, 570, f. J,73, 570 Family 291-296 Distribution 725 Seed 472-474, 570 Moth f. 292 Distribution 720, 728 Seed 472, 570, f. 1,73, 570 Mundy, H. G. 843 Munerati, O. 829, 858 Munn, M. F. 834 Munson, W. M. 843 Murray, D. 747 Musk Erodium, Distribution 725 Mustard, Ball 163, f. 163 Distribution 717 Seed 814 Black 142, 157-159, 788, f. 158, 51,2, 605 Distribution 696, 717, 725, m. 15S Seed 445-446, 541-543, 776, 810, 811, 814, f. U5, 51,2 Family 142-170, 634, 844, 846 Diseases 678, 680 Distribution 724, 733-734 Seed 441-448 Hairy, Seed 544 Hares-ear 161-162, 592, 788 Distribution m. 162 Seed 446, 814, 815, f. V,6 Hedge 164-165, 659, 677, 787 Chemical composition 165, f. 169 Distribution 717, 725, to. 165 Seed 446, 543, 544, f. W Indian, Seed 446, f. 1,1,6 Mildew 678 sp. 657, 660, 692, 709, 725, 773, 826, 847. 848, 850 Tansy 660 Treacle, Distribution 741 Tumble 794 Tumbling 165-167, f. 166, 733 Distribution 717, m. 167 Seed 446, 544, 815, f. W, 51,2 White 142, 663, 716 Seed 444, f. 1,1,1, Wild 155-157, 787, f. 156 Chemical composition 157 Distribution 727, 736, m. 157 Seed 793, 794, 796, 807, 808, 810, 811, 849 Myagnmi 699 Myosotis 664 Myosurus minimus. Distribution 741 Nadelmann, Hugo 545, 585 Naftsger, T. D. 9 68 Nebraska Flora 845 Seed investigations 833 'WeeA legislation 794, 806 Weeds 693, 745, 748, 755, 757, 765, 844, 847 Neckiveed syn. Speedwell Needle Grass 89. 790, f. 666, 667 Neilreich, A. 737, 738, 740, 843 Nelson, A. 81, 188, 826, 837, 844 INDEX Nelson, A. E. 844 Nepeta cataria 273-274, 777, f. 211, Chemical composition 273 Distribution 719, m. 273 Root system 654 Seed 469, 566-567, f. Ifi9, 567 hederacea 275-276, f. 275 Distribution 719, m. 276 Nerve 867 Neslia paniculata 163, f. 1G3 Distribution 717 Seed 829 Nettle. Day 664 Dead 665, 723, 822 Distribution 719, 723, 727 Family 69-74 Distribution 725 Seeds 424-425, 524-525 Hemp, Distribution 720, 727 Horse 67, 283-284, 285, 786, 794, f. 285, 638, 765 Distribution 705, 720, 765-766, m. 285 Root system 651 Seed 471, 568, 637, f. i72, 568, 638 Sp. 736 Stinging (Urtica dioica) 667 Stinging (U. gracilis) 69-70, 788, f. 69, 602, 603 Chemical composition 70 Distribution 708, 715, m. 70 Root 652 Seed 425, f. m Nevada seed investigations 831 Weeds 757, 842 New Brunswick, Weeds of 750, 762 New England Flora 714 TV^eeds 709 New Hampshire seed legislation 833 Weeds 748, 845 New Jersey weed legislation 794 TVeeds 757, 765, 841 New Mexico, Weeds of 757, 846 New South Wales Flora 731 Weeds 843 New York Seed investigations 833-834 Weed legislation 794 Weeds 747, 750, 757, 760. 765 Newberry 766 Newell, 'W. 757, 760 Newfoundland weeds 754 .Newman, C. L. 842 Nicandra physaloides. Distribution 737 Nichols, Mary A, 477, 478, 489, 582 Nicotiana glauca. Distribution 696 Nigger-hend siin. BTack-eijed Susan Nimble Will 30-33, f. 31, S3 Distribution 715 Night-flowering Catchfly 130-132, 437, 638, 716, 790, 810, 814 Nightshade, Black 281-283, 625, 630, 777, 790, f. 281, 282 Distribution 687, 696, 697, 720, 736, m. 282 Root system 645 Seed 277, 291, 471-472, 569, f. 1,72, 568 Deadly 736 Family 277-291 Distribution 725, 765, 767 Seed 471-472, 568-569 sp. 677, 738 Spiny, Seed 569, f. 568 Three-flowered, Distribution 738 Nobbe, F. 827, 830, 850, 858 Nobtas, E. A. 850 Nodding Chickweed 122-123 Smartweed 86-87 Nodes 651, 867 North America, Indigenous plants of 740-743 Weeds 696, 731, 732, 733, 734 North Carolina medicinal plants 854 Pure Seed Act 832 Seed investigations 830, 860 North Dakota. See Dakota, North Northern Flreweed 694, 703, 726, 741 Nut Grass 63, 64, 696, 697, 715, 741, 790 Extermination 63 Northwest Territories weed legislation 793 Norton, J. B. S. 833, 844 Norway, Weeds 852 Notchweed f. 591, Nova Scotia, Tk^eeds 756 Noxious Weed Act 793 Noxious weeds 796 Nucellar layer 516, f. 513 Nucellus 619, 867 Nucleus 616, 617 Nut Grass, Northern 63, 790, f. 64 Distribution 696, 697, 715, 741, m. 61, Southern 63 Distribution 722, 723 Nuttall, Thos. 374 Nyctaginaceae 3, 119-120, 533 Distribution 716,- 724 Nyctelea 660 Oak, Distribution 695 Transpiration of 671, 673 Jerusalem, Dis*"ribution 716, 746 Oak-leaved Goosefoot, Distribution 746 Oat Grass Seed 810 Bulbous syn. Pearl Grass Tall. Seed 813 Oats 8, f. 609 Blindness of 677 Distribution 715, 736, m. 1,1 Seed 415-416, 674, 810, 814, 829, f. 1,16 Impurities in 155, 674, 692, 829 Side 689 Wild 40-41, 415-416, 664, 665, 679, 715, 736, 789, 793, 810 O'Brine, D. 837 O'Connor, John 750 Oenothera biennis 224, 225, 776, 788, 819 f 225 Distribution 690, 718, 762, m. 225 Seed 560, f. 560 grandiflora, Distribution 696 laciniata. Distribution 737 sinuata syn. O. laciniata sp. 734 Oesterle 538, 553 Offshoot 654 Ohio Flora 723 Seed investigations 831 Weed legislation 794, 807-808 Weeds 747, 753, 757, 766, 825, 842, S43, 845 Oklahoma Flora 838 Weeds 838 Okra 213 Old Witch Grass 12-14, f. 13, 706 Distribution 660, 714, 740, m. U Seed 410. 828, f. 1,10, 676 Oleaster f. 602 Oleaceae, Distribution 724 Olive, E. W. 850 Olive Family, Distribution 724 Olson, O. M. XI Omaha weed legislation 806 Onagraceae 4, 224. 225, 776 Bibliography 5 86 Distribution 718, 724, 762 Seed 460, 560 Onion 6, 66, 624 Wild 67, 623, 852, f. 68 Distribution m. 68 Seed 814 Ononis spinosa 667 INDEX 897 Onopordon acanthium 667, 677 Distribution 725, 736 Ontario weed legislation 793 Weeds 747, 841, 842, 843, 858 Oospora scabies 680 Orach 109-110, 789, f. 110 Distribution 716, 740, 746, m. 110 Seed 433. f. JfSS Garden, Distribution 736 Silvery, Distribution 746 Orange Hawkweed 502, 712, 750, 814, 842, 846, 849 Orchard Grass, Distribution 715 Seed 417, 810, 811, 813, 828, 832, 857, f. Iftt See also Marsh Muhlenberg Oregon Flora 694 Weed legislation 794 Weeds 747, 750 Organs, Essential 605, f. 605 Origanum 693 Ornamental plants become weeds 712 Orobanche ramosa, Distribution 735 Orobus 693 Orpine Family, Distribution 724 Orr, Ellison 745, 766 Orton, W. A. 833, 849, 857 Osborn, B. F. 768 Osborne, O. M. 844 Oscinis frit 677 Osmorrhiza longistylis, Seed 561, f. 561 Ostenfeld, H. C. 753, 766, 844 Osteosclerids 867 Oswald, E. I. 833 Oswald, W. L. 832, 844 Otter Moth 677 Ovule 618, 619-621, 624, 867, f. 620 Ovary 617, 867, f. 616, 618, 619 wall as disseminating mechanism 630 OXALIDACEAE 4, 199, 201-203, 634 Distribution 718, 764 Seed 456-457 Oxalis comiculata 202-203, 787, f. 202 ^ 630 Distribution 696, 697, 734, 741 Family 199, 201-203, 634 Distribution 724, m. 203 Seed 456, f. Jf57 Purple-flowered 199 sp. 618, 631, 786 stricta 201-202, f. 201 Distribution m. 202 violacea 689 yellow 199 Root system 645 Ox-eye 338-339, f. 338 Distribution 720, m. 339 Seed 486, f. iS6 Daisy 362-364, 667, 793, 794 Chemical composition 364 Distribution 727, 755, m. 36^ Root system 654 Seed 492, f. 492, 638 Rough STjn. Ox-eye Ox-tongue, Bristly, Seed 497, f. ^98 Oxybaphus nyctagineus 119-120, 787, f. 120 Distribution 716, m. 120 Seed 533, f. 53i Oxytropis lamberti 194-195, f. 195 Distribution m. 195 Seed 454, 552, f. J,5Ii, 551 Oyster Plant, Distribution 729, 755 Seed 497, f. J,98 Vegetable syti. Oyster Plant Ozonium omnivora 680 Pacific Coast weeds 725, 750 Packard, W. E. 839 Paczoski, J. 829, 844 Page, C. N. 757 Paige, F. W. XI, 755, 757, 761, 762, 767 Paint Brush swi. Orange Hawkiveed Painted Cup 702 Distribution 694 Pale Dock 716 Palea f. 609 Palet 867 Palisade Cell see Cell, Palisade Palmer, Edward 767 Palmer, S. H. 746 Pammel, L. H. 274, 581, 582, 583, 584, 585, 645, 745, 746, 749, 750, 751, 753, 759, 760, 763, 765, 766, 768, 774, 801, 823, 824, 825, 826, 834, 835, 837, 844, 850, 851, 854, 858, 861 Pampas Flora 701 Panic Grass, Scribner's 660, 689 Panicum capillare 12-14, 790, f. 13, 706 Distribution 690, 705, 714, 740, 844 Seed 410, f. J,10 dichotomiflorum 14, f. 15 Distribution 714, m. 15 glabrum syn. Digitaria humafusa miliaceum. Seed 411, f. ill proliferum, Seed 410; f. ilO scribnerianum 688 sp. 511, 517 Distribution 701 virgatum, Seed 410-411, f. Ifll Pansv, Common, Distribution 727 Wild, Distribution 722 Panton. J. H. 836, 858 Papaver 539, 633 rhoeas. Distribution 735 somnifennn, Seed 440, 536-538, f. UO, 531, 538 Papaveraceae, Distribution 724 Seed 440-441, 536-539 Papilla 617, 868 Pappaphorum, Distribution 701 Pappus 868, f. 6li Papua, Weeds of 733, 734 Papyrus 63 Parachute as seed carrier 629, 633 Parenchyma 868 Cells see Cell, Parenchyma Parietal placenta f. 619 Parietaria pennsylvanica 72-74, 788, f. 72, 73 Distribution 738, to. 73 Paris quadrifolia. Distribution 693 Parish, E. O. 845 Parish, S. B. 725, 845 Parosela. dalea syn. Dalea alopecuroi- des. f. 192 Pink 192, f. 192 Distribution m. 193 Seed 550-551, f. 551 Parrv, C. C. 748, 751, 767 Parrish, C. L. 831, 859 Parsley f. 612 Family svn. Carrot Family Fool's 663 Distribution 736 Parsley-piert 664 Parsnip 224, 788 Seed f. 6SS Cow 234, f. 23-'i Seed 5 62, f. 561 Water, Distribution 734 Wild 228-230, 794. 796, 807, 808, /=. 229 Distribution 688. 719, m. 230 Root svstem 648 Seed 461, f. -',62 Parsons, C. L. 831, 859 Partridge Pea, Distribution 718 Paspalum platycaule. Distribution 722 sp.. Distribution 701 Passiflora foetida 847 898 INDEX Pastinaca sativa 228-230, 788, 796, f. Distribution 719, m. 230 Seed f. 6SS Pasture Thistle 651 AVeeds 83 8, 845 Patience Dock 763 Patrick, G. E., 826, 837 Pavon, J. 753 Pawpaw 687 Pea 180 Partridg-e, Distribution 718 Sweet ISO Wild 790 Peach 175, 632 Peach-leaved Dock 78-79 Pear 175, 632 Pearl Grass 664, 665 Pease, A. 845 Peavine Clover, Seed 812 Pedicel 868 Peduncle 864 Pegomyia betae 676 Pelargonium f. 602 Pellitorv 72-74, 788, f. 72, 73 Distribution 738, in. 736 "Wall f. 597 Pennisetum typhoideum. Seed 813 Pennsylvania seed Investigations 831 Smartweed 90-91, 430-431, 645, 657, 658, 659, 660 "Weed legislation 794 Weeds 750, 759, 765, 768, 839 Pennycress 143-144, 788, 793 Distribution 692, 699, m. lU Seed Ml, 814, 815, f. W Field, Seed 814 Pennyroval 2 68 Pepper. Water 92-93, 594, 775, f. 93 Distribution 734 Seed 430, f. m Mild 95-97, 594, 788, f. 95 Distribution m. 96 Seed 430, f. m Peppergrass, Large 144-145, f. 1J,5 Distribution 717, 728, m. 1J,5 Seed 441-442, 539-540 Small 146-147, f. HiG, 692 Distribution 691, 717, 734, m. U7 Seed 441, 540, f. U2, 51,1, 03S, 6S8 Southern 723 sp. 660, 785 Diseases 678 Seed 674, 815, f. 676 Virginia sijii. Larpe Peppergrass Wild Sim. Lame Peppergrass Peppermint 268, 709, f. 270 Distribution 720 Percival, John 677. 825, 843 Perennial Ragweed 331-332, 651, 689 Rye Grass 420-421. 789. 811. 813 Sow Thistle 394-396, 499, 663, 753, 793, SOS, 814, 819, 826, 842 Perennials 648-649, 650, 691, 695, 786, 868 Perfect flowers 605, f. 60.', Perianth 609, 868 Pericarp 516, 868, f. 516 Peridermium pini 678 Perigynium S68 Perigynous flowers f. 610 Perisperm S6S Peronospora effusa 678 parasitica 677, 678 Perrin, C. M. 750 Persicaria s'ni. Lady's Thumb Persimmon 6S7 Pertinpcity of weeds 714 Peru, Weeds of 753 Petal 604, S68 Peter, A. M. 837 Petersen, N. F. 845 Peterson, C. E. 762 Peterson, Maude G. 854 Petiole 591, 868, f. 591 Petunia grandiflora, Distribution 727 Phacelia sericea. Distribution 695 tanacetifolia. Distribution 73 8 Pheasant as seed destroyer 629 Phenology of weeds 785-790 Philadelphia Lily 689 Phleum pratense f. 505 Distribution 715 Seed 414-415, 517, f. J,l.'i, 505 Phloem 868, f. 59^ Phlox drummondii. Seed 829 Phorbia brassicae 677 Photosynthesis 516, 599-600, 868 Phrasmites communis. Distribution 733, 736 Phvllotreta nemorum 676 Phvsalis heterophylla 279, f. 280 lanceolata 279-280, f. 2S0 Distribution m. 280 pubescens, Seed 569, f. 56S sp. 651, f. 623 .subglabrata 279, 789 virginiana 279, 281 Distribution m. 281 Phytolacca decandra 776 Distribution 705. 763 Phytolaccaceae 3. 776 Bibliographj^ 586 Distribution 763 Pickerel "Weed, Distribution 712 Picris echiodes. Seed 497, f. i98 Pieper, H. 828 Pie-plant 74 Pierce, R. E. 749 Pieters, A. J. 583, 835, 859 Pigeon Grass 17-20, f. IS Chemical composition 19 Distribution 714, 732, m. 19 in cornfields 17 Seed 22, 413, 640, S14, f. m, 676 Pigweed (Amaranthus) 113-115, 645, f. 11!, , 595 Chemical composition 115 Distribution 716, 723, 734, 737, m. 115 Seed 434. f. J,35. 636. 676 (Chenopodium) 67, 107-109, 664, f. 108. 217 Chemical composition 109 Distribution m. 109 Familv 113-119 Seed 434-435 (See Amaranth) Green (A. retroflexiis) svn. Pigweed Prostrate 117-llS. 788. f. 117 Distribution 716, m. 117 Seed 434, f. m Rough syn. Tumhling Pigioeed Russian, 'Seed 814 sp. 657. 687. 723. 786, 834 Spreading sun. Prostrate Pigioeed Tumbling 115-116. 790, f. 116 Distribution 716, m. 116 Seed 434, f. .',35, 638 Winged 99-101, 788, f. 100, 101 Distribution 693, 716, m. 100 Seed 451, 740, 746, f. ^31, 730 Pilose Eragrostis syn. Spear Grass Pimpernel, Distribution 719, 740 Pine 3. 6 Cluster-cup 678 Lodge-pole. Distribution 694, 695 ■White 6 Pink f. 606 Dalea 454 Familv 120-134. 435-438, 533-536 Distribution 724 Garden 120 Parosela 192-193 Smartweed 86-87. 430, 742 Pineapple T^^eed, Distribution 725, 729 Pinus murrayana, Distribution 694 INDEX Pistil 604, 616, 617-620, 868 Compound 619, f. IS19 Pistillate flowers 605, f. 606, 607 Pitchforks syn. Beggar-ticks Placenta 618, 86 8 Axillary f. 619 Central /'. 619 Parietal f. 619 Plantaginaceae 296-307 Bibliography 586 Distribution 721, 762-763 Seed 474-476, 571-572 Plantago arenaria. Distribution 726 aristata 304-307, f. 306 Distribution 720, 740, m. 307 Seed 474, 572, 810, f. J,~Ji, 572 coronopus, Distribution 736 lanceolata- 301-303, 787, 796, f. 302 Chemical composition 303 Distribution 696, 697, 698, 720, 736, 762, m. 302 Root system 654, f. 6JtS Seed 475, 572, 810, f. 475, 571 major 297-299, 664, f. 298, 299 Chemical composition 299 Distribution 696, 698, 720, 736, 742, m. 299 Seed 475, 572, f. Ipa, 572 maritima. Distribution 736 media, Distribution 736 purshii 303-305, 787, f. 304 Distribution m. 305 rugelii 299-301, 788, f. 300 Distribution 720, m. 301 Seed 475, f. 475, 676 sp. 778 Plantain, Bracted 305-307, 740, f. 306 Distribution 720, m. 307 Seed 474, 571, 572, 810, 814, f. 47^^ 572 Buck syn. Buckhom Common 297,299, 664, f. 29S, 299 Chemical composition 299, 720, 742 Distribution 696, 698, 720, 742, m. 299 Seed 475, 571, f. 4t6, 571 Doorvard syn. Common Plantain Family 296-307 Distribution 724, 735, 762-763 Seed 474-476, 571-572 Indian, Seed 493, f. 493 Prairie 303-305, f. 304 Distribution m. 305 Pursh's 7 87 Rat-tail, Seed f. 638 Ribbed syn. Buckhom Rugel's 299-301, 788, f. 300 Distribution 720, m. 301 Seed 475, 814, f. 4T6, 676 sp. 637, 665, 667, 677, 708, 710, 736, 778, 785, f. 623 Root system 645 Plants, Dioecious 605 Monoecious 605 Polygamous 605 Plasmodiophora brassicae 677, 680 Plasticity of plants 706-707 Plum 175, 687 Plutella maculipennis 677 Plymouth Flora 845 Poa annua 6 64, 677, f. 59S Distribution 715, 725 arachnifera. Seed f. 639 compressa. Distribution 715 Seed 418, 811, 812, f. 4I8, 639 Impurities of f. 639 nemoralis. Seed f. 639 pratensis f. 598 Distribution 715 Seed 418, 811, 812, f. 4IS, 639 sp. 693 trivialis, Distribution 715 Seed f. 639 Pod 868 Poinsettia 205 Poison Darnel 52-53, 520, 522-524, 692, 696, 699, 715 Hemlock 709, 710, 719, 728, 768-769, 776 Ivy 213, 214, 215, 652, 683, 787, 843 Poisonous weeds 52, 53, 66, 67, 194, 195, 213, 214, 215, 652, 683, 709, 710, 715, 719, 728, 768-769, 776, 787, 838, 847, 848, 852, 853, 854 Pokeweed 776 Distribution 763 Polanisia graveolens 171-172, f. 172 Distribution 717, m. 172 trachysperma 171, 788, f. 173 Pollen 615-617, 869 causes disease 681 grains 616, 617 mother cells 616, f. 615 sacs 616, f. 616 Pollination 616, 869 Polygamous plants 606 POLTGONACEAE 3, 74-99, 633 Bibliography 586 Distribution 715, 724, 763 Seed 425-431, 525-532 Polygonum acre 97, f. 96 Distribution 716 Seed 428, f. J,28 aviculare 84-85, 663, 788, f. 84 Distribution 716, 736, 742, m. 84 Seed 428, 429, 431, 663, 677 convolvulus 97-99, 789, f. 98 Distribution 696, 698, 716; 829, m. 99 Seed 429, 528-531, f. 429, 526, 528, 529, 530, 531, 536, 729 dumetorum v. scandens 527 erectum 82-83, 789, f. S3 Distribution 696, 716, 725, m. S3 Seed 429, 527, f. 429, 526 hydropiper 92-93, 594, 775, 789, f. 93 Distribution 734, 742 Seed 430, 527, f. 429, 526 hydropiperoides 95-97, 594, 788, f. 95 Distribution m. 96 Seed 430, f. i?9 lapathifolium 86-87, 788, f. 87 Distribution 716, 734, 742, m. S7 Seed 430, f. 430 muhlenbergii 88-90, 789, f. SS, 89 Distribution 716, m. SS Root system 652 Seed f. 431 orientale, Distribution 763 Seed 428, f. 42S pennsylvanicum 90-92, 594, 660, 664, 7 89, f. 91, 92 Seed 430, f. 430 perslcaria 92, 93-95, 665, 788, f. 94 Chemical composition 673, 674 Distribution 691, 716, 736, m. 95 Seed 430, 527, f. 430, 526, 676 ramosissimum 85-86, 789, f. 86 Distribution m. 86 Seed 431, f. 431 sp. 691, 785 virginianum 527 Polytrichum commune. Distribution 693 Popenoe, E. A. 766 Poplar 605 Distribution 695 Poppv 663, 665, f. 623 Seed 440, 536-538, f. 4-'iO, 537, 538 Corn f. 618 Family, Distribution 724 Mexican, Distribution 696, 839 900 INDEX Prickly 440-441, f. !,!,0 Distribution 729 Seed 539, f. 539 Rocky Mountain syn. Prickly Poppy Populus grandidentata 703 tremuloides 703 Porcher. F. P. 854 Porcupine Grass syn. Needle Grass Pore-canal 869 Portulaca oleracea 136-138, 788, f. 1ST, Chemical composition 138 Distribution 691, 696, 697, 701, 717, 723, 729, 763-764, m. 138 Seed 438, f. J,38 sp. 701 PORTULACACEAE 3, 134-138 Distribution 717, 724, 763-764 Seed 438 Potato 67, 277, 283 Family syn. Nightshade Family Scab 680 Sweet 241 Potentilla anserina 177-178, 663, 787, f. 177 Seed 448, f. US canadensis. Seed 448-449, f. U9 fruiticosa 632 monspeliensis 175-176, 596, 789, f.U9 Distribution 742, m. 176 monspeliensis v. norvegica 614 seed 449, f. U9 Poverty Grass 28-29, 790, f. 28 Distribution m. 29 Long-awned 29-30, f. 30 Poverty Weed syn. Marsh Elder Prairie Clover, Hairy 550, 551, 552 Farmer 247, 382, 826 Iowa, Native Flora of 688-692 Larkspur 142, 439 Plantain 303-305 Rose, Wild 178-180, 449, 450 Sunflower 342-343, 487, 488 Thistle 376-377, 789, 790 Prenanthes alba 501, f. 501 sp. 703 Prentiss, A. M. 845 Preston, E. H. 756 Prickles 869 Prickly Lettuce 396, 397, 398, 399, 500, 501, 596, 645, 664, 721, 725, 729, 747, 758, 789, 819, 826, 838, 840 (integrata) 396-399, 500, 501, 721, 747 Poppy 440, 441, 539, 729 Sida 218, 219, 559, 560, 718, 722, 723, 734, 789 Primrose. Evening 224-225, 592, 776, 788, 819, f. 225 Distribution 718, 762, m. 225 Root system 645 Seed 460, 560, f. 560 Evening (O. grandiflora). Distribu- tion 696 (O. sinuata), Distribution 737 Family 224-225 Distribution 724 Seed 460, 560 Primulaceae, Distribution 719, 724 Prince's Feather 74 Distribution 763 Seed 428, f. 428 Prister 5 83 Privet f. 59.', Procambium 869 Propagation of weeds 650-651 Propertv tax for weed destruction 800, 802 Prostrate Pig^'eed 117-118 Spurge 208-209 Vervain 267-268, 690 Protein 869 Prunella vulgaris 270-271, 667, 777, f. 271 Distribution 142, m. 271 Seed 470, f. J,71, 638 Prunus emarginata. Distribution 694 pennsylvanica 703 serotina f. 637 Psedera quinquefolia 213 Pseudotsuga taxifolia. Distribution 694 Prussian weeds 754 PTERIDOPHYTA 3, 5-6 Pteris, Distribution 693 aquilina 667, f. 691, Distribution 693 caudata. Distribution 693 sp. 693 Puccinia coronata f. 629 graminis 678, 680, f. 679 hieracii 67 8 pringsheimiana 678 rubigo-vera 680, f. 678, 679 Puccoon, Narrow-leaved, Seed 467, f. 1,67 Puget Sound "Weeds 727 Pulse Family 180-199, 450-455, 545-554, 592, 734 Distribution 724, 759-761 Purity of Seeds, Standard 812-813 Purple Cockle 814 Cone-flower f. 666 Locu-weed 194-195 Thorn Apple syn. Jimson Weed Stramonium syn. Jimson Weed Purslane 136-138, 788, f. 137, 764 Chemical composition 138 Distribution 691. 696, 697, 701, 717, 723, 729, 763-764, m. 138 Seed 438, 814 Family 134-138 Distribution 724, 763-764 Milk syn. Creeping Spurge Pusley syn. Purslane Pyrethrum 307 Pyrola, sp. 702 Quack Grass 8, 27, 53-58, 241, 273, 664, 665, 688, 773, 774, 781, 786, 794, 796, 810, 819, 822, 844, 847, 848, 850, 852 Chemical composition 57-58 Diseases 680, 736 Distribution 715, 736, m. 55 ergot 680 Root system 648, 651, f. 6iS Seed 421-423, 640, 674, 810, 814, f. J,22, 688 Quade, C. R. XII Quaking Grass 667 Quassia Family, Distribution 725 Quebec weed legislation 79 3 TS^eeds 768 Queensland Weeds 838 Quick Grass svn. Quack Grass Quince 175, 632 Raceme 611, 869, f. 612 Rachilla 869 Rachis 869 Raddin 765, 766 Radial leaves 592 Distribution 717, m. 269 Radicula armoracia 168-169, 788, f. 169 Distribution 717. m. 2G9 nasturtium-aquaticum. Distribution 717 palustris 167-168, f. 167 Distribution 742, m. 168 Seed 447. f. 447 Radish 142, 788 Cystopus on 678 Seed 444, f. 444 ■V^Tiite 845 Wild syn. Jointed Charlock INDEX 901 Rafinesque, C. S. 774, 854 Ragweed, Greater 326-327, 789, f. 337^ 671. 691 Distribution 691, 720, m. S27 Root system. 645 Seed 484, 574, 674, 814, f. m Lance-leaved, Seed 483, f. iSS Large syn. Greater Ragweed Perennial 331-332, f. 332 Distribution 689 Root system 651 "Seed 484, f. ^83 Pollen 681 Smaller 328-331, 657, 658, 659, 660, 778, 789, f. 329, 330 Distribution 698, 705, 720, 730, 740, in. 330 Root system 645 Seed 482-483, f. m, 557 sp. 625, 793, 807, 822 Western syn. Perennial Ragweed Ragwort 665, 667, 678, 743, 750 Ranunculaceae 4, 139-142 Bibliography 586 Distribution 717, 724 Seed 438-440, 536 Ranunculus abortivus 139-140, 787, f. 139 Distribution 717, m. HO Seed 440, 536, f. UO, 536 acris, Distribution 717 Seed 440, f. UO arvensis 663 Distribution 736 bulbous. Distribution 717 cymbalaria. Distribution 742 flammula. Distribution 736 multifidus. Embryo f. 621 pennsylvanicus. Distribution 742 repens. Distribution 742 septentrionalis 140-141, 787, f. Ul Distribution 717, 736, m. Ul Rape 142 Seed 445, 810, 811, 813, f. US Broom 665, 735, 827 Raphanus raphanistrum 153-155, 665, f. m Chemical composition 674 Distribution 696, 699, 717, 735, 736, m. 15', sativus 788 Distribution 725 Seed 444, f. m Raphe 869 Raspberry 175, 703 Black 632 Rat-tail Plantain 638 Rattle, Yellow 667 Distribution 742 Rattle-box (Astragalus) 193-194, f. 19^ Rattle-box (.Crotalaria) 182-183, 788, f. 1S2 Distribution 718, m. 1S3 Seed 450, 545-546, f. 450, 5^6 Rattlesnake Root, Seed 501, f. 501 Weed 703 Ratzeburg, J. T. C. 754, 767, 826, 845 Rawson, W. B. 85] Raymond, L. H. 749 Receptacle 869 as seed disseminator 631 Red Bud 180 Campion 605, 716 Cedar 6 Cherry 694 Clover 78, 130, 149, 175, 360, 451, 674, 692, 698, 705, 712, 726, 810, 811, 812, 828, 830, 831, 832, 833, 835, 836, 855, 856, 857, 858, 859, 860 Mammoth 811, 812 Medium 811, 830 Small 812 Top 415, 680, 715, 805, 806, 810 Red River Valley Weeds 751 Redroot 113-115, f. 116 Chemical composition 115 Distribution m. 115 Red-seeded Dandelion 390-391, 498, 631, 721 Red-shank syn. Lady's Thumb Red-veined Dock syn. Bitter Dock Reed Grass, Distribution 733, 736 Reed Bent Grass 693, 736 Reed-mace Fungus 677 Rees, Bertha 829 Register and Leader 803 Rehnstron, B. 750 Reinbott, C. 746 Reppert, F. 745, 749, 760, 763 Reseda lutea. Distribution 717 ResedaceaEj Distribution 717, 724 Respiration 600, 869 Rest-harrow 607 Reum, J. A. 845 Reynold, A. P. 749 Rhamnacbae, Distribution 724 Rhinanthus crista-galli major. Distri- bution 736, 742 crista-galli minor. Distribution 736 Rhizoctinia violacea 677 Rhizome 649, 650, 651, 869, f. 6^8, 651, 652 Rhode Island Weeds 766 Rhodin, S. 851 Rhomb-leaf Sida 723 Rhus glabra 841 toxicodendron 213, 214, 787, f. 214,215 Root system 652 Rib 869 Ril) Grass syn. Buckhorn Ribbon Grass 8 Ribwort 665 Rice Cut Grass f. 739 Distribution 740 Rice weeds 840, 847 TVild, Seed 856 Richardia scabra. Distribution 723 Richman, Mrs. 766 Ricinus communis. Distribution 696, 697, f. 697 Ridley, H. N. 859 Road funds. How applied in Iowa 800 Roberts, B. D. 762 Roberts, H. F. 831, 859 Robinia pseudo-acacia. Distribution 718 Rocket 159, 160, f. 159 Distribution m. 160 Yellow 787 Robinson, B. L. 731, 754, 767, 768 Rocky Mountain Bee-plant 173-175, 448 Sand bur 794 Weeds 729 Rolfs, P. H. 557, 586, 745, 748, 751, 755, 756, 859 Rollins, J. 766 Romer, P. 845 Rommatin 852 Root 869 Aerial 645 Annual 647, 649 Winter 647, 657 Biennial 648, 649, 650 Central 644 Classification 647, 649 Fibrous 645, 650, f. 649 Fleshy 648, 650 Forms 644-650 Functions 644, 645 Lateral 644 Parasitic 645 Perennial 648-649, 650 Primary 644, 650 Multiple 644 902 INDEX Resei-ve food 645 System 643-650 Noxious weeds, Table 645 Tuberous 645 Vertical 651 Root-rot, New Zealand 678 White 678 Root-stock 650, 869 Root weeds 736 Roots of weeds 643-650, 861 Rosa arkansana syn. of pratincola ITS- ISO. 632, f. 17S, 119 Distribution 717, m. 179 Root 652 Seed 450, f. H9 RosACEAE 4, 175-180 Distribution 717, 724 Seed 448-450, 545 Rose, J. N. 825 Rose Family 175-180, 44S, 450, 545, 592. 632 Distribution 724, 734 Moss 134 Prairie syn. Wild Rose sp. 3, 6, 67, 175, 631, 695 Wild 178-180, 632, f. 178, 179 Distribution 717, 711. 179 Root 652 Seed 450, f. J,I,9 Rosellinia necatrix 677 radiciperda 678 Rosenberg- 754 Rosenthaler 5 83 Roster 766 Rothamsted, Experiment Station 664 Rothrock 767 Rotminstror 64 3 Rough Ox-eye syn. Ox-Eye Pigvjeed syn. Tumbling Pigweed Rough-stalked Meadow Grass 639, 715 Rousseau, H. 843 Roussille 851 Roger, C. B. 766 Rubber shoes. Weeds distributed by 710-711 Rubber plants 234 RUBIACEAE 572-573 Distribution 724 Seed 476 Rubus nutkanus. Distribution 693 ursinus. Distribution 693 Rudbeckia hirta 339-340, 689, 787, f. 339 Distribution 705, 737, m. 339 laciniata. Distribution 737 Seed 486, f. J186 Rue, Meadow, Seed 438. f. J,39 Rugel's Plantain 299-301, 475-476, 720, 788, 814 Ruiz, L, 75 3 Rumex acetosa 667 Seed 526 acetosella 667, 774, 787, 819 Distribution 696, 697, 716, 735, 736 Root svsteni 651 Seed 810 altissimus 7S7, 796 Distribution 716 Root 654 Seed 810 crisDus 74-76, 774, 788, f. 7J,. 630, 727 Chemical composition 75 Distribution 697, 716, 725, 736, in. 75 Root system f. 6.'i7. 652 Seed 426, 427, 527, 810, f. m. 526 obtusifolius 78, 79, 595, 774, 789, f. 79 Distribution m. 79 Seed 427. f. .',37, 726 patientia. Distribution 763 sanguineus. Distribution 716 sp. 663, 67 6 Rumler-Breslau, Dr. 851 Runch 664, 665 Runge 753 Runner 869 Rush Family 63-65, 623 Grass, Sheathed 37-38, 790, f. 37 Distribution 715, m. S8 Small 38-39, 790, f. 39 Distribution 715, m. 39 Slender 65, f. 65 Distribution 715, m. 65 Spike, Seed 407-408 Rushlike Lygodesmia 403-404 Russian Pigweed 814 Thistle 67, 433, 532-533, 631. 699, 716, 727, 728, 729, 730, 743-747, 789, 794, 796, 805, 807, 808, 814. 825-S26, 834, 837, 839, 841, 842, 845, 846, 847, 848. 861 Tumhleweed syn. Thistle Weeds 757, 829, 843, 844 Rust, Cereal f. 679 Chrysanthemum 678 Wheat 678 White 677, f. 681 Rutledge, F. T. 766 Rydberg, P. A. 747, 755 Rye 6, 8 Ergot 678 Grass 7S5, 789 Seed 810 English syn. Perennial Rye Grass Italian 787 Seed 421, 811, 813, f. i21 Perennial 789 S^ed 42 0, 813 W^ild 680 Seed 813 Impurities S29 Saffron. Meadow, Distribution 736 Sage, Blue 277, 279, f. 278 Distribution 759, m. 279 Lance-leaved syn. Blue Sage Scarlet 268 Wood 272-273, f. 273 Distribution m. 273 St. John'p-wort 223-224. 788, f. 223 Distribution 70S, in. 22i Family 221, 223-224 Distribution 724 Saint-Ouentin 852 Sale 766 Salicaceae. Distribution 724 Salsify, Seed 497, f. ',98 Meadow 497, f. Ji98 Sal.sola kali 677, 808 Salsola kali v. tenuifolia 111-113, 7S9, 79 6, f. 112 Chemical comuosition 113 Distribution 699, 716, 727, 728, 729, 743-746, m. 112 Seed 433, 532-533, f. ^33, 533, 730 Saltbush 99 Saltwort 677 Salvia lanceaefolia 277, f. 278. 279 Distribution 759, m. 279 Samek. J. 82S, 859 Sample, A. F. 761 Sandbur 25-26, 637, 790, f. 26 Distribution 714, m. 26 Seed 412, 517, f i!2 Rocky Mountain 794 Sanderson, Mrs. 766 Sand or, C. 851 Sandy soils. Weeds of 819 Sapindaceae Bibliography 586 Sapling Clover, Seed 812 Saponaria officinalis 134, 136, 790, f. 135. 136 Distribution 712, 717, m. 136 INDEX 903 Seed 533-534, f. 535 vaecaria 132-134, 789, f. 133 Distribution 696, 697, 717, 728, in. Seed 438, f. ^ Saskatchewan weed legislation 793 Satureja nepeta. Distribution 720 vulgaris Distribution 720 Saunders, Wm. 836 Saururus, Distribution 693 Saiv-toothed Sunflower syn. Meadow Sunfloxoer Saxipragaceae^ Distribution 724 Saxifrage Family, Distribution 724 Saxony, weeds 845 Sayre, L. B. 837, 845 Scabiosa australis, Distribution 839 Scale 869 Scaly Grindelia syn. Gumweed Scandix pecten-veneris 663 Distribution 736 Scape 870 Scarlet Sage 268 Scentless Chamomile 638 Scherer 699, 713, 740, 766 Schips, K. 547, 585 Schively, A. P. 585 Schleiden, M. J. 5 85 Schoepf, M. D. 733, 854 School of Instruction 800 Schorler, B. 766, 845 Schreiber, E. C. 767 Schroder 583 Schroter, C. 852 Schultz, G. 845 Schwabia, "Weeds 848 Schwere 5 83 Sclerenchyma 870 Cell, see Cell, Sclerenchyma Sclerotic cell f. 57Jt Sclerotinia 6 SO sclerotiorum 677 Sclerotium Disease 677 Scotch Thistle 806 Scribner's Panic Grass 660, 689 Scrophularia leporella 294 marilandica 294-295, 789, f. 295 Distribution m. 295 SCROPHUI.ARIACEAE 4, 291-296, 777 Bibliography 586 Distribution 725 Seed 4:72-4:74:, 570 Scutch Grass syn. Quack Grass Secale cerale, Seed 813 Sedge 407, 630, 788, f. 603 Family 63, 407-408, 623, 636, 678 Distribution 624 sp.. Seeds f. 407 Sedum stenopetalum Distribution 695 telephium Distribution 712 Seed coat as a factor in germination 829, 856 as weed disseminator 631 Control Stations 85 6 Develonment 624 General characters of 407-502 Investigations Arizona 834 Australia. 837 Canada 836-837 Connecticut 830 Denmark 82 8 Hamburg 827-828 Iowa 834-835 Kansas 831-832 Kentuckv 832 Maine 832 Maryland 835 Massachusetts 833 Michigan 830-831 Minnesota 832 Nebraska 833 Nevada 831 New Hampshire 833 New York 833-834 North Carolina 830, 832, 860 North Dakota 834 Ohio 831 Pennsylvania 831 Texas 834 Tharandt 827 United States Department of Agri culture 835-836 Vermont 833, 857 Wisconsin 834 Zurich 828 Laboratory XII Legislation Canada 808, 814 Iowa 80^-814 Maine 809, 814, 860 Michigan 814 North Carolina 832 North Dakota 814 Washington 809 Wisconsin 809, 814 Wyoming 809 Production 615-624 Testing 828, 830, 831, 832, 833, 834, 835, 836, 855, 856, 857, 858, 859, 860 Weeds 736 Seeds, Adulterated 811-815, 827, 856, 857, 858, 859, 860 Agricultural 810 Destroyed by birds 629, f. 636 Germination 24, 99, 829, 830, 831, 832, 833, 834, 835, 836, 837, 855, 856, 857, 858, 859 Microscopic structure of 505-587 Purity of. See Seed-testing Scattered by birds 629, f. 637, 638 Viability, Standard 812-813 Vitality 821, 828, 829, 830, 831, 832, 833, 835, 836, 837, 855, 856, 857, 858, 859 "Weeds 855-60 Self-heal 270-271, 660, 665, 667, 777, f. 271 Distribution 742, m. 271 Seed 470, f. .',71 Seidler, L. 673, 837 Selby, A. D. 825, 826, 831, 845, 851, 859 Sempolowski, A. 553, 581 Senebiera pinnatifida. Distribution 723 Senecio canus. Distribution 694 jacobaea 667 Distribution 750 palustris. Distribution 743 sp. 678, 693, f. 6S3 . triangularis. Distribution 694 vernalis. Distribution 735-754 vulgaris, Distribution 725, 736 Seed 493, 663, f. m Senna 180 Distribution 723 Low, Distribution 723 Sepal 604. 870 Setaria glauca 17-20, 789, f. IS, 22 Chemical composition 19 Distribution 691, 714, 732, m. 19 Seed 22, 413, 511, 512, f. J,1S, 676 italica. Seed f. m panis. Seed 510, 511 sp. 517, 664 verticillata 22-24, 790, f. 23 Distribution 696, 714, 732, in. 23 904 INDEX viridis 20-22, 506, 511, 790, f. ?.l, 501, 509, 510, 605 Chemical composition 21-22 DistrllDution 691, 714, 729, 731, m. Seed 412-413, f. 1,12, 511, 512, 676 Seton, R. S. 851 Settegast 82 8, 859 Severance, G. 861 Shamel, A. B. 857 Shaw, A. B. 748 Shaw, Thomas 371, 822, 851 Sheath 870 Sheathed Rush Grass 37-38, 715, 790 Sheep Sorrel 80-82, 667, 774, 787, 819, f. SI Chemical composition 82 Distribution 696, 716, 736, m. 82 Root svstem 651 Seed 425-426, 640, 810, 814, f. ^26 Sheep's Burr 849 Fescue 715 Sheldon, Parley 745 Shepherd's Purse 151-153, 604, 659, 660, 665, 677,^ 776, 786, 819, f. 152,622 Disease 680, f. 6S1 Distribution 696, 708, 717, 734, 740, m. 653 Root system 648 Seed 443, 540-541, 815, f. 1,1,3, 51,2, 638 Sheepiveed svn. Stinkiveed Shimek, B. V. XI Shoo-fly 221-222, 796, 822, f. 222, ~61 Distribution 688, 696, 697, 710, 712, 713. 718, 761, 762, 794 Seed 460, 7. 1,59 Shoe-string 88 Devil's 88 Showy Milkweed 237-238, 719, 787 Shrub 870 Shrubby Cinquefoil 842 Shull, C. A. 861 Siberian Weeds 757 Sieyos angulata 5 9 3, f. 59', Distribution 737 Sida, Prickly 218-219, 789, f. 218 Distribution 718, 722, 728, 734, vi. 219 Seed 560 rhombifolia. Distribution 698, 723 Rhomb-leaf, Distribution 698, 723 spinosa 218-219, 789, f. 218 Distribution 718, 722, 723, 734, 740, m. 219 Seed 5 60, f. 559 Side Oats 689 Silene antirrhina 788 Distribution 716 Ssed 534-535, f. 535 dichotoma 128-130, f. 1x9 Distribution 712, in. 130 Seed 436, f. 1,37 gallica, Distribution 725 inflata, Seed 535 latifolia, Distribution 716 Seed 436, f. 1,36 noctiflora 130-132, 790, f. 131 Distribution 712, 716, m. 132 Seed 437, 810, f. 1,37 vespertina, Seed 4 37, f. 1,37 virginica. Seed 535, f. 535 Silesia, Weeds of 754 Silky Bent Grass 639, Seed f. 639 Cinquefoil 734 Sophora 551 S'ilphium perfoliatum 482, f. ^83 Silverweed 177-178, 663, 665, 787, f. 177 Distribution 742, m. 177 Silvery Cinquefoil syn. Silvertoeed Orach 74 6 Silybum marianum 701 Distribution 725 SiMARUBACEAE, Distribution 725 Simpson's Honey Plant 291, 294-295, 789, f. 295 Distribution m. 295 Sinapis arvensis syn. Brassica arvensis Sinus 870 Sirrine, Emma 525, 586 Sirrine, F. A. 759, 763 Sisal substitute 216 Sisymbrium altissimum 165-107, f. 166, 733 Distribution 717, 734, 789, m. 167 Seed 446, 544, f. 1,1,7, 51,2 canescens, Seed 544 officinale 164-165, 664, 787, f. 16!, Distribution 717, 725, 734, m. 165 Seed 446, 534, 544, f. 1,1,7 Slum latifolium Distribution 734 Skeleton Weed syn. Lygodesmia Skunk-tail Grass syn. Squirrel-tail Grass Skunkweed 708 Sleepy Catchfly 716, 788 Slender Catchfly 534-535 Foxtail 665 Rush 65, 715 ■V^Hieat Grass 53, 57, 422, 423 Small, A. J. XII Small Beggar-ticks 489, 720 Bindioeed syn. European Bindioeed Peppergrass 146-147, 441-442, 540, 541, 638, 688, 692, 717, 734 Ragioeed syn. Smaller Ragweed Red Clover 812 Rush Grass 38, 39, 715, 790 Squirrel-tail Grass 7 87 Stick-tight 489 Small-flowered Buttercup 787 Catchfly 725 Crowfoot 139-140, 446, 536. 717 Dandelion syn. Red-seeded Dandelion Mallow 725 Small-fruited False Flax 638 Smaller Ragweed 328-331, 482-483, 645, 657, 658, 659, 705, 720, 789 Smartweed 95-97, 822, /. 21, Common /. 93 Familv 74-99 Seeds 425-431 Marsh syn. Tanweed Mnlilenh erg's syn. Tanweed Nodding Sim. Pink Smartweed Pennylvania 90-92, 594, 657, 658, 659, 660, 664, f. 91, 92 Distribution 716, m. 91 Root svstem 645 Seed 4 30. f. 1,30 Pink 86, 87, 788, f. 87 Distribution 716, 734, 742, m. 87 Seed 430, f. 1,30 Slender svn. Pink Smartioeed sp. 687, 691, 788, f. 661 Water 97, f. 96 Distribution 716 Seed 42 8, f. i2S Smith, J. H. 756 Smith, M. G. 825 Smith, P. H. 833. 851, 859 Smith, -W. G. 845 Smoke Tree 213 Smooth Brome Grass syn. Hungarian Brome Grass Crab Grass 10-12, 408-409, 505, 714, 789, 810 Dock 76-78, 427, 654, 787, 794, 796, 799 Goldenrod 315-316, 480 Snake-bites, Antidote 778 INDEX 905 S^akeroot, "White 312-313, 780, 789, f. 312 Distribution m. 313 Seed 477, f. J,78 Snapdragon 291 • Also see Toadflax Sneezeweed 354-356, 780, 790, f. 355,356 Distribution 721, m. 355 Seed 490, f. m Narrow f. in Distribution 722 Snow, Seed Scattered by 629, 687 Snow-on-the-mountain 205, 210-211, 787, f. UO, 712 Distribution 712, 757, m. 211 Seed 458, f. ps Snowball f. 595 Snyder, Harry 115, 157, 165, 273 Soapwort syn. Bouncing Bet Soft Chess 46-48, 419, 715, 733, 789 Grass, Creeping 665, 667 Woolly 665 Maple 634 Soil affected by weeds 681-682, 860 SOLANACEAE 4, 277-291, 777 Bibliography 586 Distribution 725, 756-767 Seeds 471-472, 568-569 Solanum carolinense 283-284, 777, 787, 796, f. 285 Distribution 705, 720, 765-766, m. 285 Root system 651 Seed 471, 568, f. 472, 568 heterodoxum, Distribution 738 nigrum 281-283, 625, 777, 790, f. 281, 282 Distribution 696, 697, 720, 736, m. Seed 471, 569, f. i72, 569 rostratum 284, 286-288, 787, f. 286 Distribution 720, 722, 738, 766-767, 844, TO. 286 Seed 471, 569, f. m, 568, 635 triflorum, Distribution 738 Solidago canadensis 313-314, 790, f. 3U Distribution 690, 721, 737, m. 3U Seed 479, f. 480 lanceolata, Distribution 737 missourlensis, Distribution 689 odora, Distribution 689 rlgida 316-317, 689, 790, f. 317, 633,738 Distribution 689, m. 317 Seed 480, f. J,80 serotina 315-316, 790, f. 315 Distribution 738, m. 316 Seed 480, f. J,80 Solitary flowers 611, f. 611 Solomon's Seal, Rhizome f. 652 Somervllle, Prof. 851 Sonchus arvensis 394-396, 663, 790, 808, 819, f. 395 Distribution 736, 753, m. 395 Seed 499, f. 499 asper 393-394, f. 393 Distribution 721, 736, to. 394 Seed 499, f. 499 oleraceus 391-393, 787, f. 392 Chemical composition 674 Distribution 696, 736, to. 393 Seed 500, f. 499 palustre. Distribution 736 sp. 676 Sophora sericea f. 551 Silky f. 551 Sorauer, P. 820, 846 Sorghum, Seed 813 Sorghum halepense 7, 8, f. 7, 722 Distribution 722, 732, to. 7 Seed 408, f. m 58 Sorrel, Field 202-203, f. 202 Distribution 734, 741, to. 203 Seed f. 630 Yellow, 201-202, f. 201 Distribution m. 202 Horse sun. Sheep Sorrel Lady's 659, 787 Distribution 696, 697, 718 Seed 456, f. 457 Sheep 80-82, 540, 667, 774, 787, 819, f. 81 Chemical composition 82 Distribution 696, 716, 735, 736, to. 82 Root 651 Seed 425-426, 640, 810, 814, f. 426 sp. 678, 833, f. 59!,, 638 Also see Sour Clover Violet Wood 689 Yellow-floivered syn. Field Sorrel Sour Dock syn. Curled Dock South America, AVeeds of 696, 713, 726, 731 732 733 734 Southern Nut brass 63, 722, 723 . Peppergrass 723 Spear Grass 45-46, 416, 517, 715, 732, 740 Sow Thistle 393-394, 661, 665, 577, f. 393 Distribution 708, ?n. 394 Seed 499, f. 499 Annual 391-393, 787, f. 392 Chemical composition 674 Distribution 725, m. 393 Seed 500, f. 499 Field syn. Perennial Sow Thistle Perennial 394-396, 663, 793, 808, 819, 826 f 395 Distribution 753, 842, to. 395 Seed 499, 814, f. 499 sp. 736 Spinjr, Seed 499, f. 4S9 Soybean 180 Spacht 768 Spanish Dagger 645 Needle syn. Bootjack Sparrow, E. E. 767 Sparrows as seed destroyers 629 Spear Grass, Low 664 Distribution 715 Southern 45-46, f. 45 Distribution 715, 732, 740, m. 46 Seed 417, f. 4^6 ■ Spearmint 268 Distribution 720 Specific gravity of seeds 828 Speedwell 664 Corn, Distribution 723 Purslane, 296, 297, f. 298 Distribution 720, 723, 740, w. 297 Seed 473, f. 414 Spergula arvensis, Chemical composi- tion 674 Distribution 723 sp. 853 SPFRMATOPHYTA 3, 6-404 Spike 611, 870 Spike Rush, Seed 407-408 Spikelet 870 Spillman, W. J. 846, 852 Spinach 99, Disease 678 Distribution 712, 725 Seed 432, f. 4S2, 730 Spinacia oleracea, Distribution 725 Seed 432, f. 432, 730 Spinage syn. Spinach Spine 870 Spiny Amaranth 697, 723 Clotbur 334, 336, 485, 486, 713, 737, 754, 821 Cocklebur syn. Spiny Clotbur 906 INDEX Knapweed syn. Knapweed Nightshade syn. Buffalo Bur Sow Thistle 494 Spiny-leaved Sow Thistle syn. Sow Thistle Spiraea 175 Distribution 693 Spleenwort 5 Spooner, A. 766 Sporangium 616, 870 Spore 870 Sporobolus neglectus 38-39, 790, f. 39 Distribution 715, m. 39 vasiniflorus 37-38, f. 37 Distribution 715, m. 38 Spotted Cowbane 596 Spurge 207-208, 458, 556-557, 657, 718, 788 Large 660. 718 Spraying S47, 848, 849, 850, 851, 852 Spreading Amaranth syn. Prostrate Pigweed Dogbane 235, 237, 719, 788 Pigweed syn. Prostrate Pigweed Spring Beauty 134 Spring grain field, Weeds of 661 Sprouting Crab Grass 14-15, 410, 691, 714 Spruce 3, 6 Spurge, Creeping 208-209, f. 209 Distribution in. 209 Seed 458, 557, f. J,51, 557 Cypress 212-213, f. 212, 735 Distribution 718, 736, m. 213 Seed 557, f. 557 Family 205-213 Distribution 724 Seed 457-458, 556-557 Flowering (corollata) 210, f. 211 Distribution 718, 690 Seed 458, 596, f. J,58, 597 Flowering (maculata) syn. creeping spurge Flowering (presUi) syn. Spotted spurge Milk syn. Creeping Spurge Prostrate svn. Creeping Spurge sp. 658, 659, 660, 664, 786. 787, 819 Spotted 207-208, 657. 718, 788, f. 208 Distribution m. 208 Seed 458, 556-557, f. 458 Larere 660, 718 Upright syn. Spotted Spurge Yellow stin. Cypress Spurge Spurrey 120, 664, 665. 677 Chemical Composition 674 Distribution 723 Corn, see Corn Spurrey Squash 6 Squaw-weed f. 623 Squires 766 Squlrrel-tall Grass 58-61, 788, f. 59, 60 Chemical Composition 60-61 Distribution 691, 693, 715, 729, 730, TO. 60 Puccinla on 680, f. 678, 679 Seed f. 730 Squirrel-tail Grass (H. murinum) 677, 698 Small 787 sp. 729 Stachys palustris 789 Distribution 743 Stadler 583 Stamens 609-610, 615-617, f. 609, 615 Diadelphous 609, f. 610 Eplpetalous 609 Monadelphous 609. f. 610 Stamlnate flowers 605, f. 606, 607 Star Thistle syn. Knapweed Starch cell, see Cell, Starch parenchyma f. 518 Stebler, F. G. 828, 852 Stellaria media 121-122, 663, 776, f. 121 Distribution 696, 716, 725, m. 122 Seed 435, 810, f. J,35 Stem Eelworm 677 Stemless Lady Slipper 702 Loco Weed syn. Purple Loco weed Stems, Underground 651-653, f. 651, 652 Stereome f. 599 Sterile flowers f. 607 Stevens 760 Stevens 824 Stewart, F. C. 748, 756, 760, 767, 833, 834, 859 Stokes 766 Stickseed 260-262,' f. 261 Distribution 719, m. 262 Seed 466, 565-566, f. 1,67, 565 Stick-tight syn. Beggar-ticks Small 489, f. ^89 Stickweed 180, f. 181 Distribution 717, m. 181 Seed 545, 829, f. 51,5 Stiff Goldenrod syn. Yellow-flowered Stigma 616, 871 Papillary f. 616 Petal-like f. 617 Shield-shaped f. 618 Stinging Nettle (U. dioica) 667 (U. gracilis) 69-70, 425, 602, 603, 652, 708, 715, 788 Stink Grass syn. Candy Grass Stinking Clover syn. Rocky Mountain Bee-plant Willie syn. Ragwort Stinkweed 171-173, 793, f. 172, 173 Distribution 693, 717, m. 172 California 840 Also see Pennycress Stipa 636 spartea 689, 790, f. 666, 667 sp. Distribution 701 Stipule 591, 592, 871, f. 591, 593 Stolon 871 Stoma 597. 871, f. 598 Stone, A. L. 850. 852, 861 Stone, G. E. 833, 851, 852, 859 Stone Clover 718. 760 Stonecrop, Distribution 695 Storksbill, Distribution 713, 725, 729, 734 Seed 457, f. i57 Stramonium, Purple syn. Jimson Weed Strap-shaped flowers f. 611 Strawberry 175 False 175-176, f. 176 Distribution m. m Strophostyles helvola 199-200, 790, f. m Distribution 718, m. 200 Seed 455, f. 1,55 Stubbleberry syn. Black Night-shade Studley 766 Sturtevant, B. L. 846 Stutzer, A. 673, 837 Style 617, 871 Successful Farming 826 Succory syn. Chicory Sugar 600 Cane 600 Suksdorf 751 Sumach 213 Family 213, 214, 215 Summers 746 Sunflower Annual svn. Common Sunflower Common 340-342, 596, 601, 789, f. 31,1, 31,2 Distribution 693, 720, 730, 756, m. Sil Seed 487, 575, f. iS7, 5% Trlchomes f. 488 INDEX 907 Diseases 680 Family 307-404, 633 Distribution 724, 734-735, 747-758 Inflorescence 614, f. 61S Seed 477-502, 574-580 Maximilian's 348-349, 790, f. 3^',S Distribution m. S^S Meadow 344-346, 790, f. 3U, SJ,5 Distribution 691, in. 3J,5 Petiolate syn. Prairie Sunflower Prairie 342-343, 788, f. SiS Distribution 730, m. SiS Seed 487, f. i88 Trichomes f. iSS Saw-toothed syn. Meadow Sunflower sp. 695, 794 "Western, Distribution 689, 69 6 Trichomes f. iSS Wild svn. Wood Sunflower Wood, Seed 488, f. m Suspensor 621, 871 Swamp Buttercup 140-141, 717, 787 Milkweed 462, 463 Sweden, Weed Seeds 829 Weeds 846 Sweet Cicely 561 Clover 794, 815, 834 White 187-190, 451-452, 548, 644, 645, 648, 718, 725, 726, 729, 760, 788, 794, 810, 811, 831, 832 Yellow 186-187, 452, 548, 713, 718, 725, 729, 759, 776, 810, 811 Potato 241 Vernal Grass 693, 714 Switch Grass 6, 410-411 Switzerland Weeds 754, 820, 845 Symphoricarpos orbiculata 790 Symphytum officinale, Distribution 719 Tagetes erecta. Distribution 696 Tall Buttercup 440, 717 Doclc syn. Smooth Dock Five-finger 657 Hedge Mustard 789 Thistle 494 ranacetum vulgare 364-365, 780, 790, f. S65 Distribution on. 365 Tandberg, G. 852 Tannin 213 Tansy 307, 364-365, 773, 780, 790, f. 365 Distribution 688, 709, 720, m. 365 Mustard 660 Tanweed 88-90, 789, f. 88, 89 Distribution 716, m. 88 Root 652 Seed f. J,31 Tapetal cell 891 Taraxacum erythrospermum 390-391, 787, f. 390 Distribution 721 Seed 498, f. ^98 officinale 386-389, 676, 780, 787, 819, f. 386, 388, 389, 7i3 Distribution 696, 697, 721, 736, m. 387 Seed 498, 499, 579, f, 498, 580 Tarred paper as weed exterminator 134 Tatnall 765 Taylor, F. W. 833, 860 Taylor, W. A. 836 Tea, Mexican 103-104, 790, f. IO4 Distribution 738, 746, m. lOi Teasel 714 Distribution 711 Family Distribution 724 Teilitzen, H. 849 Teindl, J. C. 861 Tener. W. E. 746 Teneriffe Weeds 693 Tennessee medicinal plants 853 Weeds 766 Ten Eyck, A. M. 250, 643 Testa 871 Teucrium canadense 272-273, 789, f. 273 Distribution m. 273 Seed 469, f. 470 Texas Blue Grass 639 Seed legislation 834 Thaer, A. 735, 819 Thalictrum purpurascens 688-689 Seed 438, f. J,39 Tharandt 827 Thaspium barbinode 808 Thellung, A. 846 Thistle, Distribution 821 Barnahy's syn. Knapweed Bull 372, 373, 789, f. 373 Distribution 687, 695, 721, 725, m 373 Root system f. 650 Seed 495, f. m, 676 Canada 67, 379-382, 592, 633, 665, 788, 793, 794, 796, 803, 804, 805 806, 807, 819, 826, 844, 847, 848, 852, f. 380, 381, 592 Distribution 688, 708, 721, 748-749 m. 381 Root system 648, 651 Seed 494, 636, 810, 814, 833, 834, f. m, 638, 639, 676 Cotton 667, 677 Distribution 725 Family syn. Sunflower Family Field 376-377, 789, f. 376, 377 Distribution m. 378 Root system 645 Seed 495, 577-578, f. 1,95, 578 Iowa 377-379, 789, f. 378 Distribution m. 378 Seed 495, 578, f. J,95 Lady's 495, 578 Distribution 725 Pasture syn. Wavy-leaved Prairie 376-377, f. 376, 377 Distribution m. 377 Seed 577, f. 578 Russian 67, 111-113, 789, 794, 796, 805, 807, 808, 825-826, 845, 846, 847, 848, f. 113 Chemical composition 113, 826, 837 Distribution 699, 716, 727, 728, 729, 743-746, 838, 841, m. 112 Seed 433, 532-533, 814, 834, f A33, 533, 631, 730 Scotch 806 Sow 393-394, 665, 673, f. 393 Distribution 708, 721, m. 39.', Seed 499, f. J,99 Annual 391-393, 661, 676, f. 392 Chemical composition 674 Distribution 725, 735, m. 393 Seed 500, f. 1,99 Field syn. Perennial Sow Thistle Perennial 394-396, 663, 808, 819, 826, f. 395 Distribution 753, m. 395 Seed 499, 814, f. 499 Spiny syn. Sow Thistle sp. 664, 665, 667, 676, 677, 693, 736, 748, 786, 794, 844, 848 Star syn. Knapweed Tall 790 Seed 494, f. 1,95 Wavy-leaved 788 Root system 651 Seed 495, f. 1,95 Wood syn. Prairie Thistle Woolly 374-376, 790, f. 371,, 375, 71,9 Distribution 721, 749-750, m. 376 INDEX Thlaspi arvense 143-144, 788, f. US Distribution 700, 717, m. m Seed 441, f. Ul Thom§ XII Thompson, J. 749 Thorn-apple 288, 289-291, f.?.90 Distribution 290 Purple syn. Jimson Weed Thornber, J. J. 834, 859 Thorne, C. E. 846 Thornton, R. W. 846 Three-flowered Nightshade Distribution 738 Three-seeded Mercury 205-207, 457, 718, 788 Threshing machines scattering weeds Legislation 794, 806-807 Thrift, f. 616 Thurber, Geo. 754, 822 Thyme 268 Distribution 720 Tickle Grass syn. Old-witch Grass Tickseed 352-354, f. 353 Distribution m. S5Jf Tilia americana. See f. 632 Tillman, O. I. 832, 860 Timothy 805, 806 Distribution 715, 785 Meadows, weeds of 144, 147, 322, 660, 845 Seed 415, 517,' 674, 810, 813, 827, 828, 832. 833, /. il5, 638, 676 Impurities 144, 165, 674, 857 Tissue, Spongy 59 8 Titus, W. N. 768 Toadflax 292-294, 788, 794, 808, 849, f 293 Distribution 688, 696, 708, 720, m. 2H Seed 473, 814, f. -',7J Tobacco 277 Flowering 277 Smooth 696 Tolf, R. 846 Tomato 6, 277 Tomentum 871 Tomson 753 Torrey, John 753, 754, 756, 759, 760, 761, 762, 767, 768 Touch-me-not 630 Toumey, J. W. 861 Tourlet, E. H. 738, 846 Tovey, J. R. 840 Tracy, S. M. 766 Tragopogon porrifolius. Seed 497, f. i9S Distribution 696, 729 pratensis f. .'fiS Distribution 729, 755 Seed 497, f. m Trailing Arbutus 702 Wild Bean 455 Transpiration 601, 871 Transvaal, Flora of 695-696 Trapa natans, Distribution 712 Treacle Mustard 741 Trefoil, Bird's-foot, Distribution 734 Yellow, Seed 453, 640, 787, 810, 811, 815, 831, f. i53, 63S Triboulet 852 Tribulus terrestris 203-205, 789, f. 20J, Distribution 697, m. 205 Trichome 871 Trifolium agrarium 183-184, f. 18-'i Distribution 734, 760 ar\'ense, Distribution 718, 760 hybridum. Seed 450, 812, f. !i51 incarnatum, Seed 812 pratense, Seed 451, 811. 812, f. ^51 pratense var., Seed 811, 812 procumbens 184-185, 612, 787, f. 185 Distribution 718, 760, m. 185 Seed 451, f. J,51 repens, Distribution 718 Seed 450, 813, f. J,51 Triglochin maritima 820 Tristegis glutinosa, Distribution 693 Triticum (Wheat) Seed 813 (Quack Grass) 774 Tronmer 861 Trubenbach, P. 852 True, R. H. 855 Tschirch, A. 538, 553 Tube cell 516 Tuber 871 Tubular flowers f. 611 Tumbleweed 113-116, f. 116 Distribution 690, 698, 738, m. 116 Root system 645 Seed 434, 834, f. m. 631 Iowa syn. Tumhleweed sp. 788, 843 Russian syn. Russian Thistle Western f. 100 Tumbling Amaranth syn. Pigweed Mustard 165-167, 446-447, 542, 544, 717, 733, 815 Pigweed 116, 645, 790 Turnip 142 Finger and Toe Disease 677 Flea Beetle 676 Gall Weevil 676 Root system 648 Wild Seed 445, f. U5 Tussilago farfara 663 Distribution 735, 736 hybrida. Distribution 736 petasites. Distribution 736 Tussock Grass 667 Twitch Grass 851 Tylenchus devastatrix 677 Ulex 667 Uloth, W. 583, 586 Umbel 612, 871, f. 612, 6U Umbellifer 785 Umbelliferae 4, 224-234, 776, 864 Bibliography 587 Distribution 719, 725, 734 Seed 460-462, 561-562, 767-769 Umbrella Plant, Seed 533, f. 53i United States, Weeds 840 Upham 751 Upright Spurge syn. Spotted Sptirge Urban, I. 731 Urtica dioica 667 Distribution 736 gracilis 69-70, 788, f. 69 Chemical composition 70 Distribution 715, m. 70 Root 652 Seed 425, 525, f. ^25, 525 urens Distribution 736 Urticaceae 3, 69-74 Bibliography 587 Distribution 715, 725 Seed 424-425, 524-525 Utah Weeds 712, 728, 747, 757. 769 Utricle 871 Vahl, M. 701 Valerian Family, Distribution 725 Valeria NACEAE^ Distribution 725 Valve 871 Vandevelde 82 8, 830, 859 Vanilla Grass svn. Holy Grass Vasev. George 371. 751, 846 Vegetable Ovster 497, 498, 729 Vein 871 Veining of leaves 592 Netted 592 INDEX 909 Palmate 592 Parallel 592 Pinnate 592 Velvet-leaf syn. Indian Malloiu Grass 693 Weed syn. Indian Mallow Venus' Comb 663 Distribution 736 Verbascum blattaria f. 29,2 Distribution 720 Seed 472, f. 47S thapsus 291-292, 777, 789, f. Z91 Distribution 720, 727, m. 292 Seed 472, f. ^73 Verbena, Bracted syn. Bracted Vervain bracteosa 267-268, 787 Distribution 690, 719, m. 268 Seed 468, f. i68 Creeping syn. Prostrate Vervain Family 263-268 Distribution 725 Seed 468-469, 566 hastata 263-264, 777, 789, f. 261, Distribution 704, 719, to. 26Jt Seed 469, f. i6S sp. Distribution 701 stricta 264-265, 789, f. 265 Distribution 689, 690, 719, m. 265 Seed 469, 566, f. J,69, 566 urticaefolia 264. 267, f. 266 Distribution 704, m. 267 Root 654 Seed 469, f. i69 Verbbnaceae 263-268 Distribution 719, 725 Seed 468-469, 566 Verbesina helianthoides. Seed 575, f. 577 Vermont Seed investigations 838, 857 Weeds 747, 842 Vernal Grass, Sweet, Distribution 693, 714 Vernonia baldwini 309-310, f. 310 Distribution m. 310 Seed 477, f. 477 fasciculata 310-311, f. 311 Distribution m. 311 Seed 477, f. 477 Veronica arvensis Distribution 723 peregrina 296, 297, 787, f. 296 Distribution 704, 720, 723, to. 297 Seed 473, 829, f. m sp. 659, 664 Vervain, Blue, 263-264, 777, 789, f. Z6i Distribution 689, 690, 719, to. 264 Seed 469, f. i6S Bracted syn. Prostrate Vervain Family 263-268 Distribution 263-268 Seed 468-469, 566 Hoary 264-265, 659, 789, f. 265 Distribution 719, m. 265 Seed 469, f. 469 Large-hr acted syn. Prostrate Vervain Nettle-leaved svn. White Vervain Prostrate 267-268, 787, f. 267 Distribution 690, 719 Seed 468, f. 46S White 264, 267, f. 266 Distribution m. 267 Root system; 645, 654 Seed 469, f. 469 Vetch Common 197-199, 596, 663, 787, f. 19S Chemical composition 198 Distribution 692, 696, 697, 699, 709, 718, to. 19S Seed 455, 553. f. 455. 551 Dakota, Distribution 761 Hairy. Distribution 718, 735 Seed 455, f. 455 Milk 193-194, f. 194 Spring syn. Common Vetch Vetchling 693 Vicia americana 688 hirsuta. Distribution 735 sativa 197-199, 596, 663, 787, f. 198 Distribution 692, 696, 697, 699, 718, m. 198 Seed 455, 553, f. 455, 551 villosa Seed 455, f. 455 Viability of seeds, Standard 812-813 Victoria, Weeds 840, 841 Vienna flora 843 Vilke, A. 829 Vinall, H. N. 836 Viola arvensis. Distribution 722 cucullata f. 598 Family, Distribution 725 sp. 663 tricolor. Distribution 727 VioLACEAE, Distribution 725 Violet, Blue 598 Root-rot 677 sp. 663 Violet-colored seeds 828 Viper's Bugloss, Seed 488, f. 468 Virginia Catchfly 535 Creeper 213 Ground Cherry 279, 281 Peppergrass syn. Large Peppergrass Vitality of seeds 821, 828, 829, 830, 831, 832, 833, 835, 836, 837, 855, 856, 857, 858, 859 Vitek, E. 861 Voelcker, J. A. 846, 852 Vogl 538 Von Degen 828 Waddell, C. H. 846 Waldron, L. R. 839, 846, 852, 859, 861 Wall Pellitory f. 597 Wallace, Henry 751 Wallace's Farmer 80, 90, 113, 119, 216, 241, 247-248, 250, 254, 305, 307, 310, 322, 328, 337, 382, 826 Walters, L. G. 768 Warming, Eug. 701 Warneke, 830, 857 Washington seed legislation 809 Weed legislation 794 Water Chestnut 712 Cress 142, 717 Hemlock syn. Cowhane Hemp 118-119, 435, 716, 789 Parsnip 734 Pepper 92-93, 429-430, 734, 775, 789 Mild 95-97, 429-430, 594, 788 Seeds scattered by 629, 587, f. 630 Smartweed 96-97, 428 Waterleaf 254 Distribution 719 Family 254-256 Waterweed, Distribution 740 Waterwort Family, Distribution 724 Watson, E. B. 334, 681 Watson, S. 746, 757, 769 Waugh, E. N. 749 Wavy-leaved Thistle 495, 651, 788 Weaver, A. T. 861 Weaver, C. B. 745 Weed, C. M. 826, 852 Weed, C. N. 749 Weed Commissioner, Iowa 801, 802, 803 803 Illinois 804 Community 657-661 Definition of 820-821 Distribution Bibliography of 837-846 Geographical, Africa 722, 731, 732, 733 734 America 698, 737-740 Nortn 696, 731, 732, 733, 734 910 INDEX South 696, 713. 726, 731, 732, 733, 734 Arkansas 757 Asia 731, 732, 733, 734 Brandenberg 845 California 708, 712, 725, 755. 757 Canada 693, 733, 753, 757, 762, 766, 825, 839 Cliile 728 Colorado 745, 747, 748, 755, 757, 759 Connecticut 766 Dakota 693, 753 North 744, 757 South 744, 756, 757, 767 Delaware 765 Denmark 753, 766, 795, 844 England 763 Europe 703, 704, 706, 713, 731, 732, 733, 734, 737-740, 748 Florida 762 Prance 753, 754, 763 Georgia 754 Germany 713, 735, 736, 753, 766, 820, 841, 845 Great Britain 660, 663-664 Gulf States 722 Hanover 753 Holland 763 Idaho 745, 757, 842, 844 Illinois 745, 751, 757, 765, 766 India 767 Indiana 747, 757, 766, 768, 838 Iowa 838, 840, 841, 844, 845, 851, See species Ireland 846 Kansas 708, 751, 754, 757, 766, 837, 842 Kentucky 747 Louisiana 840 Maine 750, 754, 841 Manitoba 693 Maryland 833, 844 Massachusetts 750, 754, 757, 763, 842 Mediterranean Region 696 Mexico 733, 767-768 Michigan 708, 757, 766, 768, 824- 825, 830-831, 838, 855 Minnesota 745, 751, 753, 757, 844, 845, 848 Mississippi Valley 751, 769 Missouri 754, 757, 759, 766 Nebraska 693, 745, 748, 755, 757, 765, 844, 847 Nevada 759, 842 New Brunswick 750, 762 New England 709 New Jersey 757, 765, 841 New Mexico 757, 846 New South "Wales 843 New York 747, 750, 757. 760, 765 Newfoundland 734 Norwav 852 Nova Scotia 756 Ohio 747, 753, 757, 766, 825, 842, 843, 845 Oklahoma 838 Ontario 747, 841, 842, 843, 858 Oregon 747, 750 Pacific Coast 725, 750 Papua 733, 734 Pennsylvania 750, 759, 765, 768, 839 Peru 753 Prussia 754 Puget Sound 727 Quebec 768 Queensland 838 Red River Valley 751 Rhode Island 766 Rocky Mountains 729 Russia 757, 829, 843, 844 Saxony 845 Siberia 757 Sil6sid< 754 South Amierica 696, 713, 726, 731 732 733 734 South Dakota 744', 756, 757, 767 Sweden 846 .Switzerland 754, 820. 845 Tennessee 766 United States 840 Utah 712, 728, 747, 757, 769 Vermont 747, 842 Victoria 840. 841 West Virginia 843 Wisconsin 745, 747, 751, 754, 757, 760, 762, 766, 767, 841, 845 Wyoming 757, 844 Yellowstone Park 757 Yorkshire 825, 845 Eradication 846-853 Also see species Inspectors 793, 852 Legislation 794-808 Alberta 793 Australia 793 Connecticut 830 Delaware 794 France 795 Germany 795 Illinois 794, 803-804 Indiana 747, 757, 766, 768, 838 Iowa 794, 801 Isle of Man 793 Kansas 794, 805 Kentucky 794 Manitoba 793 Michigan 794 Minnesota 794, 805-806 Missouri 794, 806 Nebraska 794, 806 New Jersey 794 New York 794 North Dakota 794, 806-807 Northwest Territories 793 Ohio 794, 807-808 Oregon 794 Pennsylvania 794 Quebec 793 Saskatchewan 793 South Dakota 794, 808 Washington 794 West Virginia 794 Wisconsin 794, 808, 809, 814 Scattering 630-640, 687-770, 837-846 Weeds and moisture 671-673 Weeds, Diseases of 677-681 Food of 673-674 Injurious 671-683 Weekly Register 273 Weems, J. B. 10, 17, 19, 46, 48, 57, 60, 837 Wegelin 737 Weinhold 82 Wells, C. A. 756 Weschke, C. 855 "Weshoff 740 West Indies, Flora of 731 Virginia weed legislation 794 Weeds 843 Western Ironweed 310-311 Lamb's Quarters 432 Mugwort 366-367, 790 Ragweed 484 Tumbleweed 100 Wheat Grass 53. 56. 423, 715 Westgate, J. M. 187, 838 Wheat, 6, 8, 139 Grass, Awned, Distribution 715 Slender 53 Distribution ■>?!. 57 Seed f. m sp. 844 INDEX 911 Western 53, f. 56 Distribution 715, to. 56 Seed 423, f. iZS Mustard 155 Powdery mildew of f. 682 Rust of 678, 680 Screenings 810 Seed 813 Impurities 674, 709. 829 Transpiration of 673 Wheeler 753 White, G. C. 748 "White-man's Foot" 710 White, P. J. 846 White Aster syn. Many-flowered Aster Avens syn. Stickseed Campion 126-128, 638, 664, 716, 810, 814 Charlock syn. Jointed Charlock Clover 183-184, 638, 718, 830, 831 Cockle syn. White Campion Mildew 85 Mustard 14, 142, 444, 663 Pine 6 Radish 845 Root-rot 678 Rust 677, f. 681 Snakeroot 312-313, 477, 478, 780, 789 Sweet Clover 187-190, 451-452, 548, 549, 550, 644, 645, 648, 718, 725, 726, 729, 760, 788, 794, 810, 811, 831, 832 Vervain 264, 266, 469, 645, 654 Wormwood 366-367 Wliite-leaved Franseria 484, 485 Wliiteweed 321-322, 595, 788, f. 321, 621 Distribution 695, 720, 737, m. 322 Seed 482, f. m Whiting-, W. S. 768 Whitson, A. R. 846 WTiitlavia grandiflora. Seed 829 Whorl 872 Whorled Foxtail syn. Bristly Foxtail Milkweed 463 Millet syn. Bristly Foxtail Wilcox, B. M. 833, 852 Wilcox, E. V. 852 Wilcox, Fred 766 Wild Balsam Apple 573, 574 Barley syn. Squirrel-tail Grass Bean 199-200, 455, 718 Trailing syn. Wild Bean Black Cherry 637 Buckwheat 97-99, 429, 528-529, 530, 531, 532, 536, 636, 674, 814 Carrot 227-228. 635-637. 667. 676, 688, 692, 698, 712, 767-768, 786, 788, 794. 796, 802, 819, 833 Comfrey 258-259, 466, 564-565 Cranesbill 718 Endive 793 Four-O'clock 119-120, 533, 534, 660, 716, 787 Foxglove, Yellow 702 Garlic 67, 787 Heliotrope 695 Hemp 645 Lettuce 399-400, 500. 501. 595, 645, 780, 788. 807, 838. 846 Liquorice 196-197, 551, 554, 718, 729, 760, 787 Marjoram 693 Morning Glory 241. 245-248, 464, 563, 564, 624, 649, 651, 652, 660, 674, 671, 719, 787, 789, 848 Mustard 155-157. 727, 736. 787. 793. 794, 796. 807. 808, 810, 811, 849 Oats 8. 40-41, 415-416, 664, 665. 679, 715. 736, 789, 793, 794, 810, 814. 829 Onion 67, 623, 814, 852 Pansy 722 Parsnip 228-230, 461, 462, 648. 719, 794, 796 Pea 790 Peppergrass syn. Large Peppergrass Prairie Rose 178-180 Radish 134, 673 Rose 178-180, 449, 450, 632, 717 Rye 680 Sunflower 488 Timothy 35-37 Turnip 445 Willey 748 Williams, F. A. 765, 826, 852, 861 Williams, George 766 Willow, 3, 605, f. 607 Family, Distribution 724 Primrose, Distribution 734 Willow-leaved Aster 319-320, 481, 790 Wilson, A. D. 852, 861 Wilson, F. W. 853 Wilson, James- 825, 846 Wilson, J. K. 859 Wiltz, Albert 337 Wind as seed distributor 629, 687, f. 631 Wing 872 Winged Pigweed 99-101, 451, 693, 716, 730, 740, 746, 788 Winter Annuals 647-648, 660, 785, 786, S72 Cherry 623 Chess 170-171, 447 Cress 170-171, 447-448, 542, 544, 677, 717, 733, 744 Winton, A. L. 21, 43, 107, 138, 190, 299, 303, 364, 389, 505, 506, 511, 517, 520, 524, 528, 536, 554, 575, 581, 582, 583, 584, 585, 586, 587, 837 Wire Grass 41-43, f. 1,2 Chemical composition 43 Distribution 697, 715, 741, m. !i2 Seed 418, f. 418 Wisconsin drift. Flora of 689-692 Farmer 251-252 Seed legislation 834 Weed legislation 794, 808, 809, 814 Weeds 745, 747, 751, 754, 757, 760, 762, 766, 767, 841, 845 Wittrock, V. B. 853 Wollny, E. 828, 846, 859 Wood Hair Grass 639 Sage 272-273 Sorrel Family 199, 201-203 Sunflower syn. Wild Sunflower Thistle svn. Prairie Thistle Woodbine Family 307 Woods, A. F. 836, 853 Woods, C. D. 832, 853, 860 Woolen Mills, Weeds spread by 711 Woolly Soft Grass 665 Thistle 374-376, 721, 749-750, 790 Wooten, E. O. 826, 846 Wormseed 103, 774 Distribution 696 American 775, 855 Wormwood. Biennial 367-368, 790, f. S67 Distribution 721, m. 368 Seed 492, f. 1^2 White 366-367, f. 366 Distribution to. 367 Woundwort 789 Wrapp, J. M. 756 Wright. R. P. 830 Wyoming forage plants 837 Weeds 757, 844 Xylem f. 598 Xanthium canadense 334-337. 796, f. 335, 682 Distribution 720, m. 355 912 INDEX Seed 485, f. J,S5 sp. Distribution 704 Seed 829, 861 spinosum 335, f. 336 Distribution 698, 713, 737, 754 Seed 4 85, f. J,85 strumarium 486 Xylem 872 Xylopleurum tetrapterum. Distribution 696 Yard Grass sijn. Crowfoot Grass Yarrow 358-360, 778, 787, f. 359, 7J,1 Chemical composition 673, 674 Distribution 698, 704, 708, 720. 736, m. 359 Seed 491, f. m Yellow Clover 183-184, 450, 451 Dock syn. Curled Dock, Foxglove, Wild 702 Foxtail 17-20, 413, 511-512, 616, 657, 658, 659, 660, 676, 691, 714, 789 Oxalis 199, 645 Rattle 667, 742 Rocket syn. Winter Cress Sorrel, Field syn. Field Sorrel Svurge syn. Cypress Spurge Sweet Clover 186-187, 452, 548, 713, 718, 725, 729, 759, 776, 810. 811 Trefoil 453, 638, 640, 787, 810, 811, 815, 831 Yellow-flowered Goldenrod 316-317, 480, 689, 738, 790 Yellowstone Park, Weeds of 757 Yorkshire Fog 665, 667 Yorkshire Weeds 825, 845 Young, F. B. 855 Yucatan Flora 731 Zapparoli, T. V. 829, 858 Zeeuw, R. 831 Zea mays f. 505 Seed 813 Zinger, N. 853 Zinnia pauciflora. Distribution 696, 698 Zurich Seed Control Station 828 Ztgophtllaceae 4, 203-204