fi-tffHftiaa:- Watii;, Come 11 mnivc tsit^ Xibrari? OF THE IRew l^ort? state College of agriculture a4.^-/i-^ n\n\s. . 3778 The sweet potato. 3 1924 003 303 116 Cornell University Library The original of tiiis book is in tine Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/cletails/cu31924003303116 PUBLICATIONS OF THE UNIVERSITY OF PENNSYLVANIA CONTRIBUTIONS FROM THE BOTANICAL LABORATORY OF THE UNIVERSITY OF PENNSYLVANIA Vol. IV- No. 1. THE SWEET POTATO BY B. H. A. GROTH, A.B., Ph.D. UNIVERSITY OF PENNSYLVANIA D. APPLETON AND COMPANY, Agents, NEW YORK 1911 VX. S9G-8 ^c^.\^\s ^ Copyright, 1911 Uy the University of Pennsylvania The John C. Winston C!o. PniLiLDBLPHIA CONTENTS. PAGB I. Obigin and Histoey 1 • A. Origin 1 ' B. History 6 C. List of References 21 • D. Historical Summary 25 I E. List of Synonyms 27 II. Economic Impoetance 33 A. Distribution and Comparative Yield 33 B. The Sweet Potato as a Starch Producer 36 C. The Sweet Potato as a Sugar Producer 45 III. The Stkucttjbe of Ipomcea Batatas 47 A. Root 47 B. Stem 48 C. Leaf 51 IV. Classification of Vakieties 57 A. Popular Varieties 57 B. The System of Classification 59 C. Key to Varieties 75 D. Alphabetical list of Formulas 80 E. Alphabetical List of Varieties 82 F. Descriptions , 85 V. List of Ihustrations 100 PREFACE. This work was undertaken with, a view to sift- ing the historical records of Ipomoea batatas and furnish a working basis for future experimenta- tion with its many varieties. It is now recognized among botanists in general, and physiologists and agriculturists in particular, that for obtaining reli- able data, the variety and not the species must form the basis of experiments. I wish especially to acknowledge my indebtedness to Dr. John M. Macfarlane for general directions and valuable suggestions. Herewith I present this work as a thesis offered to the University of Pennsylvania in partial fulfilment of the requirements for the degree of Doctor of Philosophy. B. H. A. Geoth. Philadelphia, June, 1906. The Sweet Potato. I.. OEIGIN AND HISTORY. A. Origin. There are tropical shores where cocoanuts and bananas do not thrive; there are tropical districts where the sweet potato is unknown. Both are excep- tions. In the far East, where rice is the daily food of millions ; on a thousand isles of the Pacific, where bananas and cocoanuts are the common fare; in the lands of the Aztecs and Incas, where beans are the national dish, the sweet potato is universally culti- vated. Even in the great country where "Corn is King" and wheat the "Staff of Life" it has been for hundreds of years a favorite among the vege- tables. But that has not always been so. The sweet potato has spread over the entire tropics and. sub-tropics within the last four hundred years. Whence it came is a much-discussed ques- tion. There are two opinions regarding its origin, one that it is American, the other that it is Asiatic. De CandoUe, after summing up the arguments in favor of both, concludes that it is probably Ameri- can, but does not commit himself. He has often been criticised as basing his opinion upon inadequate evidence. With a view to ascertaining what con- clusions the evidence at hand really warrants, the 2 THE SWEET POTATO. writer has briefly stated below De CandoUe 's princi- pal arguments, with a few additional ones. The contention that the sweet potato is of Asiatic origin is based upon the following facts : 1. D'Hervey, Saint Denis (Eech. sur 1 'Agri- culture des Chin., 1850, p. 109) states that the Chinese Encyclop. of Agric. speaks of the sweet potato and mentions different varieties long before the discovery of America. 2. Piddington (Index) claims that the sweet potato has the Sanskrit name "ruktalu." 3. Cook, on his first voyage around the world in 1769, found sweet potatoes cultivated at Tahiti, and in 1770 large plantations of them in New Zealand. (Low, Cook's Three Voyages Around the World, pp. 45, 76). Forster (De Plantis Esculentis, p. 56) in 1783 describes Convolvulus chrysorhyzus as being culti- '^vated there, which Hooker (Handbook of N. Z. Flora) identifier as the sweet potato. Pickering (Chron. Hist, year 1273) states that he saw varieties unknown in America cultivated on Metia, Tahiti, the Hawaiian, Samoan, and Tonga Islands. The contention that the sweet potato is of Ameri- can origin rests on the following: 1. Columbus found it in Cuba on his first voyage (F. Columbus, 28; Gomara, 16). 2. No reliable reference to the sweet potato, dated prior to 1492, has been discovered, as (a) No reference exists which is accompanied by an accurate description. (b) The existing references may as well apply to the yam as to the sweet potato. (c) The sweet potato mentioned in the Chinese THE SWEET POTATO. 3 Encyclopedia prior to 1573 was not the cultivated sweet potato which was introduced into China between 1573 and 1626, The old Chinese sweet potato was known as "chu," the introduced sweet potato as ' ' an-chu. ' ' The information was obtained by Bretschneider from Chinese records of the six- teenth century, i. e., the time of the introduction. (Bretschneider in a letter to De CandoUe, after read- ing "De CandoUe" on the origin of the sweet potato. Quoted in footnote 2, Or. des PI. Cult., end of article). 3. The word "ruktalu" seems a Bengalu name composed of the Sanskrit "alu," which is the name of Arum campanulatum, and "rukta," of unknown meaning and derivation (A. Pictet in a note to De CandoUe). The word "alu' is now employed to mean yam and potato. Eoxburgh mentions no, San- skrit name; and Wilson's Sanskrit dictionary does not give "ruktalu." According to Watt (Diet, of Econ. Prod, of India, under Ipomoea batatas) the present-day vernacular contains, among others, the following: Mita-alu, Sweet potato. Hind. ; Eanga-alu, lal-alu, lal-shakarkand-alu (the red form) ; shine-alu (the white), Beng. ; Goria-alu (white form), Assam; Gajar lahori (Lahore Carrot), Sind. ; Lardak lahori (Lahore Carrot), Pers. All of these names compare the sweet potato to another tuber or root, which is certainly a better argument in favor of the opinion that it was introduced than against it. The author has not been able to find out the meaning of the word "rukta," but its combination with the word "alu" suggests that it describes some quality of the sweet potato, in which it differs from the arum. 4. The fact remains that the sweet potato was 4 THE SWEET POTATO. found by Cook and others in Taliiti and New Zealand. According to native tradition, it is not native to New Zealand, but was introduced from the direction of Tahiti or Samoa (Pickering, Chron. Hist., years 1273 and 1740). Its introduction is estimated from indirect evidence to have occurred at about 1740 (Pickering, Chron. Hist., under 1740). Captain Cook, on his first voyage, took on board a native of Tahiti, by the name of Tupia, who could readily converse with the natives of New Zealand and other islands of that region. From this it, appears not only that the New Zealanders and Tahitians were of the same stock, but that their separation must have been comparatively recent. But if it was recent, it could not have been accidental or due to shipwreck, as then both New Zealand and Tahiti could not have been so well populated as Cook found them. So it must have been due either to a whole- sale emigration or to a gradual expansion. But neither mode of separation would account for the striking fact that the New Zealanders were, up to 1740, without so important a food plant as the sweet potato. The significance of this becomes the more apparent when we consider that bananas, cocoanuts and yams, which yield staple foods in Tahiti, could be of little importance in New Zealand. In all prob- ability, therefore, the Tahitians became acquainted with the sweet potato only after they had separated from the New Zealanders for so long a time that communication between them had practically ceased. It is possible, of course, that the sweet potato was native in Tahiti. In that case it must be supposed that communication liy sea between two great branches of a seafaring people stopped at once after separation. The only argument known to the THE SWEET POTATO. 5 author which would support such a supposition is Pickering's statement that he observed varieties unknown in America under cultivation on Metia, Tahiti, the Hawaiian, Samoan and Tonga Islands. The author has obtained eleven native varieties of sweet potatoes from Hawaii, some of which do not differ markedly from some of the varieties received from Jamaica, although they can be easily distin- guished from any of the varieties common in the United States. Pickering gives no description of any of the varieties. As he was unable to distinguish from the cultivated plants in Tahiti what he calls, "... seemingly the same species springing up spon- taneously, usually as a weed in cultivated ground, but distinguished by the natives, and its roots not used" (Chron. Hist., under 1273), it seems that he made no thorough investigation, but made his statements in regard to the varieties from casual observation. ^Moreover, Pickering himself calls the sweet potato a native of tropical America (Chron. Hist., under 1273). Should the varieties of Tahiti or Samoa prove distinct from American varieties, that would in itself be no proof that these islands should be considered the native countries of the sweet potato, as the plant varies readily and had ample time to vary. There is then really no proof that Tahiti or the neighboring islands should have originated the sweet potato, except that it was found there as early as 1769. But long before that time it had spread through tropical America. It had been reported ti-om Cuba by Oviedo, from other West Indies by Sloane and Hughes, from Surinam by Merian, from Brazil by Marcgrav and Piso, from Peru by de Vega. 6 THE SWEET POTATO. If the sweet potato were a native of Tahiti it would have to be assumed that the Tahitians, who did not supply the New Zealanders until about 1740, had brought the plant to tropical America so early that it had spread across the continent before 1492. This seems highly improbable. It seems very probable, on the other hand, that the sweet potato was carried from South America across to Tahiti. If we had any tradition, name, or other evidence, pointing to an early intercourse between tropical America and Tahiti, that would decide the question as completely as one could expect at this late date. Such proof we have. The writer is not aware of any tradition in regard to the sweet potato, but a similarity in names is apparent. According to Forster, the natives of Tahiti and New Zealand called the sweet potato "gumarra," and according to Markham '(Trav. in Peru, p. 234) and Seemann (Journal of Bot., 1866, p. 328) it is called "cumar" by the Quichuen tribe near Quito, Ecuador. Besides, we have ample proof that other economic plants, such as cocoanuts and bananas, have been carried from South America to the Pacific Islands, and vice versa. (The reader is referred especially to Cook, Bulletin Food Plants of Ancient America, Bureau of Plant Industry, United States Depart- ment of Agriculture). The writer is of the opinion that the evidence pre- sented warrants fully the conclusion that the sweet potato, Ipomoea batatas, Lam., is a native of tropical America. B. History. Among the many references to the sweet potato there are some which have been so often cited and THE SWEET POTATO. 7 some whicli sum up so well what was known at the time about the plant that they must be o,f great interest alike to the student and to the reader. Below the writer has given quotations, translations, and extracts from such important references, in chrojiological order. ''"T'or over a hundred years after the discovery of America the sweet potato was rarely mentioned in botanical literature. Here and there some casual remarlis are encountered about sweet roots, sweet potatoes or yams, which are not definite enough to be considered of value here. The first thorough account is given by Clusius (Hist. Plant., published 1601, second part, p. 77). He distinguishes three types: The Camotes, Batatas, and Inhames Lusitanorum. Under Batatas he explains that there are three kinds, which he has found growing in Baetica (a province of south- western Spain), differing in color. Some were red or purplish outside (and these were prized most), others of a paler color, others white. ' A few had white meat. They had vines spread diffusely over the ground like those of the wild cucumber, and rather thick, succulent leaves, from green to gray, in shape resembling those of spinach. He could not learn from anybody whether the plants ever bloomed or bore fruit. The roots, which he had seen in London in 1581, he describes as being usually "clodrantalis," weigh- ing a pound or more, uneven, with two or three or more fibers growing from one heg-d, with roots sim- ilar to those of "Siseris," thicker at the lower end, and becoming more slender at the upper end. Clusius says that the sweet potato originated in the New World and was brought first over to Spain, 8 THE SWEET POTATO. and was at that time introduced into many maritime districts of Baetica. The sweet potato as raised at Malaca (a city in Baetica) was considered the finest, and had been previously exported to Cadiz, Spain, and Ulosipons.^^ Specimens taken to Belgium would not sprout and soon spoiled before he could plant them. He doubts that the plant was known to the ancients, and knows no Greek or Latin name for them. He gives the names Batatas, Camotes, Amotes, and Ajes, which he hears do not differ, except, perhaps, that the Batatas have longer and more tender roots. The Inhame, which he describes next, is certainly the Dioscorea batatas. He had several specimeps a foot or more in length and four inches in diameter, and he describes them as being all rough, like the long roots of Aristolochia, and tasting at first pleas- ant, when eaten raw, but becoming after a short time somewhat sharp. ) (Jlusius gives three figures, one of the roots of "camotes" still hanging together at the top, one of the Batatas vine and roots, and another of the Inhame Lusitanorum, and his figure of the Inhame shows a yam. 'Tn 1623, Bauhin (in his Pinax, p. 91) refers to the sweet potato as batatas, battades, and potatoes called camotes in the "West Indies. He describes three types, all radish-shaped, but much larger, dis- tinguished by their exterior coloring, which may be either purplish, pale, or pure white. He' states that it serves as a common food to the "negroes" in the West Indies, is used in Angra, and is mentioned by Linschoten as occurring in the East Indies, where it takes the place of fruit and vegetables, j Linschoten 's THE SWEET POTATO. 9 potato "was the yam, however (Watt, under IiDomoea batatas). As his authority, Bauhin gives Joseph Acosta, lib. 4, cap. 18 ; Frag. 9, 1, 4, c. 18 ; 6, 38 ; 3, 6, 4, cap. 12 ; 8, 9. In 1636, aerarde (Herball, pp. 925-930) calls the sweet potato Sisarmn Pernvianorum, Batata His- panorum Potatus, and Potato. His illustration is a copy of the "Batatas" of Clusius. According to him, the plant was known as the ' ' skyrrets ' ' of Peru. A few plants grown in his garden did not flower, and he states distinctly that "not any said anything of the flowres." The roots were "many, thicke and knobby . . . joined together at the top into one head." His tubers were bought at the Exchange in London, and he states that the sweet potato grows in "India, Barbarie, Spaine and the hot regions," and that they are common food among Spaniards, Italians, and Indians. He has quite a selection of recipes for making palatable dishes from them. Whether he meant India or the New World with his India, the writer does not know. In 1640 Parkinson gives a pretty full account of the sweet potato, as then known (Theater of Plants, pp. 1382-1383). Under "Pappas, batatas, Potatoes," he translates a large part of Clusius, as given before, but he does not at all keep separate the account of "Camotes" from that of "Inhames," and so he makes it appear as if Clusius had applied the same name to both. Later on he, states that Lobelius (in Adversaria) says that the Inhames brought from Aethiopia and Guiney were different from the pota- toes of Spain and the Canary Islands. Parkinson uses the name "Virginia Potato." He quotes Scaliger as saying, "The Spaniards know three other sorts of roots besides the ordinary, which will 10 THE SWEET POTATO. abide good without perishing for a whole yeare, and therefore they use to bring them to Sea with them and call it Igname cicorero. The other will last nothing so long." The writer has not seen Scali- ger's statement, but the name Igname coupled with the statement that it keeps longer than the other Sweet potato, seems to point to the conclusioii that Scaliger refers to the yam. He then relates some- thing about the methods of culture as practiced at St. Thomas. He speaks of planting pieces of the vines, and not tubers, and that the vines ran up poles, like hops. Perhaps he had the accounts of the sweet potato and the yam mixed, although some of the varieties of the sweet potato are excellent twiners. That he was not any too sure of his ground is seen from his closing words : ' 'This manner of planting the Inhame favoureth something of that of the Manihot or Yucca, whereof the Cassavi is made, if there be not a mistake, it is wonderful that the roots should be so propagated." / In 1648 Marcgrav (IfotOTTari^iarrfearumy- part II, p. 1-6) gives a very good account of the sweet potato, as cultivated in Brazil under the names of " Jetica" and "Quinquoa quianputu." He points out the variability in the shape of foliage and tubers, and illustrates it. He is familiar with the habit of the plant to form tubers at each rooting joint, and states also that it yields latex. According to Marcgrav the Brazilians added a little water to the freshly macer- ^ ated tuber to make it ferment into an alcoholic drink. J He has seen some tubers golden-white without and clean white within, others red throughout (so much so that on cooking they colored the hands), the out- side dark red. Marcgrav remarks that a surface freshly cut by a knife becomes black like ink. So THE SWEET POTATO. 11 far as known to the writer, this occurs only when a rot has attacked the tuber. In 1686 John Ray (Hist. Plant. Tomus I, p. 728) describes the sweet potato under: Convolvulus indicus, Battatas dictus. He quotes Clusius and Marcgrav largely, and also says that the roots, when cut, give off latex. He thinks it must be a species of Convolvulus, not so much, he says, on account of "the similarity in foliage and vines and in the pos- session of latex, but because a certain Fr. Hernandez painted and ascribed to this species, which he (F. H.) called Cacamotio Tlanoquiloni or Batatas purga- tivum, malvaceous flowers, i. e., ' ' Caliculorum forma vel cymbalorum." Ray cites Marcgrav as describing other species under the names of "Omenapo," "Yeima Brasilien- sibus" and "Pararo," the first a white variety, which turned red on boiling, the last with purple stems and veins. As he gives no exact reference, the author has not been able to verify this state- ment. Marcgrav, however, does not include such descriptions under the headings of Jetica or Batatas. In 1688 Rheede (Hortus Malabaricus, p. 95, pi. 50), under Kappa-Kelengu, Batatas (Bramannice) Cananga, Lusit. Batatas, Belgice Pattates, describes the sweet potato as blood-red outside' and flesh- colored within, watery, of a somewhat sweetish taste ; with hairy, rough stems, watery within ; petioles oblong, round, green, falcate, hairy, more or less rough ; leaf -bases surrounded by roots ; leaves cuspi- date, incised around base, thin, soft, glabrous, dark green above, light below; the midrib giving off two lateral veins, from which others spring, arching in near the margin, protruding on the lower side. Rheede states distinctly that this is the ' ' Camotes 12 THE SWEET POTATO. Hispanorum" of Clusius and Bauhin (and the Getica of Piso). He gives an excellent illustration which tallies with his description. In 1696 Plukenet (Almagestum Bot., p. 114) men- tions the sweet potato under: Convolvnlus Indicus, Batatas dictus, following Ray. He also gives the names of Batatas Occidentalis Indiae, Inhame Ori- entalis Lnsitanorum, Park., and Conv. Indie, radice' tuberosa ednli, cortice rubro, Batatas dictns, P. B. P. 326. In the same year (1696) Commelin (Flora Mala- barica) mentions the sweet potato, but simply gives references. In 1705 Merian (Insectes de Surinam', p. 41) describes under Battattes a climbing plant, with light red tubers which taste like chestnuts. Her illustra- tion shows a sweet potato vine with blue flowers, twining through a rosebush. Each branch, bending down to the ground again, takes root. Here then we have a proof that the twining habit was observed. In 1707 Sloane (Jam. Nat. Hist., Vol. I, pp. 150- 151) de'scribes the sweet potato thoroughly. In his reference he quotes Plukenet as naming it Conv. Malabaricus, which is wrong. Plukenet in the place cited (Aim:, p. 114) calls it Conv. Indicus. He says that the plant flowers in Jamaica. "The Leaves stand on five inch long green Foot-Stalks. They are almost Triangular, having two Ears and a sharp point opposite to the Foot-Stalk. They are five Inches broad from Ear to Ear, and three from the Foot-Stalk's end to the point, having under them purple Eibs, being soft, smooth and of a yellowish green color, something resembling the Leaves of Spinage. The Flowers come out ex alis fol. stand- THE SWEET POTATO. 13 ing on a three or four Inches long, green, Foot- Stalk, being monopetalous, Bell-Fashion 'd, not very open, purple within, and whitish without, having in the middle some Stamina and a Stylus. After each flower usually follows one Seed, brown and having several depressions in it. It is enclosed in a roundish, brown, membranaceous Capsula, under which stand five brown capsular withered Leaves, as in the other Convolvuli." This is perhaps the first description of the fruit. The red potato, "which differs from the white in nothing taut the color, is as common as the white and grows indifferently with it." He gives ah account of the culture, which may perhaps best be given in full: ' ' They are everywhere planted after a rainy Season in the Plantations, for Provision by the flip, a piece of the Stalk and Leaves, being put either into the plain Field after Howing or into 'little Hillocks raised through the Field, in which they are thought to thrive better. In four months after planting tKey are ready to be gathered, the ground being filled with them, and if they continue therein any longer they are eaten by worms." We find then that even at that time there were advocates of both hill and flat culture. He proceeds as follows : ' ' They vary very much as to the figure and bigness of the Root, the color of its Skin being sometimes red and most commonly white. They are sometimes turbinated, at other times round and most commonly biggest in the mid- dle and tapering to both extremes." "They are boiled or roasted under the ashes and thought extraordinary good and nourishing Food, and because of their speedy attaining their due 14 THE SWEET POTATO. growth and perfection, they are believed to be the most profitable sort of Root for ordinary Provision. ' ' "They are used in great quantities to make the Drink called Mobby." Further on, he says that "They are common at Velez-Malaga, whence ten or twelve Caravels are loaded with them every year to Sevil." He gives Thevet as authority for the statement that "people feed with them in Trinidad" ; and Lopez de Gomara for : ' ' These Roots were by Colon brought from the West Indies into Europe, in his first voyage, to show the different Productions of the one and the other. ' ' Under:' Convolvulus radiee tuberosa, esculenta, minore, purpurea, Cat., p. 54, batatas Ind. Or., part 6, p. 85, Red Spanish batatas, he describes a very young plant of another tuber, as large as one's finger, of deep red or purple color, resembling the sweet potato in foliage, and containing an abundance of latex, which dyes of a purple color." No sweet potato is known to the writer in which the latex is colored anything but white, and no other reference has been found to a latex which dyes purple. The purple color of the purple stems and tubers of some varieties, however, does stain when they are handled. Feuillee, 1725 (Hist, des Plantes, Tome III, p. 16), accepts Ray's nomenclature. Convolvulus Indicus, vulgo Patates dictus, and states that the sweet pota- toes were quite common in Europe. He compares their flavor to that of the chestnut — ^which is cor- rect — and says that they are common and in use throughout America. Catesby, in his Nat. Hist, of Carolina, defines the sweet potato as: "Convolvulus radiee tuberoso, esculento — the Virginian Potato. He resided in the Carolinas from 1723-1726, and was very familiar THE SWEET POTATO. 15 with the actual conditions of agriculture there. As he was commissioned especially to gather useful information about plants in the colonies, and a^ he resided for years in the very district in which sweet potatoes were a staple crop, his observations are cer- tainly entitled to the greatest weight. His remarks are therefore given in full : "This excellent root seems to merit the prefer- ence of all others, not only in regard to the whole- someness and delicacy of its food, but for its more general use to manldnd than any other root, it being one great part, if not the principal subsistence of the greater part of Africa, and is likewise in great use, both in America and in the Southern' parts of Asia. They being of so" easy culture, so quick of g'rowth, and of so vast an increase, that the propa- gating it seems more agreeable to the indolence of the Barbarians than cultivating grains, which requires a longer time, with more labor and uncer- tainty. In all our Colonies of America, as well Islands as Continent, these roots are in great esteem and use; the common White People, as well as the Negro slaves, subsisting much upon them, nor are they thought unworthy a place at principal tables. In Virginia and to the North thereof they are annuals and produce no flowers. They plant them in March and dig them up in October, and to prevent their rotting, keep them in holes underground near their fires. In Carolina, where the winters are more moderate, they are not necessitated to keep them so warm; and in Bahamas Islands, and other places between the Tropicks, they are perennial and pro- duce flowers, yet are annually planted. The most kinds and best potatoes that I have observed were in Virginia, and because the names they are called 16 THE SWEET POTATO. by, in different Colonies, are so various, I shall call them by those names only by which they are known herQ" (Virginia). "I have observed only five kinds of Potatoes specifically different from one another: The Common, the Bermudas, the Brim- stone, the Carrot and the Claret Potatoes. ' ' ' The Common Potato is of a muddy red color on the outside, but being cut appears white with a reddish cast: they commonly weigh from half a pound to four, five or six pounds, usually are long, irregularly shaped and pointed at both ends : this is an excellent kind and is most planted. ' ' The Bermuda Potato is larger and rounder than the Comrdon, very white within, and covered with a white skin: this is a tender kind, requiring more warmth in keeping, and a different culture from the rest : this is the most delicate sort, but not so much planted as the Common Potato, because of its not keeping so well. This potato only produces a white flower, the flowers of the other Idnd being purple. ' ' The Brimstone Potato grows to a large size, and is shaped like the Common; the colour of it hath given its name, and in goodness it is esteemed next to the Common. "The Carrot Potato is named so from its color both without and within being like a carrot: these grow to a very large size, and are of great increase, though of little esteem, being the most insipid. "The Claret Potato seems to be propagated more as a curiosity than for any peculiar excellence it hath. The colour of it, without and within, is that of claret. ' ' It should be noted that Catesby based his notes on thf. sweet potato culture in the Carolinas solely on his own observation. Tie is the first to describe THE SWEET POTATO. 17 the method of storing then used, which differs not very much from the method of storing employed in the South at present. He was aware that the plant was really a per- ennial, and forced into the habit of an annual only by the shortness of the season. Catesby makes the first attempt at a classification of varieties. From his description it is, of course, not possible to tell exactly which varieties he picked out as standards, still his "Common Potato," "Brimstone Potato" and "Carrot Potato" may well have been varieties like the Eed Jersey, Up River and Pumpkin, respectively. A variety which would correspond to his ' ' Claret Potato ' ' is unknown to the writer. When Catesby tells us that the sweet potato was one of the principal food plants of Africa, he is, no doubt, mistaken, as it was not introduced into Africa until later. That with such good descriptions it could be pos- sible to present the figure which Catesby gives is hard to understand. He shows a vine with the flowers of a Convolvulus, with a rough tuber like that of a yam, leaves like a Smilax (or Dioscorea), and a tendril at the growing tip. It could not be the misplacing of a picture, as such a picture could surely not fit any plant. As we shall see later, his peculiar figure has given rise to Meyer's synonym, which still persists in some books, namely, "Con- volvulus Catesbaei." In 1737 Burmann (Thesaurus Zeylanicus), under Battattas, gives a resume of the literature bearing on Batatas, but he does not state that he has seen the sweet potato himself, and some of the references he cites refer to the yam. He does not decide on 18 THE SWEET POTATO. any specific name, but accepts that it is a creeping Convolvulus. In 1737 Linnaeus (Hortus Cliff ortianus, p. 67) describes the sweet potato as follows: "Convolvulus." "3. Convolvulus foliis cordatis angulatis, radice tuberosa. Convolvulus radice tuberosa esculenta, spinaciae foliis, flore albo fundo purpureo, semine post singulos flores singulo. (Sloan flor, 53). Convolvulus indicus. Batatas dictus (Ray, Hist., 728). Convolvulus indicus orientalis. Inhame sen Bat- tatas, Sisarum peruvianorum seu Battata hispan- orum (Moris. Hist., 2, p. 11, f. 1, t. 3, f. 4). Batatas (Bauh., pin., 91; Bauh., Hist., 2, p. 792; Clus., Hist., 2, p. -78). Jetica (Marcgr. bras. 16). Kappa-Kelengu (Eheed, mal., 7, p. 95, t. 50). Crescit culta in utraque India vulgaris; foliis variat." Under 1740, in Pickering's Chronological History of Plants, appears the following: "In the time of Teraraku (great-grandfather of Pomare) the chief seen by us at the Bay of Islands (Hale ethnogr. Expl. Exp. 146, and Races of Man, IV, 4), the 'kumara' (batatas edulis) sweet potato, brought to New Zealand in a 'canoe formed of separate pieces' by Pani and his sister Hinakakirirangi of Hawaii (Savaii)." The account is confirmed by the "con- struction of the canoe, peculiar to Samoan Islands, by the slender finger-rooted variety, seen by us only in the two localities," and which a separate tradition made "the only kind formerly known in New Zealand." THE SWEET POTATO. 19 In 1762 Linnaeus (Species Plantarum) describes it as follows: "Batatas." "Convolv. foliis cord., hast, quinque-nervis, caule repente hispido tuberifero. Conv. radice tub. escul., Catesb. Conv. indicus vulgo Patates dictus, Eay. Batatas, Bauhin. pin.; Eumph., Kalm. Kappa-Kelengu, Rheede. Habitat in India utraque. Confer. Con. ind. vulgo Patates dictum. Few per 3 p. 16 II foliis palmatis." In 1784 Thunberg (Flora Japonica, pp. 84-85), under Convolvulus edulis, describes it as grown abundantly around Nagasaki, and states that it was even then unknown in the higher parts of Japan and that it had been introduced by the Portuguese. He describes it as : A Convolvulus with entire and three- lobed, heart-shaped glabrous leaves, stem creeping, angular; Flowering rarely — he has never seen the flowers — but not the same as Ipomoea triloba. The roots were often the size of- one's fi*, tuberculate, flesh-eolored like Batatas; esculent, very soft and well-flavored. The plant differs from Convolvulus Batatas in having heart-shaped, entire leaves, 3 and 5-lobed, and in not being constricted in the center, "ut sagittaria evadant." In 1789 Linnaeus (Amoenitates Academicae, Vol. VI, p. 121) says: "Conv. Batatas, Indiae occiden- talis, tuberosa, peregrina. Editur assa sub cineri- bus, coctione rubieuifda evadit. Sapor praecedentis,* etjam ergajstulocum cibus indis. Tubera per hyemem ab omni humido studiose praeservanda. ' ' In 1793 Loureiro (Flora Cochinchinensis, p. 107) * Before goes Dioscorea, of which he says: "Siecior optime sapit et frequena illis est." 20 THE SWEET POTATO. describes it imder Convolvulus Batatas Khoai Hoanxy, and states that it is found both in Cochin- china and in China. He says it flowers annually not- withstanding Osbeckius's statement to the contrary (It. ad. Ind. edit. Angl., p. 3117), and that it grows equally well on both sides of the Ganges. Eoxburgh (Flora Indica, Vol. II, p. 69), under Convolvulus Batatas, states that "the red sort is in very general cultivation all over the warmer parts of Asia, and very deservedly esteemed one of their most palatable and nutritious food. I suspect Con- volvulus edulis Thumb. Japan. 84 is the same or a variety. ' ' Choisy (De CandoUe, Prodromus, Part IX, pp. 338-339, and Choisy Conv., p. 53), 1824-70, gives the following descriptions, with numerous references : "Batatas edulis (Prodromus), caule repente raro volubili, foliis variis saepius angulatis etiam lobatis 2-6 poUices longis acutis cordatis petiolatis, pedun- culis petiolum aequantibus aut superantibus 3-4-floris, sepalis acuminato-mucronatis raro sub- truncatis exterioribus paulo brevioribus, corolla campanulata purpurea. Ex India orientali nata, fere ubique in tropicis regionibus culta ob radicem tuberosam edulem. ' ' "Variat: a 1. radice purpurea aut alba. 2. omni parte nunc glabra nunc hirsuta. 3. caule, petioles et pedunculis - purpura- scentibus. 4. foliis hastatis, anguloso-sinuatis, quinque- fidis aut 5-partitis, nunc etiam integris. 5. longitudina peduncularum. " p. xanthorhiza, radice lutes (Bat. zanthorhiza Boj. h. maurit., p. 225). Hanc varietatem el. Bojer THE SWEET POTATO. 21 vulgo dici patate jaune in suo libello monet, Patate junot in desiccatis speciminibus ; orta ex India, China aut Cochinchina culta in ins. Mauritii. Caeteram a B. eduli non earn sejungere possumus (v. s. cult. comm. a el. Bojer). y. platanifolia, foliis palmatim 3-5-fidis, lobis ovato, rotundatis, acuminatis acumine obtuso glaber- rimis; petiolis villesulis, pedunculis longis mnlti- floris. In Guyana britann, legit Schomb. n. 701 (V.O.). _ Description (from Clioisy. Conv.) : Radix tuberosa, pro alimento in India, Japonica, China, America colitur. Caulis prostratus. Folia cordata petiolata acuta 2-6 pollices longa; petiolus sequalis. Pedunculi ascendentes incrassati, pedi- eelli 2-3 lineas longi. Sepala ovato-lanceolata. Corolla poUicaiis glabra. Stamina et stylus dimid- ium corollae attingentia. C. List or References. All references marked with an asterisk (*) have been looked up by the author. The year refers to the publication of the book or the date of observa- tion, when known. The author does not assume any responsibility for the correctness of the references not marked with an asterisk. An ( 1) denotes doubt that the reference is to Ipomcea batatas. lAcosta (C), Aromatum, India, 1582. Acosta, J., lib. 4, cap. 18, Frag. lAmmami, Character Plant, naturalis, 211, Yam(?). Atkinson, E. I., Economic Products, North w. Prov. (India), Pt. V, p. 19, 1876. Baden-Poioell, Pb. Pr., 259 (India), 1872-3 (?). *Bailey, Cyclop, of Am. Hortic, under Ipomcea batatas. *Bauhin, Pinax. teatr. hot., 91, 1623. BauMn, Hist. Plant., 2. p. 792, 1650. 22 THE SWEET POTATO. Benzo, under "Hayas"(?). Bertero, Spec. Medic. nonnuUse. Biet, p. 334. Birdwood, Cat. Econ. Prod., Bombay, 1862. *Bianco, Flop de Filipinas, Vol. 1, p. 53; Vol. 1, p. 129; Vol. IV, p. 140, Manila, 1837. Boisaier, Voyage botanique en Espagne, 1839-45. *Bouton, p. 47, Medic. PI., Mauritis, 1857. *Boyer, Hort. Maurit, 225, 1837. Bretschneider, Study and value of Chin. Bot. Works, 1870. *Bretschneider, Letter to DeCandolle, De. C. Orig. d. P. C. C. Browne, Nat. Hist Yam, 155( ?), 1756. *Burmann, Thesaurus Zeylanicus, 1737. Burns (India). Burr, Field and Card. Veg., p. 99. Campbell, Econ. Prod. Chutia Nagpur, No. 8163, 1873. Gandolle (Be), Sapport sur les voyages botaniques, 1813. Oandolle (De), Arch, des sc; phys. et natur., 1882. *Candolle (De), Orig. Cult. Plants, 53, 1882. *C Fiance, second ser., Vol. V, 450. SaUsiury, Prodr., 123, 1796. Scaliger, Exercitat, 181, cap. 17, lib. 15. Krhomhnrgk, British Guyane, n. 701, 1840. Hcemann, Journ. of Bot., p. 328, 1866. Sloane, Catal. Plant. Jam., p. 53. Sloane, Hist., 1, p. 152 (?) v * Sloane, Jamaica Natural Hist., I, 150, 1096. *Smith, Diet, of Econ. Plants, 399. Spr. Syst.( ?) Ip., 609. 8 Cade, H. (Brazil) (?). Stewart, Punjab Plants Pb. PI., 150, 1809. Stoclcs, Account of Sind. Sweert, FloriIegiura( ?), part 2, tab. 35, 1012. Thevet. *Tliunberg, Flora Japonica, p. 84, 1784. *Thurher, Am. Weeds and Useful PI., 1860. *Tschirch & Oesterle Anat. Atlas der Pl)arinakogn., 229. Turpin, Mem. der Musee, Vol. XIX, pi. I, 2, 5(?). Tussac, Flora Antillarum, 4, t. I; 8T. 565, 1808-27. Vnger (Mexico) (?). Vega (de), Eoy. Com. Hak. Soc. Ed., II, 359. *Velloit:o, Flora Flumenensis, t. 57, t. 58, t. 59, t. 60, t. 61, Rio de Jan., 1827. Tilmorin, Les Plantes Pot.( ?) 401, 1865. Wallksh, Cat. 1356, 1828. Wallich, Flora lAdica (Eoxb.) II, 69, 1830. *Watt, Econ. Prod, of India, Ipomoea batatas. Watt, in Sel. Gor't of India, 1888-89, 147-154. Wiesner, Mikrosc. Untersueh., p. 65, 1872. *Wiesner, Eohstoffe under Batatas edulis. Wilkes, U. S. Expl. Exped., lY, p. 282, 1838-42. Will'd. in Linn. Spec, plant. I, p. 881, 853(?). D. Historical Summary. A short summary stating when the sweet potato was definitely reported from different parts of the world will doubtless prove of value to future workers 26 THE SWEET POTATO. on tliis subject. Below has been given such, a sum- mary, as compiled from references found through- out the literature consulted. The writer has purposely" omitted to state the sources in which these were found, as most of them occur in many books, and it would require much useless labor to deter- mine which author gave a particular reference first. The sweet potato was probably first recorded by Oviedo, as found in 1492 in Cuba, and as being intro- duced into Spaia in 1526. From the West Indies it was also reported by F. Columbus, Gomara, Sloane 1696, Hughes 1750, Tussac 1808, Descourtilz 1821-29, Schomburgk 1840, and Grisebach 1864. In Brazil it was observed by Marcgrav 1640, Piso 16— (?), Vellozo 1827, Martins 1829, Stade (?). From Peru it is reported by de Vega, Feullee, Hum- boldt, Markham, and Seemann. In Mexico it was seen by linger; Merian, 1705, describes it as culti- vated in Guiana; Catesby, 1731, and Michaux, 1820, report it as much grown in the Carolinas. In Spain it was well known at an early time, and was mentioned by Oviedo in 1526 as brought from Cuba, by Cardamus in 1556, and Clusius in 1576. By the Spaniards it was introduced into the East Indies, where it was distributed by the Portuguese (De CandoUe, Orig. des Plant Cult.). In India, where it was brought very early, we find successive mention of it as follows: Acosta 1582, Osbeckius, Burmann 1737 (Ceylon), Piso, Lisboa, Eoxburgh 1820, Wallich 1828, Piddington 1832, Birdwood 1862, Drury 1864, Stewart 1869, Hooker 1880, Watt 1872, Baden-Powell 1872, Campbell 1873, Atkinson 1876, V. Mueller 1880, Bums (?), Firm (?). In the East Indies it is mentioned by Eheede 1678, Commelin 1696, Rumphius 1750, Loureiro 1790, THE SWEET POTATO. 27 Mason 1851, and Miguel in 1856. From China it is reported by Bretschneider (as of about 1600) and Loureiro 1790. Thunberg, 1784, mentions it in Japan, and Mozo and Pickering, 1740, Blanco, 1837, in the Philippines. In Hindostan it was observed by Roxburgh 1832 (?) and Burns (?). In Arabia and Egypt by Forskal, 1775, Clot Bey, and in other parts of Africa by Grant (Egypt to Zanzibar), Krap:^ (Eastern Africa), Henze (Sou- dan), Gray (W. Africa) and Pickering (Zanzibar), 1740. From Mauritius it was reported by Boyer, 1837, and Bouton, 1857. In the Pacific Islands it was seen by Captain Cook, 1769, in New Zealand by Hale, where native tradi- tion puts its introduction back to 1740 (Pickering), Forster 1783, Bertero, Wilkes 1840, Hooker 1867, and Pickering. From Hawaii it is reported by Gaudichaud-Beaupre, Hale, and, Wilkes, 1840. E. List op Synonyms. In the following the writer has attempted to pre- sent a complete list of all synonyms by which the sweet potato has been referred to. Unless the writer was able to convince himself of the correct- ness of the synonym by consulting the original authority, the later authority has been given in parentheses. Ahe (Choctaw), Gray (Ck^e A Kingsley). Ajes, Clusius. This is doubtless the yam, although it is often given as a synonym of the sweet potato. Amotes, Clusius. ^Apichu (Peruv.), de Vega (Cope & Kingsley),. Artichaut des Indes, Vilmorin (Cope & Kingsley). Axe, Pharmacographia (Cope & Kingsley). 28 THE SWEET POTATO. Batala (Cingalese), Birdwood (Cope & Kingsley). Batala (Sing.), Watt. Batata de Malaga, Tliurber-Darlington. Batata Hispanorum, Gerarde. Batata Lusitanis, Marcgrav. Batata purgative, Fr. Hernandez ( Ray ) . Batatas anthorliiza, Eumphius (Hooker), Bojer (Meyer). Batatas, Clusius (Malay origin), Birdwood (Cope & Kingsley). Batatas, Eatable, Thurber-Darlington. JBatatas edulis, Chois. DeCandolle, Px^od., etc. Batatas Oceiden talis Indias, Parkinson ( Plukenet ) . Batatas platanifolia, Schomberg (Meyer). Bataten-Winde (German), Thurber-Darlington. Batates douces, Payen. Batatas Lusitanorum, Rheede. Batatas, Sloane. Battades, Aeosta (Bauhin). Battatas Oceidentalis Indije, Parkinson. Battatas, Parkinson and later writers. Boga (red var. Assam), Watt. Cacamotic, Humboldt. See Camote. Cacamotic Tlanoquiloni, Er. Hernandez ( Ray ) . Canange ( Bramannice ) , Rheedc. Camote, Meyen. Camote (Aztec Cacamotic), Humboldt (Meyen). Camote, Clusius. Camote Hispanorxim, Clusius (Rheede, Ray). Chelagada (Tel.), Watt. Chillagada (Telinga), Di-ury (Cope &, Kingsley). Convolvulus angulosis soliis, Malabaricus radice tuberosa eduli., quoted from Plukenet by Sloane. Not given by Plukenet under sweet potato. Convolvulus batata, Lilley & Wait. (Veg. Subst. Used for Food). Convolvulus batatas, L. Am. Ac, Mason, Payen, Blume, Wall ( Hooker Brit. Ind. ) . According to Hooker, Catesby also uses C. batatas. Roxburgh vises C. Batatas Willd because Willd wrote convolvulaceae in Syst. Veg. Convolvulus chrysorhyzus, Forster ( DeCandolle, Or. d. PI. ) . Convolvulus cordatifolius, Vellozo, Fl. Plum., 60. Convolvulus edulis, Thunberg, wlio thinks it differs from C. batatas. THE SWEET POTATO. 29 Convolvulus esculenta, which DeOandolle quotes from Catesby, is a contraction of Conv. rad, tub. esc. Convolvulus esculentus, Salisb., Prod. Convolvulus foliis cordatis angulatis radice tuberosa L. Hort., Cliff. (Meyer). Convolvulus foliis cordatis hastatis quinque-nervis caule repente hispido tuberifero. L. Sp. PL; Mill. Diet., n. 7, Plonk (Meyer). Convolvulus indicus orientalis, Morison (Meyer). Convolvulus indicus radice tuberosa eduli, cortice rubro. Batatas dictus. Par. Bat. Prod. (Commelin). Convohnilus indicus, vulgo Patates dictus. By Lin. quoted from Ray, by Ray from Clusius, who does not give it(?), quoted by Meyer from Feullfie, wlio does not give it( ?). Convolvulus mayor heptaphyllus gloane (Meyer). Convolvulus mayor heptaphyllus floribus albis, fuiulo purpureis, Sloane (Meyer). Convolvulus radice tuberosa esculenta, Catesby. Convolvuhis radice tuberosa esculenta espinachioe fol., flora alba, Catesby, as quoted by Sloane; not ineutioned by Catesby under sweet potato. Convolvulus radice tuberosa esculenta minore purpurea, Catesby, 54, quoted by Sloane; not mentioned by Catesby under sweet potato. Convolvulus septangularis, DeCandolle, Prod. Convolvulus tuberifer Stend., DeCandolle, Prod. Convolvulus tuberosum, Vellozo, Fl. Fluni., 57. Convolvulus varius, Vellozo, Fl. Flum., 61. Convolvulus xanthorhiza, DeCandolle, Prod. Cumala (Otaheite), Cook (Cope & Klngsley). Curaar (Quichuen), Seeman (DeCandolle, Or. des PI.). Cumar, Markham (Cope & Kingsley). Dankali (Soudan), Henze (Cope & Kingsley). Doukali (Soudan), Henze (Cope & Kingsley). Fiasi (W.inika-land), Krapf. (Cope & Kingsley). Gajar lahori (Lahore Carfot, Sind.), Watt. Genasu (Kan.), Watt. Getica . ( Brazil ) , Piso ( Rheede ) . Goria-alu (white variety, Assam), Watt. Grasugada (Telinga), Drury (Cope & Kingsley). Gumalla, Forster (DeCandolle, Origin des PI. Cult.). Gumara, Forster (DeCandolle, Origin des PI. Cult.). 30 THE SWEET POTATO. Haias (Benzo), Sloane. Hantsoa (Chinese at Batavia), Nienhoif (Cope & Kingaley). Hetich (Tupi), Gray (Cope & Kingsley). Hoanxy (Cochinch.), Loureiro.- Igname cicorero, Scaliger (Parkins) (?). Probably the yam. Ign,aine, Clusius ( Parkinson )(?) . Probably the yam. Imo (Jap.), Thunberg. Inhame, Clusius (?). Probably the yam. Inhame Orientalis Lusit., Parkinson (Plukenet) ( ?). Probably the yam. Inhame rubra, Burmann(?). Probably the yam. Ipomoea Bata-tas Lam. (DeOandolle). Ipomcea Batatas Lam. Flor. Brazil, var. indivisa, Grisebach. . var. leucorhiza, Grisebach. var. porhyrorhiza, Grisebach. var. Xanthorhiza, Choi^. Ipomcea batatas (L.), Poir. Mohr. Geol. Survey, Alab., July, 1901, p. 828. Ipomoea batatas, Poiret. v. Mueller. Ipomoea Catesbaei, Meyer. This was given by Meyer simply because Catesby's figure did not agree with Ipomoea batatas while the description did. Meyer explains that fully in a note, which, haa often been overlooked. Ipomcea heptadactyla mayor, Brown, Jam. (Meyer). Ipomoea tuberosa, Willd, Sp. Plant (excl. syn. Pluk.) and Mill. Diet. n. 5 (Meyer). Jetiea (Brazil), Marcgrav. Jetica (Brazil), Piso (Commelin). Jettika (Brazil), Stade (DeCandoUe, Orig. des PI. Cult.). Kan-chu, Bretschneider (DeCanddle, Or. d. PI. Cult.). Kapa-Kalengu (Malay), Watt. Kappa-Kelengu, Rheede. Kara-imo (Japan), Thunberg. Kazwan (Burmah.), Watt. Kiasi (Canga), Hoist (Sadebeck). Kindolo (Canga & Usambara), Hoist ( Sadebeck y. Kimhella (Usambara), Hoist (Sadebeck). Kitaiti (Usambara), Hoist (Sadebeck). Kitetta (Usambara), Hoist (Sadebeck). THE SWEET POTATO. 31 Kumana (N. Zeal.), Wilkes (Cope & Kingsley). Kumara (Tahiti, N. Z., etc.), Hale-Pickering. Lal-shakarkand-alu (red variety, Beng.), Watt. Lal-shukur-kunda-aloo (red variety, Beng.), Roxburgh. Lardak-lahori (Lahore Carrot, Persian), Watt. Lohita (Sung.), Roxburgh. Lohitaloo (Sung), Roxburgh. Maby (Antilles), Descourtilz (Cope & Kingsley). Mankutu (Usumbara), Hoist (Sadebeck). Mawandres, Flacourt (Sloane). Mita-alu (Hind.), Watt. Myonk-ni (tBurmah)^ Watt. Obi-djawa (Java), Ann. Jard. Buitenz., Vol. I, p. 77. Omenapo Yeima, Marcgrav (Ray). Pararo, Marcgrav (Ray). Pappas, Parkinson. Patales, Bouton (Sloane). Patata, Esquemeling (Sloane), Vilmorin (Cope & Kingsley). Patatas, Red Spanish, Sloane. Patate Jaune (French) (Thurber-Darlington). Partates, Ray (Linn. Sp. PI. and Feuill6e). Patattes, Nienhoff (Cope & Kingsley). Pattates (Belgice), Rheede. Potades, Gerarde (Cope & Kingsley). Rotates, Acosta (Bauhin). Potato, Virginian, Catesby. Varieties: The Common Potato. The Bermuda Potato. The Brimstone Potato. The Carrot Potato. The Claret Potato. Potato, sweet, Gerarde. Potato, Carolina, Thurber-Darlington. Potatoes, Gerarde (Cope & Kingsley). Potatoes, Spanish, Ray. Potatos, Gerarde. Potatus, Gerarde. Pendaloo (Hindustani), Birdwood (Cope & Kingsley). Quinquoa quianputu (Congenibus), Marcgrav. 32 THE SWEET POTATO. Ranga (red var., Assam), Watt. Ratali (Mar.), Watt. katalu (Bomb.), Watt. Rizophora indica, Burmann ( ? ) . Probably the yam. Rukta-kunda (Sung.), Roxburgh. Ruktaloo (Sung.), Roxburgh. Ruktalu, Piddington (DeCandolle, Dr. d. PI.). Ruktupindaloo (Sung.), Roxburgh. Ruktupinduka (Sung.), Roxburgh. Sakara-kenda (Sant.), Watt. Sakaria (6uz.), Watt. Sakkarei-vellei-kelangu (Tarn.), Watt. Shakarkand (Punjab.), Watt. Schumbalino ( Usambara ) , Hoist ( Sadebeek ) . Shakarkand (Hind), Watt. Shakarkand-alu (red variety, Beng.), Watt. Shakar-kandu (Bombay), Watt. Shine-alu (white variety, Beng.), Watt. Shvikar-kundo (India), Firm (Cope & Kingsley). Shukar-kundoo-aloo (Bengali), Drury (Cope & Kingsley). Sisarum Peruvianorum, Gej-arde. Skirrets ( Peru ) , Nieremberg ( Loudon ) . Skyrrets (Peru), Gerarde. Suffet-shukur -kunda-aloo (Beng., white variety), Roxburgh. Sukkarag-vullie (Tamil), Birdwood (Cope & Kingsley). Truffe douce, Vilmorin (Cope & Kingsley). Ubi (Java), Nienhofif (Cope & Kingsley). Ubi-castela, Rumphius (Burmann). Ubitora (Maley), Nienhoff (Cope & Kingsley). Umara (South Sea Islands), Forster (DeCandolle, Or. d. PI.). Vallikilangu (Tam.), Watt. Veeazee (C. Africa), Grant (Cope & Kingsley). Ycam (Peru), CIusius(?). Probably the yam. Yeti (Tupi-Guarani), Gray (Cope & Kingsley). Zardak-lahori (Persia), Birdwood (Cope & Kingsley). THE SWEET POTATO. 33 11. ECONOMIC IMPORTANCE. A. Distribution and Compaeative Yield. The sweet potato is primarily a tropical plant, and it has found its widest distribution in the tropics. As with other tropical products, sor with-this^we know that it is one of the most important food plants, but we cannot even approximately estimate the amounts produced. Even in a country like Mexico the statistics on agricultural products are so utterly unreliable that they are of no practical value. Inthe tropics the sweet potato is a perennial. The tubers are constantly dug up without removal of the parent plants, until replanting seems advis- able. Since the immature tubers are as good for use as the mature ones, the natives merely dig up the largest potatoes, no matter whether they are ripe or not. The large potatoes can usually be detected by the cracking of the earth above them. There is no part of the tropics now where several varieties of sweet potatoes are not cultivated. In Mexico, Central, and South America they are a staple crop in all the states down to Argentine and Chile. In Africa they are cultivated largely by the natives of all the European colonies as well as by those of the interior. In Mediterranean Europe they are a well-known crop. In Persia, Hindustan, India, Farther India, China, Japan, and the entire Malay Archipelago they form one of the principal productions, utilized in many ways. In Japan the 34 THE SWEET POTATO. tubers, cut into small pieces and roasted, can be bought on the streets, like roasted chestnuts here. Australia and New Zealand also cultivate the tuber extensively. But, of course, what concerns us most is what the sweet potato is at present and what it ought to be, in the United States. In no other country is the sweet potato cultivated successfully so far north as with us. That is princi- pally due to our tropical summers. The plant requires a hot, dry season to mature the tubers, and such we can offer as far north as central New Jersey and Illinois. In the Gulf States it continues to crop throughout the summer and fall, if occasional rains supply enough moisture. This means that whereas in New Jersey the sweet potato under favorable con- ditions has five months and a half in which to mature the tubers, in the Gulf States it has seven and a half. As new tubers are started on the roots at the joints as well as on the main stem throughout the season, it is evident that those which have not time to mature in a short season and are so small as to be unsalable (the "culls," as they are called) would have matured in a longer season.' So it happens that in a favor- able season the crop in the Gulf States may be easily twice as large as in the Northern State, and, as the quantity of immature tubers at harvest time even in the South shows, a still longer season would have matured still more. Now there can be no question that sweet potato culture is profitable in the North. In New Jersey, where sweet potato farming is practiced on as thorough a plan as anywhere, a crop of 150 to 200 bushels per acre, at an average price of $0.60 a bushel, and an outlay of $60.00 an acre, well repays cultivation. As to the crops which can THE SWEET POTATO. 36 be raised in some of our Southern States, I refer the reader to the Bulletins of the agricultural stations, referring to tests of fertilizers and tests of varie- ties. These can easily be found in the catalogue of the Department of Agriculture. We find there that crops of 400-600 bushels per acre in a good season, and 300-500 in a dry season, are not rare, and that 800-1,000 bushels per acre have been obtained in experiment station work. The writer does not for a moment suppose that 1,000 bushels per acre could be raised everywhere even in the South, where the season is as long as at Baton Eouge, but it seems that 500 bushels should constitute more nearly the average yield of some varieties than 60 to 120 bushels. At present the yield per acre in our principal sweet potato States is far below that. The following table gives the total yield and the number of acres cultivated in sweet potatoes, as given in the United States Twelfth Census Eeport, and the approximate yield per acre : Bushels Bushels. Acres. Per Acre. North Carolina 5,781,587 68,730 84 Georgia 5,087,674 70,620 72 Virginia 4,470,602 40,681 110 Alabama 3,457,386 South Carolina 3,369,957 48,831 69 Texas 3,299,135 43,561 76 Mississippi 2,817,386 36,169 78 New Jersey 2,418,641 20,588 113 Louisiana 1,865,482 27,372 68 Tennessee 1,571,575 27,372 67 From this we can see that Louisiana, where the heaviest crops have been raised on one of the experiment stations, is almost at the bottom of the 36 ^ THE SWEET POTATO. list when it comes to the actual average crops raised there. Now, while it is conceivable that the experi- ment station at Baton Rouge may contain the very best potato soil in the state, still . the difference between what can be done and what is done is so enormous that one cannot but think that the average could be made very much higher if all the potato fields were given the necessary care. But even at present the average sweet potato farming is, on the whole, profitable in Louisiana, or it would soon stop. B. The Sweet Potato as a Starch Producer. Now, it is true that those varieties which have given the largest yields are not usually the best table varieties, although even on that opinions differ. On the other hand, it is commonly stated that those coarse varieties which do give enormous yields are , the ones richest in starch. Now the question of the proportion of starch contained in the tubers of different varieties grown under the same con- ditions, and of the same variety under different con- ditions, has not been investigated thoroughly, and when we hear from one experimenter that a certain variety contains 20 per cent, of starch, and from another that it contains ,15 per cent., and from still another that it contains 30 per cent., that is only what we should expect as long as our varieties are not well defined and as long as very little is known concerning the influence of variety, climate, fertil- izer, cultivation, and storage upon the starch con- tents in the sweet potatoes. As to the percentage of starch in different varie- ties grown under the same conditions, we find the following data: THE SWEET POTATO. 37 "Wiesner (Eolistoffe I, under Batatas edulis) states that the yellow varieties are richest in starch. In Arkansas Eeport, 1890, p. 125, Professor Teller, the station chemist, reports- the analyses of ten varieties of sweet potatoes. Below are given here only the water-contents, starch, cane-sugar and glucose : Water. Starch. Cane Sugar. Glucose. Per cent. Per cent. Per cent. Per cent. Shanghai or California Yam 65.35 20.84 6.94 1.41 Red Nansemond 71.80 14.52 6.43 1.85 Red Bermuda 69.76 16.34 3.60 1.83 Southern Queen 70.00 17.98 6.13 1.15 Yellow Yam 71.13 16.64 5.19 1.25 Poplar Spanish 58.87 19.45 6.08 2.41 Early Nansemond . 75.66 9.79 5.41 1.63 Early Jersey 75.65 11.39 5.68 1.64 South Carolina Bulletins 28 (1897) and 63 (1901) are devoted almost entirely to the sweet potato as a starch producer. Mr. Shiver, assistant chemist of the station, conducted thorough and elaborate experi- ments, which cannot be given here in detail. The experiments were made in order to determine to what extent the starch contents change on storing, and what effect the method of storing has on this change. The paper is well worth reading. The results which interest us are the following : Analyses of Original Samples Which Had Stood FOR Some Months After Harvesting. Water. Starch. 1894. Per cent. Per cent. Spanish 55.93 29.58 Southern Queen 59.70 25.67 Yams 60.37 22.30 Poor Land 67.62 16.93 38 THE SWEET POTATO. Water. Starch. 1895. Per cent. Per cent. Airiean Red 66.38 23.64 Poor Land 67.29 22.82 Southern Queen 66.19 21.74 Water. Starch. Cane Sugar. Glucose. Dry Season. Per cent. Per cent. Per cent. Per cent. Southern Queen 63.52 27.36 2.45 .51 Red Bermuda 63.04 28.00 1.81 .78 General Grant 64.36 26.12 2.75 .48 White Bermuda 67.55 23.74 2.27 .62 Georgia Yams 64.04 27.32 2.53 .47 Yellow Jersey 64.60 25.20 2.32 .71 Bunch Yam 63.81 26.42 2.80 .66 Season 1898. Water. Name of Variety. Per cent. Georgia Buck 75.35 Bunch Yams 72.37 Bunch Yams from different sources 67.99 Horton Yam 70.29 Georgia Bucks from different sources_ 71.56 Vineless Yams 70.03 Hanover Yams 76.16 Georgia Yam 70.01 Starch. Per cent. Glucose. Per cent. Sucrose. Per cent. 13.13 .77 4.31 15.12 1.09 4.45 19.58 .56 4.49 15.06 1.05 6.23 14.35 .73 6.61 16.85 .54 5.01 13.61 1.10 4.22 18.87 1.00 4.08 Season 1899. (C. C. McDonnell, Analyst.) Water. Starch. Glucose. Sucrose. Name of Variety. Per cent. Per cent. Per cent. Per cent. Pumpkin Yam 68.94 17.38 1.08 5.17 Bunch Yam 72.04 13.72 1.38 5.47 Georgia Sugar Yam 67.81 18.41 1.08 5.08 Tennessee Yam 70.42 15.74 1.41 5.02 From Texas Bulletin 36 (1893) is taken the fol- lowing table, which gives only the percentages of water, invert sugar, and total sugar: THE SWEET POTATO. ' 39 November, 1893. Water. Per cent. Bunch Yam 70.83 Early Bunch Yam 73.26 Vineless 66.06 Nansemond 71.81 Red Nose 77.59 Brazilian Yam 1 67.23 Negro Choker 68.23 Tennessee 65.83 Southern Queen 61.58 Red Bermuda 75.81 Early Golden 74.70 Peabody 79.04 Delaware 78.26 Barbadoes 75.44 Norton 66.69 Pumpkin 69.19 Invert Sugar. Per cent. Total Sugar. Per cent 2.14 3.74 2.66 4.60 4.16 6.41 3.33 5.00 3.27 5.20 2.52 5.26 2.84 7.69 2.19 2.77 5.10 9.20 2.77 5.26 3.00 6.75 3.35 6.41 2.08 5.00 2.92 6.98 4.67 11.90 3.76 8.07 Although this tahle does not give the starch con- tents, it is plain that in some varieties examined, as for instance the Peabody, where water and sugar alone make 85.45 per cent., after allowance is made for fiber, proteids, and fats, there is not much left for the starch contents ; while in the Ten- nessee Yam, where water and sugar together make only 68.60 per cent., there may be a very high per- centage of starch. All of these analyses were made with sweet pota- toes at harvest time, and they are sufficient to show that the varieties differ so markedly in starch con- tents that it is of the utmost importance to choose the variety carefully if sweet potatoes are to be raised for starch production. It is obvious that a reliable definition of the varieties is absolutely neces- sary before one can begin such a systematic selection. What effect climatic conditions have upon the yield in starch has never been accurately deter- mined. 40 THE SWEET POTATO. Wiesner states that sweet potatoes may contain as much as 10 per cent, of sugar, but only about 9 per cent, of starch in the tropics, while in the sub- tropics they may contain as much as 15 per cent, of starch and only 3-4 per cent, sugar. From the analyses quoted above we can see that the last part of the statement is inaccurate. General statements of persons holding the same or the opposite view may be found now and then, but the writer is not aware that accurate experiments have been made anywhere to settle this question. It is very likely that the constitution of the fer- tilizer used should have an influence upon the starch contents, and particular attention has been paid to this question by the South Carolina station. It must be borne in mind, however, that the experiment extended only over one season, with only one variety to test. So, while it may suggest certain lines of experimentation, it can in no way be considered con- clusive. Below are parts of the table as given in the South Carolina Bulletin, 63, 1901, giving the percentages of water, starch and sugar in different lots of Horton Yam sweet potatoes grown with different fertilizers : November 28, 1898; Variety, Horton Yam; Wet Season. Water. Starch. Glucose. Sucrose. Fertilizer, Per cent. Per cent. Per cent. Per cent. 400 lbs. Kainit 1 ' "1.81 22.86 .96 5.41 I 63.8 100 lbs. Muriate of Potash , „„ „ „„ „, , „„ ' 63.77 22.21 1.20 6.10 1,000 lbs. Compost 1,000 lbs. Compost | Nothing 62.07 24.58 1.19 5.28 100 lbs. Sulphate of Potash , „^^_g^ ^^_^^ ^_^^ ^^^^ I 64.9 1,000 lbs Compost . . . 250 lbs. Silicate of Potash 1,000 lbs. Compost . . . 1,000 lbs. Compost 65.26 20.80 1.41 6.21 I 65.87 20.70 1.27 6.03 THE SWEET POTATO. 41 As far as this experiment goes, it seems that the given variations in fertilizer produced a difference in starch percentage, although not nearly as great as a selection of varieties fertilized in the same way. If this should be confirmed and applied to a variety naturally rich in starch, that would, of course, be a farther means of evolving a first-class starch-yield- ing variety. It is not at all improbable that the method of culti- vation and the soil in which the sweet potato grows may seriously influence the starch percentage, but, as far as known to the writer, no experiments have been made to determine that. That storing makes the sweet potato sweeter is well known. By a series of analyses instituted by the South Carolina and Texas stations, independ- ently, it has been determined that an actual increase of sugar, mainly cane sugar, takes place during stor- ing, and that this is accompanied by a decrease in starch. It is strongly suggested by Mr. Shiver that the starch which is lost is actually changed into cane sugar. The general trend of the table seems to favor this view. Still, there are in the analyses quoted in Bulletin 63 some instances which are so much out of accord with the averages given that they strongly suggest that the samples may have been much less uniform than was supposed. For exam- ple: In Table XVIII we find the two samples of Bunch Yam, from different sources, analyzed on November 28, 1898, as follows : Water. Starch. Glucose. Sucrose. Per cent. Vev cent. Per cent. Per cent. Bunch Yam (No. 1) 72.37 15.12 1.09 4.45 Bunch Yam (No. 2) 67.99 19.58 .56 4.49 42 THE SWEET POTATO. Samples from the same lot, analyzed January 7, 1899, gave : Water. Starch. Glucose. Sucrose. Per cent. Per cent. Per cent. Per cent. Bunch Yam (No. 1) -67.31 13.66 2.02 9.90 Bunch Yam (No. 2) 67.29 13.83 2.40 9.43 Here, then, the contents in sucrose have risen over 100 per cent, in both cases, while the starch contents have become nearly even, whereas they were very different at the beginning. The second analysis, in which all the results correspond closely, suggests at least that the large difference in the first analysis may be due to individual variation among the tubers of the same lot, and that the samples of either analysis would not have given the other results at the time of the other analysis. Moreover, there are cases in the tables where the starch percentage act- ually rose during a storage of six weeks, while at the same time both sugar percentages rose, while the water percentage fell, as in the case of Ueorgia Buck, which analyzed : Water. Starch. Glucose. Sucrose. Per cent. Per cent. Per cent. Per cent. November 28 71.56 14.35 .73 6.61 January 7 67.63 14.43 2.12 7.85 The loss of water alone could not have caused a rise of even 1 per cent, in the total of the other three compounds, but we find a total increase of 2.61 per cent. Similarly we find, in Table XXV, that the starch contents of the Bunch Yam show two breaks during storing, as follows : November 14, 1899, 13.92 per cent. ; December 14, 9.61 per cent. ; January 15, 12.30 per cent.; February 15, 8.18 per cent., and March 15, 8.83 per cent. Twice during storing, then, the starch contents rise. THE SWEET POTATO. 43 In Tables XXX and XXXI we find another exam- ple in the storing of Georgia Buck in the usual way (straw, corn-stalks, etc.). They analyzed: Water. Starch. Glucose. Sucrose. Per cent. Per cent. Per cent. Per cent. November 28 75.35 13.13 .77 4.31 January 7 69.52 13.51 1.74 7.66 March 1 75.8» 9.88 3.21 3.77 These three, of course, do not seem to be in accord. We can easily find quite a number of similar cases in other tables of the same bulletin. Now, the writer's purpose is not to criticise the experiments — they are a step in the right direction — but it should be emphasized that, with such individual differences as these occurring in the analyses, we can hardly be too careful in explaining the results of others which agree more or less. It seems clear, however, from the tables given in the bulletin, that sweet potatoes lose a large part of their starch on storing, and that they gain in sugar. Bulletin 36 of the Texas station gives these extremes of variation in sugar contents: Variety. Time of Analysis. Tennessee November 1, 1893-94 Early Bunch Yam March 6, 1894 The extremes in starch contents, as taken from the South Carolina Bulletins 63 and 28, are: Spanish, some months after harvest, 29.58 per cent. Georgia Buck, January 7, stored in straw in a cov- ered house, 7.20^ per cent. In South Carolina Bulletin 28, Mr. Shiver com- pares the probable yield of starch per acre with that from wheat and corn, in the following table : Invert Sugar, "fir cent. Total Sugar. Per cent. 2.19 2.77 7.25 19.71 44 TPIE SWEET POTATO. Yield Starch Vev Acre. Starch. Per Acre. Pounds. Per cent. Pounds. Wheat 1,200 57 684 Corn 1,960 65.5 1,283.8 Sweet Potatoes 12,000 22.0 2,640.00 This is based on a yield of 200 bushels per acre and 22 per cent, of starch. Two hundred bushels are even now, with, table varieties, considered a mod- erate yield. "With a yield of 500-600 bushels with the varieties which are reported from the South, and 28-29 per cent, of starch from selected varieties, the yield of starch per acre would be simply enormous. The Irish potato, which is raised for starch exten- sively in Germany and France, yields only about 14-21 per cent, of starch, and 150-300 bushels of tubers per acre. We see, then, that it is well established that the sweet potato contains enough starch to be considered as an excellent source for its manufacture. We now have to consider the other sides of the question: What is the quality of the starch? and. Can it be profitably extracted? Wiesner ("Eohstoffe") states that the sweet potato starch commonly manufactured in Martin- ique, Guadelbupe, Eeunion, Cochin China, India, etc., which has been exhibited at various world's fairs, is not pure white, but grayish-yellow. By washing this in pure water he obtained a much whiter prod- uct, but not pure white. He thinks, however, that a process might be found by which a pure white product could be obtained at once. He cites -Gintl (Appreturmittel, p. 4) for the statement that sweet potato starch is even now imported to England in limited quantities from the tropics, to be used for technical purposes. THjCi SWEET POTATO. 45 Tschirch and Oesterle (Anat. Atlas der Pharmac. und Nahrungsm., p. 229) treat sweet potato starch under "Brazilian arrowroot," and state that it is manufactured everywhere in the tropics, as, for example, in India. We have the statements, then, that sweet potato starch is actually used for technical purposes now, and that it is manufactured on a more or less extended scale hy crude methods. As far as known to the writer, no thorough experiments have ever been made to manufacture sweet potato starch by modern processes on a scale sufficiently extensive to warrant accurate conclusions. This question the writer intends to take up in the future. C. The Sweet Potato as a Source of Sugar. It has often been suggested that the sweet potato would be a valuable source of cane sugar, and the sugar beet, in which the sugar contents have been raised greatly by proper selection, is cited as an illustration of what can be done. - It is true that some varieties of sweet potatoes, especially after storing, are much higher in cane sugar percentage than the sugar beet was at the beginning. The Texas station Bulletin 36, for example, reports a percentage of cane sugar as high as 12.46 in the "Early Bunch Yam." The great difficulty is that the 12.46 per cent, of cane sugar are accompanied by 7.25 per cent, of glucose, which is noncrystallizable, and which, besides, prevents the larger part of the cane sugar from crystallizing. It may be well to remember here that sorghum cane, which has a more favorable cane sugar percentage (up to 14 per cent, of cane sugar with 3-4 per cent, of glucose) 46 THE SWEET POTATO. than the sweet potato, has been tried and has proved unprofitable. With the manufacture of sugar from the sweet potato we may then as well wait until the making of sorghum sugar is a profitable business. Still sorghum is an important source for molasses in the South, and there is no reason why the sweet potato should not so be utilized. Other starch crops, such as corn and Irish potatoes, always yield a big product of glucose, manufactured from the starch, which could not be separated, and the glucose already contained in the plant. Here the sweet potato is certainly superior to either, as the percent- age of glucose is high and the additional amount of cane sugar would be a very desirable factor in manufacturing syrups. The syrup should be an important product in a sweet potato starch factory. No reliable data are at hand to show whether the refuse, after starch and sugar have been separated, would still be useful as cattle feed. On account of this high total percentage of starch, glucose, and sucrose, the sweet potato should prove a good source for the manufacture of alcohol. III. THE STRUCTURE OF IPOMCEA BATATAS. In the following is given a detailed description of macroscopical and microscopical characters of Ipomoea Batatas. When the macroscopic charac- ters varied with the varieties, that has been stated; where differences were found in the microscopic structure of different varieties, that was also recorded, but the writer wishes it to be understood that the material studied microscopically was not abundant enough to justify him in saying that the special characters found in particular varieties are typical of them. For the sake of convenience the plant is consid- ered^ under the headings of Root, Stem, and Leaf. ^"^ {A) Root (Figs##1?^-6-) : Springing from two sides of a stem at every joint, and from five longitudinal rows on tubers, which are usually more or less dis- arranged; white, yellowish, pink or purple, long and of uniform diameter for a shorter or longer distance, until thickened into a tuber. Tuber fascicular to spherical, smooth or veiny, terete or 5, 4, or 6-lobed in cross-section, with roots coming off in 5, 4, or 6 longitudinal rows, or apparently irregularly; with large conspicuous or small inconspicuous lenticels, with dormant shoots usually near the lenticels and root traces, but often apparently irregularly placed. Shoots sprout earliest at proximal end of tuber, breaking through skin, later in centre and distal end. Color of tuber, white, yellowish-white, pinkish-white. 48 THE SWEET POTATO. golden-yellow, bronze-colored, yellowish-purple, light or dark purple ; flesh, white, cream-colored, pinkish- white, pinkish-orange, with or without purple marks ; cambium and wood elements, white, dirty-white, yel- low or orange, very distinct, or indistinct. Latex abundant or scanty. Flesh soft, so as to cut very e asily, o r hard, so as to break better than cut^ Root (Microscopical): In young root, xylem shows five patches more or less separated by medullary rays. In tuber, groups of xylem elements, or iso- lated elements, each surrounded by actively dividing area, scattered throughout the fundamental tissue. Fundamental tissue and dividing tissue filled with starch consisting almost entirely of compound grains. Cambium with ring of xylem elements re- mains near outside of tuber, with or without xylem elements radiating towards center. Occasionally five or more strands of xylem elements run along the outer surface of the tuber, outside of the cambium, forming the longitudinal ridges known as "veins." These may or may not divide up and anastomose prof usely.^_^ •—— . (B) 'Biem (MacEoscopical) : Variable in length, from about two feet in some bunch varieties (Fig. 39) to 20 feet or more in those with running vines. Variable in thickness, depending on the variety, from % inch to more than % inch in diameter at its largest part. Variable in habit, depending on the variety, strongly twining or not at all, strongly running or growing in a clump, prone to fasciation or not. Variable in color; usually more or less purple col- ored when emerging from the tuber; when grown, light green throughout, or purple at the very base THE SWEET POTATO. 49 only, or purple below the attachment of the petioles, or purplish or dark purple all over, or brownish green on exposed places, often darker on the upper or lower side. Lenticels abundant. Hairs usually present in young shoots from tuber, persistent or not in the old stem. At every joint roots develop on the two opposite sides of the stem. These roots may mature into tubers, depending on the length of season and _the_yariety^ _^^ Stem (Microscopical)': (a) Section through tip (Fig. 13). Epidermis beset with numerous gland cells, of which some have much darker contents than the rest. Hairs more or less abundant, depending on the variety. Epidermis block-shaped, thin- walled; one or more layers of hypodermis well marked, depend- ing on the variety, cortex loose, with intercellular spaces, containing many well-marked latex canals with usually five, occasionally four or six secreting cells, largest latex canals toward the interior of the cortex; endodermis sharply marked, occasionally with a more or less marked accessory endodermis, depending on the variety, the cells of which are intermediate in length (on longitudinal section) between the short endodermal cells and the long cortex cells. Below endodermis an interrupted ring of very thin-walled pericambium, one to three cells thick; phloem very narrow, or of medium thick- ness, depending on variety, xylem well developed, internal phloem consisting of small isolated patches of dividing cells among pith cells smaller than the rest ; pith of large cells with intercellular spaces and numerous latex canals as in cortex. 50 THE SWEET POTATO. No crystals seen in any young tip, cut where the folded leaves are about i/g inch in length. (b) Section through base of old stem (Fig. 15). Epidermis with rather few gland cells, with or without hairs, with numerous lenticels. (The writer has not been able to decide whether the lenticel-like patches are made up of cortical tissue, or are pro- liferations of the epidermis.) Epidermal cells block-shaped, thin-walled, hypo- dermis more or less well marked, depending on the variety, with or without crystal cells, depending on the variety ; three to five outer layers of cortex form a collenchyma sheath, not very strongly thickened, latex canals well preserved, or flattened out, or both kinds in the same section, secreting cells well marked, or hardly recognizable, depending on the variety. With or without crystal cells, depending on the variety. Endodermis well marked, sometimes accompanied by slightly-marked accessory endodermis. Pericambium a ring of strongly thickened fibers, or occasionally not much thickened, depending on the variety. Phloem thick or thin, unevenly dis- tributed in thickness, with or without crystal cells, depending on the variety, occasionally with a few latex canals, cambium strongly marked, xylem wide or narrow, usually with, sometimes without, large vessels toward external margin, depending on the variety, these vessels often with an abundance of tyloses. Xylem cells showing spiral and reticulated thickenings of various patterns, and bordered pits. Whenever large vessels are present, they are arranged only on the two opposite sides of the stem, one patch on either side, unequal in size. The THE SWEET POTATO. 51 broader patch is sometimes divided in the middle. Crystal cells occasionally occnr in unlignified xylem. Xylem cells are not lignified uniformly (as shown by saffranin stain). Inside of protoxylem patches there are narrow areas of tissue similar to fundamental tissue, with the cells smaller than the cells of the pith. These cells divide the protoxylem from the cambium of the internal phloem. They are probably part of the internal phloem. Internal cambium well marked or not, rarely con- tinuous around cross-section, depending on variety. Internal phloem thick or thin, thickest below xylem patches with large vessels, depending on the age of the stem and the variety; with or without crystal cells, occasionally enclosing latex canals. Occasionally a few secondary xylem cells were found regularly between the protoxylem patches and the internal phloem, giving rise to bundles of reverse orientation. Occasionally the internal phloem and the joining pith cells near such reverse bundles con- tain large fat globules not observed in any other part of other varieties. Fundamental tissue of large thin-walled cells with large intercellular spaces and many latex canals, which often show plainly the former plains of divi- sion. Pith cells connected by pore-plates. Crystal cells abundant or not, or absent. Pith cells of normal size and shape, often divided into chambers, each chamber containing a crystal. Occasionally crystals cut off in the corner of a pith cell. Ring fasciation common in some varieties, fare in others. (C) Leaf (MRcroscupicalJ : Leaf cordate, hastate, slightly or deeply lobed, or cut (Figsr-?4y 73— 7-0^, —627^17^)7- Apex of leaf and lobes obtuse to acute, 52 THE SWEET POTATO. midrib prolonged beyond lamina into a short awn- likfitongue, base cordate or tjraneate, margin^ntire. 'The c'erdate leaves "are tlie first ones to appear in most varieties on the young shoots from tubers as well as on seedlings. They may be retainefiLor_be_ succeeded by hastate, lobed, or cut leaves^,) Size of leaf varying~wT0T"i:ge~6f~steotpvariety, and food supply. Normally developed leaves vary in differ- ent varieties from 2% to 6 inches or more in their widest diameter. Veins more or less palmately arranged, projecting on both upper and lower, sur- faces, especially on the lower, Tiiey are either paler or darker green than the lamina, or faintly or deeply purple on the lower surface or on both surfaces. \^- ^Haw-s/ consisting of several epidermal eelk -sup- ''^'' porting -two or three short and one terminal long, pointed cell with-thickened walls (Eigs:. 12 and 13), disteibuted. on entire uppe;r surface^ with, the excep- tion of a space around the base, or only along veins, or scattered in a few places around edge and apex, or absent, depending on the variety; occasionally occurring on lower surface of veins. Color o f leaf varies with the age, exposure to sun- light, the variety, and for other reasons unknown, from light green, througli dark green, brojrnish- green, light purple, to dark greenish purple. —•—-, ?oung leaves usually shiny on upper surface, old leaves less so or not at all. Young leaves folded along midrib (FigrSS). In some varieties the sur- face of the lamina has a tendency to pucker towards the upper surface (Norton, etc.). Petiole long, varying with size of leaf and habit of plant on normally grown leaves from 2% to about 9 inches in length, varying in thickness, depending on variety! (Pi^:sr27, 41).) The base usually thick- THE SWEET POTATO. 53 ened into a cushion on lower surface, where it bends sharply upwards. Cushion sometimes purplish on ^■;een^etiole, depending p.n variety.j Base of petiole twines around'support moreor ' less, depending on variety. Petiole more or less grooved on upper sur- face, rounded on the lower. Just below the attach- ment of the lamina there are two small papillae, one on the right and one on the left side of the petiole, containing the petiolar nectaries. Leaf (Microscopical). Epidermis: Consisting of irregularly shaped, more or less sinuate thin-walled cells (Figs. 1 to 4), convex towards the outer surfaces (Figs. 6 to 9), modified in shape when elongated over bundle traces (Figs. 1, 2), or radiating from gland cells (Fig. 2), or su.rrounding base of hairs (Fig. 1), sometimes showing peculiar wall striations (Figs. 3, 4). Stomata very frequently on both surfaces (Figs. 1, 3, 4, 5, 6), most abundant on the lower, often showing the successive divisions of surrounding cells and guard cells (Fig. 4), sometimes .showing double guard cell formation (Fig. 5) ; less abundant in modified epidermal cells over bundle areas (Fig. 1) ; on level with surrounding cells (Figs. 6, 7). Gland hairs scattered over both surfaces of leaf (Figs. 1, 3, 6), chiefly the upper, consisting of a plano-convex basal cell, on which rests a solid ellipsoidal mass of 6-8 elongated cells. The basal cell rests on a somewhat broadened epidermal cell which is usually sunk (Fig. 6). Mesophyll of two or occasionally three layers of palisade parenchyma (Figs. 5 to 7), with stomatic chambers (Figs. 6 and 7), in which may be very thin- walled cells containing calcium-oxalate crystals. Among both the palisade and loose parenchyma cells 54 THE SWEET POTATO. there may be cells containing the same kinds of crystals (Fig. 8), varying much in size. Loose parenchyma 3-4 cells thick, with stomatic chambers (Figs. 6, 7). Veins (Fig. 9) protruding on both surfaces; the upper epidermis modified into narrow, papillate cells, somewhat more thickened than ordinary, underlaid by a patch of more or less thickened coUenchyma cells, which may be entirely or partially separated from the pith by the palisade cells, which are then usually shorter and at leiast three deep. Fundamental tissue with numerous latex canals, the secreting cells of which are not well differentiated from the other cells. Bundle crescent-shaped, con- cave side up, the horns of the crescent of the xylem connected by a string of separate small patches of internal phloem, in which there may or may not be a small patch of xylem, entirely distinct from the main xylem mass. Fundamental tissue underlaid by a band of coUenchyma cells, less strongly thickened than those near the upper surface. Then follows a single row of small, round hypodermal cells, and then a modified epidermis, less markedly papillate tha,n that of the upper surface. Very small veins enclosed in the loose parenchyma and surrounded by large non-chlorophyllous cells (Fig. 7), sometimes accompanied by one or two rows of coUenchyma and modified epidermal cells, even if entirely cut off from epidermis by chloro- phyllous parenchyma. Tip of midrib forming an awn-like tongue built of non-chlorophyllous cells. Petiole. Petiolar nectaries (Fig. 10) consist of invaginations of the epidermis, to form cavities which are thickly lined with glandular hairs similar THE SWEET POTATO. 55 to those already described as occurring on the lamina, but consisting of more cells. That insects may be attracted by these gland areas appears prob- able from the fact that one of the sections contains an insect in the nectary. Fungal hyphse are com- monly found in these petiolar nectaries. Petiole, sectioned one inch from the base (Figs. 11, 12) : Great difference in size, depending 'chiefly on variety; in those with larger diameter all cells are also proportionately larger, the epidermal cells being increased least. Epidermis shows gland cells as in leaf, may show hair as on leaf, usually larger, and sometimes a peculiar proliferation, which gives the impression of a lenticel. One to two layers of modified chlorophyllous hypodermis are present, and the entire fundamental tissue is enclosed in a sheath of collenchyma from two to five or six cells wide, varying in width with the different parts of the same section, and in corresponding parts of the sections from different varieties. Latex canals frequent, irregularly distributed throughout pith tissue, secreting cells well or fairly well marked, depending on the variety. Arrangement of bundles in petiole typically in five parts, the three central ones enclosed by a common endodermis and pericambium, and two upper ones each with its own. Pericambium at times two layers thick. Depending on the varieties, the arrangement of the bundles may be in more than five patches, and instead of three patches of endodermis, there may be four. In all cases small patches of internal phloem are found isolated from the xylem and from each other, among small pith cells interior to the xylem. In some varieties small groups of dividing cells 58 THE SWEET POTATO. are found between the separate lower patches of bundles, in the region of the cambium (Figs. 11, 12). Crystal cells may be many, few, or absent. They are formed chiefly in the fundamental tissue near the bundles and in both external and internal phloem. IV. CLASSIFICATION. A. POPULAE VaEIETIES. It is very commonly stated that in the North the dry, mealy varieties are alone marketable, while in the South the wet, sugary varieties are preferred. In looking over the reports of our experiment sta- tions and other publications the writer finds that the following varieties are favorites of one section or another: According to Fitz (Sweet Potato Culture) the "Hanover" or "Nansemond Improved" is popular in the region around Richmond, the "Spanish" for home use on the eastern shore of Maryland and Vir- ginia, "Southern Queen" around Baltimore early in fall and late in winter, the "Nansemond" in Vir- ginia, New Jersey and Delaware, and the "White Yam" and "Yellow Spanish" in the South for home consumption. "Yellow" and "Red Nansemond," also "Early Jersey," are all old and standard sorts. (By way of explanation it may be well to repeat that the name "Yam" is applied to some varieties of sweet potatoes.) Mr. Starnes (Bailey's Enc. Hort.) states that the Northern markets prefer a dry, mealy potato repre- sented by the "Jersey" or "Nansemond" strain; the Southern market a rich, sugary potato, like the "Georgia" or "Yellow Yam," which is generally considered to be the standard of excellence. For Northern shipment the "Jersey Sweet" is prefer- able; for local sale the "Orleans Red" (Nigger 57 58 THE SWEET POTATO. Killer), "Early Golden" or "Bermuda Eed" head the list. The Louisiana Bulletins repeatedly refer to cer- tain varieties as commonly cultivated or standards of excellence. In Bulletin 13, p. 329, it is said that the "Greorgia Yam," also called "Common Louisi- ana Yam, " is in general cultivation throughout that State. "Southern Queen" ranks next to the "Georgia" and "Sugar Yam" in popularity. Bulletin 21, p. 648, confirms this, with the addi- tional remark that the "Peabody," probably identi- cal with the "Nansemond," and certainly the same as "Brazilian," is very popular in N. Louisiana for hog feed. In Bulletin 22, p. 709, it is stated that the cut- leaved varieties, ' ' Sugar, " " Georgia, " " Spanish, ' ' "Barbado" and "Vineless," are considered best for table use. Bulletin 30 of the same station says that the ' ' New Jersey" and the "Yellow Nansemond" ("Missis- sippi Yellow") are grown for Northern markets. In 1898, Bulletin 52, p. 310, we find that the "Georgia," "Sugar," "Pumpkin," "Hayman" and "Vineless" are varieties everywhere preferred in the South for table use. In 1894, the Georgia Bulletin 25, p. 155, states that the "Georgia Yam" is the standard of quality. The Iowa Bulletin 47, of 1900, confirms most of these statements. North Carolina Bulletin 112, p. 78, states the same. Bulletin 132, p. 319, states that the popular potato in that region (near Ealeigh) is the "Baydus" (cor- ruption of ' ' Barbadoes, ' ' of which there are a yellow and a white-fleshed variety). North Carolina Bulletin 74 contains the same THE SWEET POTATO. 59 statement, with the remark that the bulk of the pota- toes sold as "Bardos" belong in reality to the variety "Southern Queen." B. The System of Classification, At present one system of classifying the varieties of sweet potatoes is in use among experimenters, but none among growers in general. That used by experimenters, the foliage system, was elaborated by Mr. Price, of the Texas station, and reported in Bulletins 28 and 36 of that station. It classifies the sweet potatoes in three groups by the typical shape of their leaves, and then describes each variety separately. But as no key is given further than that referring to the foliage, it is of course not possible to determine a special variety, if the name be unknown or .doubtful; for to compare it with all varieties described under that group and to be still left in doubt as to whether the variety was repre- sented at all, is of course an uncertain and unsatis- factory method. Mr. Price deserves great credit for introducing some order into the previous chaos, and the writer acknowledges that the "foliage system" of Mr. Price was one of the early stimuli which induced him to work on the classification of varieties. To give an idea of how necessary it is at present to describe certain standards closely may be seen from the following. Below are given extracts from various bulletins published at our experiment sta- tions, the descriptions of one of the best-known varieties, "Southern Queen." Mr. Price describes it as follows : Round leaved, foliage pale green, sometimes prominently notched on one side, vines very vig- 60 THE SWEET POTATO. orous, root profusely, lengtli eight feet, tubers obtuse, medium size, white. Eeliable, much grown in the South. Soft, damp, late. Maryland Bulletin 33. — The Southern Queen is a good yielder, a very handsome and salable potato. Iowa Bulletin 47. — Southern Queen, medium run- ner, leaves large, dense mat of foliage, tubers large, fairly smooth, incline to run to roots. Skin greenish- brown, rough ; flesh yellow, very wet, coarse ; not very sweet nor pleasant. Very popular in the South. North Carolina Bulletin 74. — Southern Queen, very productive, good keeper, heading the list in keeping qualities. Arkansas Eeport, 1890. — Southern Queen, heavy growth of vines, tubers large and smooth. An early variety. Georgia Bulletin 25. — Southern Qiieen. Leaves shouldered. Foliage deep green. Vines quite vig- orous. Tuber quite large, both round and ovoid. Skin white, flesh grayish-white or grayish-yellow, quality very poor, stringy, coarse, fibrous and taste- less. Bather early and productive. Louisiana Bulletin 13. — Southern Queen. Most popular in the South, excepting the Georgia and Sugar Yams. Tubers round and mealy.) Vines very strong. Good producer. Improve in flavor by storage. Louisiana Bulletin 21.— Southern Queen. Large, round ; light yellow skin and meat, fair quality ; very early and popular ; a good potato. Louisiana Bulletin 30.— Southern Queen, white, rather hard, dry, late. Strong grower. Vines large and green. Leaves large, broad, rather bluntly pointed, and have side points. THE SWEET POTATO. 61 Flesh, nearly white and rather dry. A very pop- ular variety and good producer. Louisiana Bulletin 36, p. 1266. — Southern Queen is recommended for both quality and quantity. Louisiana Bulletin 52. — Southern Queen, One of the most productive varieties (720 bushels per acre in last experiment), but not an excellent table variety. Suggests an enormous amount of hog and stock food, and should be g^own largely for this purpose. Fitz (Sweet Potato Culture, p. 9). — Southern Queen is the earliest of all sweet potatoes. In eating condition (near Baltimore) by the middle of July when first dug, too wet in fall and early winter. Eoot very large, light color, good keeper, vine vig- orous, leaves large. Good quality. So we find that the Southern Queen, one of the best-known sweet potatoes in the United States, has been variously characterized as round-leaved and shouldered, foliage pale green and dark green, vines very vigorous and medium; tubers obtuse, round and inclined to run to roots, medium sized, and large, smooth, and rough ; skin white, greenish-brown, and light yellow; flesh yellow, grayish- white, grayish- yellow, light yellow, soft, and hard ; damp, very wet, mealy, and dry; quality poor, fair, recommendable, a good potato, good hog and stock food, flavor coarse, fibrous, tasteless, yet a very popular table variety in the South; late, rather early, very early and the earliest of all sweet potatoes. The writer has purposely considered chiefly the work of the agricultural stations, in order that there could not be the objection that the men giving the descriptions were unfamiliar or unskilled as regards such work. These men have been selected as efficient 62 THE SWEET POTATO. men for that kind of work, and there is no doubt but that every one of these descriptions fits the sweet potato known by the particular worker as ' ' Southern Queen. ' ' The question might well be asked : How can such statements be reconciled? Much has been said about the variability of varieties, yet it seems hardly pos- sible that such changes affecting everything that is regarded as essential -in a sweet potato should occur in the same variety. That sweet potatoes vary con- siderably is certainly true. This is just as true, however, with other plants long in cultivation, as, for instance, corn, the- common bean, the banana, cabbage, etc. Still in all these we can distinguish certain types, which may be variable in their repre- sentatives, but which differ enough from each other to be easily distinguished. So we have dent corn, flint corn, sweet corn, pop corn; the drumhead and Wakefield cabbage, cauliflower, Brussels sprouts, kale, etc., and similarly different types of the bean and banana. The sweet potato types certainly are not nearly as distinct as those of cabbage or corn, but they are perhaps as well marked as those of the bean. Now, what has been done to distinguish these types ? In Farmers' Bulletin 129, 1902, Mr. Nesbit says, concerning classification : "Classifications of varieties based on different principles have been attempted without, as yet, res- cuing the subject from disorder. The most elabor- ate system, and perhaps the only one worthy of a name, is that adopted by R. A. Price, horticulturist of the Texas Experiment Station in 1893, which he calls the 'Foliage System.' He divides sweet pota- THE SWEET POTATO. 63 toes into three groups, having 'round or entire foli- age,' 'shoulder foliage' and 'split or lobed foliage.' He says, 'If this foliage system is taken in connection with a short description of the color of the tubers and of the vines, there is scarcely a variety which cannot be distinguished from all other varieties.' ' 'This system has been applied at several stations, yet it would be quite impossible to recognize some varieties as known in one section by descriptions given of them according to the foliage system in another section if the name were omitted. So strong are the influences tending toward diversity that the writer is convinced that no system of classi- fication can demonstrate much value until the sup- posed varieties are all brought together and propa- gated under uniform conditions for several years." Before going further into the subject, one might well ask if there is any urgent necessity for the classification of the varieties. The writer's reason will be given later. In the following are quoted the opinions of others who are practical farmers or are otherwise interested in the subject: In Farmers' Bulletin 129, p. 38, Mr. Nesbit, a practical sweet potato grower of Maryland, gives some suggestions for future experiments. In regard to improvement of varieties he has this to say : "If all the varieties or supposed varieties for which merit is claimed should be collected and cultivated for several years under favorable conditions and with, a system calculated to develop excellence, planters might, at the conclusion of such a course, be able to select from a few varieties of marked characteristics such as give promise of special use- fulness to them. The value of such work in estab- lishing varieties and determining their relative 64 THE SWEET POTATO. worth by comparison and in opening the way for an orderly nomenclature can not be doubted." In North Carolina Bulletin 74, p. 3, Mr. Massey says : ' ' There is much confusion in the nomenclature of this vegetable. 'Peabody' and 'Early Eed' are so near alike that they may be regarded as synony- mous; 'Southern Queen,' 'Hayman,' 'Bahamas' and 'Yams' are the same. 'Norton Yams' and 'Buck^ skins' are also identical. 'African Eeds,' 'Black Spanish' and 'Nigger Killer' are also synonymous, etc., etc. . . ." In the Arkansas Eeport for 1890, p. 123, Mr. Ben- nett says : "Much confusion arises with the different varieties of sweet potatoes by the many different names by which the separate varieties are known. They invariably have local names in the particular locality in which they are grown, and, as might be expected, there is great similarity between some of the so-called varieties." In Georgia Bulletin 25, p. 153, Mr. Starnes: "In grouping the different varieties of sweet potato we have followed at the Georgia station the general custom of arrangement with reference to the leaf, in default of a better system. Indeed it can scarcely be called a system at all, for the reason that the same vine will sometimes hold half a dozen different shapes of leaf; and while a distinction appears to exist between the 'split leaf varieties and all others, it is by no means easy to determine with some varieties whether the 'round' or 'shouldered' form of leaf prevails. Yet when we endeavor to classify by other forms of resemblance, as shape, size, color or quality of tuber, we are met by even worse incon- gruities, and are forced to fall back on the 'leaf classification,' clumsy and unsatisfactory as it is." THE SWEET POTATO. 05 Attempts have been made to erect, in addition to the three forms of leaf generally accepted, to wit: "Split leaf," "Shouldered" and "Bound," a fourth form, "Semi-shouldered"; but the difficulties are too great in the way of its adoption, and hence the regular division into "Split-leafed," "Shouldered" and "Round" must suffice. In Louisiana Bulletin 30, p. 1053, Mr. Burnette says: "Much time and expense have been spent in trying to properly classify these so-called varieties and adopt a nomenclature which can be followed throughout the country, but so far, only with partial success." These questions give a fair idea of what others think. Another good indication of the desire for a uniform nomenclature are the frequent attempts to reduce a number of varieties to a group, and the abundant descriptions of many varieties, given in various bulletins. The writer's own reasons for working on a classi- fication of varieties are as follows : The sweet potato at present forms one of the staple crops in various sections of our Atlantic and Gulf States. Experi- ments have demonstrated that there is an enormous difference between the yields of different varieties. It is well known that there is a great difference in the quality and market value of different varieties. Some varieties contain a starch content of as much as 29 per cent., and could probably be utilized for starch. But one of the most serious drawbacks to experiments in any of these lines is the confusion in nomenclature. When one experimenter has detected a desirable quality, another who tries to verify the result secures another variety under the same name and fails; others having sweet potatoes 66 THE SWEET POTATO. with the same name growing in their own patches, observe and condemn, and so experimentation gets into discredit. As the writer himself intends to work further on the sweet potato in the future, he feels the necessity of straightening out the nomen- clature first of all. Before advancing any opinion on the character to be used in the classification, the following deserves to be carefully considered: All varieties of the sweet potato ate supposed to have originated from the same plant; they have varied enormously, and so they are apt to vary more. Therefore, a variety which fits a certain description at present may in the course of a few years produce certain sports which cannot be referred to the original type. This should be expected and would not invalidate the system of classification. These sports belong to a new category and, unless they have developed into a variety already known, they form a new one. This principle seems self-evident, but objections have been made to certain descrip- tions, because plants in the same patch, the produce of the same ancestors, did not agree with each other. Then, also, no system of classification can provide names for varieties which are in accord with all names now in use. The example of "Southern Queen" and the quotations from the various bulle- tins already cited amply demonstrate this. In naming the varieties priority of nomenclature should be considered. This the writer would gladly do if the labor involved were not altogether out of proportion to the results. In 1731 Catesby tried to reduce the varieties under cultivation in the Caro- linas to five types. He states, as quoted, that there were at that time a number of conflicting names for THE SWEET POTATO. 67 the varieties. In order to consider priority prop- erly one would have to go back then to Catesby at least. The writer has received over seventy so-called varieties under various names, and finds himself utterly unable to determine the majority of these from the scanty description given in previous litera- ture. Those varieties have been given the names under which they were secured, unless those names gave rise to confusion. It must also be taken into account that certain varieties will in all probability produce normal tubers only in certain sections, and that some varie- ties when transplanted from one climate to another will exhibit different characters. "We find the same to be true of other plants. Sweet corn, growing six feet high in the Northern States and having the ear about 2% to 3 feet from the ground, will scarcely grow 4 feet tall when planted in western Texas, and make the ears right on the ground, in the first season. Such may be due to one of two things: Either the variety will not grow under the new conditions, or it needs to be acclimated. It is, of course, probable for that very reason, that some varieties with which the writer has experimented should not do well in Xew Jersey. Therefore, unless good typical tubers were received from which to give the characters, the tubers of varieties which did not seem to thrive have not been included in the key. Primarily, the varieties have been classified for he writer's own convenience, and the intention is to continue the work on sweet potatoes in various directions dttring spare hours, as opportunity pre- sents. In any classification of varieties the following are essentials • 68 THE SWEET POTATO. The distinguishing characters must be reasonably permanent, i. e., the great majority of the descend- ants of the same plant grown together under normal conditions ought to maintain uniformity in those characters. The distinguishing characters ought to be so clear that they can easily be determined. It is very desirable in a key that it should take up the characters in such an order that varieties which differ but little from each other and are very likely closely related can be easily compared. This is perhaps best effected by using the same characters in classifying all varieties. As it is not always possible to determine all the characteristics of a variety at one time, the char- acters given should be as abundant as possible, so that the variety may be determined even if not all parts of the plant are present. The key, as evolved below, was elaborated to meet these different requirements. The distinguishing characters, as utilized in the key, were determined in the following manner : Thirty-five so-called varieties were obtained from the Agricultural Experiment Stations at Washing- ton ; Baton Eouge, La. ; -Experiment, Ga. ; and from Mr. Rose, of Wilmington, Del., and Mr. Trouncer, of Wenonah, N. J. AH these were planted in the same patch at Wenonah and studied throughout the season. All types of leaves produced by all varieties, as the season advanced, were collected and pressed. Photographs were taken of typical hills and vines of each variety to show characteristic growth and leaf arrangement. Careful notes were taken repeat- edly and independently of the comparative length THE SWEET POTATO. 69 and thickness of tlie vines, their exact color near the tip, the center, the base, on top, and below; the size of the leaves, the color of young and old leaves, the length of the petiole, the amount of hairiness on leaves and stem, the coloration of the veins on both upper and lower surface, the amount of latex, etc. After the harvest the tubers were studied in regard to size, shape, exterior color, distribution and size of lenticels, roots, and shoots, hardness when raw, color of flesh, wood elements, and cambium, and relative abundance of latex. Samples were boiled and baked ol all varieties of which there was mate- rial to spare, and observations made on the color, odor, softness, flavor, sweetness, and stringiness of the cooked tubers. The great difference in the outer appearance of foliage, stems, and tubers suggested corresponding differences in their internal structure, and to deter- mine the extent of such differences, slides were prepared from fifteen varieties which could easily be distinguished, showing the following parts: Upper and lower epidermis of leaf, cross-sections through the leaf, petiolar nectaries, petiole, the tip and base of a full-grown stem, and the upper and lower part of a tuber, and longitudinal sections through the stem. During the winter the writer received an abun- dance of material from the already named stations and also from Jamaica, India, Barbadoes, the Sand- wich Islands, Mauritius, and Colombia. As many of the tubers were in a rather poor condition on arrival, the only way to save them was to plant them at once. Accordingly all the tubers were started in the greenhouses of the Botanical Garden of the Uni- versity of Pennsylvania, and the entire lot planted 70 THE SWEET POTATO. out in May. The varieties, received under more than a hundred different names, were studied in the same systematic fashion as the thirty-five varieties of the previous year. As was expected, the majority of the characters noted proved unreliable. The abundance of the latex and the color of the leaves, for example, while distinctly variable with the varieties, were not con- stant enough to be used as a characteristic. By studying all the plants of every variety planted (about 15-30 plants on an average), the writer came to the conclusion that certain characters were suffi- cient to distinguish all varieties which could be dis- tinguished at all by the closest macroscopical obser- vation. Microscopical characters were not utilized because they could not be easily applied, and because the writer is not prepared to say that the micro- scopical differences found are constant. The character by which the groups can be sep- arated most readily is, doubtless, the shape of the leaf. Mr. Price recognized this in his system of classification, and the author has adopted his terms, "round-leaved" and "cut-leaved." The shape of the leaves enables one to divide all varieties at hand into five main groups. The first group comprises all varieties with "cut" leaves. As "cut" leaves are counted all those in which the projecting lobes constitute almost the entire leaf surface, so that little remains when all the lobes are cut off at their bases by cuts perpen- dicular to their median lines. In all but one or two varieties it is very easy to tell whether the leaf is cut or not ; but even if that should be impossible, that fact does not interfere much with the determina- tion of a variety, as will be seen later. THE SWEET POTATO. 71 The second group is formed by those varieties which have only "round" leaves. By a "round" leaf is meant a heart-shaped entire leaf. In the third group have been placed the "long- leaved" varieties. In all well-formed, full-grown leaves of these varieties the length of the large cen- tral lobe, as measured along the median line from the base of the lobe to its tip, exceeds the greatest breadth of the same lobe. The "broad-leaved" varieties constitute the fourth group. In these the greatest breadth, i. e., the base of the central lobe, exceeds its length from the base to the tip. Some varieties invariably have several types of leaves, so that it is hard to tell which shape is the most common. All varieties which normally have well-developed, full-grown, "round" leaves, as well as "long" or "broad," have been classed as "mixed- leaved" in group five. In the key there has also been provision made for varieties in which both "long" leaves and "broad" leaves are frequent. It should be kept in mind that all references to leaves, unless otherwise stated, apply only to full- sized leaves developed at least two months after planting, for the first leaves developing from a tuber are usually ' ' round ' ' leaves, even in varieties which later never produce them. The writer has even observed them occasionally on plants with normal "cut" leaves. Almost as characteristic as the shape of the leaf is the size of the leaf. Weather and soil conditions exert a certain influence on the size of plant parts; still, the author has convinced himself that neither the difference between the compost soil used in 72 THE SWEET POTATO. greenhouses and the soil of a sandy New Jersey field, nor the difference between the comparatively dry growing season of the summer of 1905 and the extremely wet and hot season of 1906, affected the value of the size of the leaf as a characteristic in the least. All varieties begin the season 's growth with small- sized leaves. The largest leaves do not appear until after two or three months of growth, and therefore all references to size apply only to those later large leaves. The "small-leaved" varieties never have normal leaves measuring over four inches in width from tip to tip. In fact, most of their leaves are less than three inches wide. These "small-leaved" varieties are, however, most given to fasciation, and fasciated branches may have larger leaves. These have not been considered in the key. The "large-leaved" varieties have many of the later large leaves measuring over four inches at their widest part. Some varieties, commonly grow leaves six to seven inches across. A character as definite and as easy to determine as the shape and size of the leaves is the length of the stems. The bunch varieties and other "short-stemmed" varieties never have stems measuring as much as four feet long, even in a wet season. The color of the stems is another very helpful character which is easily determined. Some varieties have entirely green stems with at the most a few blotches of brownish sunburn. These are classed together as "green-stemmed." Others have green stems which bear small purple marks around the axils of the leaves, i. e., around the base THE SWEET POTATO. 73 of the leaf-stalks, with perhaps occasional other spots of purple. Still' others have steins which are for the most part purple, but shade into a dull greenish-brown, and from that into green at the base and tip and in various other places, so that while a large portion of the stem is actually purple, the dull greenish-brown color is also quite evident. Thin or young stems are often entirely green. These stems have been called ' ' greenish-brown to purple. ' ' Then there are varieties in which the stems are unmis- takably purple. It may be that even in these a few inches at the base and tip are green, but there are no entirely green young stems, and there is no green- ish-brown color in evidence. These varieties are termed "purple-stemmed." Almost as constant as the width of the leaves is the thickness of the stems. In the "thin-stemmed" varieties the stems never measure more than one- eighth inch in diameter ; the diameter is determined by laying the stem across a rule and looking with one eye. The "thick-stemmed" varieties measure at least three-sixteenths of an inch at the thickest part of their full-grown stems, and some of them even measure more than one-quarter inch. Another character, which can be seen at a glance, is the purple star-shaped spot which some varieties have on the upper surface of the leaves at the point where the basal primary veins spring from the petiole. This purple spot has been called the "star." It may be present or absent. The lower surface of the midrib and the other large veins affords another easy means of distin- guishing between varieties. In some varieties the lower surface of the primary veins is more or less deeply colored purple. In others some of the older 74 THE SWEET POTATO. leaves, usually those which, happen to be supported by darker petioles than the r'est, have a faint streak of pink running part-way up the midrib only. Other varieties have a small purplish area on the lower surface of the base of the midrib, i. e., just before the petiole divides into the primary veins. Still others have the lower surface of the veins green. The leaves offer another distinguishing feature in the arrangement of the hairs on the upper surface. Some varieties have the leaves entirely covered with hairs. Others have the hairs only along the veins and perhaps over a more or less extended area on the tip of the central lobe. Still others have no hairs on the upper surface of the leaf. Although the root, or "tuber," is the most impor- tant part of the plant, it offers few characters of stability which might be used in a practical key. The outside color of the tuber, however, is as easily determined as it is important. Some varie- ties have grayish-white or popularly called "white" tubers. Others have yellowish, golden, or bronze- colored tubers. Still others have them colored a yellowish-red, or a pinkish-yellow, and some have dark red or purple ones. Although not quite so constant as might be desired, the coloration of the cut surface of a freshly cut normal-sized tuber is characteristic enough to be used as a distinguishing character. On cutting some varieties one finds that the flesh is colored pure white. In others the flesh is cream-colored or yel- lowish-white. Still others show a pinkish hue dif- fused through a white or yellowish mass color. A few have the flesh colored a deep pinkish-orange. THE SWEET POTATO. 75 while some have part or the entire heart of the tuber stained with purple. About as definite a character as the color of the flesh is the distinctness of the bundles which are scattered irregularly throughout the mass of the starch-bearing tissue of the tuber. In a few varie- ties a freshly cut tuber shows at a glance the loca- tion of these bundles. Small, sharply-marked spots dot the surface, standing out ' ' distinctly. ' ' In most tubers a freshly cut surface shows to a certain extent the location of the bundles, but the bundles appear only as slightly darker areas or watery specks not sharply cut off by a line from the surrounding tissue. The bundles appear "blurred." Still other tubers show no indication of the position of the bundles on a freshly cut surface. In these the bundles are "not visible." It is certainly desirable that other important characters, such as dryness or dampness of the flesh of the cooked tubers, flavor, earliness, etc., should be considered in a comparative classification. So far the writer has not succeeded, however, in establishing standards of flavor, and he was not in a position to make tests of the dryness and earliness of the tubers. The description of the varieties, as given later on, will therefore only serve to distin- guish them, and not as an index to their market value. C. Key to Vabieties. With all the above facts in his possession, the writer began to evolve a key. The style of key that naturally suggested itself was the one commonly used in botanical text-books for the determination of species. After careful thought the writer decided to use the key given below, although it 76 THE SWEET POTATO. requires somewhat more work for the determination of some varieties. The reasons will be given later, A. — Shape of Leaf. 1. Cut. 2. Bound. 3. Long. 4. Broad. 5. Mixed (round and lobed). B. — Sise of Leaf. 1. Small (less than four inches across). 2. Large (more than four inches across). C. — Length of Stem. 1. Long (more than four feet long). 2. Short (less than four feet long). D. — Color of Stem. 1. Green (with or without brownish areas). 2. Green, with purple around the axils of the leaves. 3. Greenish-brown to purple. 4. Purple. E. — Size of Stem. 1. Thin (less than % iiich in diameter). 2. Thick (more' than % inch in diameter, often rV or more). F. — Presence of Star. 1. Star present. 2. Star absent. G. — Color of Loiver Surface of Veins. 1. Veins purple. 2. Midrib pinkish in some old leaves. THE SWEET POTATO. 77 3. Purple spot at the base of the midrib. 4. Veins all green. H. — Arrangement of Hair on Upper Surface of Leaf. 1. Hair all over. 2. Chiefly on tip and along veins. 3. Absent. I. — Outside Color of Tubers. 1. White. 2. Yellow, golden or bronze. 3. Yellow-red or pinkish. 4. Eed or purple. J.- — Color of the Flesh of the Tubers. 1. White. 2. Cream-colored or yellowish-white. 3. Pinkish-white or pinkish-yellow. 4. Pink-orange. 5. Marked with purple. K. — Distinctness of Wood Elements in Tuber. 1. Distinct. 2. Blurred. 3. Not visible. In the determination of most varieties known to the author there is no difficulty in referring all their characteristics to the different alternative numbers expressing them. In some varieties, however, it is hard to tell whether the leaves reach a greater width than four inches, as there are such few leaves that do, and those might be exceptions. A similar diffi- culty will sometimes present itself in other places. All that is necessary is to express by the figures the actual condition. Thus : A. 3-4 means that both long 78 THE SWEET POTATO. and broad leaves are frequent on the plant; B. 1-2, that most large leaves are below four inches in width, but that quite a number measure more than four inches between their extreme tips from side to side. Similarly, E. 1-2 means that the stems occa- sionally attain a diameter of rs of an inch, but that most of the stems are less than A of an inch thick, and a few even as little as or less than % inch. These peculiarities of some varieties will rather help than hinder in the work of determining them. How to Use the Key. The plants should be examined in the field, under normal conditions. The tubers may as well be examined after they are mature, as they show the details better than immature ones. Given a plant whiph was received under some unfamiliar name, and it is to be determined whether it is an old variety appearing under a new name. The leaves are cut. That gives us A. — 1. Most of the later, full-grown leaves measure more than four inches across at their widest points, i. e., from tip to tip of the most spreading lobes. That means B. — 2. The full-grown stems are shorter than four feet. So we put down C. — 2. As the stems are green with purple marks around the axils of the leaves, we have D.— 2. The full-grown stems meas- ure 1^ of an inch at their thickest point, which is expressed by E. — 2. The purple star is clear and the lower surface of the vein is purple, which gives us F. — 1 and G. — 1. As a few of the younger leaves show a few scattered hairs on the midrib, and some of the older leaves have no hair at all, we express that by H. — 2-3. The tubers we find to be white outside and inside, which means I. — 1 and J. — 1. THE SWEET POTATO. 79 The bundles, or wood elements, are not visible on tbe freshly cut surface. That gives us K. — 3. Thus our formula runs: Al— B2— C2— D2— E2— Fl— Gl— H2-3— II— Jl— K3. When we refer to the alpha- betical arrangement of the formulas we find that it is the formula of Ticotea. To make entirely sure, we compare our plant with the photograph of Ticotea and with its description. If all these points agree, we may be certain that the variety is Ticotea. Advantages of This Key Over the Ordinary Botanical Key. At the beginning of the chapter the writer prom- ised to give his reasons for choosing this key. This key is preferred on account of the following advan- tages : 1. It is a key and a classification combined. All varieties are determined by the same characters and can be readily compared, while in the ordinary key each variety is thrown out at an opportune moment by a character which may be common to many others already separated by some other character. One comes to associate that particular character with that variety, while in reality it depends entirely on the arbitrary arrangement of the key whether the character is used at all. Similarly there is little attempt made in the arrangement of the ordinary key to keep together the varieties most resembling each other, while in this key they stay together nat- urally. For example. Bronze Spanish, as the name indicates, has a peculiarly colored tuber. In the ordinary key this character would very likely be used at an early stage to separate it. Black Spanish has a tuber which is similar to several others, and it would be hard to separate it by that character. Yet 80 . THE SWEET POTATO. the two cannot be told apart in the field, unless one dig for the tubers. 2. It can be used with incomplete specimens. If a certain character cannot be determined from the material on hand, the space reserved for it may be left blank, and the next character taken up. One is not continually before alternatives which may be at the time unanswerable. It is likely that the deter- mination is possible even without that character. 3. It is more convenient to the non-scientist. In the determination of all varieties the same process is gone through, and once that process is learned by heart it need not be changed again for the deter- mination of the next variety. 4. It is flexible. The writer is certain that he has not studied all varieties existing. New varie- ties can be easily catalogued and inserted in the list by anyone. In the ordinary key the advent of a new variety necessarily causes confusion, as it not only could be wrongly determined itself, but would also interfere with the determination of other varieties which might agree with it in the critical characters. A considerable number of new varieties would make an ordinary key useless, while this key provides for all. Should other characters be found which would aid in the determination, they could simply be entered under subsequent letters, L — , M — , N — , etc., without interfering in the least with the work- ing of the key. D. Alphabetical List op Formulas. Al B2 Cl DI El F2 G4 HI 13 J3 Kl = Belmont. Al B2 Cl Dl El-2 F2 Gl -f- 3 H3 12 J2 K3 = Kala. Al B2 Cl Dl El-2 F2 G4 HI 12-3 J3 Kl = Georgia. Al B2 Cl D2 E2 Fl Gl H2 II Jl K3 = White Gilk. Al B2 Cl D2 E2 Fl Gl H2 12 J2 K3 = John Burnet. THE SWEET POTATO. 81 Al B2 CI D2 E2 F2 G3 H3 13 Jl K3 = Kawelo. Al B2 CI D4 El-2 PI Gl H2-3 13 J3 K3 = Huamoa. Al B2 CI D4 E2 El Gl H3 14 Jl K3 = Ihumai. Al B2 C2 Dl E2 F2 G3 H2 14 J3 K2 = Vincentonian. Al B2 C2 D2 E2 Fl Gl H2-3 II Jl K3 = Ticotea. *A1 B2 C Dl E F2 G4 H2 13 Jl K.3 = Gros Gandia. A2 Bl C2 Dl El-2 Fl Gl HI II J3 K3 = Minnet. A2 Jil-2 C2 Dl El-2 F2 G4 Hl-2 II Jl K3 = Vineless Beech. A2 B2 CI Dl El-2 F2 G4 Hl-2 II Jl K2-3 = Caroline Lee. A2 B2 CI Dl E2 F2 G4 H2 11 J2 K3 = White Sealy. A2 B2 CI D2 E2 PI Gl HI 14 J2 K3 t= Trinidadian No. 1. A2 B2 C2 D2 E2 PI Gl H2 11-2 Jl Kl = Shanghai. A2 B2 C2 D3 E2 Fl Gl HI 14 J2 K3 = Brass Cannon. •A2 B C D4 E2 PI Gl Hl-2 14 Jl K3 = Muffard. A3 Bl CI D4 El Fl Gl HI 12 J2 K3 = Laiakpna. A3 Bl CI D4 El PI Gl H2 14 J5 K3 = Kapo. A3. Bl-2 C2 D4 E2 Fl Gl H2 II Jl K2 = Thompson's Favorite. 'A3 B2 CI Dl Bl Fl Gl H2 14 Jl K = India Red. A3 B2 CI D2 El-2 Fl Gl H2 14 J2 K2 = Governor. A3 B2 CI D2 E2 PI Gl H3 II Jl Kl-2 = Roosevelt. A3 B2 CI D2 E2 PI Gl H3 12 J2 K3 = Pilipili. A3 B2 CI D2 E2 Fl Gl H3 14 Jl K3 = Kauaheahe. A3 B2 CI D4 E2 PI Gl H2 13-4 J2 K3 = Yellow Bed. A3 B2 CI D4 E2 Fl Gl H2 14 J5 K3 = Black Spanish. A3 B2 CI D4 E2 Fl Gl H3 12 Jl K3 = Bronze Spanish. A3 B2 CI D4 E2 Fl Gl H3 12 J3 K3 = Pikonui. A3 B2 CI D4 E2 PI Gl H3 13 J2 K2 = Key West. •A3 B C Dl E2 Fl Gl H2 12 J2 K3 = Sulla. *A3 B C Dl E2 P2 G4 H2 13 J2 K2 = Trinidadian No. 2. •A3 B C D2 B Fl Gl H3 14 Jl K3 = Chazal. A4 Bl CI D3 El-2 Fl G4 H2 12 J2-3 Kl = Yellow Colombia. A4 Bl CI D3 El-2 Fl G4 H2-3 II J2 Kl = White Colombia. A4 Bl CI D3 El-2 F2 G2 H2 11-2 J2 K2 = Southern Queen, weak type. A4 Bl-2 C2 D2 E2 Fl Gl HI 13 Jl K2 = Red Sealy. A4 B2 CI D3 E2 F2 G2 H2 11-2 J2 K2 = Southern Queen, strong type. •A4 B2 C2 D2 E2 PI Gl HI 12 J K = Florida. A4 B2 C2 D4 E2 Fl Gl H3 14 Jl K3 = Halonaipu. A4 B2 C2 D4 E2 F2 G2 + 3 H3 12 J3 K3 = Pu. •A4 B CI D2 El PI Gl H3 14 J5 K3 = Violette Rouge. 82 THE SWEET POTATO. A4 B C D2 E Fl bl H3 13 J5 K3 = Violette Blanche. A3 + 4 Bl CI El F2 G3 HI 13-4 J2 K2 = Peabody. A3 + 4 Bl-2 CI Dl El F2 G3 HI 12 J2-3 Kl = Carolina Extra Early. A3 +4 B2 CI Dl E2 F2 G4 HI 12 J3 Kl = Norton. A4 + 3 Bl CI Dl El F2 G4 HI 13 J4 K2 = Pumpkin. *A4 +3 B2 C Dl E2 F2 G4 HI 13 J3 K3 = Fire Brass. A5 Bl Ci Dl El F2 G3 HI 12 J2 K2 = Up River. A5 Bl CI Dl El F2 G3 HI 12 J3 Kl — Yellow Jersey. A5 Bl CI Dl El F2 G3 HI + 2 14 J2 K2 = Red Jersey. A5 Bl-2 01 Dl El F2 G3 HI 12 J2 K2 = Pepper's Choice. A5 Bl-2 01 D3 El-2 Fl Gl H(l-)2 11-2 Jl-2 Kl =yellow Straussberg. A5 Bl-2 01 D4 El-2 Fl Gl H2 11-2 J2 K2 = Alabama... A5 Bl-2 01 D4 El-2 Fl Gl H2 14 J2 K2-3 = Red Nansemond. A5 Bl-2 01 Dl El-2 F2 G3 HI 14 J3 Kl — Van Ness Red. A5 B2 01 D4 E2 Fl Gl H2 11-2 J2 K? = Early General Grant. A5 B2 02 Dl E2 Fl Gl HI 13 J3 K2 = Nancy Hall. *A B D2 E Fl Gl H3 12 J2 K3 = Yellow Mauritius. E. Alphabetical List of Varieties. Alabama.— A5 Bl-2 01 D4 El-2 Fl Gl H2 11-2 J2 K2. Archer's Hybrid. — See Southern Queen, strong type. Belmont.— Al B2 01 Dl El P2 G4 HI 13 J3 Kl. Big Stem Jersey — See Yellow Jersey. Black Spanish.— A3 B2 01 D4 E2 Fl Gl H2 14 J5 K3. Brass Cannon.— A2 B2 02 D3 E2 Fl Gl HI 14 J2 K3. • Brazilian. — See Southern Queen, strong type. Bronze Spanish.— A3 B2 01 D4 E2 Fl Gl H3.I2 Jl K3. Carolina Extra Early.— A3 + 4 Bl-2 01 Dl El F2 G3 HI 12 J2-3 Kl. Caroline Lee.— A2 B2 01 Dl El-2 P2 G4 Hl-2 II Jl K2-3. Chazal.— A3(?) B(?) C(?) D2 E(?) Fl Gl H3 14 Jl K3. Dooley.- — See Ticotea. Early Carolina. — See Up River. Early General Grant.— A5 B2 01 D4 E2 Fl Gl H2 11-2 J2 K2. Early Golden. — See Southern Queen, weak type. Eclipse Sugar Yam. — See Georgia. Fire Brass.— A4 + 3 B2 C(?) Dl E2 P2 G4 HI 13 J3 K3. Florida.— A4 B2 02 D2 E2 PI Gl HI 12 J K. * Plants were too young to be fully determined, if the full formula is not given. THE SWEET POTATO. 83 Florida. — See Southern Queen, strong type. Florida Bunch. — See Southern Queen, strong type. Florida Yam, No. 2. — See Southern Queen, strong type. General Grant. — See Florida. General Grant. — See Southern Queen, weak type. Georgia.— Al B2 CI Dl El-2 F2 G4 HI 12-3 J3 Kl. Georgia. — See Alabama. Gold Coin. — See Southern Queen, strong type. Gold Skin. — See Southern Queen, strong type. Governor.— A3 B2 CI D2 El-2 Fl Gl H2 14 J2 K2. Gros Gandia.— Al B2 C( ?) Dl E( ?) F2 G4 H2 13 Jl K3. Halonaipu.— A4 B2 C2 D4 E2 Fl Gl H3 14 Jl K3. Hamburg. — See Southern Queen, strong type. Hayman. — See Southern Queen, strong type. Huamoa.— Al B2 CI D4 El-2 PI Gl H2-3 13 J3 K3. Ihumai.— Al B2 CI D4 E2 Fl Gl H3 14 Jl KB. India Red.- A3 B2 CI Dl El Fl Gl H2 14 Jl K. John Burnet.— Al B2 CI D2 E2 Fl Gl H2 12 J2 K3. Kala.— Al B2 CI Dl El-2 F2 Gl + 3 H3 12 J2 K3. Kapo.— A3 Bl CI D4 El Fl Gl H2 14 J5 K3. Kauaheahe.— A3 B2 CI D2 E2 Fl Gl H3 14 Jl K3. Kawelo.— Al B2 CI D2 E2 F2 G3 H3 13 Jl K3. Kentucky White. — See Southern Queen, weak type. Key West.— A3 B2 CI D4 E2 Fl Gl H3 13 J2 K2. Koali. — See Kawelo. Laiakona.— A3 Bl CI D4 El Fl Gl HI 12 J2 K3. McCoy. — See Southern Queen, weak type. Miles Yam. — See Southern Queen, strong type. ' Minnet.— A2 Bl C2 Dl El-2 Fl Gl HI II J3 K3. Mufifard.— A2(?) B( ?) C(?) D4 E2 Fl Gl Hl-2 14 Jl K3. Nancy Hall.— A5 B2 C2 Dl E2 PI Gl HI 13 J3 K2. Nigger Choker — Killer. — See Black Spanish. Norton.— A3 -f 4 B2 CI Dl E2 F2 G4 HI 12 J3 Kl. Peabody.— A3 + 4 Bl CI Dl El F2 G3 HI 13-4 J2 K2. Pepper's Choice.— A5 Bl-2 CI Dl El F2 G3 HI 12 J2 K2. Pierson. — See Southern Queen, weak type. Pikonui.— A3 B2 CI D4 E2 Fl Gl H3 12 J3 K3. Pilipili.— A3 B2 CI D2 E2 PI Gl H3 12 J2 K3. Polo. — See Southern Queen. Pu.— A4 B2 C2 D4 E2 F2 G2-3 H3 I2( ?) J3 K3. Pumpkin.— A4 -f- 3 Bl CI Dl El F2 G4 HI 13 J4 K2. Red Bermuda. — See Red Nansemond. 84 THE SWEET POTATO. Red Jersey.— A5 Bl 01 Dl El F2 G3 Hl-2 14 J2 K2. Red Nansemond.— A5 Bl-2 01 D4 El-2 Fl Gl H2 14 J2 K2-3. Red Sealy.— A4 Bl-2 02 D2 E2 El Gl HI 13 Jl K2. Roosevelt.— A3 B2 01 D2 E2 PI Gl H3 II Jl Kl-2. Shanghai.— A2 B2 02 D2 E2 Fl Gl H2 11-2 Jl Kl. Southern Queen, strong type. — ^A4 B2 01 D3 E2 F2 G2 H2 11-2 J2 K2. Southern Queen, weak type.— A4 Bl 01 D3 El-2 F2 G2 H2 11-2 J2 K2. Spanish (Yam). — See Black Spanish. Strassburg, Straussberg. — See Southern Queen, weak type. Sugar Yam. — See Georgia. Sulla.— A3 B(?) C(?) Dl(?) E2(?) Fl(?) Gl H2 12 J2 K3. Thompson's Favorite.— A3 Bl-2 02 D4 E2 Fl Gl H2 II Jl K2. Ticotea.— Al B2 02 D2 E2 Fl Gl H2-3 II Jl £3. Trinidadian, No. 1.— A2 B2 01 D2 E2 Fl Gl HI 14 J2 K3. Trinidadian, No. 2.— A3(?) B(?) C(?) D1E2(?) F2G4H2I3 J2 K2. True Parson Prince. — See John Burnet. Up River.— A5 Bl 01 Dl El F2 G3 HI 12 J2 K2. Up River. — See Southern Queen, weak type. Van Ness Red.— A5 Bl-2 01 Dl El-2 F2 G3 HI 14 J3 Kl. Vincentonian.— Al B2 02 Dl E2 F2 G3 H2 14 J3 K2. Vineless Beech.— A2 Bl-2 02 Dl El-2 F2 G4 Hl-2 II Jl K3. Violette Blanche.— A4( ?) B( ?) 0( ?) D2( ?) E( ?) Fl Gl H3 13 J5 K3. Violette Rouge.— A4 (? ), B( ?) 01 D2 Ei Fl Gl H3 14 J5 K3. White Oolombia.— A4 Bl 01 D3 El-2 Fl G4 H2-3 Il( ?) J2 Kl. White Gilk.— Al B2 01 D2 E2 Fl Gl H2 II Jl K3. White Gilkes, 3 mo.— See White Gilk. White Gilkes, 6 mo.— See White Gilk. White Sealy.— A2 B2 01 Dl E2 F2 G4 H2 II J2 K3. White Yam. — See Southern Queen, weak type. Yellow Bean. — See Southern Queen, strong type. Yellow Oolombia.— A4 Bl ( ?) 01 D3 El-2 Fl G4 H2 12 J2-3 Kl. Yellow Jersey.— A5 Bl 01 Dl El F2 G3 HI 12 J3 Kl. Yellow Mauritius.-=A( ?) B( ?) 0( ?) D2 E( ?) Fl Gl H3 12 J2 K3. Yellow Red.— A3 B2 01 D4 E2 Fl Gl H2 13-4 J2 K3. Yellow Straussberg.— A5 Bl-2 Oi D3 El-2 Fl Gl H ( 1-) 2 11-2 Jl-2 Kl. In addition to tlie above varieties a number of seedlings and young plants too young for full determination have been left by the writer in the care of the United States Experiment Station at Wash- ington. THE SWEET POTATO. 85 The writer wishes it to be clearly understood that he elaborated the key for the convenience of workers in this field, and that therefore he welcomes criti- cisms and corrections. For sweet potato material the writer feels espec- ially indebted to Mr. Beattie, of the Washington Experiment Station; Mr. Starnes, of the Georgia Station; Mr. Burnette, of the Baton Rouge Station; Mr. Eosa, of Milford, Delaware; Mr. Pittier, of Washington, and to the Botanic Gardens of Jamaica, Barbadoes, Calcutta, Mauritius, and Honolulu. The writer wishes to express his sincere thanks to Dr. Macf arlane for the facilities for study offered in the Botanic Gardens of the University and the many sug- gestions made ; to Mr. Trouncer, of Wenonah, N. J., for the generous offer of his field, and to Mr. Maisch, photographer of the Philadelphia Museums, for the care he has taken with the photographs. , P. Descriptions. Alabama (Georgia). Southern States. Formula : A5 Bl-2 01 D4 El-2 PI Gl H2 11-2 J2 K2. Stems long, between % and ^ inch thick, bright light purple. Star clear, but small. Lower surface of veins dark purple. Hair chiefly along the veins, scant. Type leaf Fig. 71. Differs from Early General Grant only in its less vigorous growth. Belmont. Washington. United States. Formula : Al B2 CI Dl El P2 G4 HI 13 J3 Kl. Stems thin, about ^^r of an inch in diameter, green. Often brownish or even faintly purplish where exposed to the sun. Haiiy. Large grown leaves, about 4-4% inclies across from tip to tip. Type leaf figure omitted by mistake, resembles Georgia very closely. 86 THE SWEEl POTATO. Black Spanish. Various States of the Union. Formula : A3 B2 01 D4 E2 PI Gl H2 14 J5 K3. Stems very long, ^ inch in diameter, very dark purple. Petioles also purple, except those near the tip, if shaded. Star bright and large. Leaves dark colored, i^ower surface of veins purple. Leaves often 5 inches long and broad. Type leaf Fig. 50. Latex very abundant, dripping off when stem is cut. Hair mostly on tip only, or continued down on larger veins. Brass Cannon. Jamaica. Formula: A2 B2 C2 D3 E2 Fl Gl HI 14 J2 K3. Stems short, thick [-^s inch ) , greenish brown, to purple on upper side. Star large, lower surface of veins strongly marked purple. Hair thick all over the upper surface of the leaf. Type leaf Fig. 40. Bronze Spanish. Washington, D. C. Formula : A3 B2 CI D4 E2 Fl Gl H3 12 Jl K3. Stems long, ^ inch in diameter, or a little thinner, but never thinner than % inch, very dark purple. Petioles also purple. Star bright and large. Leaves dark colored. Lower surface of veins purple. Leaves often 5 inches or more long and broad. Hairs practically absent. Type leaf Fig. 51. Carolina Extra Early. Georgia, etc. Formula : A3 + 4 Bl-2 01 Dl El F2 G3 HI 12 J2-3 Kl. Stems long, less than % inch in diameter, green. Faint purplish spot at the lower surface of the base of the midrib. Type leaf Fig. 63. THE yWEET POTATO. 8V Caroline Lee. Louisiana. Formula : A2 B2. CI Dl Bl-2 F2 G4 Hl-2 II Jl K2-3. Stems longer than four feet, rarely more than fj inch thick, light green. Hair almost all over young leaves, all over tip and along the veins in old ones. Type leaf Fig. 36. Slightly shouldered leaves occur occasionally, even among the later leaves. Early General Grant. Various States of the Union. Formula : A5 B2 CI D4E2 Fl Gl H2 11-2 J2 K2. Stems long, '^ inch thick, purple. Star clear, veins strongly marked purple belovir. Hair scant along the veins. Type leaf Fig. 75. Fire Brass. Jamaica. Formula : A4 B C Dl E F2 G4 HI 13 J3 K3. Stems light green to brownish, but without purple. Hair all over leaf. Florida. Various States of the Union. Formula : A4 B2 C2 D2 E2 Fl Gl HI 12 J K. Stems about 1 foot long. Plant very bushy. Stems A to % inch thick, green, with purple spots around the axils of the leaves. Star very large. Vein strikingly marked purple below. Leaves very much sunk in the center, deeply sailoer-shaped. Type leaf Fig. 59. 88 THE SWEET POTATO. Georgia (Eclipse Sugar Yam.) United States. Formula: Al B2 CI Dl Bl-2 P2 G4 HI 12-3 J3 Kl. Stems long, often ^ thick, but usually between -^^ and A inch thick, long, green, with brownish sunburnt patches where exposed. Large leaves 6 inches across from tip to tip. Type leaf Fig. 27. Governor Jamaica. Formula: A3 B2 CI D2 El-2 Fl Gl H2 14 J2 K2. Stems not much longer than 4 feet as a rule; about A inch thick at thickest point, but often thinner; greenish brown with purple around' the axils of the leaves. Star rather faint, lower surface of veins rather weakly colored purple. Type leaf Fig. 45. Halonaipu. Sandwich Islands. Formula : A4 B2 C2 D4 E2 Fl Gl H3 14 Jl K3. Stems about 3 feet, ^ inch in diameter, purple. Star plain, veins purple below. Hair absent. Type leaf Fig. 60. Large leaves, over 4 inches across, but most leaves 3-4 inches in diameter. Huamoa Sandwich Islands. Formula: Al B2 01 D4 El-2 Fl Gl H2-3 13 J3 K3. Stems long, thin or medium-sized, purple. Star large and clear. Type leaf Fig. 32; little over 4 inches in diameter. Hair very scant on veins, or almost entirely absent. THE SWEET POTATO. 89 Ihumai. Sandwich Islands. Formula : Al B2 CI Hi E2 Fl Gl H3 14 Jl K3. Stems not much longer than 4 feet, extremely thick, sometimes measuring over % inch in diameter at the thickest point. Very dark purple. Star extending half-way up the veins or farther, bright. Under side of veins brilliantly set off in purple in younger opened leaves. Hair absent from surface of the leaf, present only at the edge. Type leaf Fig. 33. India Red India. Formula : A3 B2 01 Dl El Fl Gl H2 14 Jl K. Stems long, whitish-green, with pinkish-purple blotches around the axils of the leaves and occasionally in other places; thin, only rarely over Ys inch in diameter. Star large, bright red. Type leaf Fig. 44; largest leaves over 4 inches across, but most full-grown leaves are 3-4 inches across. Hair scattered along the larger veins. The young leaves, just opened, are characteristically colored pinkish-brown. John Burnet. (True Parson Prince). Jamaica. Formula : Al B2 01 D2 E2 Fl Gl H2 12 J2 K3. Stems little over 4 feet, ^ inch thick, green, with purple marks around the axils of the leaves and purple sunburns on the upper surface, where exposed. Star small, but plain. Lower surface of veins well marked with purple, out to the margin of the leaf. Leaf like type Fig. 30, not cordate at the base. Hair rather far down the central lobe, and along larger veins. Large leaves, about 5 inches across from tip to tip. Latex very abundant. 90 THE SWEET POTATO. Kala. Sandwich Islands. Formula : Al B2 01 Dl El-2 F2 Gl + 3 H3 12 J2 K3. Stems little longer than 4 feet, green, with here and there brownish or slightly purplish patches, -^ inch in diameter or less. No star. On the lower surface of the base of the midrib there is a purple spot, usually noticeable only in young leaves. In some leaves even the lower surface of the veins is purplish. Type leaf Pig. 28. Ka'po. Sandwich Islands. Formula : A3 Bl 01 D4 El Fl Gl H2 14 J5 K3. Stems long, % inch in diameter, very rarely thicker; dark purple, lighter purple at the tip, but even there dark purple around the axils of the leaves. Star very small. Lower surface of veins rather light purple. Latex very abundant, dripping off from a cut stem. Type leaf Fig. 42. Kauaheahe. Sandwich Islands. Formula : A3 B2 01 D2 E2 Fl Gl H3 14 Jl K3. Stems long, green, with purple around the base of the leaves and near the tip. The tips are either entirely purple for about six inches, or green with purple around the axils of the leaves. Star small, but clear. Veins rather weakly marked with purple on the lower surface. Hairs absent on surface, scattered on the edge of the leaf. Type leaf Fig. 48. Kawelo. (Koali). Sandwich Islands. Formula : Al B2 01 D2 E2 F2 G3 H3 13 Jl K3. Stems long, ^ inch or more in diameter, whitish, with purple around the axils of the leaves, and occasional sunburnt patches on the upper surface. Leaves very light yellowish-green. Type leaf Fig. 31. Especially in young, full-grown leaves there is a faint purple spot on the lower surface of the midrib, where it springs from the petiole. Hair absent. THE SWEET POTATO. 91 Key West. Washington, D. C. Formula : A3 B2 01 D4 E2 Fl Gl H3 13 J2 K2. Stems very long, -^ inch diameter or more at thickest point, bright purple, but often green at the very base. Star large, extending up the veins; lower surface of veins strongly marked purple. Type leaf Fig. 53. Leaves often 6-8 inches broad; hair absent on surface, present along edge. Laiakona. Sandwich Islands. Formula : A3 Bl 01 D4 El Fl Gl HI 12 J2 KZ. Stems little more than 4 feet long, seldom more than % inch in diameter, purple. Star small, lower surface of veins strongly marked purple. Hair almost all over the upper surface of leaf. Type leaf Fig. 41. Nancy Hall. Louisiana. Formula : A5 B2 02 Dl E2 Fl Gl HI 13 J3 K2. Stems less than 4 feet long, A to % inch in diameter, entirely green. The plant has a bunch habit. Star plain, veins purple below. Most leaves are slightly lobed on the sides, but many are without projections. Type leaf Fig. 74. Hair all over upper surface of leaf. Norton. Washington, D. 0. Formula: A3 + 4 B2 01 Dl E2 F2 G4 HI 12 J3 Kl. Stems long, ^ inch or more in diameter, green, with opcasional patches of brownish in exposed places. Hair very thickly covering the entire upper surface of the leaf. Type leaf Fig. 64. 92 THE SWEET POTATO. Peabody. Louisiana. Formula: A3 + 4(?) Bl 01 Dl El F2 G3 HI 13-4 J2 K2. Sterna long, % inch in diameter, green. Leaf with a purplish spot on the under side of the base of the midrib. Hair^ thick all over upper surface. Both long-lobed and broad-lobed leaves frequent. Leaves about 3 inches across. Type leaf Fig. 62. Pepper's Choice. Delaware. Formula ; A5 Bl-2 01 Dl El F2 G3 HI 12 J2 K2. Stems long, less than % inch in diameter, light green. Leaves round and lobed, of about equal frequency, or the lobed ones predominating. Most leaves are less than 4 inches across, but some are larger. In young leaves there is a. faint purple spot on the under side of the base of the midrib. Hair all over the upper surface of the leaf. Type leaf Fig. 69. Plkonui. Sandwich Islands. Formula : A3 B2 01 D4 E2 Fl Gl H3 12 J3 K3. Stems not much longer than 4 feet, ^ inch thick or thicker. Star very small, but bright. Veins purple below. Hairs absent. Type leaf Fig. 52. Pilipili. Sandwich Islands. Formula; A3 B2 01 D2 E2 Fl GI H3 12 J2 K3. Stems long, -^ inch in diameter, light green, with small purple spots in the axils of the leaves. Star very small, but clear. Veins purple below. THE SWEET POTATO. 93 Leaves range from light yellowish-green to rather dark green on the upper surface. The largest leaves on long stems are the darkest. Type leaf Fig. 47. Hairs absent from upper surface of leaf, present on the edge. Pu. Sandwich Islands. Formula : A4 B2 C2 D4 E2 F2 G2-3 H3 12 J3 K3. Stems about 2 feet, ^ inch thick, pinkish-purple. Leaves, which are on purplish petioles, have the lower surface of the midrib with. a hue of pink. Sometimes there is a purplish spot at the base of the midrib on the lower surface. Type leaf Fig. 61. Pumpkin. Various States of the Union. Formula : A4 + 3 Bl CI Dl El F2 G4 HI 13 J4 K2. Stems long, % inch in diameter, green, with occasional brownish places, where exposed to the sim. Exceptionally a few leaves have a hue of pink on the lower side of the midrib. Hair thick all over upper surface. Type leaf Fig. 65. , Red Jersey. Washington, D. C. Formula : A5 Bl 01 Bl El F2 G3 Hl-2 14 J2 K2. Stems long, less than ^ inch in diameter, green, brownish in patches. A purplish spot on the under side of the base of the midrib. Leaves rarely more than 3 inches across, both round and lobed. Hairs all over young open leaves, but chiefly on the veins in the oldest ones. Type leaf Fig. 68. 94 THE SWEET POTATO. Red Nansemond (Red Nancemond — Ked Bermuda). Louisiana. Formula : A5 Bl-2 01 D4 El-2 Fl Gl H2 14 J2 K2-3. Stems long, between % and ^ inch thick, purple. Star clear, lower surface of veins strongly marked purple. Hair scant along veins and tip of median lobe.. Most leaves a little less than 4 inches across, especially the round ones, but many measure more than 4 inches. Type leaf Fig. 72. Red Sealy. Jamaica. Formula : A4 Bl-2 C2 D2 E2 Fl Gl HI 13 Jl K2. Stems about 3 feet long. Plant bushy. Stems A inch in diameter, green, with a purplish crescent around the base of each petiole, which sometimes extends slightly over the side of the stem. Star small, but bright. Veins purple below. Hair all over upper surface of leaf. Type leaf Fig. 57. Roosevelt. Jamaica. Formula : A3 B2 01 1)2 E2 Fl Gl H3 II Jl Kl-2, Stems- long, ^ inch in diameter at the thickest point, greenish- brown, with purple around the axils of the leaves. Star small and bright. Lower surface of veins well marked purple. Hair absent. Type leaf Fig. 46. Large leaves often over 5 inches across. Shanghai. Washington, D. 0. Formula : A2 B2 02 D2 E2 Fl Gl H2 11-2 Jl Kl. Stems less than 4 feet long, -ft inch thick or thicker, green, -with purple marks around the axils of the leaves and in other places. Star very small, veins purple on lower surface in old leaves. THE SWEET POTATO. 95 Hair plentiful along tHe veins, rarely between the veins, except at the tip. The young open leaves are typically purplish, with the veins darker purple on the upper surface. Type leaf Fig. 39. Southern Queen, Strong type. (Miles Yam, Hayman, Archer's Hybrid, Gold Coin, Florida Bunch, Florida, Brazilian, Florida Yam No. 2, Gold Skin, Caroline Lee, Yellow Bean, Polo, Hamburg.) Formula: A4 B2 CI D3 E2 F2 G2 H2 11-2 J2 K2. Stems long, A-% inch thick, greenish-brown to purple. Midrib of old leaves, especially such as have purplish petioles, is often pinkish below. Leaf often 5-6 inches in its widest diameter. Hair chiefly along the veins. Type leaf Fig. 58. Southern Queen. Weak type. (Early Golden, McCoy, White Yam, Kentucky White, General Grant, Up River, Pierson.) Formula : A4 Bl CI D3 Bl-2 F2 G2 H2 11-2 J2 K2. Leaves sometimes over 4 inches, but usually 3 inches in diameter. Otherwise like the strong type of Southern Queen. Type leaf Fig. 56. Thompson's Favorite. (Jamaica), Formula : A3 Bl-2 C2 D4 E2 Fl Gl H2 II Jl K2. Stems short, rarely over 18 inches, A inch thick or thicker, dark purple. Star very large and striking, running up the veins in thick purple lines. Lower surface of veins purple. All older petioles are entirely dark purple. Hair scant on the tip and alrfng the veins. Type leaf Fig. 43. Mosfr leaves are less than 4 inches across, but some measure more than 4 inches. 96 THE SWEET POTATO. Ticotea (Dooley). Southern States. Formula : Al B2 02 D2 E2 PI Gl H2-3 II Jl K3. Stems short, ^ inch thick or thicker, green, with purple patches around the axils of the leaves. The plant forms thick bunches. Star bright and large, veins very strongly marked purple on lower surface. Hair scant along the veins, or almost absent. Type leaf Pig. 35. Trinidadian No. 1. Jamaica. Formula : A2 B2 01 D2 E2 Fl Gl HI 14 J2 K3. Stems usually less than 4 feet long, but occasionally more, very hairy all over down to the base, A iuch thick at thickest point, purplish or purple. Star large and clear, running part way up the veins in very thin lines. Practically all leaves are round. Hairs thin all over the upper surface. Lower surface of veins strongly marked purple. Type leaf Pig. 38. Up River (Early Oarolina). Various States of the Union. Formula : A5 Bl 01 Dl El P2 G3 HI 12 J2 K2. Stems long, thin, less than % inch as a rule, never as much as ^ inch thick, green. A faint purplish spot on the under side of the base of the midrib. Both round and lobed leaves frequent. Leaves usually less than 3 inches across. Type leaf Pig. 66. Van Ness Red. Washington, D. 0. Formula : A5 Bl-2 01 Dl El-2 P2 G3 HI 14 J3 Kl. Stems long, less than % inch in diameter, with some stems a little thicker, green, with brownish patches where exposed. Leaves mostly less than 4 inches in diameter, sometimes a little THE SWEET POTATO. 97 larger. Small purplish spot on the lower side of the base of the midrib. Hair all over upper surface of leaf. Type leaf Eig. 73. Vincentonian. Jamaica. Eormula : Al B2 02 Dl E2 F2 G3 H2 14 J3 K2. Stems usually less than 3 feet long, ^ inch thick or more, green, with occasional blotches of sunburn. Plant of bushy habit. Veins faintly purple for a short distance on the lower surface, or only at the place of junction of the primary veins. Hair over a large part of the tip of the center lobe, continued down along the veins. Type leaf Eig. 34. Vineless Beech. Louisiana. Formula : A2 Bl-2 02 Dl El-2 F2 G4 Hl-2 II Jl K3. Stems short, rarely over 3 feet, green, between ^ and A inch in diameter. Hair covering a large part of the apex of the leaf, and continued down along the veins. Latex very abimdant. All leaves are round. Type leaf Fig. 37. Eesembles Caroline Lee, but differs from it in the length and thickness of stalk, and size and shape of leaf. White Colombia. Oolombia. Formula : A4 Bl 01 D3 El-2 Fl G4 H2-3 II J2 Kl. (Plants not old enough to be certain about all the measurements). Stems long, between % and A inch thick, green to purple. Star very large in young leaves, disappearing in old ones; at times not present in young leaves. Color of leaves ranging from deep purple to green. Hairs few along the veins, or absent. Type leaf Fig. 55. So far no difference has been observed between this and Yellow Colombia. 98 THE SWEET POTATO. White Gilk. Southern States and West Indies. = (W. Gilkes, 3 months.) (W. Gilkes, 6 months.) Formula : Al B2 CI D2 E2 Fl Gl H2 II Jl K3. Stems not much longer than 4 feet, -^ inch thick, greefl', with purplish spots around the axils of the leaves and in other places. Star conspicuous, veins strongly marked with purple on the under surface. Hair scattered along veins and on the tip. Type leaf Fig. 29. Differs from John Burnet in having the star smaller in the young leaves and larger in the old ones. White Sealy. Louisiana and West Indies. Formula : A2 B2 01 Dl E2 F2 G4 H2 II J2 K3. Stems long, thick, green, no purple on entire plant. Type leaf omitted by mistake. Hair scattered along midrib and principal veins. Yellow Colombia. Formula ; A4 Bl ( ?) 01 D3 El-2 Fl G4 H2 12 J2-3 Kl. (Plants not old enough to be certain about all the measurements.) See description of White Colombia. Type leaf Fig. 54. Yellow Jersey. (Big Stem Jersey). Washington, D. C. Formula : A5 Bl CI Dl El F2 G3 HI 12 J3 Kl. Stems long, less than % inch in diameter, light green. Purple spot under side of the base of the midrib. Type leaf Fig. 67. THE SWEET POTATO. 99 Yellow Red. Louisiana. Formula : A3 B2 CI D4 E2 Fl Gl H2 13-4 J2 K3. Stems long, ^ inch in diameter at the thickest point, dark purple. Star well marked, lower surface of veins purple. Hairs on tip of middle lobe and along large veins. Type leaf Fig. 49. Yellow Strauwberg. Various States of the Union. Formula : A5 Bl-2 CI D3 El-2 Fl Gl Hl-2 11-2 Jl-2 Kl. Stems long, between % inch and ^ inch in diameter, greenish- brown to purple, but purple for most of their length. Halberd-shaped leaVbs prevailing. iMany leaves over 4 inches in diameter, but most leaves less than 4 inches across. Star faint, veins faintly purple on the lower surface. Hairs, scant along the veins. Type leaf Fig. 70. V. LIST OF ILLUSTEATIONS. Pig. 1. Surface view 5f lower epidermis of the leaf of Norton. a. Normal cell. b. Cells modified over bundle traces. c. Cells modified around gland cells. d. Gland cells. e. Stomata. Fig. 2. . Withdrawn. Fig. 3. Striations on lower epidermis of leaf of Norton. Fig. 4. Striations on upper epidermis of leaf of Norton. Fig. 5. — — — — . Withdrawn. Fig. 6. Cross-section through a leaf of Up River. a. Gland cells. Fig. 7. — — — — . Withdrawn. Fig. 8. . Withdrawn. Fig. 9. Section through midrib of Van Ness Red. a. Modified epidermis. b. CoUenchyma. c. Latex canals. d. Internal phloem. e. Abnormal xylem inside of internal phloem. Fig. 10. Perspective section of a, petiolar nectary of Yellow Jersey. Fig. 11. Section of petiole of Georgia, two inches from the base, to show arrangement of bundles. a. Internal phloem. b. Dividing cells between bundles. c. Crystal cells. d. CoUenchyma. Pig. 12. Section of petiole of Up Biver, one inch from the base, same magnification as Fig. 11. a. Endodermis. b. Hair. Fig. 13. Section through tip of stem of Van Ness Red. a. Hairs. b. Gland cells. THE SWEET POTATO. 101 Fig. 13- Fig. 14. Fig. 15. Pig. 16. ■Oontiimed. c. Latex canals. d. Endodermis. e. Pericambium. f. Protoxylem. g- Internal phloem. Diagram of cross-section of base of stem of Florida. a. - Epidermis. b. Cortex. c. Endodermis. d. Pericambium. e. Phloem. f. Cambium. g- Xylem. h. Vessels. i. Tyloses. k. Cambium of internal phloem. 1. Fundamental tissue. Cross-section of old -stem of Southern Queen. a. Epidermis. b. Hypodermis. c. Cortex. d. Latex canals. e. Endodermis. f. Pericambium. g- Phloem. h. Cambium. i. Xylem. J- Vessels. k. Protoxylem. 1. Internal cambium. m. Internal phloem. n. Fundamental tissue. Development of reversed bundle in cross-section of old stem of Eed Jersey. a. Normal metaxylem. b. Protoxylem. c. Internal phloem. (?) d. Abnormal metaxylem. e. Internal phloem. f. Oil cells in fundamental tissue. g- Crystal cells. 102 THE SWEET POTATO. Fig. 17. Longitudinal section of old stem of Georgia. a. Epidermis. b. Hypodermis. e. Cortex. d. Latex canals. e. Endodermis. f. Fericambium. g. Phloem. h. Vessel with reticulated thickenings, i. Vessel with bordered pits, j. Protoxylem. k. Internal phloem. 1. Fundamental tissue. Fig. IS. Crystal cells in longitudinal section of pith of Southern Queen, weak type. (In course of formation) (t). a. Crystals. b. Protoplasm, e. Nucleus. d. Nucleolus. e. Double crystal. f. Crystal, isolated in the corner of a pith cell. Fig. 19. Latex canals in Van Ness Red. a. In cortex of tip of stem. b. In pith of old stem. Lenticel or proliferation of the epidermis of old stem of Georgia. A tuber of Red Jersey, fascicular type, smooth, with roots coming off in vertical rows near lenticels. Lenticels not conspicuous. A tuber of Florida, spherical, five-lobed, with roots coming off in the sunken areas. Lenticels conspicuous. A tuber of Up Kiver, cylindrical, smooth, with lenticels inconspicuous. A tuber of Shanghai, with many conspicuous lenticels and long and large roots. a. A tuber of Belmont, with five longitudinal veins. Roots deeply simk between the veins. Lenticels scattered, inconspicuous. b. Diagram of cross-section through tuber, showing the five exterior bundles. Fig. 26. A tuber of Pumpkin, showing anastomosing veins. Lenti- cels conspicuous. Fig. 20. Fig. 21. Fig. 22. Fig. 23. Fig. 24. Fig. 25. THE SWEET POTATO. 103 Fig. 27. Georgia. All photographs of hromehes are reohioed on the same scale, so that the photographs show exact compara- tive sine. Fig. 28. Eala. Pig. 29. White Gilk. Fig. 30. John Burnet. Fig. 31. Kawelo. Fig. 32. Huamoa. Fig. 33. Ihumai. Fig. 34. Vincentonian. Fig. 35. Ticotea. Fig. 36. Caroline Lee. Fig. 37. Vineless Beech. Fig. 38. Trinidadian No. 1. Fig. 39. Shanghai. Fig. 40. Brass Cannon. Fig. 41. Laiakona. Fig. 42. Kapo. Pig. 43. Thompson's Favorite. Fig. 44. India Red. Pig. 45. Governor. Fig. 46. Roosevelt. Fig. 47. Pilipili. Fig. 48. Kauaheahe. Fig. 49. Yellow Red. Fig. 50. Black Spanish. Fig. 51. Bronze Spanish. Fig. 52. Pikonui. Fig. 53. Key West. Fig. 54. Yellow Colombia. Fig. 55. White Colombia. Fig. 56. Southern Queen, weak type. Pig. 57. Red Sealy. Fig. 58. Southern Queen, strong type. Pig. 59. Florida. t Pig. 60. Halonaipu. Fig. 61. Pu. Fig. 62. Peabody. Fig. 63. Carolina Extra Early. Pig. 64. Norton. Fig. 65. Pumpkin. Fig. 66. Up River. 104 THE SWEET POTATO. Fig. 67. Yellow Jersey. Fig. 68. Red Jersey. Fig. 69. Pepper's Choice. Fig. 70. Yellow Straussberg. Fig. 71. Alabama. Fig. 72. Red Nansembnd. Fig. 73. Van Ness Red. Fig. 74. Nancy Hall. Fig. 75. Early General Grant. Bot. Contrib. Univ. Perm. Vol. IV, Plate I. Pig. 1. Fig. 4. Fig. 3. Fig. 6. Bot. Contrib. Univ. Penn. Vol. IV, Plate II. Fig. 9. --r Fig. 11. Bot. Contrib. Univ. Penn. Vol. IV, Plate III. ^Xj.^i!a^i.t,vt,\^) Fig. 12. Fig. 13. Fig. 16. Fig. 14. Bot. Contrib. Univ. Penn. Vol. IV, Plate IV. \^: ■: V—j .^.—L-^: V C : . 'I'f Fig. 18. ^g^^. Fig. 19. («Ml. Fig. 17. Fig. 20. Bot. Contrib. Univ. Penn. Vol. IV, Plate V. ^ ; \ Fig, 22 Fig. 21. Fig. 24. Fig. 25. Fig. 26. Bot. Contrib. Univ. Penn. Vol. IV, Plate VI. Fig. 27 — Georgia. Bot. Contrib. Univ. Penn. Vol. IV, Plate VII. ■ 1 H ^ I ^M H PH|^^^^^B ^^^^^^ "/^^^^^^^^H jH ^M ■ m^ ^PMH^^^I H \ ^ wS^^^ ^B^ S!^ ^^^t^^^^ -^^ifl^^^lr 'i^lv '-^-La^M ^ Hi |H ^^^ "^'.^I^^H^^H pp^^^p^P^^^ dpi ^H ^2 fe ^^1 •**! '"iSlKn^^- a^f "VS^^^S^w^: ' ' t s^ n H ^^^^^^^^^ ^ IB r^^^frM'h ''^I^I^H 1^ 9 ■fl ^^^^^H ^^H 1 K ■i s SI ^H ^^H i Si H ^^^^^■p p^ ^^ ^^^2 ^^^^^^^r 4 ^^^r * f:^ ■ s ^^H H i ''^ 1 1 Fig. 28— Kala. Bot. Contrib. Univ. Penn. Vol. IV, Plate VIIL Fig. 29 — ^White Gilk. Bot. Contrib. Univ. Penn. Vol. IV, Plate IX. Fig. 30 — John Subnet. Bot. Contrib. Univ. Penn. Vol. IV, Plate X. Fig. 31 — KAWEro. Bot. Contrib. Univ. Penn. Vol. IV, Plate XI. Fio. 32 — HUAMOA. Bot. Contrib. Univ. Penn. Vol. IV, Plate XII. ^^^^^^■i^^r^lK^ ■' ^^^^^^^^^^^^^^^B^^SV^^^^^^^^^^^^H ^^VL^^HI^i^ ' ''^v^^^^^^^^^^^^^^^^^^^^l ^B^^^^H^HRpH^^^ i^H^H ^H Pi@l ^^^H ^^^r^ ^.^e^f^^^Sr''^ A^ ^^^^^^^^^^F ^^^^K l^^l K ^^HHr '':^^H B^^H^' J '11 |HH P^rH^H p^PH ^M^^^H B^H Fig. 33 — Ihtjmai. Bot. Contrib. Univ. Penn. Vol. IV, Plate XIIL FlG. 34 — ^VlNCENTONIAN. Bot. Contrib. Univ. Penn. Vol. IV, Plate XIV.' Fig. 35 — Ticotea. Bot. Contrib. Univ. Perm. Vol. IV, Plate XV. FiQ. 36 — Cabolihe Lee. Bot. Contrib. Univ. Penn. Vol. IV, Plate XVI. Pig. 37 — Vineless Beech. Bot. Contrib. Univ. Penn. Vol. IV, Plate XVII. w ^^ J^ /^^^m HI -^ -'i^^^ -^S-^' \ ^ w ^ i^^BBi Pi-^ i^- '\\.i fe^^^^B^ r%« < ^^^^^^^^K^^^~j^^fF' --^ K V ' W^f ^ ^P -, 1 '^fetnyii 5^ s v;'; .', ■ ^II '' • ■ li^';3 15^ 1 yj %l "rTpm c^ 'i mi- ■ , ^b^immj^.^ ^^i'^^^B^I • '''■'^i''Ci,mJi^^^ • ■ *'- ■ . ■ '^i&l . Fig. 38 — ^Tbinidadian No. 1. Bot. Contrib. Univ. Penn. Vol. IV, Plate XVIII. Fig. 39 — Shanghai. Bot. Contrib. Univ. Penn. Vol. IV, Plate XIX. / ,^^^ k ^^_P^^;'^^.;.'., ;,j.,^-jg . '^[^fl^^BBi^^^ ^^^^^^^ "j»- K. .>i -^ iH^Mx ^^Hb\,jH| D^ V'*r^ '■'■ J^^^k ^ Ji^^A .- ~, /K -^^Bii^ I^Hjj^ I^^F^ A. ^H ^^^^K.^-.A '^'f..^! '^^-- ^^^ ^^^^^^^^^H|nSr ' - ''^^^^^^^ ^^H 'WMSUKf II W\L 1^ ^P ir IPF^ '^ • , ^^. <^y^y" ' ,^^^K.\ ^^r ...v'. « , :^i^k. - -: «LK. ^ ^"'^^^^^B' ' fe^ ■ ;^0|teii^^mj'::_^ Si%4 p - J — .j^i_ ' ■ ^fe-'C'**^ i»-^ J ,,^j^L;#:. •"".'< _^jt^ ^y^ ^^^^^^H ^ ^ /3 / ^M^^^H 1 IK^SL^i . . ^ ^' ;'^9v fl^^^^^lK^^^l^l 1 "s S*C~.^^^^i^^H ■ ri? a^'^N^D^^^^^H • . s ■ "' ^^^^^l^liMg ,, rilS^A 1 ^ ^^^^B^?%^^^^ ■ ^^■i^P^vilk ^^HbSI^^/.'*' r 1 ^^^^^^SytSf^S ^ f8p^^? ^v^ "^^"^^^BW ^-^^^ Pig. 40 — Brass Cannon. Bot. Contrib. Univ. Penn. Vol. IV. Plate XX. Fig. 41 — Laiakona. Bot. Contrib. Univ. Perm. Vol. IV, Plate XXI. FiQ. 42 — ^Eapo. Bot. Contrib. Univ. Penn. Vol. IV, Plate XXII. Fig. 43 — Thompson's Favorite. Bot. Contrib. Univ. Penn. Vol. IV, Plate XXIII. Fig. 44 — India Red. Bot. Contrib. Univ. Penn. Vol. IV, Plate XXIV. Fig. 45 — Govebnoe. Bot. Contrib. Univ. Penn. Vol. IV, Plate XXV. Fig. 46 — Roosevelt. Bot. Contrib. Univ. Penn. Vol. IV, Plate XXVI. Pie. 47 — PiLiPiLi. Bot. Contrib. Univ. Penn. Vol. IV, Plate XXVII. Fig. 48 — ^Kauaheahe. Bot. Contrib. Univ. Penn. Vol. IV, Plate XXVIII. Pig. 49 — Yeixow Red. Bot. Contrib. Univ. Penn. Vol. IV, Plate XXIX. Fig. 50 — Black Spanish. £ot. Contrib. Univ. Penn. Vol. IV, Plate XXX. Fig. 51 — Bronze Spanish. Bot. Contrib. Univ. Penn. Vol. IV, Plate XXXI. Fig. 52 — Pikontji. Bot. Contrib. Univ. Pciiii. Vol. IV, Plate XXXII. Fig. 53 — Key West. Bot. Contrib. Univ. Penn. Vol. IV, Plate XXXIII. I^^^^^^^^^^^^^rr~337" ^n^^^^^^^^^^^^^^l BSH WiS^mk ^EK^^I ■rik^^sWE^ ^^^^B^ ^^^H ^^^^^^^^m "^^^'.v ■. ^H ^^^^^^^^H ^^H 'SIl ^ "wSmi^^ B^ -,/:S H B^ '^^^^1 WKSri ^^^^^^H ^^^^£» ^fci^^^^^^^^M mmf^T A ^^^^^H ^^H^wJ^K^^v jHJI ^M ^^^■I^^^H '''''I^^^B ^^^^^^^^^^^^^1 ^, -''jf ■^ ^^^M Hi^g IbN^B ^^^v; ^ '''^^, . '"^P^^^^^^^^^^^l H^^^^^B^c?- ' '^S^^^l ^^^^B '-'-i^'-^^^^^^^^^^^^^^^H .^^^BJ''""''"- ^ ^^^^^£. Z^^^^^^^^^K^m *'■- ■' ^^PPjK'^^**'*'''**!' .^K - v.. -:;>. -*. _j^fl^^^^H ^^^^^H^ i^^Mj'^^%^ * ^ ^^^^^^^^^^^^^m^^'-' '' '' ' v ^ ^^^^^''.' ' ' ' s^ "^tfM^^^^^^^^^^I v^^^^i H Fig. 54 — ^Yellow Colombia. Bot. Contrib. Univ. Penn. Vol. IV, Plate XXXIV. Fig. 55 — White Colombia. Bot. Contrib. Univ. Penn. Vol. IV, Plate XXXV. I^P ■■ P^^flJI^^/^^^^^^^^^^^H ^H^^^^^^HHh^^^' ^ ^K^^^^^Kt^^Kf^^Sk iSSikj ^^^^^^^1 ^^^^^^HpHM^^ ■^^^H^H^^^vhH W^^9^_^ ij^^HH ^^^^^^B^^S ' ^ ^a^S^^^^l^j^^^ II' ^^^"^s^^^^^H ^^^^^H^^& ' "W^Sl^m^^^-' ^^& ' .^^^^ "^^^^^^^^^^H ^^^^^^^^^^^^^^^ ^^^^ M^^^^^^^^^^^ ^^^^Hiflfe^^l^H ^^^^^^^^^^Hi|^BM^^fia|[^P js^^^^^^^^Kf^^ ^ /;t^VmH|iH|^^^^^^^^| ^^^^^r^ '^WPjlP^ fl^^l^0f ' ll^r". '-^A. ' 'flH^^H ^^^^^^^^ ^^^^^x/^C BBrl^ J (^h£^ ^^I ^^^^^^^^i^r^ ^^m ^^^ ^^^^Hl^^ \^H B^Vrak;: ^^^ .jfl ^^^^^^^B^^^^IHk^ ^^^^^^I ^^^B^Vn^r ^^^^^^L. .^^^^^1 ^^^■kjK| '-^V . ^H^l ^^^^*^' viS ^B^e Jt^i^^^^^^l ^^^^^fc ^ ^^^^^^^^L^i/Mm ^M ^^^1 ^^^^BSKv '^^^^^^^S^^^^^^^^^^k ^^^^^HHe^^^* ,' ^^^^H ^^^^^B jfl^f^^BnV^^^B^^^H ^^■^^^Kjt •^■'^^^^^^^^^^^^m ^^^^^^^HkPwq^ ^ ^^^^^^H ^^^^K^ % '^♦.^"^^P^^fP^^Pi^^l ^L '.^.^^^^^1 ^^^H^lZ^ '^~ ^^^^1 (^iPi^^^l ^HHHH ^^^^^^^^^^^^^■^^Sr^ K ^^H ^^^^^^^KV<^^^ ^^^^^^1 ^^^^^^^Hi^' j| ^^v^ l^^^^^^^^^l ^^K^; i^H ^^^^^^^^^^E^ ^^^^ ^H ^^ir ■^^i^^^^^^^^^i ^^^^^Hr^ l^l^H HHHHh ^^^fSN^ ^^^^^^, '^'"'' ^^^^^^^^^^^^^1 ^^^^^^ -Hh 1 -''"^'^^^^H^^i IK^i'ii- .^BH ^^^aBBBMa|^^^^^^^^^^^^^^K'^^^^^^^B ^^^^^I^m^^mL.'' ^^^^b^Sb^^* w^ ^ ^^^HH||ijKj ^ ^^^^^^H ^mammma^^g^g^^^^^^^^m^^^^^^^k ^^^^^^^^^^^^^^^^H^^^^»^ > Tk- ^ ^^^^^^H^^K ^^^l^^l ^^^^B ^ ^"^^^^^l^^l ^^H^^afn ^^^^^^^^K ^^^^^^^^fa ^^^^^^Hs^i :. ^^^^^^^B^^^^^^^H ^^^^^^^^^^K ^ .^^^^^^^^^^^^^^1 1^ jf"^ ^ ' fllJ^^^^^^^^I^H ^wK/^^k ^K^^^^^^^^^^^^^^^^^K-^^^ ^^Sb^^m ^HH^HSHj^BSPIBBSSpHi^^ ^I^HBPflB^r^ ^^^r^^^^^^^M ^^^^^^^k' ''^'^^^^i'rimwmn\ .'-^ ';'■'>/' ^^B^^^Bs^f.. '/j.f*^A^'^!'^'^. ''^^g^^^^^B Fig. 56 — Southern Queen, Weak Type. Bot. Contrib. Univ. Penn. Vol. IV, Plate XXXVI. Fig. 57 — Red Sealy. Bot. Contrib. Univ. Perm. Vol. IV, Plate XXXVIL Fig. 58 — Southern Queen, Stbong Type. Bot. Contrib. Univ. Perm. Vol. IV, Plate XXXVIII. Fig. 69 — Flobida. Bot. Contrib. Univ. Penn. Vol. IV, Plate XXXIX. w^ ^ h ^v N / ^3» ^^^. ,^^^^fc I ^^^^H^HF ^ W- J -w\ ^ w^Hfl^^V^ /■ v4. C^^^^k ^^^^K^^f A'^ ^m ^ } r ^1 V ' ' '^ ^^^^K^^ V -A r Fio. 60 — Haionaipu. Bot. Contrib. Univ. Penn. Vol. IV, Plate XL. Fig. 61— Pu. Bot. Contrib. Univ. Penn. Vol. IV, Plate XLI. Fig. 62 — Peabody. Bot. Contrib. Univ. Penn. Vol. IV, Plate XLII. Fig. 63 — Carolina Extra Early. Bot. Contrib. Univ. Penn. Vol. IV, Plate XLIII. SBmJ ^^^^^^^^^^^^^^V ^Bfi^Sii ' ^^^#^^^^^^^1 ^^^^mi fl^KKm^i^/ - ; HH^^^Vf^^l^^^l ^^^i f^^^^^^K^^^^K " C ^^^^^^^^^^^^^11 Wi ^^B m i^^^l ^^M^M 1 m m ^^^^m^'g -^ ^^V ^^^^^^^^^^H ^Hi ^jfiH ^''a. fW m^^^^^^l ^^^^^^^^^^R ft in^^^^^^H^^^^^^^B£ t. • ^^^r ^ iBI ^^r^^ /5 Fig. 64 — Norton. Bot. Contrib. Univ. Penn. Vol. IV, Plate XLIV. Fig. 65 — Pompkin. Bot. Contrib. Univ. Penn. Vol. IV. Plate XLV. Fig. 66— Up Erras. £ot. Contrib. Univ. Penn. Vol. IV, Plate XLVI. ^^■Mj K ,,,,,,„. ^m^^Kll^S Qi i MB Fig. 67 — ^Yeulow Jersey. Bot. Contrib. Univ. Penn. Vol. IV, Plate XLVII. ^^^^k' > ' ^^^-^^^^K^^^^^^^^^^m ^^^^■^^^^^^H ^H[^^^^^I^^^^^^^^^^^^^^^^^^IHlF'^'>^'^^^^^^l ^^^^^^^^^^^^^1 ^^^^H ' ^k^il^^l pipwwH Fig. 68 — Red Jeksey. Vi Bot. Contrib. Univ. Penn. Vol. IV, Plate XLVIII. Fig. 69 — ^Peppee's Choice. Bot. Contrib. Univ. Penn. Vol. IV, Plate XLIX. Fio. 70 — YEiiOW Straitssbeeq. ^••''i^''- Bot. Contrib. Univ. Penn. Vol. IV, Plate L. Fig. 71 — Alabama. Bot. Contrib. Univ. Penn. Vol. IV, Plate LI. Pig. 72 — ^Red Nansemond. Bot. Contrib. Univ. Penn. Vol. IV, Plate LII, Fig. 73 — Van Ness Eed. Bot. Contrib. Univ. Penn. Vol. IV, Plate LIII. Fio. 74 — ^Nanct Haix. .^. Bot. Contrib. Univ. Penn. Vol. IV, Plate LIV. Fig. 75 — Eably General Grant.