• • • 111 tJt • • • 
 
 Queen Acme No. 5 Microscope 
 
 NEW MODEL 
 
 n 
 
 
 £ 
 
 n. 
 
 !^ E 
 
 r" 
 
 Co '-A 
 
 55 
 
 ^r^ 
 
 ■— t 
 
 5Cf 
 
 < 
 
 5 s: 
 
 S 
 
 > 
 
 ^ 
 '•y) 
 
 ^^ 
 
 »*— • 
 
 '7 
 
 ACME No. 5 
 Outfit No. 3101 with % in. and ^ In. Objectives, one Ocular and Double Nose-piece. 
 
 We cfaim that this instrument fills, as does no other at the price, the 
 wants of the amateur and the teacher. 
 
 In the smooth, precise and permanent action of its focal and other adjust- 
 ments it stands unapproached. 
 
 QUEEN & CO., Inc. 
 
 NEW YORK OFFICE 
 
 ■ 16 FULTON STREET 
 
 loiQ Chestnut Street 
 
 PHILADELPHIA 
 
CORNELL UNfVERSITY LIBRARY 
 
 3 1924 089 431 997 
 
 DATE DUE 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 GAYLORD 
 
 
 
 PRINTED IN U.S A 
 
 Trom the Estate of 
 
 Bruce Voeller 
 
ANALYTICAL KEYS 
 
 TO THE 
 
 GENERA AND SPECIES 
 
 Fresh Water Alg^ 
 
 The iJesmidieae of the Tnited States, 
 
 KOUNUEIJ l)N THE CLASSIFICATION OF 
 
 THE REV. FRANCIS WOLI-E'S MONOGRAPHS, 
 
 DR. ALFRED C. STOKES, 
 
 Author of "Microscopy for Beginners;" "A Contribution toward 
 
 a Natural Histor\' of the Fresh Water Infusoria 
 
 of the Lfnited States," etc. 
 
 PORTLAND, CONN.: 
 
 ElJWARD F. BiGELOW, PUBLISHER. 
 
 '893. 
 
ManM 
 
 51 I 
 
 SSlx 
 l^^3 
 
 Entered according to act of Congress, in the year iSpj, by 
 
 E. F. BIGELOW, Publisher, 
 in the office of the Librarian of Congress, at Washington. 
 
CONTENTS. 
 
 PAGE. 
 
 Explanation of Plate, 7 
 
 Value of of Mikrons in parts of an inch, 9 
 
 Introduction, 11 
 
 Key to the Classes of the Fresh-water AlgK, 25 
 
 Key to the Genera of the Fresh-water Algae, 25 
 
 Key to the Species of the Fresh-water Algae, 37 
 
 Key to the Genera of the Desmidiese, 78 
 
 Key to the Species of the Desmidiese, 80 
 
 Glossary, in 
 
 Index, 115 
 
Cornell University 
 Library 
 
 The original of this book is in 
 the Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924089431997 
 
Explanation of Plate. 
 
 [FRONTISPIECE.] 
 
 CxENERA OF DESMIDS. 
 Each Figure is numbered to correspond with the number of the genus. 
 
 FIG 
 
 I 
 
 2 
 
 3 
 
 4. 
 
 5 
 6 
 
 9 
 
 lO 
 
 II 
 
 12 
 13 
 
 14 
 
 15 
 16, 
 
 17 
 18, 
 
 19 
 
 20 
 21 
 
 22 
 23 
 24 
 
 Gonatozygon. Omitted; the cell needs no figure. 
 
 Genicularia. 
 
 Hyalotheca. 
 
 Bambusina. 
 
 Leptozosma. Omitted; the cell needs no figure. 
 
 Desmidium. 
 
 Phymatodocis. 
 
 Sphaerozosma. 
 
 Onychonema. 
 
 Mesotsenium. 
 
 Spirotaenia. 
 
 Penium. 
 
 Closterium; three figures, showing central inflation and ends 
 
 produced into beaks. 
 Docidium. 
 
 Triploceras; end and part of cell. 
 Calocylindrus. 
 Cosmarium. 
 Tetmemorus. 
 Xanthidium. 
 
 Arthrodesmus; 20a, front view, h, end view. 
 Euastrum. 
 
 Micrasterias; five forms. 
 
 Staurastrum; four forms; 23a, front view, b, end. 
 Pediastrum; three forms. 
 
Value of Microns (m) in fractions of an inch. 
 
 /< Inches. 
 
 /x Inches. 
 18.0=1-1383 
 
 /t Inches. 
 45-° = i-S33 
 
 /J. Inches. 
 79.0=1-316 
 
 /x Inches. 
 
 1.0=1-25000 
 
 113.0=1-221 
 
 1.5 = 1-16666 
 
 18.5 = 1-1351 
 
 46.0=1-543 
 
 80.0=1-312 
 
 114.0 = 1-219 
 
 2.0=1-12500 
 
 19.0=1-1315 
 
 47.0=1-532 
 
 81.0=1-308 
 
 115.0=1-217 
 
 2.5 = 1-10000 
 
 19.5 = 1-3333 
 
 48.0=1-521 
 
 82.0=1-304 
 
 116.0=1-215 
 
 3.0 = 1-8333 
 
 20.0=1-1250 
 
 49.0=1-510 
 
 83.0=1-301 
 
 117.0=1-213 
 
 3.5 = 1-7222 
 
 20.5 = 1-1214 
 
 50.0=1-500 
 
 84.0=1-297 
 
 118.0=1-211 
 
 4.0 = 1-6250 
 
 21.0=1-1143 
 
 51.0=1-490 
 
 85.0=1-295 
 
 119.0=1-209 
 
 4-5 = 1-5555 
 
 21.5 = 1-1162 
 
 52.0=1-480 
 
 86.0=1-291 
 
 120.0=1-208 
 
 5.0 = 1-5000 
 
 22.0 = 1-1131 
 
 53.0=1-471 
 
 87.0=1-287 
 
 121.0=1-206 
 
 5-5 = 1-4545 
 
 22.5 = 1-1111 
 
 54.0=1-464 
 
 88.0=1-284 
 
 122.0=1-205 
 
 6-0=1-4333 
 
 23.0=1-1087 
 
 55-0=1-454 
 
 89.0=1-281 
 
 123.0=1-203 
 
 6.5 = 1-3846 
 
 23.5 = 1-1064 
 
 56.0 = 1-446 
 
 90.0=1-277 
 
 124.0=1-201 
 
 7.0=1-3285 
 
 24.0=1-1042 
 
 57.0=1-438 
 
 91.0 = 1-274 
 
 125.0^1-200 
 
 7-5 = 1-3333 
 
 24.5 = 1-1020 
 
 58.0 = 1-431 
 
 92.0 = 1-271 
 
 126.0=1-198 
 
 8.0=1-3125 
 
 25.0=1-1000 
 
 59.0=1-423 
 
 93.0=1-268 
 
 127.0=1-196 
 
 8.5 = 1-2941 
 
 26.0^1-961 
 
 60.0=1-416 
 
 94.0 = 1-266 
 
 128.0=1-195 
 
 9.0=1-2777 
 
 27.0=1-926 
 
 61.0=1-409 
 
 95.0=1-263 
 
 129.0=1-193 
 
 9.5=1-2631 
 
 28.0 = 1-893 
 
 62.0 = 1-403 
 
 96.0^1-260 
 
 130.0=1-192 
 
 10.0 = 1-2500 
 
 29.0 = 1-862 
 
 63.0=1-396 
 
 97.0=1-259 
 
 131.0=1-191 
 
 10.5 = 1-2381 
 
 30.0=1-833 
 
 64.0=1-390 
 
 98.0=1-255 
 
 132.0=1-189 
 
 11.0=1-2272 
 
 31.0 = 1-806 
 
 65-0 = 1-384 
 
 99.0=1-252 
 
 133-0=1-188 
 
 11.5 = 1-2173 
 
 32.0=1-781 
 
 66.0=1-378 
 
 100.0=1-250 
 
 134.0=1-186 
 
 12.0=1-2166 
 
 33.0=1-787 
 
 67-0=1 373 
 
 101.0=1-247 
 
 135.0=1-185 
 
 12.5 = 1-2000 
 
 34.0=1-706 
 
 68.0=1-368 
 
 102.0=1-245 
 
 136.0=1-183 
 
 13.0=1-1923 
 
 35.0=1-714 
 
 69.0=1-390 
 
 103.0=1-242 
 
 137.0=1-182 
 
 13.5 = 1-1851 
 
 36.0=1-694 
 
 70-0=1-357 
 
 104.0=1-240 
 
 138.0=1-181 
 
 14.0=1-1785 
 
 37.0 = 1-675 
 
 71-0=1-352 
 
 105.0=1-238 
 
 139.0 = 1-179 
 
 14-5 = 1-1724 
 
 38.0=1-657 
 
 72.0=1-345 
 
 106.0 = 1-235 
 
 140.0=1-178 
 
 15.0 = 1-1666 
 
 39.0 = 1-641 
 
 73.0 = 1-342 
 
 107.0=1-233 
 
 150.0 = 1-166 
 
 15-5 = 1-1612 
 
 40.0 = 1-625 
 
 74-0 = 1-337 
 
 108.0=1-231 
 
 175-0=1-142 
 
 16.0=1-1562 
 
 41.0=1-609 
 
 75-0 = 1-333 
 
 109.0=1-228 
 
 200.0^1-125 
 
 16.5 = 1-1515 
 
 42.0=1-593 
 
 76.0=1-328 
 
 1 10.0^1-227 
 
 
 17.0=1-1470 
 
 43-0=1-583 
 
 77.0=1-324 
 
 111.0 = 1-225 
 
 
 17.5 = 1-1421 
 
 44.0 = 1-567 
 
 78.0=1-320 
 
 112.0=1-223 
 
 
INTRODUCTION. 
 
 To know the origin of any object, event or act, is always of in- 
 terest. To know what lead up to a certain acceptable innovation or 
 aid is pleasing to everyone, and often important to the historian of 
 any department of the world's work. What was the form of the first 
 analytical key, who made it and what induced him to make it, are in- 
 teresting questions that the writer at least cannot answer. Such 
 tables have become very popular in the various departments of bot- 
 any and of zoology, but who originated them is not known; nor 
 when the first was published, nor where. Like many other good 
 things, these keys may have been the result of simultaneous thoug'ht 
 and experiment on the part of several workers that felt the need of 
 some outside aid to the inside treasures of the ever increasing mass 
 of scientific knowledge. But to whomsoever belongs the credit of or- 
 iginating these devices, to him belong much praise and many hearty 
 thanks. 
 
 That analytical keys were needed is proved by their popularity. 
 They are welcomed by the student in all the sections into which Na- 
 ture is for convenience divided. It is true that there are some ob- 
 servers who scoff and laugh in derision when "keys'" are mentioned, 
 but these few belong to that class, fortunately limited, whose mem- 
 bers are unable to use them. There are persons that seem to be de- 
 ficient in those mental qualities that make the use of such tables a 
 pleasure and a delight, as there are others unable to arrange even 
 the simplest of keys. If in a scheme of the kind there are three 
 groups, a blue, a black and a green, these unfortunate opponents of 
 keys seem unable to decide what to do next, when the specimen hap- 
 pens to be green while the first description in the list calls for a blue 
 
12 INTRODUCTION. 
 
 object. That they should glance down the list to see if by any 
 chance a green specimen may have been provided for, does not oc- 
 cur to them; they toss the paper aside, and laugh at the utter folly of 
 the statement that any intelligent person should be able to use a 
 key. ■ The truth is that inability to use these valuable aids is an evi- 
 dence of a defect in the mental organization. Such critics are forced 
 to page through the monographs they attempt to study, with great 
 loss of time and with much labor, to find the information that may 
 be wanted; whereas with the object and a key to its class in hand the 
 labor becomes a delight, and the result a valuable acquisition, be- 
 cause no key to any department can be used even to a limited extent 
 without teaching the student many facts that he might otherwise have 
 overlooked. 
 
 A table of the kind will draw attention to the morphology of the 
 object in a way that will lead not only to its proper classification, 
 but to something much more important, the enlarging of the stu- 
 dent's powers of observation. Some of those that oppose the use of 
 artificial keys are themselves compelled not only to page through an 
 unfamiliar monograph, but in many instances to scan the pictures for 
 the light they are groping after; and failing pictures they guess as 
 to the character of the object from its resemblance to something re- 
 motely similar, and in the end, at great expense of time, and perhaps 
 of temper, may get a clue that may lead them to the goal they have 
 been so laboriously seeking. With the intelligent use of an artificial 
 key the place, the character, and even so unimportant a matter as 
 the name, can be rapidly obtained, and the student be led on to fur- 
 ther study and investigation. 
 
 It is always encouraging to feel that by one's efforts a way has 
 been opened to further conquests, or even that a path has been cut to 
 some previously unknown view. This the use of artificial keys 
 always accomplishes. When the beginner feels that he can do some- 
 thing unaided he is inspired to do more. When he feels that he has 
 travelled alone through soine pathway in some department 
 of natural science, he is anxious to go further. One step taken 
 with the aid of an artificial key is sure to be an encouragement toward 
 another. The powers of observation are increased. The ability 
 to balance one thing against another is cultivated. In a word, an 
 artificial key can be made one of the most important aids in the 
 mental development of the beginner that can be imagined. The ob- 
 server that scoffs at these aids, the observer that refuses to take 
 advantage of them, is doing a foolish thing and losing a good one. 
 
INTRODUCTION. 13 
 
 There are two distinct varieties of these valuable aids, the nat- 
 ural and the artificial. The former is founded only on the charac- 
 ters that the advanced scientist uses in his classification. These are 
 often so exceedingly natural that to learn the proper position of the 
 object it must be destroyed. To learn something of an animal 
 through them the animal must be dissected, and the anatomy of its 
 nervous system, and the morphology of its osseous system, and the 
 structure of its heart be accurately observed, before it can be 
 classed. These arrangements may be, they often are exceedingly 
 valuable to the advanced scientist; to the amateur and the beginner 
 they are terrible. They haunt his dreams like horrid night-mares, 
 provided he is incautious enough, or ignorant enough to attempt to 
 use them-. I have not a word to say against such analytical tables. 
 I commend them for use in their proper places. They are important 
 for their purpose, but that purpose cannot be the beginner's or the 
 amateur's. It is the learned man that can delight his soul with such 
 a scientific key. To him it is instructive and helpful. To any one else 
 it is a bugbear and a horror. The beginner is not prepared to begin 
 with the nervous system of his "find," oreven with the structure of 
 its heart. He must have something nearer the surface and more easily 
 seen than are these parts. His key must deal with the external and 
 the evident characters. It is for him that the artificial key is in- 
 tended, and to him it is inspiring and helpful. 
 
 This second kind of key, this artificial kind, is as its name indi- 
 cates, founded not on what the advanced investigator would use in his 
 classification of the animal or the plant, but on some obvious, prefer- 
 ably external, points that may be of no use in the art of classification, 
 but that can be used as crutches to help the student over the miry 
 and the stony ground to the hills of science where he will be able to 
 look back and smile at his former helplessness. These artificial 
 keys have this for their object, and only this. They aim to help over 
 the hard places; to encourage the user to go further, and to do more, 
 so that finally he may become an expert, when he will no longer 
 need any but the natural aids, or may even get along without any 
 other assistance than skilled eyes and a "learned touch." 
 
 The beginner, however, must have a guide, especially if he be 
 trying to work alone. This is true in every department of natural 
 science. It is especially true in microscopy. The field is so im- 
 mense, the outlook so vast, the work so apparently endless, that with- 
 out an aid the beginner at once begins to flounder in his sea of 
 troubles, and before long he sinks discouraged to rise no more. He 
 
14 INTRODUCTION. 
 
 becomes so disheartened since everything is so new and strange, and 
 there seems to be no one within call to lead him out of the difficult- 
 ies, or out of the embarrassment of scientific riches, that he is entirely 
 discouraged, his enthusiasm is lost, and with this loss is abandoned 
 a study that would have lessened his cares, increased his joy in living 
 and lengthened his life. The beginner working alone wastes much 
 time. To be sure, he may before long learn that a green object that 
 stands still is a plant, or may be; and also before long he hears that 
 all green microscopic objects that stand still are not always plants. 
 If he have a teacher his condition is a more favorable one; but if he 
 be alone he must have an artificial guide, or fail. For such students 
 the artificial keys are providential. Once introduced to them he is 
 ready to go on to new conquests. The use of such tables in the 
 popular treatises on botany has done more to popularize that beautiful 
 study than a score of learned monographs on the subject. As soon 
 as the pupil learns that he can by his own efforts' obtain even the bo- 
 tanical name of his plant, a feeling of enthusiasm fills his heart, and he 
 is eager for another specimen to analyse. And in the analysis he is 
 learning the principles of classification, the structure of the specimen 
 and the function of the various organs. By means of the key he goes 
 with little trouble and waste of time to the order, there he finds 
 another key that leads him pleasantly to the genus, and perhaps a 
 third that takes him to the species. There he finds the plant exactly 
 described. He has had the prominent characters brought to his no- 
 tice in a pleasing way, and the final result is that he not only learns to 
 love the science of botany, but that he soon learns to know at a 
 glance, without the use of the artificial key, to what order a strange 
 specimen may belong. He has become scientific without knowing 
 how he became so. He has travelled by the royal road. It is so, or 
 should be so, in the science of microscopy, to call for convenience a 
 science that which is really a combination of all the sciences. 
 
 If every department of microscopy could have an artificial key to 
 open the doors of its treasure-houses, the amateur would have a hap- 
 pier time, science would be benefitted and the maker of the key, the 
 scientific artisan, would himself be blessed both in this world and in 
 the next. Such a pleasing state of affairs can not be attained. The 
 doors are too numerous to be opened by a single key. To make the 
 proper number is not possible for one worker, however willing he may 
 be to try. Each specialist could forge a key to the doors or to the 
 dark passage-ways of his- special scientific castle, and offer it to those 
 that would follow after him if they could. But the specialists are not 
 
INTRODUCTION. 15 
 
 disposed to become scientific blacksmiths, and to forge keys to the 
 treasures they have locked up in their formidable monographs. In- 
 deed, it is not possible that they should. They have no time to make 
 the entrance ways easy and agreeable. They are after the facts of 
 the science; they are seeking the internal secrets of the creatures 
 they have studied and written about; they are content to leave the en- 
 larging of the building to other specialists that may come after. It is 
 no fault of the writers of learned monographs that they put forth 
 their treatises without a single loop-hole of entrance for those that 
 would, if they could, enter in to see some of the treasures of which 
 rumor has told. When a man has spent his days and his nights and 
 his earthly and bodily substance on the production of a treatise that 
 shall make his name known to the world, he is naturally disin- 
 clined to labor longer and harder to make easy grades and smooth 
 paths and shady retreats along the way to his treasure house; and 
 when the learner has 'arrived at the gates, the learned man is not dis- 
 posed to stop his further investigations to throw a pretty key out of 
 the window and ask the uninvited guest to come m and sup with him. 
 He is too busily engaged in the new investigation that his completed 
 investigations have made necessary. There is no end to the questions 
 to be studied and decided. He cannot, much as he may be willing 
 condescend to make keys for the beginners. If he makes any at all, 
 they will be of the severest kind and intended for his scientific equals 
 only, not for the humble followers in his foot-steps. We should 
 never blame the writers of learned monographs for not offering these 
 gilded keys. They cannot. They have gone up too high to stop for 
 the higher they go the more there is to be done. And they that have 
 climbed that high are the ones best adapted to climb higher, for they 
 find it easier to go up than to come down. 
 
 But if such books are to be used by any others than the rather 
 limited class of experts that have the knowledge needed to find their 
 way unaided through the pages, then a guide of some kind must be 
 furnished. An index will not answer the purpose, as to use it de- 
 mands just that information not at the disposal of the novice orof the 
 amateur. All of these scientific treatises may be as useful to the 
 modest student as to the learned investigator, provided, as I have so 
 often said and repeated, some means can be devised by which he 
 may be helped to make an intelligent entrance into its various depart- 
 ments. 
 
 Mr. Wolle's monographs on the Algse and the Desmids are no 
 exception to the rule. They are not adapted to the use of the ama- 
 
l6 INTRODUCTION. 
 
 teur microscopist in the state in which the author has left them. It 
 is not possible for the youthful microscopist to read the description 
 of one hundred and twenty genera of Algse in order to locate a 
 single specimen that he may find in the wayside ditch. To ascertain 
 with any degree of comfort the probable resting place of the speci- 
 men he must have some help. It is that help that this little compila- 
 tion hopes to supply. By its intelligent use the student may ascer- 
 tain the specific name of any fresh water Alga or Desmid in the ponds 
 and the ditches of the United States. This he can do with the ex- 
 penditure of the least time and labor, leaving them to be spent in the 
 subsequent study of the plant, after he has had the satisfaction to 
 learn what it is, and where in the classification it belongs. If the 
 worker has the name of the specimen, he then feels that he has a sup- 
 port on which he may hang his subsequent information, and a starting 
 point for further investigations. Not to know the name of the ob- 
 ject and yet to try to study it, is like an attempted conversation with 
 a stranger whose antecedents and local habitation are unknown. 
 The effort is not an agreeable one. The conversation languishes, and 
 interest is lacking. The name and the habitat of the person add 
 much to the pleasure of the meeting, and many suggestions to the in- 
 terview. So the name of the microscopical or other specimen is al- 
 most essential to the well being of the young student. 
 
 The name is, too, about the first thing the advanced scientist tries 
 to learn. It is impossible to do otherwise.' The object can not be re- 
 ferred to by speech or in writing until its name is known; what other 
 workers in other parts of the world may have said about it or done 
 with it, can not be known until its name is learned, as without the name 
 all indexes are closed in all the books of all the libraries. The name 
 is the clue to further knowledge, its starting point, even the hook upon 
 which further information is to be hung. Whatever advanced scien- 
 tists may say to the contrary, their first effort, perhaps it is an uncon- 
 scious one, but their first real effort is to ascertain the name of their 
 new specimen. If it has none, they at once proceed to give it one. 
 All the wild talk about the un desirability of learning the name is 
 wrong in principle. The name is, as every one will cheerfully admit, 
 only of secondary importance when compared with a study of habits 
 or of morphology, but it is as essential, since it is and must ever be 
 the starting point for further investigations, at least on the part of the 
 amateur. If he chooses to stop at the name, that is his misfortune; 
 but even then he has gained something. If those whom I may be able 
 to help by these keys shall do nothing more than identify their 
 
INTRODUCTION. 17 
 
 "finds," I shall feel that I have done some little thing to help them 
 and their friends. I shall feel pretty sure that the mere finding of 
 the name will not be the end; but if it should be, where will be the 
 harm ? Is it a crime to know the scientific name of the plant or of the 
 animal ? Knowing that is knowing something, I think. Would you 
 have the pupil dissect the nervous system before he has learned to 
 recognize a nerve, or before he knows the muscles to which the nerves 
 are distributed ? Of course he might say "This is a nerve," and "That 
 is a nerve and it goes to that muscle," but would you have him carry 
 the dead body about with him in order to dissect it and point out the 
 nerves and the muscles that receive them whenever he wished to com- 
 municate with you or with any of his friends in refere'nce to the nerves 
 and the muscles of that special creature ? This is exactly the result 
 which those that cry out against learning names would accomplish 
 if their desires prevailed. No, no ! Get the name the very first 
 thing, if you wish. It will make a good starting point. It is not the 
 end and the aim of any study; it is only the bridge that takes us over 
 the swamp. After awhile we will be big enough and strong enough 
 to pass the swamp without the bridge, as after awhile we will be able 
 to get along without an artificial key. But do not condemn the bridge 
 that has carried you safely over. 
 
 The keys in this little book are as artificial as they could be made. 
 In some instances they are perforce somewhat natural; that is, the 
 fruiting plant has been used to the exclusion of the more frequent 
 sterile condition. This, however, has been avoided as much as possi- 
 ble, and in several instances two keys have been prepared to the same 
 genus of plants, one for the fertile, the other for the sterile filaments. 
 They are all, as the title page indicates, founded on the classification 
 contained in the admirable monographs by the Reverend Francis 
 Wolle on the fresh water Algae and the Desmids of this country. Un- 
 til Mr. Wolle took up the subject our American microscopic plants 
 had scarcely been touched, except by a few observers in a desultory 
 way. He has brought order out of chaos, and has prepared two mon- 
 ographs that are monuments to his learning, skill, care and patience. 
 These keys are made not alone with the object of leading the begin- 
 ner to the study of the fresh water Algae and the Desmids, but to in- 
 troduce him to these fine works of Mr. WoUe's. While the beginning 
 mcroscopist in his study of microscopical botany may, to a certain ex- 
 tent, succeed in identifying his "finds" with these keys alone, to do 
 so with entire satisfaction he should have access to the monographs 
 on the Algae and on the Desmids. The references at the end of the 
 
18 INTRODUCTION. 
 
 classes and of the genera are to the numbers preceeding those classes 
 and genera in this list; those following the species are in every case 
 for reference to the pages on which will be found the extended de- 
 scriptions in the monographs already so often referred to, where ref- 
 erences will also be found to the illustrations. 
 
 The measurements of the Algse are given in parts of amikron (/i) ; 
 in the Desmids, by both fractions of an inch and of mikrons. The 
 former will necessitate a little calculation, if the reader is not en- 
 tirely familiar with the minute space called a mikron and represented 
 by the Greek letter fA.. It measures the ^g^^ ^, of an inch in length, and 
 the calculation needed to bring it to the fractions of an inch as given 
 in the measurements of the Algse, are slight. Twenty-five mikrons, 
 for instance, being g g^^, ;, inch, or -j-ifW inch. It is only necessary 
 therefore to use the number of mikrons as given with the Algae for 
 the numerator of a fraction of which the 25000 forms the denomi- 
 nator, and reducing the whole to the lowest terms. In the Desmids the 
 calculations have been made, and the measurements given in both 
 forms. The student will therefore need an eye-piece micrometer, but 
 it may be ruled to parts of an inch. The use of the mikron, like the 
 use of the metric system, has not and probably never will come into 
 popular favor. 
 
 Does the reader know how to use a key of this kind ? To some 
 this appears to be a mysterious thing, although a little inspection of 
 the key itself should make it plain. It is simply a matter of exami- 
 nation, comparison and rejection. ' With the specimen in hand, which 
 in this instance means under the microscope, begin at the beginning 
 of the key and compare the description in the first sentence with the 
 object under the instrument. Do the two agree in every particular? 
 If not, leave that reference and go to the next having the same letter 
 or other symbol at its front. If that should describe the specimen, 
 notice the letter in the parenthesis at the end of the line, and seek 
 that same letter at the beginning of a line in some other part of the 
 key. You will probably find several lines beginning with that letter. 
 Starting at the first, compare the description there given in a word or 
 two with the actual specimen, and if it does not agree pass to the line 
 next below. If at the end of this line there is another reference let- 
 ter in parenthesis, turn to that, and so continue until at the end of 
 some line you find the generic or the specific name of the plant. Mis- 
 takes are easily made, here as elsewhere. If you should happen to 
 make one at the start every step forward will lead you further and 
 further astray. With care and intelligent observation, errors may be 
 
INTRODUCTION. I9 
 
 avoided and the specimen readily run down to its proper place. Af- 
 ter a little practice, the use of such artificial keys becomes a great 
 pleasure. The benefit has already been referred to. The only secret 
 of their successful use is to be certain that each progressive step is 
 right before it is abandoned for the next. And after a little practice, 
 too, the student will become so familiar with the Algae or with the 
 Desmids that he will not need to apply to the generic keys for aid, 
 but will be able to turn at once to the proper genus, and there use the 
 keys to the species; and with a little further experience he will be en- 
 abled to recognize at a glance the species, and then will be prepared 
 to proceed with his investigations, or to refer intelligently to the ob- 
 ject so as to communicate with his friends and fellow workers in re- 
 gard to it. It is as impossible to speak or to write of an Alga or of a 
 Desmid without using its proper name, as it is to speak or to write of 
 your most intimate friend without using his. 
 
 AlgK and Desmids are singly invisible to the naked eye. It is 
 only when they occur in large masses that the eye can take cogni- 
 zance of them. It rarely occurs, however, that the Desmids are so 
 abundantly congregated that they thus obtrude themselves on the 
 observer. When a large quantity has been collected and the vessel 
 placed near a window, they will collect in a green film at the surface 
 of the water on the lighted side, and there become visible in mass. 
 In the ponds and shallows such an occurrence is not common. At 
 times they are found so abundantly that by holding a glass vessel of 
 the water up to the light they may be seen floating about as minute 
 green objects, which the trained eye will recognize and the pocket 
 lens make distinct. But these varieties are among the largest of the 
 forms; according to my experience they are always exclusively con- 
 fined to the Closteriums. Other large forms, like Micrasterias, at 
 least in the writer's locality, rarely occur in such profusion. To col- 
 lect the Desmids, therefore, it is necessary to collect by faith. The 
 microscopist can know exactly what he has only when he gets home 
 and examines the water drop by drop under the microscope. 
 
 With the Algae it is different. These are usually visible to the 
 naked eye, as they are almost invariably collected in large masses 
 floating on the surface, submerged just beneath the surface, or at- 
 tached in waving tufts or fringes to sticks and stones and other 
 plants in the ponds. The eye of faith is not needed to recognize 
 them. They usually force themselves on the wondering attention of 
 the observing pedestrian in the wayside lanes, beside the ditches and 
 slow brooks. As soft emerald clouds, or graceful streamers floating^ 
 
20 INTRODUCTION. 
 
 in the sluggisji current, or resting like a green slcum on tiie surface, 
 they are readily seen and as easily gathered. No collecting tools are 
 demanded for either Algse or Desmids, except a dipper of some 
 kind, a common tin dipper is as good as anything, and a few bottles 
 or other vessels to carry the treasures home, and to keep them con- 
 cealed from inquisitive people; the collecting naturalist must always 
 be prepared for a meeting with such persons. 
 
 Many media have been recommended for the preservation of these 
 beautiful plants. The trouble with the majority of these prepara- 
 tions is that they will in time, some usually in a very short time, 
 allow the cell contents to contract and to become so distorted that 
 the object is worthless for any serious study, and worthless, too, as 
 the object of beauty that it was when first mounted. Some of the 
 commended media act well on some kinds of Algae and Desmids, but 
 fail on others. The following are among the best, yet even these are 
 not all adapted to all the different kinds. They are mentioned in 
 the order of their excellence. 
 
 CAMPHOR WATER. — This is made by placing a lump of camphor 
 in distilled water and leaving it there for several days. Mr. W. H. 
 Walmsley, an expert preparer of microscopical slides, says that he 
 has had a specimen of Draparnaldia in camphor water for twenty 
 years, and that it is now as beautifully green as when first mounted,' 
 and that the chlorophyll, its green coloring matter, seems to be un- 
 changed. When he desires to mount an Alga or a Desmid, he places 
 it in a small quantity of camphor water to which a few drops of glyc- 
 erine have been added. At first the plant will become lemon color, 
 but after a few hours the original green returns in all its vividness, 
 and then he at once mounts the plant in some of the fluid. 
 
 CARBOLIC ACID WATER, made by adding a few drops of the acid 
 to a phial of water, is recommended by the Rev. Mr. WoUe, but he 
 says that although this will preserve them for months or even years 
 without deterioration, it may allow the coloring matter, the chlor- 
 ophyll, to fade; this however in the case of the Desmids is of little 
 importance. 
 
 A SOLUTION OF CHLORAL HYDRATE, in the proportion of five 
 grains of the salt to one ounce of water, answers well for some 
 specimens. Like camphor water it has the merit of being easily 
 made and easily used. 
 
 A SOLUTION OF COPPER made after the following receipt is admir- 
 able for some of the Algs, preserving the color and the form entirely 
 unchanged, while on others it will not act so favorablj'. 
 
INTRODUCTION. 21 
 
 Camphor water, - 50 grammes; 
 
 Distilled water, 50 grammes; 
 
 Glacial acetic acid, - 0.5 grammes; 
 
 Crystallized chloride of copper, 2 grammes; 
 
 Crystallized nitrate of copper, 2 grammes. 
 
 Dissolve and filter. 
 
 When mounting with this copper solution the cell should be 
 made and the cover cemented down with shellac. With almost any 
 other cement failure is pretty certain, as the cement will surely 
 run under and ruin the preparation. After the shellac is hard, it is a 
 good plan to add some of Brown's rubber cement around the cover. 
 This is entirely transparent and will make the mount more secure, 
 and at the same time add something to the beauty of the finish. 
 
 TRENTON, N. J., 1892. 
 
PART I. 
 
 Key to the Classes and the Genera of the 
 Fresh- Water Algae. 
 
KEY TO THE CLASSES AND THE GENERA OF THE 
 FRESH WATER AI.GJE. 
 
 CLASSES OF THE ALG^. 
 
 § Rosy red, blood-red, reddish-brown, purple or blackish; many- 
 celled . . . . . CLASS I. 
 
 § Chlorophyll-green, sometimes becoming crimson, purplish, flesh- 
 color or yellow-brown; 1,2 or many celled; often nucleated, 
 
 CLASS II. 
 
 § Never chlorophyll-green; colorless or variously colored; i or many 
 celled; in jelly when out of the water . . . . class iii. 
 
 KEY TO THE GENERA OF THE ALG^. 
 
 CLASS I. 
 ^ Olive, brown or grey, black with age; filamentous, often hollow, 
 
 bristle-like, rigid (A). ' 
 Tf Violet, violet-purple or bluish-green; filaments articulate, branched 
 
 or not (E). 
 T[ Purple; tufts loose; filaments i in. long, not branched (D). 
 T[ Purplish, smooth, forming a firmly attached coating to stones, 
 
 Hildebrantia, 7 
 *{ Brownish red, Vermillion, or greenish with red centre; cells 4-8, 
 free or in a short lived cluster Chlamydococcus, 38 
 
 *{ Blood red, cells large, tegument thick, lamellose, stem ringed, 
 
 Urococcus, 66 
 A. Filaments nodose, tufted; fertile filaments hollow, with internal 
 axillary thread; in rapid water (B). 
 ■A. Filaments transversely banded or annularly constricted; with in- 
 ternal central axis (C). 
 
26 GENERA OF ALG^. 
 
 B. Axillary thread a single series of cells with transverse threads at 
 
 regular intervals .... Lemanea, i 
 
 C. Axillary thread of cohering filaments, with many whorls of mon- 
 
 iliform branchlets . . . ... Tuomeya, 2 
 
 D. Simple or branched, slippery; cells in a single layer, membrane 
 
 thick, colorless ... . ... Bangia, 3 
 
 E. Branched; main stem often with an external, parallel series of 
 
 cells; branches moniliform, clustered . . Batrachospermum, 4 
 
 E. Branched; main stem without external parallel series of cells; 
 
 branches not moniliform (F). 
 
 F. Filaments articulate, villose, branchlets dichotomous . Thorea, 5 
 F. Filaments articulate; branches not whorled; plant steel blue or 
 
 purplish .... . Chantransia, 6 
 
 F. Filaments articulate; branches erect-spreading; plant olive-green, 
 
 Compsopogon, 8 
 
 CLASS II. 
 § Multicellular or apparently so (A). 
 
 § Unicellular, the cells often clustered or forming a colony (F). 
 A. Chlorophyll diffused, not in patterns (B). 
 
 A. Chlorophyll in spiral bands, axillary laminae, or twin, stellate 
 
 nuclei {p). 
 
 B. Filamentous (C). 
 
 B. Not filamenious; articulate, prostrate, or net-like, often membra- 
 
 nous, sometimes parasitic (M). 
 
 C. Basal cell lobately divided, or with a terminal disk attaching the 
 
 young plant (D). 
 
 C. Basal cell not lobate nor disciform (E). 
 
 D. Not branched; terminal cell sometimes setiform, CEdogonium, 10 
 D. Not branched; no setae; strongly contracted at intervals, 
 
 Schizomeris, 24a 
 D. Branched; with long terminal setae bulbous at base, BulbochcBte, 11 
 
 D. Branched; no setae; cells long, cylindrical . . . Sciadium, 46 
 
 E. With branches (G). 
 
 E. Without branches, but sometimes with lateral processes (L). 
 
 F. Plants filamentous (N). 
 
 F. Plants not filamentous, sometimes curved or spiral, without root- 
 lets (T). 
 
 F. Plants globose, small, on moist earth, with colorless rootlets (O). 
 
 G. Filaments erect (H). 
 
 G. Filaments prostrate or creeping, branched or not (*). 
 
GENERA OF ALG^. 27 
 
 * Without dorsal spine; cell walls thick . . . Gongrosira, 21 
 
 * With dorsal spine . . Aphanochmte, 20 
 
 H. Immersed in firm jelly ... . . . Chcetophora, 18 
 
 H. Not in a firm jelly (I). 
 
 I. Filanjents dichotomously or trichotomously branched, 
 
 Microthamnion, 1 9 
 I. Filaments not dichotomously branched (J). 
 J. Branches in lateral clusters; cells of main stem with a transverse, 
 
 central chlorophyll band . . . Draparnaldia, 16 
 
 J. Branches not in lateral clusters (K). 
 K. Cell membrane usually thick, cells longer than broad; ultimate 
 
 branches, much thinner than the primary, 
 
 Cladophora, 23, or Pithophora, 24 
 K. Cell membrane very thin and hyaline; stem and branches barely 
 
 separably in size and appearance . Stigeodonium, 17 
 
 K. Cell membrane thin; branches radiating, umbel-like, one-celled, 
 
 Sciadium, 46 
 L. Distinctly many celled (P). 
 L. Articulate (apparently multicellular) (Q). 
 M. Articulate, branched, forming a little mass or a subdisciform 
 
 layer ..... .... Coleochmte, 9 
 
 M. Articulate, prostrate or creeping, a spine on the back, 
 
 Aphanochxte, 20 
 M. Expanded, leaf-like, smooth, formed of angular ceils; always ad- 
 herent . . . . . . Prasiola, 14 
 
 M. Membranaceous, tubular or utricular, fixed only when young, 
 
 Enteromorpha, 15 
 M. Forming a green net, visible to the naked eye, Hydrodictyon, 41 
 M. Forming a colony, plane; discoid or stellate, often perforated; 
 
 cells polygonal . . . . Pediastrum, 40 
 
 N. Filaments tufted, long, sometimes branched, . . Vat/cheria, 30 
 O. Rootlets much divided, descending from the cell base into the 
 
 earth . . Botiydium, 31 
 
 P. Cells long; chlorophyll enclosing large, regularly placed vacuoles, 
 
 Spharoplea, 1 2 
 P. Cells long, filaments somewhat geniculate, without vacuoles (f). 
 P. Cells short, cylindrical or oblong; without vacuoles; filaments not 
 
 contracted; attached when young .... Cylindrocapsa, 13 
 P. Cells short, broader than long, filaments contracted irregularly, 
 
 Schizomeris, 24a 
 Q. Filaments simple, not laterally united, (R). 
 
28 GENERA OF ALG^. 
 
 Q. Filaments 2 or more laterally united, or in flat narrow bands, 
 
 Schizogonium, 26 
 
 R. With one row of cells, (S). 
 
 S. Without lateral processes (except Ulothrix rivularis), strictly un- 
 branched . . . . .... Ulothrix, 25; Conferva, 27 
 
 S. With short, irregular, lateral processes, 1-3 or more celled, 
 
 Rhizodonium, 29 
 T. Parasitic, i. e. penetrating the membrane of the host {g). 
 T. Not parasitic (*). 
 
 * Cells united or clustered in families (U). 
 
 * Cells scattered, independent or irregularly clustered (Z). 
 U. Colonies motile, each cell with 2 cilia (V). 
 
 U. Colonies often free but not spontaneously motile, without cilia (c). 
 
 V. Colony (cKnobiuni) spherical or circular (W). 
 
 V. Colony flat, cells 4-16, angles rounded, in a colorless sheath, 
 
 Goniuin, 36 
 W. No gelatinous coating; cells many on a hollow globe Volvox, 32 
 W. With gelatinous coating (X). 
 X. Colony ovate or spherical (Y). 
 X. Colony of 8 cells at equal distances around a circle, 
 
 Stephanosphxra, 37 
 Y. Cells 16-32, globose, at regular intervals on a colorless sphere, 
 
 Eudorina, 33 
 Y. Cells 8-16-32-64, globose, crowded, often angular from pressure, 
 
 Pandorina, 34 
 Z. Cells free-swimming (a). 
 
 Z. Cells attached to aerial or to submerged objects (1^). 
 a. Ovate, granular, in a hyaline, obtuse sheath; contractile vesicle 
 
 present .... Chlamydomonas, 39 
 
 a. Cylindrical, straight or curved, ends sometimes spinous, 
 
 Ophiocytium, 47 
 
 a. Spherical, 3-15/t in diameter . Protococcus, 49 
 
 a. Spherical, 100-150/* in diameter EremosphcBra, 65 
 
 a. Compressed, 3-4-8 angled, angles often produced or bifid, 
 
 Polyedriuni, 50 
 
 b. Aquatic; form variable, cells not spinous, usually stipitate, 
 
 Characium, 48 
 b. Aquatic; form variable, cells often with a dorsal spine, 
 
 Aphanochcete, 20 
 b. Aerial; cells circular, flat, numerous, becoming red by exposure, 
 
 Protococcus, 49 
 
GENERA OF ALGVE. 2^ 
 
 b. Aerial, on moist objects; gelatinous, cells globose or angular, be- 
 
 coming red .... . Porphyridium, 57 
 
 c. Family in jelly mass, thallus pyriform, irregular, tubular, clustered, 
 
 branched, etc. (/). 
 c. Family globose {d). 
 
 c. Family plane, discoid or stellate, often perforated; cells polygonal, 
 
 Pediastrum, 40 
 c. Family cubical, cells 4-8-16, rhomboidal . . Staurogenia, 44 
 
 c. Family of laterally united, often spinous or crescentic cells (e). 
 
 c. Family of cylindrical cells (/). 
 
 d. Cells in a single stratum; ccenobium hollow . . Cxlastrum, 42 
 d. Cells 4-8-16-32, wedge-shaped, apices sinuate or bifid; ccenobium 
 
 solid Sorastrum, 43 
 
 d. Cells 2-4-8, globose or oblong . . Glmocystis, 60 
 
 e. Cells cylindrical to ovate, ends often spinous . Scenedesmus, 45 
 e. Cells not spinous, fusiform, cylindrical, straight or variously curv- 
 ed, single or united .... .... Rhaphidium, 62 
 
 /. Upper cells spreading, contracted at base . . . Sciadium, 46 
 
 g. Cells globose or pear-shaped (h). 
 
 h. Neck not cylindrical, aperture with a lid . Ckytridium, 68 
 
 h. Neck cylindrical, elongated . Olpidium, 69 
 
 i. Cells connected by fine filaments (*). 
 /. Cells not connected by filaments (7). 
 
 * Filament attached to the convex side of the cells, 
 
 Dimorphococcus, 63 
 
 * Filament attached to the concave side of the cells, 
 
 Dictyospharium, 51 
 j. Families free-swimmirig (not attached), (k). 
 j. Families not free-swimming (attached), (/). 
 k. Cells oblong, reniform, 2-4-8-16; tegument oval or reniform; 
 
 variable ... Nephrocytium, 61 
 
 k. Cells oval, small, in grape-like clusters; tegument thin, diffluent, 
 
 Botrycoccus, 59 
 k. Cells globose, large, cell walls firm, border hyaline; chlorophyll 
 
 sometimes radiate . . . .... Eremosphcera, 65 
 
 /. Cells fusiform, crescentic or straight, cylindrical, ends cuspidate or 
 
 acuminate, tegument thin . ... Rhaphidium, 62 
 
 /. Cells globose, elliptical or elongate (m). 
 m. Cells red, large; tegument thick, concentrically lamellate, stem 
 
 ringed . ... Urococcus, 66 
 
 m. Cells green; tegument not lamellate («). 
 
30 GENERA OF AhGJE. 
 
 n. Thallus soon diffluent into shapeless mucus, 
 
 Tetraspora, 54, or Palmella, 56 
 n. Thallus with a definite form (0). 
 o. Cylindrical or compressed, branched, 2-12 inches long; one pole 
 
 of cells colorless Hy drums, 52 
 
 o. Cylindrical, sometimes septate, attached at one end and spreading, 
 
 Palmodactylon, 53 
 o. Pear-shaped, fixed by the stem-like base .... Apiocystis, 76 
 p. Chlorophyll in spiral bands (ci). 
 
 p. Chlorophyll in two, many-rayed bodies in each cell (f). 
 p. Chlorophyll in axile plates (/). 
 q. Conjugation geniculate. Gulf States .... Sirogonium, 71 
 
 q. Conjugation ladder-like Spirogyra, 70 
 
 r. Conjugation ladder-like or lateral (s). 
 
 s. Spore in one of the cells Zygnemd, 72 
 
 s. Spore in the connective between the cells . . . Zygogonium, 73 
 
 /. Conjugation ladder-like {u). 
 
 t. Conjugation lateral (v). 
 
 t. Conjugation geniculate (w). 
 
 t. Conjugation absent, spore formed spontaneously in the cell, 
 
 Gonatonema, 78 
 u. Spore in the connective between the cells, 
 
 Mougeotia,i/^, or Mesocarpus, 75 
 
 u. Spores in one of the cells Plagiospermum, 77 
 
 V. Spore lateral, at the point of two cells . . . Pleurocarpus, 76 
 w. Spore formed at point of conjugation . . . Craterospermum, 80 
 w. Spore between the cells, quadrangular in front view, 
 
 Siaurospermum, 79 
 
 CLASS III. 
 § Multicellular or apparently so, filamentous (A). 
 § Unicellular, the cells sometimes clustered or in families (V). 
 A. With hair-like points (B). 
 
 A. Without " " (C). 
 
 B. Branched (but spuriously so) ; in small tufts . Calothrix, 8 1 
 B. Not branched; not in jelly mass; heterocysts yellow, at the base 
 
 of the filaments; free or in small mats . . . Mastigonema, 82 
 
 B. Not branched; in more or less firm mucilage or jelly (h). 
 
 C. Branched; in a sheath or jelly mass (E). 
 C. Branched; not in jelly. 
 
 C. Not branched (D). 
 
GENERA OF ALGiE. 3! 
 
 D. In a sheath or a jelly mass (K). 
 
 D. Not sheathed nor in jelly (P). 
 
 E. Branched at almost right angles to the stem; cells in a single se- 
 
 ries .... .... ... Hapalosiphon, 92 
 
 E. Branched irregularly or with twin branches (F). 
 
 F. Cells in single series in young plants, several series when older, 
 
 Sirosiphon, 91 
 
 F. Cells in a single series only (G). 
 
 G. Sheath broad, striate, hyaline, wing-like . . Petalonema, 90 
 G. Sheath not wing-like (H). 
 
 H. Sheaths distinct, not agglutinated to one another (I). 
 
 H. Sheaths agglutinated in erect, wick-like bundles, 
 
 Symphyosiphon, 87 
 
 I. Heterocysts present (J). 
 
 I. " not present; sheath with a single bluish filament, 
 
 Plectonema, 8g 
 
 J. Heterocysts disconnected from the twin branches, Scytonema^ 86 
 
 J. Heterocysts near the usually single branches . Tolypothrix, 88 
 
 K. In a sheath; filaments moniliform, curved . . Nostoc, 93 
 
 K. In a sheath; filaments not moniliform (Q). 
 
 K. In mucilage or jelly mass (L). 
 
 L. Jelly mass spherical; filaments transversely plicate, radiate, 
 
 Glxotrichia 84 
 
 L. Jelly mass hemispherical, filaments radiate . Rivularia, 85 
 
 L. Jelly mass a stratum or indefinite (M). 
 
 M. Filaments erect, attached at base, jelly stratum flat, often 
 incrusted . . . Isactis, 83 
 
 M. Filaments not attached at base, not moniliform, heterocysts ter- 
 minal, single . . ... . Cylindrospermum, 98 
 
 M. Filaments not attached, not moniliform, colorless, heterocysts 
 none . . ... Crenothrix, 99 
 
 M. Filaments moniliform, cells globose or elliptical (N). 
 
 M. " " cells compressed disciform (O). 
 
 N. Heterocysts intercalated in the filaments, 
 
 Anabcsna, 94, or Spharozyga, 95 
 
 O. Heterocysts intercalated at regular intervals, yellow, 
 
 Modularia, 97 
 
 P. Bluish, bluish-green, blackish (T). 
 
 P. Whitish or silvery; in sulphur waters . . . Beggiatoa, 105 
 
 Q. Two or more filaments in each sheath . . Microcoleus, 103 
 
 Q. -One filament only in each sheath (R). 
 
32 GENERA OF ALG^. 
 
 R. Parasitic; sheaths thin; cells short, tubular . Chamasiphon, loo 
 
 R. Not parasitic (S). 
 
 S. Agglutinate'd in erect, wick-like clusters, articulate, base prostrate, 
 
 Symploca, 102 
 
 S. Not agglutinated; exceptionally appearing branched; often form- 
 ing a stratum . . Lyngbya, loi 
 
 T. Filaments parallel in dense clusters; free-swimming, 
 
 Aphanizomenon, 96 ' 
 
 T. Filaments short, heterocysts at their base; not free-swimming, 
 
 Masiigonema, 82 
 
 T. Filaments slowly motile Oscillaria, 104 
 
 T. Filaments not motile (U). 
 
 U. Filaments very slender, articulations more or less indistinct, 
 
 Leptothrix, 106 
 
 U. Filaments cruciformly branched Asierothrix, io6a 
 
 V. Free-swimming, (/. e. not adherent), (W). 
 
 V. Not free-smimming (X). 
 
 W. Cells globose, or oblong when dividing, in a single, quadrate 
 layer, bluish-green ... . ... Merismopedia, 112 
 
 W. Cells globose, sometimes in a small colony, brownish or red, 
 sometimes greenish . . Clilamydococcus, 38 
 
 W. Cells wedge-shaped, in radiating families . Gompkosphceria iie, 
 
 W. Cells filamentous or ring-like, spirally twisted, usually motile, 
 
 Spirillum, 1 07 
 
 W. Cells filiform, very minute, spirally twisted . , Spirulina, 10& 
 
 X. Sheath present, gelatinous or jelly-like, often colorless (Y). 
 
 X. Sheath none; cells spherical or angular by pressure, solitary or in 
 small families . . ... ... Chroococcus, 121 
 
 Y. Aquatic (a). 
 
 Y. On moist timbers and earth; cells small, in globose bodies in a 
 thin membrane .... . ... Microcystis, 116 
 
 a. Sheaths thin, not confluent; cells tubular, short, parasitic, 
 
 Chamasiphon, 100 
 
 a. Sheaths confluent, in a mucous stratum, or elongation or membra- 
 nous (1^). 
 
 a. Sheaths bladder-like, colorless; cells cylindric, ends rounded, 
 
 Glxothece, 109 
 
 b. Sheaths confluent (<:). 
 
 b. Sheaths membranous (/). 
 
 c. Cells spherical or nearly so (d). 
 t. Cells not spherical (e). 
 
GENERA OF ALG/E. 33 
 
 d. Tegument mucous, cells spherical or elongated, one pole color- 
 less, not in families . . Hy drums, 52 
 
 d. Tegument mucous, with small indistinct families of innumerable 
 cells . . . . . ... . . Anacystts, 117 
 
 d. Tegument soft, thick . . . . Aphanocapsa, 120 
 
 d. Tegument a mucous stratum, containing groups of two cells, these 
 surrounded by another tegument . . . Glceocapsa, 119 
 
 d. Tegument a mucous stratum; thallus spherical, hollow, cells many, 
 
 small, on the surface . ... Ccelosphmrium, 113 
 
 e. Tegument confluent, firm; cells longer than broad, 
 
 Aphanothece, 110 
 c. Tegjument inconspicuous; cells elongate, cylindrical, 
 
 Synechococcus, i ii 
 e. Tegument soon perforate, breaking into lobed forms; cells very 
 small, embedded Clathrocystis, 118 
 
 /. Cells globose, united in families, clustered grape-like, 
 
 Polycystis, 118 
 g. Irregularly branched, often closely interwoven; stems and pri- 
 mary branches of the same thickness; often aerial, Chrookpus, 22 
 g. Cruciformly branched, ends acute; filaments articulate or not, 
 
 Asterothrix, io6a 
 g. Somewhat dichotomously branched, apices rounded; floating and 
 yellow, or not yellow and coating wet rocks . . Calothrix, 81 
 h. Filaments erect, laterally adherent, basally attached, forming layers 
 on flat surfaces . ... . Isactis, 83 
 
 h. Filaments distinctly sheathed at base, sheaths broad, often sac- 
 cate, transversely plicate; heterocysts basal . Glaotrichia, 84 
 h. Filaments agglutinated by mucilage, and forming hemispherical or 
 bladdery forms . . .....*.. Rivularia, 85 
 
PART II. 
 
 Key to the Species of the Fresh-Water 
 
 Algse. 
 
KEY TO THE SPECIES OF THE FRESH WATER ALG^. 
 
 1. LEMANEA. 
 
 A. Filaments straight, 4-5' in. long, . . . fluviatilis, 52 
 
 A. " arcuately curved {a). 
 
 a. 1-2 in. long, olive green, black with age. . . torulosa 5 1 
 
 a. 5 in. long, violet in mass; regularly constricted . . catenata, 52 
 
 2. TUOMEYA. 
 
 A. Much and irregularly branched; tufts 1-2 in. long . fluviatilis, 53 
 A. Not branched, ..... . grande, 53 
 
 3. BANGIA. 
 
 Filaments about i in. long; in lax purple tufts atro-purpurea, 55 
 
 4. BATRACHOSPERMUM. 
 
 A. Branches sometimes setigerous, internodes naked or nearly so; 
 gelatinous. Variable . . . ... monilifo7-me, 56 
 
 A. Branches not setigerous, whorls imperfectly developed, the branch- 
 lets often impacted; color bluish green . . . vagum, 57 
 
 5. THOREA. 
 
 Much branched, ramuli horizontal, long and short alternating, 
 
 ramosissima, 5 8 
 
 6. CHANTRANSIA. 
 
 A. Tufts I in. long; filaments with many straight branches; fertile 
 branches very short . . macrospora, 59 
 
 A. Tufts 1-6 mm. long (a). 
 a. Parasitic on other plants (b). 
 
 a. Not parasitic (c). 
 
 b. Fresh water; bright violet, 2 mm. long; branches erect, ends obtuse, 
 
 violacea, 59 
 
38 SPECIES OF ALG^. 
 
 b. Marine; 1-4 mm. long in close fringe; branches rarely opposite, 
 
 often hairy . . virgatula, 61 
 
 c. Terminal cells cuspidate or piliferous .... Hermannii, 60 
 c. " " rounded pygmcea, 61 
 
 7. HILDEBRANTIA. 
 
 a. Fresh water; cells red; on river stones rivularis, 61 
 
 a. Marine; cells spherical ... . rosea, 62 
 
 8. COMPSOPOGON. 
 
 One species .... cceruleus, 62 
 
 9. COLEOCHiETE. 
 
 A. Filaments irregularly disposed, variable in form . irregularis, 65 
 
 A. " radiating (a). 
 
 a. Filaments not laterally adhering, forming small disks . soluta, 64 
 
 a. " adhering side to side, forming a disk (U). 
 
 b. Disk irregularly orbicular; cells subquadrangular . . scutata, 64 
 b. " exactly orbicular, thin, flat, . . orbicularis, 64 
 b. " orbicular, upper surface rounded, about 2 mm. high, 
 
 pulvinata, 64 
 
 10. (Edogonium. 
 
 It is only possible to identify the sixty-three species of this genus 
 when the plants are in fruit, the forms being arranged in groups ac- 
 cording to some characteristic or peculiarity of the oospore (the seed 
 or spore), and of the oogonium (the sac containing the oospore). It 
 is therefore scarcely possible to devise an artificial key. 
 
 § Male and female organs on the same plant (A). 
 § Male and female organs on different plants (B). 
 § Male organs of fructification not known (C). 
 A. Oospores globose or nearly so (D). 
 
 A. " elliptical or ovate (f). 
 
 B. Males short (dwarf), i-celled (k). 
 
 B. Males short (dwarf), 2 — many-celled (/). 
 
 B. Males filamentous, many-celled plants i^gg^. 
 
 C. Oospores globose or nearly so (//). 
 
 C. " elliptical or ovoid (ss). 
 
 D. Oogonia globose or nearly so (a). 
 D. " elliptical or ovoid (K). 
 
 a. Oogonia opening by a pore (p). 
 
 a. " " " " lid (/). 
 
 b. Pore median; veg. cells 4-6 times as long as wide . cryptoporum, 70 
 
SPECIES OF ALG^. 
 
 39 
 
 b. 
 c. 
 c. 
 
 d. 
 d. 
 d. 
 e. 
 e. 
 
 /■ 
 f. 
 g- 
 g- 
 h. 
 
 i. 
 
 i. 
 
 J- 
 
 J- 
 
 k. 
 
 k. 
 
 I. 
 
 I. 
 
 m. 
 
 tn. 
 
 m. 
 
 n. 
 
 n. 
 
 o. 
 
 o. 
 
 P- 
 
 P- 
 
 §■ 
 r. 
 r. 
 s. 
 
 s. 
 
 t. 
 t. 
 
 u. 
 u. 
 
 Pore above the middle ic). 
 Oospore not quite filling the oogonium (d). 
 Oospore entirely filling the oogonium (e). 
 Veg. cells 3-5 times as long as wide . . 
 
 2-5-3-5 
 4-10 
 
 a u u 
 
 Veg. cells 4-5 times as long as wide 
 
 2-4 
 
 obsoletum, 71 
 
 pliisiospermum, 7 2 
 
 polymorphum, 73 
 
 fragile, 71 
 
 zig-zag, 71 
 
 Oospores subglobose, filling the oogonia . . . autumnale, 73 
 Oospores obovate, not entirely filling the oogonia (^). 
 
 Veg. cells 4-6 times as long as wide . . . vernale, 72 
 
 Veg. cells 2-4 " " " " " _ crispum, 72 
 Oogonia single, opening by a superior pore; oospore globose not 
 
 filling the oogonium ... . urbicum, 73 
 Oogonia opening by a pore above the middle (7). 
 
 Oogonia " " " lid . gracillimum, 74 
 
 Veg. cells 3-7 times as long as wide . paludosuin, 74 
 
 " " 2-5 " " a II u _ crassum, 74 
 
 Oogonia with 7-12 vertical constrictions 
 Oogonia without vertical constrictions (/). 
 Oospore globose or nearly so (in). 
 
 " subellipsoid [o). 
 Diameter veg. cells 15-1 7/<, 4 times constricted 
 " " " 28-38yu, not constricted 
 
 " " " from 9-15// («). 
 
 oospore depressed-globose 
 
 " exactly globose . . 
 
 Dwarf males adhering to all parts of the female 
 
 " " on or near the oogonia 
 
 Oospore membrane smooth (^). 
 
 " " beset with bristles (cc). 
 
 Oospores globose or nearly so (f). 
 
 " ellipsoid or ovate (w). 
 Oogonia opening by a lid.(j-). 
 
 " a pore (i). 
 Terminal cell rounded 
 
 " " apiculate . . 
 
 Pore in the middle or a little above (u). 
 
 " above the middle (v). 
 Veg. cells 4.5-6 times as long as broad 
 
 (( it 2— A " " " '' " 
 
 platygynum, 75 
 
 undulaium, 76 
 cataractum, 77 
 
 Hens, 75 
 
 Areschougii, 76 
 
 multispora, 78 
 
 cyathigerum, 77 
 
 Lundense, 79 
 macrandrium, 80 
 
 flavescens, 78 
 Braunii, 79 
 
40 SPECIES OF ALGjE. 
 
 V. Diameter of veg. cells 13-14/* ... ... pyriforme, 95 
 
 V. " " " " i6-2o/t . . ... irregulare, 79 
 
 V. " " " " 27-30/i . . \ . . . . crrssiusculum, 80 
 
 w. Oogonia opening by a pore {x). 
 
 w. " " " " lid (aa). 
 
 X. Pore above the middle (y). 
 
 X. " below " " oospore with 4 spiral ridges . Huntii, 85 
 
 y. Oospore longitudinally costate . . .... Wolleanum, 82 
 
 z. Diameter of oogonia 45-50/* by 60-75/* • ■ • Boriseanum, 81 
 z. " " " 70-83/t by 90-105/* . . . concatenatum, 81 
 z. " " " 29-32/* by 33-38/* .... sexangulare, 82 
 
 aa. Oospore longitudinally costate, filling the oogonium, 
 
 acrosporum, 83 
 aa. " not " " (dd). 
 
 bb. Terminal cell setiform . ciliatum, 84 
 
 bb. " '' not setiform obtruncatum, 84 
 
 cc. Oospores ellipsoid oogonia opening by a pore in the middle, 
 
 Hystrix, 87 
 cc. " globose (dd). 
 
 dd. Oogonia opening by a pore at the middle . echinospermum, 86 
 dd. " " " " " above the middle {ee). 
 
 ee. Spines of oospores conical (//). 
 
 ff. Diameter of veg. cells 2.5-5 times as long as wide . stellatum, 85 
 ff. " " " " 1-2 times as long as wide . Donnellii, 85 
 
 ff. " " " " 6-14 " " " " " . echinatum, 86 
 
 gg. Oogonia not or scarcely swollen (hh). 
 gg. " manifestly swollen («). 
 hh. Diameter of oospore 22-52/* by 38-62/* .... capillar e, 87 
 
 hh. " " " 47-49/* by 50-66/* .... stagnale, 87 
 
 ii. Oospores globose or subglobose (/z). 
 a. " ellipsoid or oval {pd). 
 
 jj. Oogonia opening by a pore (kli). 
 
 jj. '• " " " lid; oospore globose , . Fringsheimti, 90 
 
 - kk. Pore in the middle; membrane of veg. cells and of oogonia spirally 
 
 punctate .... . . . . . . puncto-striatum, 90 
 
 kk. Pore in the middle; membrane not punctate . . rufescens, 89 
 kk. Pore above the middle (//). 
 
 //. Oospore filling or barely filling the oogonia (mm). 
 II. Oospores not filling the oogonia (nri). 
 
 mm. Oospore globose, filling the oogonium, diameter 25-29/t by 24-30/* 
 
 Franklinianum, 89 
 
SPECIES OF ALG^. 
 
 mm. Oospore sub-globose, barely filling the oogon 
 
 by 46-56>' 
 
 nn. Diameter of oospore 37-45/^ by 40-50/^ 
 nn. " " " 5i-54>« by 73-85/* 
 
 nn. Diameter of oospore 42-6oyU by 42-60/* . 
 00. Diameter of oogonia 40-45/i by 8o-ioo/* 
 00. " " " 63-75/* by 105-120/* 
 
 00. " " " 70-85/t by 130-160/* 
 
 00. " " '' 90-100/* by 130-150 
 
 //. Diameter of veg. cells less than i6/< (gf). 
 pp, " " " " i6/i or more (rr). 
 
 qq. Diameter of oogonia 17-18/* by 20/* 
 qq. " " " 24-28/* by 28-35/* 
 
 qq. " " " 33-35M by 33-43M 
 
 ^^. " " " 24-25/* by 26-28/* 
 
 rr. Diameter of oogonia 36-40/t by 44-45/* 
 rr. " " " 61-75/t by 68-80/* . 
 
 ss. Diameter of veg. cells less than 25/* (/■/). 
 i.r. " " " " 25 /* or more [uu). 
 
 tt. Diameter of oospore 35-36/* by 45-48/* 
 tt. " " " 15-16/* by 17-19/* 
 
 uu. Diameter of oospore 54-65/* by 75-103/* 
 «a. " " " 45-50/* by 68-72/* 
 
 41 
 
 ia, diameter 42-50/* 
 
 carbonicum, 90 
 
 . capilliforme, 88 
 
 pachyandrum, 89 
 
 cardiacum, 90 
 
 Boscii, 91 
 
 Landsboroughi, 9 1 
 
 I'ivulare, 92 
 
 z^ar. major, 92 
 
 delicatiilum, 93 
 
 moniliforme, 93 
 
 Londiense, 94 
 
 hexagonum, 94 
 
 . fonticola, 93 
 
 princeps, 93 
 
 pyriforme, 95 
 
 longatum, 95 
 
 gigateum, 94 
 
 grande, 95 
 
 II. BULBOCH^TE. 
 
 In reference to the sixteen species forming this genus, the remarks 
 made in connection with CEdogoniutn might be repeated. The spe- 
 cies can be identified only when in fruit; to make an artificial key is 
 therefore almost an impossibility. . 
 
 Replying to a personal inquiry in regard to the division of the 
 species into monoecious and dioecious groups, with the presence of 
 dwarf males on or near the oogonia of all the so-called dioecious 
 forms, Mr. Wolle writes: "These male forms are not developed 
 when they appear; they are supposed to have been formed in dis- 
 tinct cells known as androsporangia, and when they have developed 
 and escaped, they float about and then attach themselves on, at or 
 near the oogonium, but they are not necessarily a part of the plant 
 on which they may be seated." 
 
42 SPECIES OF ALGjE. 
 
 § Oogonia globose or nearly so (A). 
 
 § " ellipsoid or nearly so; oospores longitudinally crenulate- 
 
 costate (F). 
 A. Dwarf males i celled, on or near the oogonia, elachistandra, 97 
 
 A. " " 2 celled (B). 
 
 B. Basal part (stem) of dwarf males, shorter than the spermogonia (C). 
 
 B. " " " " " " longer than the spermogonia; 
 oospore warty ... gigantea, 99 
 
 C. Diameter of veg. cells 20/i or less (D). 
 
 C. " " " " more than 2o/<; oospore granulate, 
 
 setigera, 98 
 
 D. Oogonia without terminal seta intermedia, 97 
 
 D. " with terminal seta, or beneath a male cell (E). 
 
 E. Dissepiment supporting oogonia in the middle of cell or slightly 
 
 below . . crenulata, 97 
 
 E. Dissepiment above the middle of the cell .... polyandra, 98 
 
 E. " below the middle ... . . Brebisonii, 99 
 
 F. Monoecious (G). 
 
 F. Dioecious (H). 
 
 G. Diameter of oogonia '2.'i-Z'ilJi by 46-56/* . . . mirabilis, 100 
 G. " " " 20-25/^ by 33-36/* .... nana, 100 
 H. Dissepiment of cells supporting oogonia obsolete (I). 
 
 H. " " " " " present (J.) 
 
 I. Diameter veg. cells 12-5/t, length less than diameter, /j/^/««a, loi 
 
 J. Diameter veg. cells i6/t or less (K). 
 
 J. " " " more than 16/i (L). 
 
 K. Veg. cells 1-1.5 times as long as wide . . . subsimplex, loi 
 
 K. " " 2-3.5 " " " " " .... repanda, 102 
 
 K. " " 1.5-2 " " " " " . rhadinospora, 103 
 
 L. Veg. cells 2.5-4.5 times as long as wide . . . insignis, loi 
 
 L. " " 1.5-3 " " " " '1 minor, loi 
 
 L. " " 1.25-3 " " " " " . . rectangularis, 102 
 
 12. SPH^ROPLEA. 
 
 Cells 8-10-20 times as long as broad, chlorbphyllose rings 20-30 In 
 each annulina, 104 
 
 13. CYLINDROCAPSA. 
 
 Ends of cells clear and pearly amxna, 105 
 
 Ends of cells not clear . . . . . . geminella, 104 
 
SPECIES OF ALG^. 43 
 
 14. PRASIOLA. 
 
 Tufts 2-6 mm. high and broad, cells 4-6jx in diameter, crispa, io6 
 " 1-3 inches long and broad, cells 6-8/t " " Mexicana, 107 
 
 15. ENTEROMORPHA. 
 
 § In brackish water {a). 
 
 a. Fronds simple, elongate; cells 3-5-6 angled . intestinalis, 107 
 
 a. " compressed, tubular .... ... compressa, 107 
 
 16. DRAPARNALDIA. 
 
 A. Every mature joint with 2-4 clusters of branches, Ravenellii, no 
 A. Branches less abundant, not at every jomt (a), 
 a. Branches opposite, their stems thick, short, tapering to a point or 
 seta ... . . . .... . spinosa, 109 
 
 a. Branches opposite or alternate . glomerata, io?>, plumosa, 1-09 
 
 17. STIGEOCLOklUM. 
 
 § In warm or hot water; 1-2 in. long, much branched, apex a bristle, 
 
 thermale, in 
 § Not in water of high temperature [a), 
 a. Branches ending in a hair or bristle (b). 
 
 a. Branches not ending in a hair or bristle [k). 
 
 b. Bristle a colorless, apparently hollow prolongation (c). 
 
 b. Bristle a delicate, filamentous, hair-like extension (d'). 
 
 c. Cells nearly cylindrical, equal or twice as long as broad, 
 
 protensum, 112 
 
 d. Pa.rasitic, dwarf, 2 mm. long; in mucus .... radians, 115 
 
 d. Not parasitic (e). 
 
 e. Diameter of largest cells 20/i or less (/). 
 
 e. " " " " 25-40/^ . . . nudiusculum, 113 
 
 f. Diameter of filaments ii-20yu; basal cells 6-8 times longer than 
 
 wide . ... subsecundum, 112 
 
 /. Diameter of filaments io-i6/i {g). 
 
 g. Branches opposite on cells smaller and more oval than the others, 
 
 flagelliferum, 112 
 g. Branch-bearing cells not smaller (Ji). 
 
 h. Upper branches clustered, moniliform . fasttgiatum, 114 
 
 h. " " not moniliform (j). 
 
 j. Two or more inches long, branches mostly opposite, 
 
 fasciculare, 114 
 
 / Two to 10 mm. long, simple to near the end, there branches 
 
 clustered longipilus, 115 
 
44 SPECIES OF ALGJE. 
 
 k. Length 4-50 mm.; somewhat branched, branches simple, 
 
 ienue, no 
 k. " 2-3 mm.; branches alternate, ends obtuse, . nanum, 112 
 k. " 12 mm.; branches mostly opposite, ends acute, 
 
 amasnum, 113 
 
 18. CHvETOPHORA. 
 
 § Jelly mass globose or nearly so (a). 
 
 § Jelly mass elongated to 3 inches, margins tattered, forming ragged 
 , branches . . .... . . . endivicefolia, 117 
 
 § Jelly mass orbicular, small; filaments hair-pointed . longipila, 118 
 a. Branches more or less moniliform; jelly mass 2 mm. diameter, 
 
 monilifera, 118 
 
 a. Branches not moniliform, radiating (b). 
 
 b. Jelly mass smooth (c). 
 
 b. " " tuberculose, ends of branches rarely hair-like, 
 
 tuberculosa, 116 
 
 c. Diameter of branchlets 6/^; 1.5-3 times longer . pisiformis, 116 
 c. " " branches 7-10//; 1-1.5 " "... elegans, 116 
 
 19. MICROTHASJNION. 
 
 But one species . . . .?■ . . . Kuetzingianum, 118 
 
 20. APHANOqjjI^TE. 
 
 § Parasitic (a). 
 
 § Not parasitic {b). 
 
 a. Cells globose, a bristle on the back . . . repens, 119 
 
 a. Cells various, elongate, curved, worm-like, sub-globose, 
 
 vermiculoides, 119 
 
 b. Cells globose, or subpyritorm, a seta on the back or apex; in 
 
 mucus . . . globosa, 119 
 
 21. GONGROSIRA. 
 
 One species . . . Sclerococcics, 120 
 
 20. CHROOLEPUS. 
 
 a. Cells globose, broadly elliptic or ovate (V). 
 
 a. Cells more or less elongate (c). 
 
 b. Dull or bright red; diameter 14-2 2/^ . . . umbrinum, 123 
 
 b. Ash color when dry; diameter 20-25 .... montliforme, 123 
 
 c. Diameter of cells more than 25-40/.*; branches rather dichotomous, 
 
 lolithus, 122 
 c. " " " less than 2S/i ((/). 
 
SPECIES OF ALGiE. 4S 
 
 d. Stratum tawny red, drying greenish; diameter of filaments 9-14//, 
 
 odoratus, 122 
 d. Stratum orange-red, drying yellow; diameter of filaments 7-9/f, 
 
 lichenicolus, 122 
 
 d. Stratum red or orange, soft, silky; much branched; diameter of 
 
 cells 10-12/^ ... ... aureus, 121 
 
 23. CLADOPHORA. 
 
 § Chlorophyll diffused, not in spirals (a). 
 
 § " disposed to be net-like or in lax spirals (d). 
 
 a. Cell membrane smooth (h). 
 
 a. " " plicate-striate; contents of young slightly spiral, 
 
 crispata, 126 
 
 b. Cells more or less swollen; irregularly branched; variable, 
 
 fracta, 1 24 
 
 b. Cells not noticeably swollen (c). 
 
 c. Diameter of branches 2 8-40 yu . , . . oligodona, 126 
 
 c. " " " about is/< . . . Flotowiana, 126 
 
 d. Branches united (connate) at base; cells 5-8 times as long as broad, 
 
 canilicularis, 117 
 
 d. Branches not connate at base (e). 
 
 e. Filaments not radiating from common centre, cells smooth (/). 
 
 e. " " " cell membrane plicate . flavescens, 128 
 
 e. " radiating from a common centre, much branched, 
 
 CBgagropila, 124 
 
 /. Diameter of stems 60-100/^ ... . glomerata, 127 
 
 /. " " " 120-135/* .... . . fluitans, 128 
 
 24. PITHOPHORA. 
 
 A. Fertile stem d^jx thick .... . CEdogonia, 130 
 
 A. " " 175/^ thick . . . . CBqualis, 131 
 
 A. " " 59/4 thick . . . Kewensis, 131 
 
 24a. SCHIZOMERIS. 
 
 One species . . . . ... Leibleinii, PL CXXV. 
 
 25. ULOTHRIX. 
 
 § Length of cells equal to width {a). 
 § " " " greater than width [e). 
 § " " " less than width {h). 
 a. Color dark, light or bright green {b). 
 a. Color yellowish green [d). 
 
46 SPECIES OF ALGiE. 
 
 b. Filaments dividing longitudinally; mucous; 4 in. long, floating, 
 
 Lenormandi, 138 
 
 b. " not dividing longitudinally (c). 
 
 c. Joints often constricted; diameter of cells 9-iOyU . rivularis, 136 
 c. Joints not constricted; aquatic; variable; diameter of cells 5-50/*, 
 
 sub tilts, 135 
 
 c. " " " " filaments tortuous, very long, 
 
 muralis, 137 
 {. " " " On damp walls, pavements, exposed rocks, etc., (*) 
 *. Cells 6-7/^ in diameter; on walls, pavements, etc. . mitens, 137 
 *. " 7-9.5/t " " cell contents usually at one side; on ex- 
 
 posed rocks, etc. . . . flaccida, 137 
 
 d. Cells i2-i4/< in diameter . aqualis, 134 
 
 d. Cells about ijx in diameter; on moist clay or sand . . varia, 138 
 
 e. Green, cell contents usually on one side, hemispherical, flaccida, 137 
 e. Green, dark, bright or pale; contents diffused (/). 
 
 /. Joints often constricted; cells 9-io/t in diameter . rivularis, 136 
 /. " not constricted; filaments attached, 17-25/^ in diameter, 
 
 tenuis, 134 
 /. " " " filaments not attached {g). 
 
 g. In brackish water, filaments 1-3 in. long, io-30/t dia., 
 
 Younganum, 135 
 
 g. In fresh water subtilis, 135 
 
 h. Filaments dividing longitudinally, 4 in. long, floating, 
 
 Lenormandi, 138 
 h. " not dividing (i). 
 
 i. Joints often constricted, cells 9-iOyM in dia.. . rivularis, 136 
 
 /. " not constricted in sterile filaments (7). 
 j. Filaments lofjL or more in diameter (K). 
 j. " less than loyu in diameter (m). 
 
 k. In brackish water; filaments 20-30/* in dia. . Younganum, 135 
 k. In brackish and in fresh water; filaments 38-5o/< in dia., 
 
 speciosa, 135 
 k. In fresh water only or on the ground (/). 
 
 /. On shaded ground; flexuous, interwoven. . parietina,- 138 
 
 /. Aquatic; filaments io-i2yU in dia. . . . oscillarina, i^y 
 
 I. " " 14-40/i" " Zonata, 133 
 
 m. Bright, grass green; filaments tortuous, very long, interwoven, 
 
 muralis, 137 
 m. Yellowish green, mucous; cells shorter than wide . compacta, 1^6 
 
SPECIES OF ALG^. 47 
 
 26. SCHIZOGONIUM. 
 
 One species; found on moist cliffs, Colorado . . murale, 139 
 
 27 CONFERVA. 
 
 § In brackish water; diameter i2-i4yU fugacissima, var. saliria, 141 
 
 § In fresh water (A). 
 
 A. Diameter of filament from 3-5 yU {a). 
 
 A. " " " from 6-12/^ (^). 
 
 A. " " " from i4-25ya [g). 
 
 a. Very pale; cells 1^-2-3 times as long as wide . tenerrima, 143 
 
 a. " " " 4-9 " " " " " . glacialioides, 143 
 
 a. Green; cells 3-4 " " " " " . . rhypophila, 143 
 
 b. Cells before division 7 times as long as wide . . . affinis 141 
 b. " " " 4-5 " " " " " (c). 
 
 b. " " " less than 4 times as long as wide (if). 
 
 c. Not constricted atthe joints ... ... fugacissima, 141 
 
 c. Slightly " " " " (d). 
 
 d. Cells before division about 4 times as long as wide . Funkii, 142 
 
 d. " " " " 5 " " " " " filaments of ir- 
 regular thickness . . .... bumbycina, 142 
 
 e. Cells more or less swollen {*) 
 
 e. Cells not swollen, joints not constricted (/). 
 
 * Diameter of filaments 10-12// . . ... vulgaris, 142 
 
 * " " " 7-9y" .... . var. Farlowii, 142 
 /. Attached; chlorophyll evenly diffused . . abbreviata, 143 
 /. Not attached; contents granular . . . • . . punctalis, 142 
 g. Diameter of filaments 20-25// ... . amcena, 140 
 g. " " " less than 20/t (/;). 
 
 h. Cells more or less swollen, about twice as long as wiAe.,floccosa, 140 
 h. " " " " constricted at the joints, 
 
 utriculosa 140; fontinalis, 141 
 
 28 CH^TOMORPHA. 
 
 Marine, therefore omitted. 
 
 29 RHIZOCLONIUM. 
 
 § On moist ground; cells 1.5-3 times as long as wide, 
 
 hieroglyphicum, 1 44 
 § In brackish water (a). 
 § In sweet waters {I)). 
 
 a. Filaments irregularly curved and angled. California, Casparyi, 145 
 a. Filaments not specially curved; diameter 20-30/t . . salinum, 145 
 "^ 33-40yM . . major, 146 
 
48 SPECIES OF ALG^. 
 
 b. Permanently attached, in rapid streams . . . fluitans, 145 
 
 b. Not permanently attached {c). 
 
 £. Diameter of filaments 13-15. 5;u . . . fontitMli, 144 
 
 c. " " " 2S-33yU stagnale, 145 
 
 c. " " " 36-40yU . . Horsfordii, 145 
 
 30. VAUCHERIA, 
 I. KEY TO THE STERILE PLANTS. 
 
 § In salt or brackish water; mats velvety, feet in extent, 
 
 Thurdii, 149 
 § In sweet water or somewhat terrestrial {a). 
 § Apparently terrestrial only (h). 
 
 a. Filaments dichotomous, branches constricted at the base of the 
 divisions, often intermediately, .... . tuberosa, 154 
 
 a. Filaments not constricted at the branching points {b). 
 
 b. Stratum dense, pellucid below, creeping; terminal branches erect, 
 
 clustered, often crooked . ... velutina, 153 
 
 b. Stratum not pellucid below {c). 
 
 c. Branches not clustered, vague. Thus far found only in California, 
 
 hamata, 153 
 
 c. Branches dichotomous or sparingly formed {d). 
 
 d. Diameter of filaments loofx or more (e). 
 
 d. " " " less than ioo/.t [g). 
 
 e. Diameter 100 to 2oo/< (/). 
 
 /. Diameter 125;.*; tufts dense, dark green . . geminata, 151 
 
 /. " loo/t; tufts loose, expanding in all directions, 
 
 aversa, 149 
 /. " ioo-2oo/t; dirty green or brownish; about limestone 
 
 springs ... . . dichotoma, 149 
 
 /. Diameter 1 8o-2ooyU, often hyaline; drying ash gray . pilus, 153 
 g. In turfy mats; filaments densely intricate; 50-75// in diameter, 
 
 se7-icea, 150 
 g. In dense, intricate tufts; filaments dichotomous, 50// in diameter, 
 
 geminata, 151 
 g. In loosely intricate clusters; filaments about 50/1 in diameter, 
 
 sessilis, 151 
 h. Stratum thin, expanded, filaments about 50/* in diameter, 
 
 Dillwynii, 150 
 h. " " densely interwoven, dark green . . terrestris, 153 
 
SPECIES OF ALG^. 
 II. KEY TO THE FRUITING PLANTS OF VAUCHERIA. 
 
 49 
 
 § Antheridia slightly bent; the opening at top (a). 
 § " bent like a horn or hook (^). 
 
 § " not known (g). 
 
 a. Oogonia nearly round (6). 
 
 a. " not round; oval, often rather oblique (c). 
 
 b. Oogonia about ioo/< in diameter .... dichotoma, 149 
 
 b. " i25-i20;u " " Thuretii, 149 
 
 c. Oogonia i-6, on one side, mouths lateral, produced beak-like, 
 
 sericea, 150 
 
 c. " erect, mouths not lateral, not produced beak-like, 
 
 aversa, 149 
 
 d. Antheridia beside or between the subsessile oogonia (1?). 
 
 d. Antheridia terminal, with the oogonia on each side or lower 
 
 down (/). 
 
 e. Terrestrial, broadly expanded; antheridia bag-shape or clavate, 
 
 Dillwynii, 150 
 e. Aquatic; antheridia short and straight, or elongate and variously 
 
 curved . . . . . sessilis, 151 
 
 /. Tetrestrial only; antheridium long, curved, oogonia on its back, 
 
 terrestris, 153 
 /. Not strictly terrestrial; fruit on short lateral branchlets, 
 
 geminata, 151 
 /. " " " fruit on short segments on the divided 
 
 ends of branchlets ... . hamata, 152 
 
 g. Branches regularly constricted at base and often elsewhere, 
 
 tuber osa, 154 
 g. Branches not constricted; filaments i8o-2oo/< in diameter, 
 
 pilus, 153 
 
 One species 
 One species 
 One species 
 One species 
 
 31. BOTRYDIUM. 
 
 32. VOLVOX. 
 
 33. EUDORINA. 
 
 34. PANDORINA. 
 
 granulatum, 155 
 
 globator, 158 
 
 stagnale, 160 
 
 morum, 161 
 
50 SPECIES OF AWJiE. 
 
 35. EUGLENA. 
 
 The question as to the animal or vegetal character of Euglena has 
 been debated. The present tendency is to consider it an alga, 
 although the evidence is rather negative than positive. For the 
 present purpose however, it seems best to leave it among the Infu- 
 soria, where the older investigators classed it. 
 
 36. GONIUM. 
 
 One species . . . . pectorale, 163 
 
 37. STEPHANOSPHjERA. 
 
 No forms yet found in this country. 
 
 38. CHLAMYDOCOCCUS. 
 
 a. Cells subglobose, brownish-red, sometimes green; variable, 
 
 pluvialis, 164 
 
 a. Cells globose, red; at first with a hyaline border; on the snow of 
 
 high peaks, etc. .... . . . nivalis, 166 
 
 39. CHLAMYDOMONAS. 
 
 § With a red pigment spot (a). , 
 
 § Without " " " (b). 
 
 a. Ovate; length twice the width; pigment spot lateral, 
 
 pluviusculus, 168 
 
 b. Pale, whitish green; oblong-elliptical . hyalina, 168 
 
 b. Bright light-green {c). 
 
 c. Ovate or oval . . . iingens, 167 
 c. Spherical or nearly so . .... pluviale, 167 
 
 40. pediastrum. 
 For full descriptions and figures of the species, see Wolle's "Des- 
 mids of the United States," from which the following classification is 
 compiled. 
 
 § Apices cuspidate, each cell with one cusp or bristle {a). 
 § " " " " " two " " " (c). 
 
 § Apices or angles, bidentate; small; cells often 4 . cuspidatum, 154 
 § Apices truncate; cells 4 in form of cross, 4-sided; small, tetras, 154 
 § Apices concave, undulate (d). 
 § Apices bilobed (if). 
 
 a. Cells six, ovate or subfusiform, radiately connected; centre closed, 
 
 simplex, 152 
 a. Cells six, 5 angled; centre open . . . Sturmii, 153 
 
 a. Cells more than six (b). 
 
SPECIES OF ALG^. 51 
 
 b. Outer circle 14, inner 7, centre closed by i; outer spaces 7, inner 4, 
 
 simplex var., 153 
 
 b. Outer circle 12, inner 4, centre open; outer spaces 4, 
 
 duodenarius, 153 
 
 b. Outer circle 14, inner 7, centre closed by 4; outer spaces 7, inner 4, 
 
 simplex var., 153 
 
 c. Marginal cells 2-lobed, each cuspidate; cells 8-16-128; centre closed, 
 
 Boryanum, 153 
 
 d. Perforated by small openings ... . brachylobum, 154 
 
 d. No openings; centre closed; . . muticum, angulosum, 153 
 
 e. Perforate by small openings, or centre open (/). 
 
 e. Not perforate, centre closed {g). 
 
 f. Cells 16-32-64 . . . 
 /. Cells 6, centre open . 
 
 g. Apices converging, space between oval 
 g. Apices not converging (li). 
 h. Each apex 2-lobed, sometimes diverging 
 
 pertusum, 154 
 
 angulosum, var., 154 
 
 forcipatum, 153 
 
 Ehr enter gii, 154 
 
 utriculatum, 169 
 
 microporum, 170 
 
 cambricum, 170 
 
 spinulosum, 171 
 
 cruaatum. 
 
 41. HYDRODICTYON. 
 
 One species 
 
 42. CCELASTRUM. 
 
 a. Cells globose, with interstitial openings . . 
 a. Cells angular, each with a tubercular process 
 
 43. SORASTRUM. 
 
 One species 
 
 44. STAUROGENIA. 
 
 One species . . 
 
 45. SCENEDESMUS. 
 
 § Cells armed with spines (a). 
 § Cells not armed with spines {e). 
 a. Aquatic (b). 
 
 a. On moist sand, Florida; cells 2-4, fusiform, 
 
 antennatus, var. recites. 
 
 b. Cells oblong, cylindrical, ovate or globose (c). 
 
 b. Cells, some at least, spindle-shaped [d). 
 
 c. Spines recurved on outer cells 
 c. Spines straight, single or sometimes two 
 
 c. Spines straight, three to five 
 
 d. Inner cells fusiform, armed, outer lunate, 
 d. Fusiform, oval or globose; spines straight 
 
 171 
 
 172 
 
 caudatus, 172 
 
 polymorpkus, 173 
 
 . rotundatus, 174 
 
 dinwrphus, 173 
 
 polymorpkus, 173 
 
52 SPECIES OF ALGjE. 
 
 e. Cells, some at least, fusiform (/), 
 
 e. Cells oblong or ovate, obtuse; 3-5 times as long as wide, 
 
 obtusus, 173 
 /. Cells in a single even row; outer cells lunate . . dimorphus, 173' 
 /. Cells usually all alike, acute, 3-6 times as long as wide, acutus, 173 
 
 46. SCIADIUM. 
 
 a. Attached, umbellate; cells usually straight; base contracted into 
 a short stem arbuscula, 1 74 
 
 a. Floating; a collection of umbels connected by a usually straight 
 cell ... gracilipes, 175 
 
 47. OPHIOCYTIUM. 
 
 § One or both ends spinous (a). 
 
 § Without spines (c). 
 
 a. Both ends spinous {J)). 
 
 a. One end spinous, one end rounded; cells curved or coiled, 
 
 cochleare, 175 
 
 b. Cells arched or nearly straight, ends more or less enlarged, 
 
 capitatum, 176 
 
 b. Cells crescentic, Closterium-\ik.t, large . cuspidatum, 176 
 
 c. Cells small, curved, often in masses, ends rounded, parvulum, 176 
 c. Cells long, narrow, repeatedly coiled, ends rounded, circinatum, 176 
 
 48. CHARACIUM. 
 
 § Sessile, no stipe; cells pyriform, apex somewhat produced, 
 
 sessile, 177 
 § Not sessile, stipe present but often short (a), 
 a. Apex rounded or truncate (b). 
 
 a. Apex acute (d). 
 
 b. Stipe short, scarcely noticeable, end dilated; cells producing a 
 
 short neck acutum, 177 
 
 b. Stipe longer, noticeable (c). 
 
 c. Apex produced as a thick neck; stipe brownish yellow, 
 
 Pringsheimii, 177 
 c. Apex always rounded, cells obovate, stipe base not dilated, 
 
 Ncegelii, 178 
 
 c. Apex rounded, truncate when open; stipe hyaline, 
 
 heteromorphum, 178 
 
 d. Producing a short neck; cells ovate acutum, 177 
 
 d. No distinct neck; lanceolate or sword-shaped, ends tapering, 
 
 ambiguuin, 177 
 
SPECIES OF ALG^. 53 
 
 49. PROTOCOCCUS. 
 
 § Aerial forms (a). 
 
 § Aquatic (c). 
 
 a. Cells without gelatinous envelope (i). 
 
 a. Cells with gelatinous envelope in which they divide; angular from 
 
 pressure angulosa, i8i 
 
 b. Common everywhere on trees, fences, etc.; cells yellowish green, 
 
 viridis, 181 
 b. On moist old wood; cells dark green; decussately dividing, 
 
 dissectus, 18 r 
 
 b. On pots, etc., in green-houses; orange, reddish-brown, yellowish 
 
 green miniatus, 182 
 
 c. Beset with small spines or hairs vestitus, 183 
 
 c. Smooth, in gelatinous tegument, . . . humicola, -l?i2; gigas, 183 
 
 c. " not in tegument [d). 
 
 d. Cells clustered somewhat grape-like .... botryoides, 182 
 d. Cells single, membrane thick, often lamellate . Wimmeri, 183 
 d. Cells varying in size, membrane not lamellate . . infusionum, 182 
 
 50. POLYEDRIUM. 
 
 § Angles rounded, not spinous (a) 
 
 § " bifid or trifid {b). 
 
 § " spinous or greatly elongated {c). 
 
 a. Cells 4 or 5 angled, diameter 35-70/1 . . . gigas, 184 
 
 a. " 4 angled, diameter 8-io/< minimum, 185 
 
 a. " 3 angled, diameter i2-i5yu . .... muticum, 185 
 
 b. Angles bifurcate, sharply tipped .... . bifurcatum, 184 
 
 b. " often repeatedly bilobed, hyaline, acute . . enorme, 184 
 
 c. Centre scarcely body-like, radii thin, much prolonged, 
 
 longispinum, 185 
 c. Centre distinctly a body; angles spinous tetragotium, minus, 184 
 
 51. DICTYOSPHjERIUM. 
 
 a. Cells ovate or subglobose . . Ehrenbergianum, 186 
 
 a. Cells reniform, about twice as long as wide . reniforme, 186 
 
 a. Cells oval, often centrally constricted . . . Hitchcockii, 186 
 
 52. HYDRURUS. 
 
 One very variable species .... . fmtidus, 187 
 
 53. PALMODACTYLON. 
 
 a. Family of cylindrical, bladder-like radiating cases; cells in i or 
 
 more rows ... . variwn, 189 
 
 a. Family simple, not branched, more filamentous . . simplex, 189 
 
54 SPECIES OF ALGiE. 
 
 :>/ / -r ' •'■'' 
 
 54. TETRASPORA. /3^/^/' /'//• ,S ///(•• 
 
 § Thallus tubular, splitting (a). 
 
 § Thallus irregularly expanded (U). 
 
 § Thallus membranous, saccate, obovate, sinuate, buUose (c). 
 
 a. Cells about i6/i in diam.; ends tapering to a fine point, 
 
 cylindrica, 1 90 
 
 a. Cells 8-io/f in diam. ; yellowish-green lubrica, 191 
 
 i. Colorless, or green edged gelati?wsa, 191 
 
 J>. Green, rather soft and slippery explanata, 191 
 
 £. Dark green, smooth or somewhat warty; cells crowed in 2s or 4s, 
 
 bullosa, 190 
 
 55. SCHIZOCHLAMYS. 
 
 Supposed to be a form of Tetraspora. 
 
 56. PALMELLA. 
 
 § Aquatic {a). 
 
 § On wet ground or dripping rocks (V). 
 
 § On wet wood . uvcsformis, 193, botryoides, 194 
 
 a. Irregularly expanded; cells minute (o. 75-1. 00/t), crowded, 
 
 hyalina, 193 
 
 a. Somewhat globose, tuberculate; cells elliptical, 5 by 8/i, 
 
 Mooreana, 193 
 
 b. Thallus expanded or indefinite . . . mucosa, 192, miniata, 193 
 
 57. PORPHRYDIUM. 
 
 One species; terrestrial cruentutn, 194 
 
 58. BOTRYDINA. 
 
 One species; terrestrial . vulgaris, 195 
 
 59. BOTRYCOCCTJS 
 
 One species; aquatic Braunii, 195 
 
 60. GLOeOCYSTIS. 
 
 § Aquatic (a). 
 
 § On wet rocks and walls; cells 3-S;U in diameter . . rnpestris, 196 
 
 a. Dirty or bright green; families 45-90// in diameter . ampla, 196 
 a. " " " " families about 35// in diameter, 
 
 vesiculosa, 196 
 
 a. Brownish-yellow or reddish rufescens, 196 
 
 61. NEPHROCYTIUM. 
 
 Families oblong or elliptical, cells reniform . . Agardhianum, ig"] 
 Families subspherical, cells oblong or elliptical . . Ncegelii, 197 
 
SPECIES OF AhGM. 55 
 
 62. RHAPHIDIUM. 
 
 a. Cells straight or nearly so, length 15-20 times the diameter, 
 
 acinilare, k)"] 
 a. " " " " " " 20-30 or more times the diameter, 
 
 contorttim, 198 
 
 a. Cells decidedly curved; often crescentic or sigmoid {I)). 
 
 b. Cells sigmoid, single or 2-4 connected .... sigmoideum, 198 
 
 b. Cells more or less crescentic (<:). 
 
 c. Cells connected back to back, crescentic, sometimes single, 
 
 convolutum, 198 
 c. Cells not connected, long, slender, .... falcatum, 198 
 
 c. " " " short, thick, diameter 5-7/* . Braunii, 198 
 
 63. DltlORPHOCOCCUS. 
 
 One species . . . . cordatus, 199 
 
 64. MISCHOCOCCUS. 
 
 One species . . . . . . ., . confervicola, 200 
 
 65. EREMOSPHjERA. 
 
 One species . viridis, 200 
 
 66. UROCOCCUS. 
 
 a. Stem densely ringed, often divided .... Hookerianus, 201 
 a. Stem short, remotely annulated . insignis, 201 
 
 67. APIOCYSTIS. 
 
 One species . . ... Brauniana, 202 
 
 68. CHYTRIDIUM. 
 
 a. On the oogonia of various ffii^^^^^/a; cells somewhat urn-shaped, 
 with a lid acuminatum, 202 
 
 a. On various filamentous Algae (i^). 
 
 b. With a low lid; pale yellow . . . . minus, 203 
 b. Without a lid; cells spherical ...... globosum, 203 
 
 69. OLPIDIUM. 
 
 § On the exterior of the host; cells globose; mouth cylindrical, 
 nearly as long as the cell ampullaceum, 203 
 
 § In the interior of the host; perforating neck tubular, middle 
 globosely dilated . . intestinum, 203 
 
 § In the interior; perforating neck straight, not inflated, 
 
 entophytum, 204 
 
56 SPECIES OF ALG/E. 
 
 70. SPIROGYRA. 
 I. KEY TO THE STERILE PLANTS. 
 
 As it is often difficult to determine the number of spiral bands 
 within a cell of Spirogyra, the following method, originally suggested 
 by "The Botanical Gazette," will be found exceedingly convenient. 
 Select a band near the middle of a cell, count those that cross it, add 
 one to the number, and the result will be the whole number of bands 
 in the cell. 
 
 § Membrane of ce'.ls folded in at the ends (a). 
 § " " " not folded in at the ends (y). 
 
 a. Chlorophyll bands one only (U). 
 
 a. " " two or more {g). 
 
 b. Membrane of spore smooth (<r). 
 
 b. " " " punctate (/). 
 
 c. Filaments 28-33/^ in diameter; cells 3 to 10 times as long as wide, 
 
 Grevilleana, 209 
 c. " 24-30// " " cells 3-9 times as long as wide, 
 
 quadrata, 208 
 c. " i8-28/i " " (d). 
 
 c. " 9-i8/t " " {e). 
 
 d. Cells 10-25 times as long as wide; spiral of i J4 to 4 turns, 
 
 Spreeiana, 208 
 
 d. Cells 6-15 " " " " " spiral of 3>^ to 6 turns, 
 
 Weberi, 208 
 
 e. Cells 4-15 times as long as wide; spiral of 3-6 turns, 
 
 tenuissima, 207 
 e. " 3-8 " " " " " spiral of 3-8 turns, inflata, 207 
 /. Diameter of filaments 36-40//; cells 6-12 times the diameter, 
 
 calospora, 209 
 g. Spirals two (K). 
 g. Spirals three; cells 30-33// wide, 4-8 times as long as wide, 
 
 Hassallii, 210 
 h. Cells i6-22// in dia., 4-8 times as long as wide, . Hilseana, 209 
 h. Cells 3o-33/< " " 4-8 " " " " " . Hassallii, 210 
 
 h. Cells 36-45// in diameter (/). 
 
 /. Cells 4-12 times as long as wide . insignis, 210 
 
 i " 3-5 " " " « '< Hantzschii, 211 
 
 j. One spiral in each cell (k). 
 
 j. Two or more spirals in each cell (t). 
 
SPECIES OF ALGjE. 
 
 57 
 
 subsalsa, 212 
 
 varians, 212 
 
 quinina, 213. 
 
 condensata, 215 
 
 k. Membrane of spore smooth (/). 
 
 k. " " " punctate {s). 
 
 I. Cells less than twice as long as wide [m). 
 
 I. Cells twice or more " " " " («). 
 
 ■m. Diameter 22-25/t; i-ij4 times as long as wide, 
 
 m. " 25-33/*; i-2y2 " " " " " 
 
 m. " 33-40//; 1-2 rarely 6 " " " " 
 
 m. " 48-75/4; i-ij^ times " " " 
 
 n. Diameter 33/* or more (o). 
 
 n. " less than 33/* (^). 
 
 (7. Diameter 33-40/i; 1-2 rarely 6 times as long as wide, quinina, '213 
 
 o. " 30-5S/" (/)• 
 
 /. Cells 3-7 times longer than wide; spiral dentate . Lutetiana, 214 
 
 p. " 2-4 " " " " fusco-atra, 215 
 
 q. Cells 3-5 times as long as wide (f). 
 
 q. Cells 2-12 times as long as wide {gg). 
 
 r. Diameter 22 /i or less . flavescens, gracilis, 211; communis, 213 
 
 r. " 24/i or more . . varians, 212; Jurgensii, 213 
 
 ^. Diameter of cells 24-27/i, 6-12 times longer than wide, /a;zrf«^a, 215 
 
 t. Spirals 2 («). 
 
 /. " 3 (x). 
 
 /. " 4 {aa). 
 
 t. " 5 (^^). 
 
 t. " 6 or more (ff). 
 
 u. Diameter of cells 40/* or less (v). 
 
 u. " " " more than 40/t (w). 
 
 w. Cells 2-4 times as long as wide decimina, 216 
 
 V. " 4-14 " " " " " . elongata, 221 
 
 w. Cells 1-2 times as long as wide subcequa, 217 
 
 a/. " 1.5-2.5 " " " " " . . . dubia, 220 
 
 X. Cells 90-100/1 in diameter, joints somewhat constricted, 
 
 jugalis, 219 
 X. Cells 50/1 or less in diameter (jc). 
 X Cells more than 50/* in diameter (z). 
 y. Cells 7-1 1 times as long as wide 
 y. " less than 7 times as long as wide 
 
 z. Cells 1-2 times as long as wide 
 _g u 2 — -3 " '' " " " 
 
 «. " 2-5 " " " " " 
 z. " 2.5-10 " " " " " 
 
 . rivularis, 220^ 
 
 dubia, adnata, 217 
 
 . . subcequa, 217 
 
 orthospira, 21S 
 
 neglecta, 226 
 
 :/(«, 221 
 
 S 
 
58 SPECIES OF ALG^E. 
 
 aa. Cells more than loo/^ in diameter (bV). 
 aa. " from 72 to loo^u " " (cc). 
 
 aa. " less than 70/t " " (id), 
 
 bb. Cells 150-156/i in diameter (the largest species) . crassa, 219 
 
 bb. " 102-iioyW " " setiformis, 219 
 
 cc. Cells 90-1 00/t in diameter . . Jugalis, 219 
 
 cc. " ■j2-'j8jA " " 1-3 times as long as wide nitida; 217 
 
 cc. " 75// " " 2-4 " " " ' 
 
 dd. Cells 58-65/^ " " 
 
 ee. Cells 65-78/^ in diameter 
 
 ^c. • " 58-65/* " " 
 
 7y. Filaments of two diameters, one 125//, the other 80/^, 
 
 incequalis, 218 
 jy. " " same diameter, i5o-i56/( 
 
 //". " " " " 102-iiOyU 
 
 ^. " " " " 1 18-125// 
 
 //. " " " " 54-62/^ 
 
 gg. Cells 4-10 times as long as broad, 24-27/* diam. 
 gg. " 2-12 " " " " " 25-30/4 diam. 
 
 parvispora, 221 
 
 orthospira^ 218 
 
 fluviatilis, 216 
 
 be His, 217 
 
 ortkospira, 218 
 
 . crassa, 219 
 
 setiformis, 219 
 
 maxima, 218 
 
 tnajuscula, 221 
 
 mirabile, 211 
 
 longata, 214 
 
 II. KEY TO FERTILE FILAMENTS OF SPIROGYRA. 
 
 For method of determining the number of bands in the cell, see the 
 
 Key to the sterile filaments of Spirogyra, p. 56 
 § Cell membrane folded in at the ends ((z). 
 § " " not folded in at the ends (7). 
 
 a. Chlorophyll band single, rarely double (^). 
 
 a. " " two or more {K). 
 
 b. Membrane of spore smooth (c). 
 
 b. " " " punctate {g). 
 
 c. Spores elliptical or fusiform (d'). 
 
 c. " ovate or oval (e). 
 
 d. Spore 24-30/t by 50-58// . . . tenuissima, 207 
 '^- " 3°-36/< in dia., twice as long . . inflata, 207 
 
 d. " 27-32/t in dia., 2-4 times as long . . quadrata, 2c8 
 <?. Spore-bearing cells inflated (/). 
 
 e. " " " slightly dilated; spore 26-30/4 in dia., 
 
 Weberi, 208 
 
 f. Spores 36// in diam., 2-3 times ^as long as wide Spreeiana, 208 
 f- " 30-36/t in diam., 2-2 J4 " " " " . Grevilleana, 209 
 
SPECIES OF ALGVE. 59 
 
 g. Mature spores yellow or orange, 40-42/^ in dia. 2-3 times longer, 
 
 calospora, 209 
 h. Spore-bearing cells not swollen, spores twice as long as wide, 
 
 Hantzschii, 211 
 h. Spore-bearing cells swollen («'). 
 
 /. Mature spore yellow, 42-48/i long . . , Hassallii, 210 
 
 i. " " brown, elliptic, 28yU in diameter . . insignis, 210 
 
 J. One chlorophyll band in each cell {k). 
 J. Two or more " " " " " (v). 
 k. Membrane of spore smooth (/). 
 k. " " " punctate (a). 
 
 /. Mature spore yellow (m). 
 I. " " not yellow (/). 
 
 m. Spore cell slightly swollen on one side, spore oval, twice as 
 long as wide gracilis, 211 
 
 m. Spore cell not swollen (ri). 
 m. Spore cell swollen (<?). 
 
 n. Filaments 20-2 2/< in diameter commimis, 213 
 
 n. " 25-30/i " " lo7igata, 214 
 
 0. Filaments 24-26// in diameter Jurgensii, 213 
 
 0. " 40-43// " " . Lutetiana, 214 
 
 /. Spore-bearing cell decidedly swollen {q). 
 p. " " " not or slightly swollen (r). 
 
 /. " " " swollen on one side only varians, 212 
 
 q. Filaments 24-2^/111x1 diameter . mirabile, 211 
 
 q. " 13-20/* " " . . flavescens, 211 
 
 r. Filaments more than 30/t in diameter (s). 
 r. " 30// or less in diameter (/). 
 
 J. Diameter of filaments 33-4o/<; spores polymorphous, quinina, 213 
 s. " " " 40-55/t; spores polymorphous, 
 
 fusco-atra, 215 
 s. " " " 48-75/;; spores broadly elliptic, 
 
 condensata, 215 
 t. Diameter of filaments 25-30/;; spore twice as long as wide, 
 
 longata, 214 
 /. " " " 22-25/<; spore slightly longer than wide, 
 
 subsalsa, 212 
 M. Mature spore yellow, spore cell much inflated, punctata, 215 
 
 V. Spirals 2 (w). 
 
 V. " 3 {y). 
 
 V. " 4 {ee). 
 
6o SPECIES OF ALGjE. 
 
 V. " s (ii). 
 
 V. " 6 or more {Jj). 
 
 w. Spore-bearing cells inflated, spore elliptic or ovate, elongata, 221 
 
 w. " " " not or only slightly swollen (pc). 
 
 X. Filaments 32-40/4 in diam. decimina, 216 
 
 X. " 43-50/^ " "... . dubia, 217 
 
 X. " 55-60/^ " " subaqua, 220 
 
 ;>>. Mature spores yellow, oval, ^ longer than wide . neglecta, 216 
 y. " " not yellow {z). 
 
 z. Diameter of filaments 90-100/4; spore oval . . . jugalis, 219 
 z. " " " 40-65/4 (a(j). 
 
 32-36/^ (dd). 
 
 aa. Spore orbicular, flattened . . orthospira 218 
 
 aa. Spore not flattened (bb). 
 
 bb. Spore spherical or broadly ovate . . . subczqua, 217 
 
 bb. Spore not elliptical or ovate (cc). 
 
 cc. Spore oval-elliptical or subcylindrical . . dubia, adnata, 220- 
 
 cc. Spore oval or subglobose, spore cells 2-4 times longer than wide, 
 
 majuscula, 221 
 
 dd. Sterile cells 7-1 1, fertile cells about 4, times as long as wide, 
 
 rivularis, 220 
 
 ee. Spore-bearing cells much inflated, spore oval, 80/t long, 
 
 fluviatilis, 216 
 ee. " " " slightly or not inflated (77)- •, 
 
 ff. Spore flattend, orbicular orthospira, 218 
 
 ff. Spore not flattened i^gg). 
 
 gg. Diameter of filaments 150-156/1 . ... crassa, 219 
 
 gg. " " " io2-iio/t setiformis, 219 
 
 gg. " " " 90-100/1 ..'.... jugalis, 219 
 
 gg. " " " 72-78/1 (M). 
 
 M. Chlorophyll bands making 1-4 turns in each cell . nitida, 217 
 hh. " " " I ^ " spore 50/1 wide, 
 
 parvispora, 221 
 ii. Spores flattened, orbicular, membrane smooth . . orthospira, 218 
 ii. Spores " " " punctate or porose, 
 
 bellis, 217 
 jj. Filaments of two widths, one 125//, the other 80/t, inmqualis, 218 
 jj. " of equal width (kK). 
 
 kk. Diameter 150-156/1 crassa, 219 
 
 kk. " 118-125/1 maxima, 218 
 
 kk. " I02-II0/1 setiformis, 219 
 
 kk. " 54-62/1 majuscula, 221 
 
SPECIES OF ALG^. 
 71. SIROGONIUM. 
 
 One species 
 
 61 
 
 sticticum, 222 
 
 72. ZYGNEMA. 
 
 §, Color soon becoming dark purple; filaments 20-25// in diam., 
 
 purpureufti, 224 
 § Color green, or when in fruit yellowish or brownish (a), 
 a. Filaments with gelatinous sheath; cells 25/t wide, anomalum, 224 
 a. " " " " cells 40-44// wide, crassum, 224 
 
 a. " without sheath (6). 
 
 b. Spore membrane smooth {c). 
 
 b. " " punctate or granulate {d). 
 £. Diameter of filaments 20-22/* 
 
 c. '• " " zt-2,ofJi . 
 
 d. Diameter of filaments 10-36/*, very variable 
 d. " " " 35-SO-W, 
 
 ermum, 222 
 insigne, 223 
 siellium, 223 
 ci-uciatum, 2 24 
 
 73. ZYGOGONIUM. 
 
 § Diameter of filaments 20/t or less (a). 
 
 § " " " more than 20/* (c). 
 
 a. Diameter of filaments 15-18/* .... ... Agardhii, 226 
 
 a. " " " i8-2o/t {b). 
 
 b. Spore spherical . . .... ... decussatum, 262 
 
 b. " compressed ellipsoid, twice as long as wide . Ralfsii 221 
 
 c. Cells slightly constricted at the joints; spore punctate, 
 
 pectinatum, 225 
 £. " not constricted {d). 
 
 d. Filaments 30-33/t in diameter . aquale, 226 
 d. " 22-24/* " " • parvulum, 227 
 
 74. MOUGEOTIA. 
 
 § Filaments 20-25/* ■'^ diameter (a). 
 
 § " less than 20/* in diameter (^). 
 
 a. Spore spherical, diameter about 40/* . . 
 
 a. " " " " 45/* . 
 
 b. Filaments 15-18/* in diameter 
 
 b. " 10-14/* " " W- 
 
 c. Spore spherical, 25-30/* in diameter 
 *:. " oval, radiately corrugated, yellowish-brown ^/j^foj^frwa, 229 
 *:. " " coarsely granular, dark brown verrucosus, 229 
 
 spharocarpa, 227 
 
 divarecata, 228 
 
 Minnesotensis, 228 
 
 delicatida, 228 
 
62 
 
 SPECIES OF ALGjE. 
 75. MESOCARPUS. 
 
 § Diameter of filament S°M': spore smooth crassa, 230 
 
 § " " " i8>t or less((2:). 
 
 § " " " 2o/< to 32/< {<■). 
 
 a. Spore membrane punctate; filaments 9-15/^ diam. nummuloides, 231 
 
 a. " " smooth (^). 
 
 b. Filaments 8-io/^ in diameter . ... . parvulus, 230 
 
 b. " io-i8yU " " recurvus, 231 
 
 c. Spore membrane punctate; filaments 25-32;^ in diam. robustus, 231 
 e. " " smooth {d). 
 
 d. With short branchlets from the middle of a cell . radicans, 231 
 
 d. Without branchlets {e). 
 
 e. Diameter of spores and filaments about equal 
 e. " " " twice that of the filaments 
 
 scalaris, 230 
 macrospora, 230 
 
 76. PLEUROCARPUS. 
 
 Diameter of filaments 25-30^1* . ... 
 37-40/^ 
 
 One species 
 One species 
 
 77. PLAGIOSPERMUM. 
 
 78. GONATONEMA. 
 
 . mirabilis, 232 
 Columbtanus, 232 
 
 tenue, 233 
 ventricosum, 233 
 
 79. STAUROSPERMUM. 
 
 Diameter of filaments 14-20//, becoming bluish, spore smooth, 
 
 capucinum, 234 
 " " " 8-1 2/<; spore punctate . . quadratum, 234 
 
 " " " 6-8/<; spore smooth . . . viride, 234 
 
 80. CRATEROSPERMUM. 
 
 One species 
 
 lativerens, 235 
 gracilis, 237 
 
 81. CALOTHRIX. 
 
 § Diameter including sheath 6-8/i at base 
 § " " " io-i4/< {a). 
 
 § " " " iS-3°y"('^)- 
 
 a. Sheath lamellose, ends colorless, torn into fibres; cells 6-8yu in diam. 
 
 Meneghiniana, 238 
 a. " not fibrous at ends; brown or black in mass, gypsophila, 237 
 a. " " " " " bluish, rarely brownish, Dillwynii, 237 
 
SPECIES OF ALG^. 63 
 
 b. Floating, dichotomously branched, apices slightly bent; diameter 
 
 15-20/^ . . ... lacucola, 239 
 
 b. Attached (c). 
 
 c. Ends rounded, obtuse, fibrous with age, bluish crustaceum, 239 
 
 c. Ends tapering, or hair-pointed {d'). , 
 
 d. Forming a stratum (/). 
 d. Forming tufts {g). 
 
 f. Branches tapering to a fine hair-point Horsfordii, 239 
 /. " cuspidate at apex or obtuse . . Orsiniana, 236 
 
 g. Tufts small, wavering; filaments somewhat curved, clustered, ra- 
 
 diating; sheath up to 30yu, wide radiosa, 239 
 
 g. Tufts bright bluish, sometimes brown ; sheath widens with age, 
 
 Brebissonii, 23 S 
 
 82. MASTIGONEMA. 
 
 § Filaments rounded or truncate at apex (a). 
 
 § " tapering to a hair-point (b). 
 
 a. Sheath thick, apex truncate, open; diam. Zjx . fertile, 244. 
 
 a. " in young plants ending in a seta, becoming open and trun- 
 
 cate; diam 12 jj. . . . . ... Halos, 243 
 
 b. Mature sheath becoming fibrillose at the ends {c). 
 
 b. Mature sheath not fibrillose or rarely so (d). 
 
 c. Filaments 4|< in diam.; yellowish or greenish; parasitic, 
 
 sejunctttm, 243 
 
 c. Filaments lo-ii/^ in diam.; bluish green; on wet xock=,, fibrosa, 244 
 
 d. Thallus subglobose or fusiform, blackish, firm; filaments bluish, 
 
 diam. 6-7/* ... ... elongatum, 243 
 
 d. Not subglobose; filaments straight, bent or curved, cerngineum, 241 
 
 83. ISACTIS. 
 
 a. Filaments closely compacted, suddenly acuminate . flmiiatilis, 244 
 a. Filaments erect, awl-shaped caspitosa, 245 
 
 84. GLCEOTRICHIA. 
 
 § Sheath irregularly constricted; variable in size and form, natans, 246 
 § " close, simple, not inflated nor constracted, subspherical, 
 
 pisum, 247 
 
 85. RIVULARIA. 
 
 a. Sheaths inconspicuous; filaments clustered, base about 7/< diam., 
 
 echitiulata, 249 
 
 a. Sheaths distinct; filaments some apparently withered, others more 
 
 swollen, base 8-9/* diam. . dura, 249 
 
64 SPECIES OF ALG^. 
 
 86 SCYTONEMA. 
 
 § On warm sandy soil; blackish; diam. with sheath io-i4yu, 
 
 thermak, 259 
 § On bark of trees, in small, olive green or brown tufts («). 
 § On old wet wood {b). 
 § On moist rocks, wall, earth, etc. {c). 
 § Submerged in sweet water, [g). 
 
 § Floating in sweet water; diam. of filaments 12-20/^ . . natans, 251 
 § " " " " " " " i4-i8yu cincinnatum, 254 
 
 § Brackish or salt; filaments curved and interwoven, f>4ryj-^<:,4/(?r«»?, 253 
 a. Filaments bluish; branches forming long loops, ends continuous, 
 
 mirabilis, 255 
 
 a. Filaments creeping; branches not looped, ends not continuous, 
 
 cortex, 256 
 
 b. Diameter of filaments with sheath about 2o/< . . intertextuni, 258 
 b. " " " " " " io-15/f . . simplice, 259 
 
 b. " " " " " " 20-25/^ . . Heppii, 260 
 
 c. More or less cushion-like, may become confluent (d). 
 c. Forming a stratum {e). 
 
 c. Tufted or turflike (/). 
 
 d. On pots etc. in conservatory; filaments bluish, sheath close, color- 
 
 less . .... Castellii, 255 
 
 d. On moist rocks, etc; sheath thick, often with a lime deposit, 
 
 cinereum, 258 
 
 e. Diameter of sheath 25-33/1, lamellate .... myochrous, 252 
 e. Filaments flexuous, long, apices rounded; diam. i2-i6-25/(, 
 
 cataracta, 252 
 
 e. " entangled, branches mostly single; cell ends somewhat 
 
 contracted ... gracile, 253 
 
 e. Filaments interwoven, cells about as long as wide . turfosum, 253 
 e. " " sheath dissolving into fibrils, 
 
 Notarissii, 255 
 /. Branches thianer, often JS4 or less than the st&m,tolypotrichoides, 250 
 
 f. Branches thinner at base only, quickly enlarging . Ncegelii 252 
 
 g. Filaments somewhat curved, branches thinner, bluish, 
 
 calotrichoides, 251 
 
 87 SYMPHYOSIPHON. 
 
 §. Diameter of filament without sheath 7/^ or less (a). 
 
 §. " " " " " more than 7// {b). 
 
SPECIES OF ALG/E. 65 
 
 a. Diameter of filaments 2-3//, of sheath at the base 6-7/^, apex 3-4// 
 
 crustaceus, 263 
 
 a. " " " 5-7/^ . ambiguum, 262 
 
 b. Surface pubescent; black; filaments 9-15/* . . Castelli, 262 
 
 b. " " filaments i5-20yu . Aiistinii, 262 
 (5. Surface not pubescent (^). 
 
 c. Diameter of filaments 15/i or less {d). 
 
 d. Filaments brown, 12-15/Y, cells j^ as long as wide, 
 
 Bornetianum, 261 
 d. " bluish, 8-io/A, cells about as long as wide hirtubis, 261 
 
 d. " bluish, 8-12/^, sheath wider at base Hofmanni, 262 
 
 88. TOLYPOTHRIX. 
 
 § On tree trunks, surface velvety, blackish; diam. ii-i4yM, 
 
 trimcicola, 266 
 
 § On wet exposed rocks {a). 
 
 § Aquatic (U). 
 
 a. Reddish brown; filaments with dark transverse bands, 
 
 Ravenellii, 265 
 
 a. Red, purple and black; filaments much branched . rupestris, 265 
 
 b. Spherical, pea-like masses, filaments bluish , yEgagrophila, 264 
 
 b. Not spherical masses (c). 
 
 c. Diameter of filaments 3-4/U . . . . . , tenuis, 265, 
 c. Diameter 10-17/^ (d). 
 
 c. " 9-11;^, often interrupted by inclined disc-like cells, 
 
 muscicola, 264 
 
 d. Impossible to separate here, distorta, 26y, ptikhra, 26^; flaccida, 265 
 
 89. PLECTONEMA. 
 
 One species . . . . mirabile, 266 
 
 90. PETALONE.MA. 
 
 One species . . . alatiun^ 267 
 
 91. SIROSIPHON. 
 
 § Aquatic; brown; cells of stems 2-rowed, in branches i-rowed, 
 
 ocellatus, 272 
 
 § On old wood and tree trunks; in black spots; often aggregated, 
 
 lignicola, 273 
 
 § In soda springs, west; not fully described . Brandegeei, 274 
 
 § On damp soil or wet rocks (a). 
 
66 SPECIES OF ALG^. 
 
 a. Branches polymorphous (6). 
 
 a. Branches not polymorphous (d). 
 
 b. Apices obtusely rounded (c). 
 
 b. " ' attenuate, or .filaments with scattered spines, Alpinus, 269 
 
 c. Plants attached only by the mucus surrounding them, 
 
 pulvinatus, 268 
 
 c. Plants firmly attached to rocks and stones coralloides, 270 
 
 d. Diameter of filaments about 50//. Alpine Crameri, 273 
 
 d. " " " less than 50/^ (e). 
 
 e. Cells broadly ovate, moniliform; on wet rocks compactus, 271 
 e. Cells small, not moniliform (y^). 
 
 /. Filaments flexuous, curved, not rigid, branched, i6-i7yu, 
 
 scytonematoides, 271 
 /. " short, intricate; branches many, irregular {g). 
 
 g. Mature sheath deep reddish brown, of branches yellowish, apices 
 colorless ... . . . argillaceus, 274 
 
 g. Mature sheath colorless, hyaline, rarely light yellow crustaceus 274 
 
 92. HAPALOSIPHON. 
 
 § Aquatic, often parasitic {a). 
 § On tree trunks (c). 
 § On wet rocks((^). 
 
 a. Diameter of filaments about 15/^; much branched, bluish; sheath 
 often yellowish brown ... . . Brebissonii, 276 
 
 a. Diameter of filaments less than 15/* {Ji). 
 
 b. Cells about as long as wide; filaments io-i2yU . . Braunii, 275 
 b. Cells about as long as wide; filaments 7-8//, branches 3-4/*, 
 
 tcnuissimus, 277 
 
 b. Cells equal to twice as long as wide; filaments 8-1 lyu 
 
 fuscescens, 277 
 
 c. Filaments 20-25//, branches rather thinner . byssoideus, 276 
 
 d. Filaments apt to be solitary, cells moniliform, bluish, 
 
 torulosus, 276 
 
 93. NOSTOC. 
 
 § Fronds soft, often without definite form [A). 
 
 § Fronds globose or nearly so, or discoid or linear, often irregular 
 with age {B). 
 
 A. Aquatic (a). 
 
 B. Aquatic (c). 
 B. Terrestrial {b). 
 
SPECIES OF ALG^. 67 
 
 a. Without mucilage; filaments in irregular masses, coiled, 
 
 tenuissimum, 282 
 
 a. With .mucilage; joints equal, rather distant . . comminutum, 282 
 
 b. Soft, becoming gelatinous cushions (if). 
 
 b. " " tongue-shaped, plane, irregularly expanded {i). 
 
 b. With a firm coating (/). 
 
 c. Fronds with a firm coating (^). 
 
 d. Mature frond suborbicular, often perforated and expanded, 
 
 commune, 283 
 
 d. " " linear, straight, long; filaments parallel, 
 
 flagelliforme, 285 
 
 e. Globose thalli within a subspherical gelatinous mass, muscorum, 282 
 e. Globose, firm; filaments olive . . . . . Aumifusum, 282 
 e. Suborbicular, soft; filaments bluish green . . . calcicola, 283 
 /. Globose, firm, coating brownish; joints -subspherical, 
 
 sphcericum, 283 
 /. " soft, sheath often colored and general mucus colorless, 
 
 rupestre, 283 
 /. " not I mm in diam.; cells cylindrical, slightly constricted, 
 
 macrosporum, 284 
 g. Cells of two kinds, unequal (K). 
 g. Cells uniform, regular [t). 
 
 h. One kind elongated, the other spherical; bluish . cceruleum, 284 
 i. Fronds globose, from 2 mm to size of a cherry . pruniforme, 284 
 /. " rounded or discoid, becoming hollow (/), 
 / Fronds subglobose, warty, brownish green . . verrucosum, 284 
 /• Fronds suborbicular, erect, smooth, tenacious . . Alpinum, 285 
 
 94. ANAB^NA. 
 
 § On tree trunks, near the water's edge, bluish . cupressaphila, 288 
 § In brackish ditches; stratum bluish .... oscillarioides, 288 
 § In sweet waters (a), 
 a. Cells 3-4 yw in diameter [b). 
 
 a. Cells 4-ii/<in diameter {c). 
 
 b. Deep blue green; filaments curved, almost parallel, 
 
 variabilis, 287 
 
 b. Pale bluish, sometimes yellowish; filaments curved, usually in 
 
 clusters . . .... ... . stagnalis, 288 
 
 c. Filaments curved, often coiled ... ... flos-aqua, 286 
 
 c. Filaments straight, often coiled when young . . gigantea, 287 
 
68 
 
 SPECIES OF ALG^. 
 
 95. SPHjEROZYGA. 
 
 § Filaments in 2-4 in. long, vertical, closed tubes, % in. thick, more 
 or less attached . ... . . . . saccata, 290 
 
 § Filaments straight, in a definite gelatinous sheath; joints subspher- 
 ical, spores cylindrical . , .... Smithii, 290 
 
 § Filaments equal, curved or coiled in thin bluish stratum, 
 
 Hassallii, 289 
 § Filaments subsolitary or associated, bluish, variously curved, 
 
 polysperma, 289 
 
 One species 
 One species 
 
 96. APHANIZOMENON. 
 
 97. NODULARIA. 
 
 98. CYLINDROSPERMUM. 
 
 § Spores about 14/^ in diam.; cells 3-4;^ 
 
 § " " ^oix(a). 
 
 a. Diameter of cells about \jx . 
 
 a. 
 
 . . flos-aqucR, 291 
 
 paludosa, 291 
 
 macrospermum, 292 
 . . flexuosum, 292 
 
 H ti 
 
 filaments 
 
 3ju; terminal cells with flexible, hair-like 
 . . . . comatum, 293 
 
 One species 
 
 Length 16-17/^ 
 25-35/^ 
 
 99. CRENOTHRIX. 
 
 100. CHAMiESIPHON. 
 
 polyspora, 294 
 
 incrustans, 295 
 confervicola, 295 
 
 lOI. LYNGBYA. 
 
 § In brackish water; filaments rigid, curved; cells 3-4 times wider 
 than long, diam. 20-28/^, astuarii, 296 
 
 § On moist ground or wet rocks (a). 
 § Aquatic {g). 
 
 § Marine . majuscula, 297; vermicularis . Omitted. 
 
 a. Stratum bright green; filaments 8-io/i in diam. . arenarium^ 299 
 
 a. Not pure green (V). 
 
 b. Stratum blue green (c). 
 
 b. Stratum blackish green (e). 
 
 b. Stratum blue, red, purplish, olive, brown or becoming yellow (/). 
 
SPECIES OF ALG^. 69 
 
 c. Filaments 4yu in diameter, curved; substratum whitish, 
 
 inundata, 303 
 c. Filaments 3-3.5 in diam., slightly curved cataracta, 302 
 
 c. Filaments 7-8 in diam. {d). 
 
 d. Cells finely punctate; on rocks . ruprestre, 300 
 
 d. Cells not punctate, joints somewhat contracted; moist ground, Fla. 
 
 subtorulosa, 300 
 
 e. More or less radiating; apices obtuse Juliana, t,o\\ Retzii, 302 
 
 /. Filaments straight, sheathed, 5-9/* diam vulgaris, 300 
 
 /. " slightly curved or flexuose; with sheath 40-80/^ diam., 
 
 pallida, 298 
 /. " forming a purple stratum, long, waving, 8-9 yu diam., 
 
 tinctoria, 301 
 g. In alpine lakes or marshes cincinnata, 296- 
 
 g. Not alpine {K). ^ 
 
 h. Tufted on stones; filaments 40-45 to 50-60/1 diam. . Wollei, 297 
 h. In a stratum or floating singly (/). 
 
 /. Filaments i2-i8/< diam. . . obscura, 298 
 
 /. " 7-9.5 diam., matted; wet marsh bottoms, 
 
 phormidium, 299 
 /. " 5-7 diam. (y). 
 
 /. Stratum thin, paper-like, substratum, pallid, of empty sheaths, 
 
 papyrina, 302 
 / " membranous, mucous, filaments yellowish, 
 
 interrupta, 302 
 
 102. SYMPLOCA. 
 
 § Stratum dull green or blackish; filaments 4-6/1 diam. 
 
 Friesiana, 304 
 § Stratum bluish green; filaments 3-4/1, lucifuga, 7,oy, fuscescens, 304 
 
 103. MICROCOLEUS. 
 
 § On rocks or moist earth {a). 
 
 § Aquatic (b). 
 
 a. Diameter of filaments 3}^ to 4^/< anguiformis, 306 
 
 a. " " " 5-6/< . . terrestris, 305 
 
 a. " " " 12/1 . .... . Ravenellii, 307 
 
 a. " " " io-13/i; in a thin membrane amorpha, 304 
 
 i. Stratum cushion-like, large, 6-8 in. or more in diam., 
 
 pulvinatus, 305 
 
70 SPECIES OF ALG.E. 
 
 b. " thin, skin-like, expanded gracilis, 306 
 
 b. " dense gelatinous, on partly submerged stones, 
 
 heterotrichum, 307 
 
 104. OSCILLARIA. 
 
 Articulations indistinct (a). 
 
 '• about as long as wide (c). 
 
 " one-half " " " " \d). 
 
 " less than half as long as wide (/). 
 In hot water from waste steam pipes; diam. 1.8-2.8/^, 
 
 amphibia, 310 
 
 a. 
 
 Not in hot water (b). 
 
 
 
 b. 
 
 Filaments i-i.S/< in diam. 
 
 subtilissima. 
 
 309 
 
 b. 
 
 " i.8-2.5;if in diam. 
 
 tenerrima. 
 
 309 
 
 b. 
 
 • 2}x in diam. 
 
 . . detersa. 
 
 310 
 
 c. 
 
 Diameter 2.8-3/*, rarely 3.5/^ 
 
 . elegans. 
 
 310 
 
 c. 
 
 2.7-3.2/^ 
 
 gracillima. 
 
 3" 
 
 c. 
 
 " 3yu . ... 
 
 chlorina, leptotricha. 
 
 311 
 
 c. 
 
 " 4-S-S-5/'; 0"^ moist ground 
 
 antliaria. 
 
 310 
 
 d. 
 
 Floating on hot water; diam. 6-7/t 
 
 Cortiana, 
 
 313 
 
 d. 
 
 On wet ground {e). 
 
 
 
 d 
 
 Aquatic (/). 
 
 
 
 s. 
 
 Diameter 4.s-5yu; on shaded mud 
 
 brevis, 
 
 312 
 
 e. 
 
 " 4-4.7/*; in greenhouses 
 
 violacea. 
 
 311 
 
 e. 
 
 " 6-7.75/*; i" swampy places 
 
 limosa, 
 
 313 
 
 e. 
 
 " 7-8/1; wet grounds, Fla. . 
 
 chalybea. 
 
 314 
 
 f. 
 
 In large jelly masses; diam. 4-5-6/* 
 
 cruenta. 
 
 312 
 
 /• 
 
 Not in distinct jelly masses {g). 
 
 
 
 g- 
 
 Stratum black (K). 
 
 
 
 g- 
 
 " bluish or not black (z). 
 
 
 
 h. 
 
 Filaments with two short cilia at the end; 
 
 diam. 4.6-6.6/*, 
 
 
 
 
 subfusca, 
 
 312 
 
 h. 
 
 Filaments without cilia; diam. 9-10/t 
 
 . nigra. 
 
 315 
 
 i. 
 
 Diameter 9-1 1/*; stratum thin 
 
 anguina 
 
 314 
 
 i. 
 
 " 5-5-8-2/^ 
 
 tenuis, 313; natans. 
 
 314 
 
 i. 
 
 4-5>« 
 
 cerugineo-ccerulea, 
 
 311 
 
 J- 
 
 In brackish or submarine waters (k). 
 
 
 
 J- 
 
 In sweet waters (/). 
 
 
 
 k. 
 
 Diameter 18-20/* 
 
 Grateloupii, 
 
 316 
 
 k. 
 
 12-15/* . . 
 
 . littoralis, 
 
 317 
 
SPECIES OF ALG^. 
 
 /. Diameter 30yU or more (m). 
 " less than 30// (n). 
 
 m. Cells :^ to ^ as long as wide; diam. 30-45// 
 m. Cells about \ as long as wide . 
 n. Diameter less than 19/t (0). 
 n. " ipyu or more (/). 
 
 o. Diameter 15/i; cells /^-/^ as long as wide 
 0. " io-i8/<; variable 
 
 /. Diameter 19-22//; cells Yi-yi as long as wide 
 p. " ,23-28/i; cells |-|- " " " " . 
 
 71 
 
 princeps, 2>'^1 
 imperator, 317 
 
 . per cur sa, 315 
 
 Frxlichii, 315 
 
 major, 316 
 
 Bonnemasotiit, 316 
 
 105. BEGGIATOA. 
 
 «. Diameter of filaments 1-1.5/i 
 «. " " " 1. 8-2.5// 
 
 niveicm, 318 
 leptom itiformis, 319 
 
 106. 
 
 LEPTOTHRIX. 
 
 ^. 
 
 In hot waste water, waving, 6 mm thick hinmilia, 320 
 
 On old wet walls; filaments strongly curved . calcicola, 319 
 
 On wet wood, herbaceous green; diam. 1.8-2.25// herbacea, 320 
 
 Aquatic, sometimes on wet rocks {a). 
 Forming spherical masses, light yellowish, tough, hollow, 4-8 mm 
 
 diam . . ... bullosa, 321 
 
 Forming cloud-like, floating fragile masses, yellowish; filaments 
 about 2// diam. . . ochracea, 322 
 
 Forming a stratum (V). 
 Forming a tuft (e). 
 Filaments 3// or more in diam. -. tenax, 
 
 " less than 3// in diam. {/). 
 
 Stratum composed of clusters, light bluish . rigidula, 
 
 " more or less expanded [d). 
 Bluish or greenish above, yellowish or colorless below, 
 
 laminosa, 
 Bright bluish, thin, membranaceous . ceruginea. 
 
 Bluish, becoming yellowish . . ccespitosa, 320 
 
 Purple green or amethyst . . tinctoria, 321 
 
 319 
 
 321 
 
 321 
 319 
 
 I06fl. ASTEROTHRIX. 
 
 One species 
 
 Creginii, 322 
 
72 SPECIES OF ALGM. 
 
 107. SPIRULINA. 
 
 § A continuous, twisted, ring-like band . . duplex, 323 
 § Not continuous but filamentous {a). 
 
 In stagnant water; diameter 7-8/x . . Jenneri, 323 
 
 a. In sulphur springs; diameter 4-5 }i tenuis sirna, 323 
 
 a 
 
 108. SPIRILLUM. 
 
 One species . . . undula, 324 
 
 109. GLCEOTHECE. 
 
 One species . . . confluens, 325 
 
 no. APHANOTHECE. 
 
 a. More or less globose, size of a cherry, usually floating, • 
 
 prasina, 325 
 a. Gelatinous, 4-6 mm thick, in siiiall masses; wet ground, 
 
 pallida, 325 
 
 HI. SYNECHOCOCCU.S. 
 
 One species; on wet rocks a.ruginosus, 326 
 
 112. MERISMOPEDIA. 
 
 a. Rarely more than 4-64 cells, 3-5/* diam glauca, 326 
 
 a. Often of 256 geminate cells, 4-^.^fi diam. . convoluia, 326 
 
 113. CCELOSPH^RIUM. 
 
 One species . Keutzingianum, ^2"] 
 
 114. CLATHROCYSTIS. 
 
 One species . ... aruginosa, 327 
 
 115. GOMPHOSPH^RIA. 
 
 One species . . . . . aponia, 328 
 
 116. MICROCYSTIS. 
 
 One species; on moist timbers, ground, tree trunks, protogenita, 328 
 
 117. ANACYSTIS. 
 
 a. Cells I /^ in diam.; thallus light brown . . . . brunnea, 329 
 
 a. Cells 2-3/< diam. " glaucous or pale bluish . pulvereus, 329 
 a. Cells 3-4/^ " " globular, margins colorless, 
 
 marginata, 329 
 
 118. POLYCYSTIS. 
 
 One species ... . icthyoblabe, 330 
 
SPECIES OF ALG^. 73 
 
 Iig. GLOeOCAPSA, 
 
 These forms have been divided into as many species as there 
 are different colors to the cells or to the integument; they are green, 
 red, black, brown, coppery, orange, yellow, olive, purple or colorless. 
 They have no value as distinct plants, being phases or stages of de- 
 velopment of higher Algae. Mr. Wolle considers them to be spores 
 or macrogonidia, of Sirosiphon . 331 
 
 120. APHANOCAPSA. 
 
 § Submerged; thallus globose . Grevillei, 333 
 
 § On wet rocks; thallus expanded virescens, 333 
 
 121. CHROOCOCCUS. 
 
 a. Cell contents bright bluish, becoming brownish; 13-25// diam. 
 
 turgidus, 334 
 a. " " reddish or yellowish brown; i2-i6/< diam. 
 
 rwfescens, 335 
 a. " " blue green; 3-6// diam. cohxrens, 335 
 
PART III. 
 
 Key to the Genera and Species of the 
 Desmidieae. 
 
A KEY TO THE GENERA AND THE SPECIES OF THE 
 
 DESMIDIE^.* 
 
 Plants composed of symmetrical cells, usually constricted in the 
 middle, often of beautiful, ornamental forms, single or conjoined 
 into filiform series, and sometimes involved in a maternal jelly. 
 Asexual multiplication takes place by transverse division, or by sep- 
 aration of the semi-cells, and by development of new parts similar to 
 the mother semi-cells.** 
 
 *The greater part of the following key was originally published in ' 'The American 
 Monthly Microscopical Journal," and is here reproduced by permission of the editor. 
 **Wolle: Desmids of the United States. 
 
KEY TO THE GENERA OF THE DESMIDS. 
 
 § Cells united into filamefnts (a). 
 
 § Cells not united into filaments (g). 
 
 a. In a transparent, jelly-like sheath (b'). 
 
 a. Not in a jelly-like sheath {d'). 
 
 b. Cells with 2 teeth on each narrow end Desmidium, 6 
 
 b. Cells deeply constricted, almost into two parts (c). 
 
 b. Cells not deeply constricted, and without teeth . . Hyalotheca, 3 
 
 c. With 'claspers' across the sutures ... . Onychonema, 9 
 
 c. Without 'claspers;' cells united by a narrow isthmus, Sphcsrozosma, 8 
 
 d. Band not twisted; cells with 'claspers' across the sutures, 
 
 Onychonema, 9 
 d. " " cells without 'claspers' (e). 
 
 d. Band twisted; cells triangular or quadrangular . Desmidium, 6 
 
 e. Cells barrel or hub-shaped, with i or 2 median bands, Bambusina, 4 
 e. " " " without bands, the sutures projecting, 
 
 Leptozosma, 5 
 e. Cells cylindrical, sometimes swollen at base (/). 
 e. Cells quadrangular, deeply constricted, often slightly twisted, 
 
 Phymatodocis, 7 
 /. Ten to 30 times longer than broad . Gonatozygon, i 
 
 /. Three to 6 times longer than broad . . . Genicularia, 2 
 
 g. Cell more or less crescentic . Closterium, 13 
 
 g. Cell cylinilrical, fusiform, dumb-bell or hour-glass shaped (/). 
 g. Cell flattened; oiljiralar, oblong, or elliptical {K)'. 
 h. Mostly orbiculai- or broadly elliptical; centre deeply constricted, 
 the semi-celh 3-5 lobed, the lobes entire or variously incised, 
 
 Micrasterias, 22 
 
 h. Mostly oblong or elliptical; margins wavy, the depressions rounded; 
 
 ends usually notched or incised ... . Euastrum, 21 
 
GENERA OF DESMIDS. 79 
 
 /. Cell constricted in the middle; no arms nor spines (/). 
 
 i. " " " with arms or spines (/). 
 
 /. Cell not constricted; no arms nor spines (ni). 
 
 j. Cell cylindrical, ends simply notched .... Tetmemorus, i8 
 
 j. " " ends rounded, truncate or divided (k). 
 
 j. Cell more or less dumb-bell, or hour-glass shaped {/). 
 
 k. Cell 6 to 30 times longer than broad Docidiuui, 14 
 
 k. Cell 2-5 times longer than broad; ends rounded, Calocylindrus, 16 
 /. Arms 2, 3 or more, radiating . . . . . Staurastrum, 23 
 
 /. Arms none; semi-cells with a central, rounded, truncate or dentic- 
 ulate tubercle; spines usually numerous and marginal, 
 
 Xanthidium, 19 
 /. Arms none; no central tubercle; spines 4to 8, two on each end, ) 
 /. " " " spines 16, four on each end, j 
 
 Arthrodesmns, 20 
 m. Chlorophyll in one or more spiral bands . . . Spirotcenia, 11 
 m. " not in spiral bands (n). 
 
 n. Surface rough with tooth-like or rounded elevations, Triploceras, 15 
 n. Surface without tooth-like elevations; ends rounded (0). 
 0. Cells in mucus, short, cylindrical or oval . . . Mesotmnium, 10 
 o. Cells not or rarely in mucus . . ... . Penium, 12 
 
 p. End view 3-6 or more angular (r). 
 
 p. End view not angular (s). 
 
 r. Angles obtuse, acute, or with horn-like prolongations, 
 
 Staurastrum, 23 
 s. Margins smooth, dentate or crenate; no spines . Cos?nartum, 17 
 
KEY TO THE SPECIES OF THE DESMIDS. 
 
 I. GONATOZYGON. 
 
 1. Cells swollen at base, with 6 longitudinal lines of short seta, 
 
 sex-spini/ei-um.'** 
 
 2. Cells not swollen at base {a). 
 
 a. With hair-like spines clothing the surface- . . . pilosum, 22 
 a. Without hair-like spines; surface minutely roughened, asperum, 22 
 
 2. Genicularia.* Fig. 2. 
 
 1. Cells 3^ to 6 times longer than broad; granules in spirals, 
 
 Americana* 
 I. Cells 10-12 times longer than broad; granules scattered, spiroicenia* 
 
 3. Hyalotheca. Fig. 3. 
 
 I. Cells slightly constricted, length }4 the width, sides not notched, 
 
 dissiliens, 2 2 
 
 1. " " " " " sides arched, cen- 
 
 trally notched . hians.** 
 
 2. Cells slightly concave, length twice the width . undulata, 23 
 
 3. Cells not co.istricted, margins straight; sheath wide, mucosa, 23 
 3. " " " " sheath absent, duhia, 24 
 
 4. Bambusina. Fig. 4. 
 
 1. Cells hub-shaped, somewhat longer than broad Brebissonii, 24 
 
 2. Cells hub-shaped, nearly twice as long as broad gracilescens.** 
 
 3. Cells subcylindrical, 4 times longer than broad ddicatissinia, 25 
 
 *Journ. R. Micr. Soc, Dec, 1885, 
 **F. W. Alg£E, p. 21. 
 
SPECIES OF DESMIDS. 
 
 8l 
 
 5. Leptozosma. 
 An immature form of Desmidium, 6. 
 
 6. Desmidium. Fig. 6. 
 I. Mucous sheath present . . 
 I. Mucous sheath absent (a), 
 a. Cells united by their entire end margins {b). 
 
 a. Cells united by the outer portions of the ends (</). 
 
 b. Cells nearly twice as long as broad . . 
 b. Cells less than twice as long as broad (c). 
 
 Celjs in side view quadrate qtiadratutn, 26; quadratigulatum, 27 
 
 cyliiidricum, 25 
 
 lonsatiim, 26 
 
 Swartzii, 26 
 
 diagonum, \e^<) 
 
 Baileyi, 2 7 
 
 Nordstedtianiim, 28 
 
 Cells in side view triangular . . . 
 
 Borders crenate or undulate aptogonmm, 27; 
 
 Borders straight, filament twisted 
 
 7. Phymatgdocis. Fig. 7, 
 One species 
 
 8. SphjErozosma. Fig. 8. 
 
 1. Cells twice broader than long, lobes not constricted (a). 
 
 1. " " " " lobes constricted near the end, 
 
 constrictum 
 
 2. Cells twice longer than broad, in sheath or not excavatum, 
 2. Cells less than twice longer than broad (b). 
 
 a. Cells closely approximate, ends rounded 
 
 a. " " " ends truncate, concave, 
 
 a. Cells more or less remote, ends rounded . . 
 
 b. Ends pointed; semi-cells remote; sinus deep, wide. 
 
 29 
 
 b. Ends rounded, spinous; cells slightly constricted. 
 
 . pulchrum, 29 
 
 rectangiilare, 3 1 
 
 vertebraium, 30 
 
 nioiiilifonne.** 
 
 spinulosum, 31 
 
 b. Ends rounded, not spinous; cells deeply constricted, filifornie, 29 
 
 Wallachii, 30 
 pitkkelhim.** 
 
 b. End truncate, concave 
 
 b. Ends truncate, not concave 
 
 fig. 
 
 FIG. 10. 
 
 serratuin, 30 
 NordstedtianHm.\ 
 
 9. onychonema.* 
 
 1. Cells with spine-like projecting ends 
 
 2. Cells without spine-like ends 
 
 10. MESOT/ENIUM. 
 
 I. Cells cylindrical (a). 
 
 I. Cells oval or elliptical, about twice longer than wide, in mucus on 
 wet wood .... . . micrococcuin, 32 
 
 *Mr. WoUe joins this to Sphcerozosma . f Journ. R. Micr. Sec, Dec, 1885. 
 **F.-w. AlgK, .pp 23 et seq. 
 
82 SPECIES OF DESMIDS. 
 
 a. Mucous masses floating; cells 2-2 J^ times longer than wide, 
 
 Braunii, 31 
 
 a. Mucous masses mingled with filamentous algse; cells 3-4 times 
 longer than wide Endlicherianum, 32 
 
 a. Mucous masses on wet rocks and mosses; cells 2-3 times longer 
 than wide clepsydra, 32 
 
 II. SPIROT^NIA. FIG. II 
 
 I. Spiral band single {a). 
 
 I. Spiral bands more than one . . obscura, 33 
 
 a. Cell 8 to 10 times longer than broad condensata, 33 
 
 a. Cell 4 times longer than broad bryophila, 33 
 
 12. PENIUM. FIG. 12. 
 
 I. Chlorophyll interrupted by i central transverse band (a). 
 I. " " " 3 transverse bands; cytioderm smooth, 
 
 interruptum, 35 
 
 1. " " " " " " cytioderm spirally 
 striate spirostriolatum.** 
 
 2. Chlorophyll concentrated into 2 or more nuclei; in mucus, crawfl, 37 
 
 3. " diffused {b). 
 
 a. Ends truncate, square . truncatum, 35 
 
 a. Ends not truncate; cells slightly constricted, sides straight, 
 
 minutum, 35 
 a. " " " " " " sides convex, 
 
 cruciferum** 
 
 a. " " " cell not constricted, 3-5 times longer than 
 
 wide . . digitus, 34 
 
 a. Ends not truncate; cell not constricted, 5-6 times longer than 
 
 wide . . closterioides, 35 
 
 b. Cytioderm smooth {c). 
 
 b. " with pearly granules in longitudinal rows, 
 
 margaritaceum, 34 
 
 c. Cells in mucus, diameter -g-i-p- to -^^ in. (63-83/<) 3 to 4 times as, 
 
 long as wide . . . oblongum, 34 
 
 c. " " " about twice as long as wide . rupestre, 37 
 
 c. " " " more than 3 times as long as wide . Brebissonii, 36 
 
 c. Cells not in mucus; each semi-cell a truncated cone . tumidum.** 
 
 d. Cells oblong, often slightly constricted .... lamellosum, 34 
 d. Cells subcylindrical, in families of various sizes intermingled, 
 
 polymorphum, 36 
 d. Cells subcylindrical, not in families . r . . . . Jenneri, 36 
 d. Cells broadly fusiform, 4-5 times longer than wide, navicula, 36 
 
 **J. R. M. S., Feb. '89. ' 
 
SPECIES OF DESMIDS. 83 
 
 13. CLOSTERIUM. FIG. 13, a, 6, C. 
 § Ends not or but slightly produced (i). 
 § Ends produced into long, often setiform, beaks (2). 
 I. Cells straight or slightly curved; ends slightly tapering (a). 
 I. " " •' " " dorsum convex, ventrum nearly^ 
 
 straight (g). 
 I. Cells conspicuously curved; ventrum concave, with a central in-- 
 
 flation (?'). 
 
 1. Cells conspicuously curved; ventrum without an inflation (/). 
 
 2, Body margins equally convex; beaks longer than body, f^/a^^«OT, 47 
 2. " " " " beaks ^ as long as the body, 
 
 2. Body margins not equally convex (m). 
 
 a. Length 5-12 times the width (6). 
 
 a. Length more than 12, less than 20 times the width (f). 
 
 a. Length 20 times or more than the width (/). 
 
 d. Ends suddenly contracted; cell fusiform, 5 times longer than wide, 
 smooth . ..... nasuium, 41 
 
 d. Ends not contracted, but tapering, acute; chlorophyll bands sev- 
 eral, granules in i row . . . lanceolatum. 39 
 
 b. Ends not contracted, rounded {c). 
 
 b. " " " truncate {d). 
 
 c. Cell slightly curved, small, 6-12 times longer than wide, smooth, 
 
 acututn, 44 
 c. " " " S-io longer than wide, smooth, obtusum, 38 
 
 c. Cell nearly straight, decussately striate . decussatum, 39 
 
 c. " " " smooth, apices obtusely rounded, didymotocum* 
 
 d. Cell slightly curved, 6-12 times longer than wide, striate; vacuole 
 
 distinct didymotocum, 39 
 
 e. Cytioderm with 4-5 longitudinal strise, often with 2 or 3 transverse 
 
 bands and decussating stri« . . . angustatum, 40 
 
 e. Cytioderm striate; ends slightly incurved; globules about 20 in each, 
 
 semi-cell, axillary , ... Itneahan, 43 
 
 e. Cytioderm striate; ends truncate, corners rounded; with three 
 
 transverse sutures ... subdirectum.** 
 
 f. Diameter 2/< or less; smooth gracillmia-lmvissinui* 
 f. Diameter 3-4yU; slightly curved, smooth, or with 1-4 trans, strias, 
 
 subtile, 158 
 
 / " 5-6/^; smooth . gracile, 39 
 
 / " io-i6/i (1). 
 
 *F.-w. Algee. p. i^etseq. **J. R. M. S., Feb. 8g. 
 
84 SPECIES OF DESMIDS. 
 
 /. Diameter 18//; about 30 times as long as wide, smooth, ends 
 
 rounded . . . . . ... . . Brebissonii* 
 
 f. " 20-21/^; striated, ends rounded . ... prelongum* 
 
 f. " 36/i; about 20 times as long as wide, smooth, ends not 
 curved . . . . . ensis* 
 
 T Surface smooth; slightly tapering from the middle . strigosum, 42 
 Tf " longitudinally striate only; diam. 11-12//, juncidum, 38 
 
 ^ " " " with 1-4 trans, striae; diam. 12-13//, 
 
 7nacilentum, 38 
 
 g. Ends inclined upward at a dorsal depression; ventrum slightly con- 
 
 cave; strise fine, numerous . turgidum, 41 
 
 g. Ends suddenly contracted to a narrow point; cell slightly curved, 
 
 attenuatum, 41 
 g. Ends not suddenly contracted (/%). 
 h. Cytioderm deeply striate; distinctly granulate or areolate, 
 
 areolatum, 43 
 h. " more or less distinctly striate; cell linear-fusiform, 
 
 15-24 times longer than wide . . acerosum, 41 
 
 h. Cytioderm 9-12 longitudinally costate; cell fusiform, 4-5 times 
 
 longer than wide . . . subcostatum* 
 
 h. Cytioderm more or less distinctly striate; cell semi-lunar, 5-6 times 
 
 longer than wide . ... Lunula, 40 
 
 i. Diameter -j-i-ij to -j^ in. (75-110//); cytioderm smooth, 
 
 Ehrenbergii, 45 
 /. Diameter j-^to -j-|-g- in. (40-60//); globules a single row, 
 
 moniliferum, 45; Leibleinii, 46 
 i. " " " cell curved, rapidly tapering into 
 
 narrow, somewhat upwardly-curved ends; cell 6-8 times 
 
 longer than wide . Ralfsii, 46 
 
 i. Diameter ^l-g^ to 3-|^ in. (35-45//); 2 or 3 sutures in the middle; 
 
 about 20 times longer than wide. . . . Delpontii* 
 
 j. Cytioderm with many distinct striae; length 6-16 times the width; 
 
 vacuole large .... . . striolaium, 42 
 
 j. Cytioderm with fine striae; length 12-16 times the width; vacuole 
 
 small . . decorum, 43 
 
 J. Cytioderm with 5-8 distinct striae; length 6-8 times the width; 
 
 vacuole large . . . costatum, 42 
 
 j. Cytioderm smooth; cell crescent-shaped, often subsemicircular {Ji). 
 
 j. " " cell not conspicuously crescent-shaped (/). 
 
 k. Ends separated 7-10 times the diameter; width y^Vo" ^o tAt ■'i- 
 
 (i6-20/<) ... ... . . ... Diance, 44 
 
 *F.-w. Alg^, p. 23. 
 
SPECIES OF UESMIDS. 85 
 
 k. Ends separated 7-10 times the diameter; width -j-i-j- to -yhws '"• 
 
 (25-28/i) . acuminatum, 44 
 
 k. Cell 6 to 8 times longer than wide, ends obtuse; width yTyVi" ^'^• 
 
 (14/^) Jenneri, 44 
 
 k. Cell 6 to 8 times longer than wide, ends obtuse; width ^^r ^ in. 
 
 (i2yu) . par-vulum, 45 
 
 /4. Cell 8 to 12 times longer than wide, nearly semicircular, ends 
 
 sharp; width -g-^ to -^^ in. (8-ioyu) , . Venus, 44 
 
 /. Cell stout, ends broadly rounded; width -gJ^ to ^^^^^ in. (25-3o/<), 
 
 cucumis, 40 
 w2. Beaks slender, nearly as long as the body, ends obtuse, curved, 
 
 Kuetzingii, 47 
 711. Beaks thin, y^. as long as the fusiform body rostratum, 46 
 
 14. DOCIDIUM. FIG. 14. 
 
 § Suture a projecting or conspicuous rim [a). 
 
 § Suture not projecting [d). 
 
 a. Cytioderm hirsute; semi-cell with 3 or 4 undulations, spinosmn, 51 
 
 a. Cytioderm not hirsute {b). 
 
 b. End dentate or crenate; semi-cell with i basal inflation (c). 
 
 b. " " '' " semi-cell with 4 regular inflations; teeth 
 
 on the margin , . . constrictum, 50 
 
 b, End dentate or crenate; semi-cell with 3 or more inflations; teeth 
 
 below the margin . . nodulosum* 
 
 b. End truncate or rounded; semi-cell with i or 2 basal inflations, 
 
 Trabecula, 48; tnincatum, 48 
 b. " ■' " " semi-cell undulate to the contracted end, 
 
 crenitlatum, 47 
 
 b. " " " '• " 1-2 undulate at base only, 
 
 Archerii.*' 
 
 c. End with i tooth on each angle Flowtnvii, 49 
 
 c. End crenulate with tubercles . coronatum, 49 
 
 d. Cytioderm hirsute; base of semi-cell slightly inflated, hirstUuni, 51 
 
 d. Cytioderm not hirsute (e). 
 
 e. End dentate or crenate (/). 
 
 e. End not dentate nor crenate (7). 
 
 f. Semi-cell with 4 or more inflations (K). 
 
 f. " with whorls of quadrangular prominences, 
 
 %>errucosmn, 52 
 
 /. " with 20 or more constrictions . . cosiatitm, 5 3 
 
 /. " with I inflation (^). 
 
 *F.-w. Algs, p. 25. 
 
86 SPECIES OF DESMIDS. 
 
 g. End with numerous pearly teeth or beads . . coronulatum, 49 
 g. End with prominent teeth, about 3 in view . . tridentulnm, 52 
 h. End with 3-5 minute tubercles; semi-cell with 4 or more undu- 
 lations . . . . ... ... Floridense, 159 
 
 h. End with toothed angles (i). 
 
 i. Semi-cell with 4 prominent nodes; 8 to 10 times longer than wide, 
 
 nodosum, 50 
 /. " " 4 constrictions; 10-12 times longer than wide, 
 
 breve, 51 
 /. " " 8 constrictions; 20-24 times longer than wide, 
 
 sinuosum, 51 
 J. Semi-cell with i basal inflation [k). 
 J. " undulate to near the end (/). 
 
 /. " with 4 larger and smaller undulations; cells 12 times as 
 
 long as wide (m). 
 j. Semi-cells not or slightly undulate; densely granulate, breve, 158 
 k. Cytioderm densely, irregularly punctate .... clavatum, 48 
 
 k. " smooth; ends truncately rounded, margins often wavy, 
 
 Baculum, 49; rectum* 
 k. " " ends round; cell minute; diam. "j-izjx, 
 
 ?mnutum, 52 
 k. " " " " cell, large; diam. ends soyU, 
 
 Woodii* 
 I. Diameter y^^ in. (25/i); about 20 times longer than wide, 
 
 repandum, 50 
 /. Diameter yjVs" ^o t"sVb ''^- (13-1^/^); 15-20 times longer than wide, 
 
 dilatatum, 50 
 /. Diameter ■j^Vb' '^^ fitW 'n. (io-i2/<); 18-20 times longer than wide, 
 
 undulatum, 51 
 m. Surface punctate; suture none; ends roundly truncate, 
 
 Georgicum* 
 
 15. TRIPLOCERAS. FIG. 15. 
 (Mr. Wolle unites this with Docidium, 14.) 
 
 I. Tooth-like prominences oblong verticillatu77i, 53 
 
 5. " acute . . . ... . . gracile, 53 
 
 16. CALOCYLINDRUS. FIG. l6. 
 
 § Chlorophyll homogeneous (i). 
 
 § " divided or scattered in each semi-cell (2). 
 
 *F.-w. AlgEe, p. 25 et seq. 
 
SPECIES OF DESMIDS. 87 
 
 I. Length twice the width or less; cytioderm punctate or granulate {a). 
 
 I. " " " " " " cytioderm smooth (i^). 
 
 I. " " " " " " cytioderm with 5-7 costae, 
 
 costatus, 5 6 
 I. Length zj^ or 3 times the width; cytioderm punctate (c). 
 
 1. " 4 to 6 times the width; cytioderm smooth . niinutus, 54 
 
 2. Cell twice or more longer than wide; cytioderm punctate, 
 
 pseudoconnatus, 55 
 2. " " " " " " cytioderm smooth, 
 
 Thwaitsii, 5 6 
 
 a. Semi-cell subquadrate ... Ralfsii, 54 
 
 a. " cylindrical, rounded; constriction slight . cuciirbita, 54 
 
 a. " " constriction wide, shallow . . connatus, 55 
 
 a. " sub-semicircular; constriction slight; ends rounded or 
 somewhat truncate; end view circular . . . Cordanum, * 
 
 b. Cell somewhat fusiform, ends subconically rounded . curtus, 54 
 
 b. Cell subcylindrical, ends broadly rounded . diplospora, 56 
 
 c. Cell subcylindrical, ends rounded; nuclei large, single or double, 
 
 Clevei, 56 
 
 17. COSMARIUM. FIG. 17. 
 
 § End view without central inflations (i). 
 
 § End view with central inflations (2). 
 
 I. Cytioderm smooth or punctate (a). 
 
 I. " more or less verrucose or granular (/). 
 
 1. " spinous {g). 
 
 2. Cytioderm smooth or punctate {h). 
 
 2. " more or less verrucose or granular (z). 
 
 a. Chlorophyll diffused (b). 
 
 a. Chlorophyll concentrated in i or more nuclei (e). 
 
 b. Margins crenate, undulate, dentate or granulate (c). 
 
 b. " not crenate, undulate, dentate nor granulate (d). 
 
 c. Margin crenate (s). 
 c. " undulate (/). 
 
 c. " granulate (u). 
 
 e. " dentate or notched; end truncafe, smooth; sides toothed, 
 convex ... . . . Reinschii, 68 
 
 e. Margin dentate; end 4-spined; sides smooth, convex, aculeatum, 66 
 
 d. Cell twice or more longer than wide (/). 
 
 d. Cell i^ or less than twice longer than wide [k). 
 d. Cells less than i^ times longer than wide (/«). 
 
 *F.-\v. AlgEE, p. 27. 
 
88 SPECIES OF DESMIDS. 
 
 ^. Margins crenate, undulate, dentate or granulate (f). 
 e. Margins smooth; basal angles not toothed (w). 
 
 e. Margins smooth; basal angles each with i, tooth or papilla, 
 
 Smolandicum, 69 
 /. Verrucae or granules in patterns, or more or less restricted {x). 
 
 f. " " " not in patterns; more or less covering the 
 
 surface (cc). 
 
 g. Spines on the whole surface; cell suborbicular; sinus elliptical, 
 
 aculeatum, 66 
 g. Spines marginal, conical; centre with 7 granules, and punctate, 
 
 trachypleurum^ 73 
 h. Margins crenate, undulate, or dentate {jj). 
 h. Margins smooth (//). 
 
 /. Verrucse or granules in patterns, or more or less restricted {nii). 
 i. " " " not in patterns, more or less covering the 
 
 surface (vv). 
 j. End rounded; semi-cell oblong, sides almost parallel, De Baryi, 58 
 j. " " semi-cell spherical, . . moniliforme, 60 
 
 j. '■ " semi-cell elliptical or oval . corda?ium* oblongum\ 
 
 j. End truncate; semi-ceil quadrate, sides almost parallel, anceps, 59 
 / " " semi-cell pyramidal . parvulum, 59 
 
 k. Cell joined by pellucid bands into families Quimbyii, 61 
 
 k. Cells not joined into f:Lmilies (/). 
 
 /. Ends rounded; semi-tells oblong . . cucumis, 58 
 
 /. " " semi-cells oval; diameter y^ij^ in. (23//), 
 
 Witrockii\ 
 I. Ends truncate; semi-cells pyramidal, sides convex; diameter -^^ to 
 
 y^ij^ (22-28/*) . . . notabile, 66 
 
 /. Ends truncate; semi-cells pyramidal, sides convex; diameter ^-^ to 
 
 -g-J-Q (So-85/O ■ • ■ • py7'amidatmn, 69 
 
 /. Ends truncate; semi-cells pyramidal, sides convex ; diameter y^ij^' 
 
 to -j-J^ (25-43yu) . . pseudopyramidatum, 69 
 
 /. Ends truncate; semi-cells pyramidal; sides straight or slightly 
 
 concave, . . . . .... . .granaium, 60 
 
 m. Cell conspicuously broader than long; semi-cells subsemicircular; 
 
 side view circular, end view elliptical; diameter 32-38/*, 
 
 scenedesmus, 59 
 m. Cell conspicuously broader than long; semi-cells subsemicircular; 
 
 side view ovoid; diameter 75-85/* . . circulare.** 
 
 * Journ. R. Micr. Soc, Dec, 1885. t Journ. R. Micr. Soc, Feb., i886. 
 ** F. W. Algse, p. 27 et seq. 
 
SPECIES OF UESMIDS. 89 
 
 //;. Cell nearly as long as broad; semi-cells rhomboid, sides all 
 equal; sinus deep, wide .... . rhombusoides.** 
 
 n. Ends rounded; semi-cell subcircular, sinus a mere notch, 
 
 globostim, 60 
 n. " " semi-cell subsemicircular (<?). 
 
 //. " " semi-cell oval (;-). 
 
 n. " " semi-cell elliptical, or hexagonal-elliptical; cell -^ 
 
 longer than wide; diam. 25-42/Y, sexangulare, 63 
 
 n. Ends rounded semi-cell elliptical; cell ^ longer than wide; diam. 
 
 25-26;^ . . . 7incrosphtnctuj?i.** 
 
 n. Ends truncate; semi-cell hexagonal; diameter xsVt i"- (^i/") or 
 less, . ....... polygonum, 65 
 
 n. Ends truncate; semi-cell triangalar; diameter -j-J^ in. (50/i) or less. 
 
 galei-ituin, 70 
 n. " semi-cell subsemicircular, smooth; sinus deep, nar- 
 
 row . nitidulum, ()2\ psendonitidulum, 62 
 
 11. " " " punctate or granular; si- 
 
 nus narrow . ... lobulatuliim .'^ 
 
 0. Sinus deep, narrow (/). 
 
 0. Sinus deep, wide, almost linear; cytioderm smooth, sejunctum, 62 
 
 o. " rounded or oval; semi-cells lunately curved; cytioderm 
 
 punctate ... . lunatum, 65 
 
 o. Sinus deep, wide, obtuse; semi-cells widening from a narrow base, 
 
 inflatum.^' 
 &. Sinus acute angled, enlarging outwardly, rarely linear, 
 
 perforatum* 
 p. Cell elliptical; basal angles acute . .... Baileyi, 64 
 
 /. Cell suborbicular; basal angles obtuse; diameter -^^ to -^-^ in. 
 
 (60-1 oo/<), Ralfsii, 69 
 
 /■ " " " diameter -^^ to ^ in. 
 
 (30-38), . .... . . constricium, 58 
 
 r. Cytioderm centrally somewhat granular; nucleus i in each semi- 
 cell, .... ... . tumidu}n, 61 
 
 r. " smooth or punctate; cells small, 
 
 bioculatum, 60; tinchim, 61 
 s. Ends rounded; semi-cells semi-orbicular; crenae usually 9, 
 
 undulatum, 67 
 
 s. " " semi-cells subsemicircular; margins finely crenulate- 
 
 dentate . . . Wolleannm* 
 
 * Journ. R. Micr. Soc, Dec, 1885. f Journ. R. Micr. Soc, Feb., 1886, 
 ** F. W. Algae, p. 27 et seq. 
 
90 SPECIES OF DESMIDS. 
 
 s. Ends rounded; semi-cells subsemicircular, with 8-10 crenulations, 
 
 Sendtnen'anuM* 
 J. Ends truncate; semi-cells pyramidal; cells small, . . notabik, 66 
 J-. " sides almost parallel; diameter -^^ to -g-^-j- in. 
 
 (30-38/^), crenatum, 67 
 
 J-. " sides converging; diameter ys^s" ^"^^ (^o/^), 
 
 Nagelianum, 67 
 /. Semi-cell quadrate, smooth, angles rounded; end retuse or convex, 
 
 quadraium, 59 
 t. " pyramidal or subquadrate; end undulate, Holmiense, 68 
 
 t. " " end truncate; diameter -,^ to -g-J-j-in. (32-36yu), 
 
 integrum, 68 
 A " " " diameter ytjVo' ^o tsW '"■ (2°-24/<), 
 
 Hammer i, 79 
 /. " " end rounded, surface smooth, octogonum.* 
 
 t. Semi-cell pyramidal, punctate, base flat, angles rounded, 
 
 ansatum, 68; Nymannianum, 79 
 t. Semi-cell sub-semicircular, end truncate, sides with 2 emargina- 
 
 tions; smooth .... Braunii* 
 
 u. Ends truncate. Diameter -g^ to Y^-g^ in. (2o-30yu), punculatum, 74 
 u. Ends convex. Diameter -j-jW '^^ tsW ^'^ (i4~i6/i) . . Iceve, 62 
 z/. Cell twice as long as wide, rectangular; sinus linear, not widened, 
 
 sinuosum, 65 
 v. Cell less than twice as long as wide; semi-cell pyramidal, 
 
 Venus turn, 68 
 V. " '• " " semi-cell subquadrate, small, 
 
 Meneghinii, 65 
 w. Sinus narrow, not widened outwardly; cell elliptical, end convex, 
 
 variolatum 63; exiguum, 66 
 ■w. Sinus widened and rounded inwardly, narrowing outwardly, cell 
 
 wider than long obsoletum, 64 
 
 -w. Sinus widened outwardly; semi-cell oval, base and end convex, 
 
 contractum, 63 
 w. " " " " base and end flattend, 
 
 depressum, 64 
 w. Sinus widened outwardly; semi-cell quadrate, Meneghinii, 65 
 
 w. " " semi-cell subsemicircular, end rounded; 
 
 diameter -j-^-j- to -g\^ in. (75-ioo/<) . . pachydermum, 70 
 
 X. Margins crenate or granulate (jc). 
 X. Margins not crenate nor granulate {bU). 
 
 * F.- — -w. Alga;, p. 27 et seq 
 
SPECIES OF DESMIDS. 91 
 
 y. Central verrucse none or scattered on each semi-cell (z). 
 y. " more or less clustered on each semi-cell (aa). 
 
 z. Verrucas none central, marginal i or 2 rows; cell about twice 
 
 longer than wide . . . . . . '. . ovale, 57 
 
 z. Verrucse none central, marginal i or two rows; cell less than twice 
 
 longer than wide triplicatum, 73; Nordstedtii, * 
 
 z. Verrucse centrally scattered, marginal in series of 3 each; semi- 
 cell quadrate, angles rounded . . triplicatiim, 73 
 aa. Central verrucse 3, in a single row; surface smooth, Donnellii, 71 
 aa. " 3, 2 above the base; punctate between, 
 
 polymorphum.* 
 aa. " S, in 2 transverse rows, a row within the margin, 
 
 quinarium.'* 
 ■aa\ " 6, in atriangle, apex toward the isthmus, 
 
 polymazum, 70 
 aa. " 6 or 9, in 2 or 3 transverse rows; marginal rows 
 
 I or 2; semi-cell semicircular, KiUhellii, 72; suborbicidare 78 
 aa. Central verrucas 10; semi-cell semicircular, end truncate, 
 
 anisochondrwn, 7 2 
 aa. " circularly clustered; semi-cell twice longer than 
 
 wide, sides emarginate, end truncate .... Seelyanum, 73 
 ib. Centre granularly rough and punctate; margin smooth; semi-cells 
 
 oval . . . ..... tumidum, 61 
 
 ib. Centre with 3 verrucas in a row; semi-cells semicircular, 
 
 Do?inelln, 71 
 ib. Central verrucas i at the isthmus, 8 or 9 marginal in i or 2 curves, 
 
 taxichondrum, 7 1 
 ib. " '■ '• 5 arched near the margin, 4 be- 
 
 low these in the form of a cross .... bidcntulum.'^ 
 
 bi). " 4 near the isthmus; semi-cells semicircular; end 
 
 somewhat truncate; basal angles often pointed, 
 
 pseudotaxichondrum, 7 1 
 ib. Central verrucas 7, i central, 6 below in a semicircle; ends retuse, 
 
 smooth . . . . oculifermn.* 
 
 ib. Central verrucse 19; 7 larger, central; 12 more or less distinct 
 
 around them . . . . . . Amei-icanum.* 
 
 cc. Chlorophyll diffused {dd). 
 
 tc. " concentrated into i or 2 nuclei {ee). 
 
 dd. Marginal verrucse or granules rounded (IiK). 
 dd. " " conical or pointed {ii). 
 
 *r.-w. Alga;, p. 27 et seq. 
 
92 SPECIES OF DESMIDS. 
 
 ee. Cells twice or more longer than wide (^). 
 ee. Cells less than twice longer than wide {gg). 
 
 ff. Cells cylindrical, sides parallel (sometimes rounded); verrucse ob- 
 tuse . . . . amo!nu7u, 78 
 ff. " " " verrucae emarginate, in lines, 
 
 elegantissimiim, 78 
 
 gg. Semi-cells oval or elliptical . . tumidum, (>\; orthosticum, 78 
 
 gg. •'■ semi-orbicular, tetraophthalmum, 75 ; intermedium, 75 
 
 hh. Semi-cells pyramidal, end truncate; basal angles rounded, 
 
 ^ octkodes, 76; Botrytis, 74 
 
 hh. Semi-cells oval or elliptical, approximate . . . trigonum*' 
 
 margaritiferum, 'jc^; punctulatum, 74 
 hh. " " " remote, granulate, portiannm, 77 
 
 hh. Semi-cells quadrangular, ends truncate; diam. -5'^ --gi^ (60-73/1),. 
 
 conspersum, 75 
 hh. " " ends concave . . . retusum.* 
 
 hh. " " diam. ^-^(30-45 /<), 
 
 pseudobroomei, 86 
 hh. " " diam. ^^-^^15^(13-14/^), 
 
 sphalerostichum. * 
 hh. Semi-cells subreniform, sinus widened and rounded inwardly, 
 
 latum, 76; renifoi-me, 76; pardalis.* 
 hh. Semi-cells subspherical, approximate . . . orbiculatum, 77 
 
 hh. Semi-cells hemispherical, remote; base flattened, excavatum, 77 
 a. Ends and sides with teeth; sinus narrow, widened outwardly; basal 
 
 angles rounded . Brebissonii, 75 
 
 a. Ends without teeth, sides with 10 to 20; sinus gaping, dentatum, 76 
 jj. Margins crenate; semi-cell semicircular, nuclei 2, end truncate, 
 
 cruciatum, 81 
 jj " undulate; sinus widening outwardly, ho7nalodermum, 81 
 
 jj. " " sinus not widening outwardly (M). 
 
 ^k. Cell longer than wide; diameter -5-^ to -jp^ in. (38-44//), 
 
 sublobatum, 80 
 kk. Cells longer than wide, diameter yuVir to Y^wa '"• (22-25//), 
 
 mai-garitum, 80 
 kk. Cell not longer than wide, end truncate . . retusum, 80 
 
 //. Diameter -j-JL-j- in. (12//), end truncate; sides convex, often ob- 
 tusely angled centrally . . . Schliephanckeanum, 82 
 //. Diameter greater than (i2/() -j-oVo '"• (fn''n). 
 *F.-w. Algse, p. 25. 
 
SPECIES OF DESMIDS. 93 
 
 mm. Sinus acute inwardly .... . . thithophorum, 80 
 
 mm. " rounded and widened inwardly . . phaseolus, 8i 
 
 mm. " rounded, but not widened inwardly, pseudogranatum., 158 
 nn. Margins crenate or dentate (00). 
 
 nn. Margins smooth; centre with one verruca; semi-cell elliptical:, 
 diameter ysVo'"- (''3y") • • '■ • • • bireme, 82. 
 
 vo. Ends truncate; diametery-|^ in. (33/^) or larger {pp). 
 00. " " diameter -^ in. (28/() or smaller (7-r). 
 
 00. Ends rounded, dentate . . . . . . . Lagoense, * 
 
 //. About i-|- times longer than wide; diameter 1^ to ^-^ in. (33-50/^) 
 
 triplicatum ■]T,;speciosum, 87 
 pp. About \ longer than wide; diameter -^ to -j-^ in. (65-7oyu), 
 
 supraspeciosum, 88 
 //. About \ longer than wide; diameter -^\-^ in. (soyu), 
 
 pychnochondnim, 89 
 rr. Diameter -g^-j to yJjTr (2o-26/<); ends 4 crenate, sides 4-6 crenate, 
 
 subcrenatum, 84. 
 ''''• " TTiVo-to tAt (^°~^S^)' sides nearly straight, 
 
 Kjdlmaiiii, 87 
 rr. " y^Vo to y-gVff (i4-2Sy");granulesnotradiate; end4crenate, 
 
 Blyttii, 87 
 
 j-j-. Marginal teeth numerous, long, pointed or aculeate, Eloiseanum, 85 
 «. ,_ 17, emarginate-truncate . qiiadrifariiim, 87 
 
 jj. Margins crenate (#). 
 
 /^. Basal inflation granulate in vertical lines {uii). 
 
 tt. " " with scattered granules . pseudopectiiwides, 89 
 
 tt. " " without granules, the marginal in 8 radiating lines, 
 
 nasKtinn, 89 
 uii. Sinus widening outwardly; granules geminate in rows, 
 
 pectiiwides, 88 
 UII " not widening outwardly; cell oblong, diameter —W {TiZ), 
 
 pulchej-ritni/m, 90 
 uii. " " " cell orbicular, diameter -jJ-^ (50/^), 
 
 radiosiim, 90 
 vv. End truncate i^wiv). 
 
 w. End not truncate {zz). • 
 
 M/?e'. Diameter T^ in. (50/^) or larger (.r.v). 
 ■a/w. Diameter smaller than (50/^), ^L- in. ( rr). 
 
 *Journ. R. Micr. Soc, Dec, 1SS5. 
 
94 SPECIES OF DESMIDS. 
 
 XX. Sides granulate, concave near the ends; semi-cell twice longer 
 
 than wide . . protr actum, 83 
 
 XX. Sides granulate, ends concave; semi-cell twice wider than long, 
 
 biretum var. Floridense.^ 
 XX. Sides crenate-undulate, converging; cytioderm verrucose, 
 
 Quasillus, 84 
 XX. " rounded, acutely toothed, ends usually nude; cell as long 
 
 as wide . . Everettense, 85 
 
 XX. " straight, diverging, verrucose; angles rounded, biretum, 86 
 
 yy. Cytioderm granulate; cell widest at base, sides converging, 
 
 sportella, 83 
 yy. " " cell narrowed at base, sides straight, diverging, 
 
 protuberans, 84 
 
 yy. Cytioderm verrucose; end more or less protruding and scolloped 
 
 (4-crenate) ... . . . . . ccslatum, 86 
 
 yy. Cytioderm verrucose; end more or less protruding, not scolloped, 
 
 ornatu7n, 82; protractum, 82 
 
 yy. " " end not protruding; semi-cell twice as long 
 
 as wide, oblong-quadrangular, angles rounded, Broomei, 86 
 
 zz. Cytioderm finely granulate or punctate; semi-cells triangular, 
 
 angles rounded, margins smooth . ... Turpinii, 158 
 
 zz. Cytioderm verrucose; semi-cell subreniform, 3 times as wide as 
 
 long . . ... commisurale, 83 
 
 zz. " " semi-cell pyramidal, angles rounded, long, 
 
 tumidum, 75 
 
 zz. " " semi-cell reniform, angles denticulate, a 
 
 central inflation granulate . ... subcruciforme.* 
 
 18. Tetmemorus. Fig. 18. 
 
 § Cytioderm smooth or very indistinctly punctate (c). 
 § Cytioderm punctate {a). 
 
 a. Cell 3 times as long as wide, irregularly granular; base slightly 
 plicate. . gtganieus, '92 
 
 a. Cell more than 3 times as long as wide (b). 
 
 b. Front and lateral views fusiform; end with colorless, lip-like pro- 
 
 jection . ... . . ... granulatus, 91 
 
 b. Front view cylindrical, not tapering; side view fusiform, tapering; 
 end rounded . . . Brebissonii, 91 
 
 * F. — w. Algae, p. 27 et seq. 
 
SPECIES OF DESMIDS. 95 
 
 c. Three times longer than wide, smooth; diameter y'tstt to x^rj- 
 (18-20/^) minutus, 91 
 
 c. Four times longer than wide, smooth; diameter -j|^ (48/*) ; linear 
 elliptical, no lip penioides* 
 
 c. Four to six times longer than wide, smooth or indistinctly punc- 
 tate; front view tapering, lateral fusiform, ^rsr '^Onrs" (20-22/*),. 
 
 Icevis, 91 
 
 19. Xanthidium. Fig. 19. 
 
 § Spines divided at the ends armatum, 92 
 
 § Spines subulate, ends not divided {a). 
 
 a. Spines more or less scattered, numerous . . acicleatuin, 92 
 
 a. " " " " 4 within the margins, Columbtanunr** 
 
 a. Spines marginal (f). 
 
 b. Basal angles with 2 spines (a'). 
 
 b. " " " I spine {c). 
 
 c. Other spines geminate in 4 pairs ... . cristatum, 93 
 c. " " " in 2 pairs on the end, single on the sides,. 
 
 astepticm, 93 
 
 c. " " not geminate, single on the ends . . Torreyi.*'^ 
 
 d. Other spines 6 to 10 pairs on semi-cell; protuberance beaded, 
 
 bisenariwn, 93 
 d. Other spines 2 to 4 pairs {e). 
 
 d. " " none . . . tetracentrotum, 95 
 
 e. Other spines, 4 pairs, terminal ... . . fasciculatum, 93 
 e. " " 2 pairs, basal, vertical . . reciocornutum, 94 
 e. " " 2 pairs, terminal; a row of granules above the cen- 
 tral projection, a spine above the granules, Minneapoliense, 94 
 
 e. Other spines, 2 pairs, terminal; a row of granules above the cen- 
 tral projection, no spine above the granules . polymazum, 94 
 e. Other spines, 2 pairs, terminal, no granules above the projection 
 
 (/)• 
 /. Diameter ^^ in. (ss-65/<) or more, Tylenanum\, fasciculatum, 93 
 
 /. " -5^ in. (soyu) or less; semi-cell truncate-triangular, 
 
 asteptum, 93 
 
 /. " " " semi-cell not truncate-triangular, 
 
 aniilopcBum, 94 
 
 *Journ. R. Micr., Soc, Feb., 1886. 
 **F. W. Algfe, p. 34 et seq. 
 fjourn. R. Micr. Soc, Dec, 1885. 
 
96 SPECIES OF DESMIDS. 
 
 20. Arthrodesmus. Fig. 20, a, b. 
 
 I Cytioderm smooth {a). 
 
 § Cytioderm verrucose or spinous (V). 
 
 a. Semi-cell with 2 spines (c). 
 
 a. Semi-cell with more than 2 spines (d'). 
 
 b. Cytioderm with deciduous spines Rauii, 95 
 
 b. " verrucose in rows, margins crenate . guadridens, 96 
 i. " " " ends alone crenate, notochondrus.** 
 
 c. Spines on the same side diverging (e). 
 £. " " parallel {g). 
 
 c. " " converging . . convergens, 95 
 
 d. Margin of semi-cell angdlar, each angle with i or two spines, 
 
 octocornis, 97 
 
 e. End truncate; spines widely divergent . . . Incus, 97 
 
 e. End convex; spines moderately divergent (/). 
 
 f. Diameter of cell -j^ (40/') • incrassatus* 
 
 f. " " 8^ — tk (3°-3S/^) • • • subulatus, 96 
 /. " " -rh^ (2°/<) o^'alis, 96 
 
 g. Nuclei, 2 in each oblong-oval semi-cell . ... fragilis, 95 
 g. Nuclei none; semi-cell oval, diameter y-^^ in. (20/i) . ovalis, 96 
 g. " semi-cell orbicular, diameter -^-gij-jj- (i2/(), 
 
 orbicularis 96 
 g, " semi-cell elliptical; spines often very short, 
 
 convergens var., 95 
 g. " semi-cell triangular, sinus wide, isthmus cylindrical, 
 
 triangtdaris, 36 
 
 ^^ 
 
 21. EUASTRUM. FIG. 21. 
 
 § End lobe evidently distinct (a). 
 § End lobe evidently not distinct (b). 
 a. End lobe deeply notched {c). 
 
 a. End lobe more or less concave or sometimes convex (^.) 
 
 b. End deeply notched (e). 
 
 b. End more or less convex; semi-cell with 7 or 8 lateral, short, coni- 
 cal teeth ... . Donnellii, 103 
 
 b. End more or less convex; sides without teeth . pingue, 105 
 
 c. Margins smooth (</.) 
 
 c. Margins more or less spinous or beaded (/). 
 c. Margins dentate (K). 
 
 *Joura. R. Micr. Soc, Feb., 1886. 
 **F. W. Aigse, p. ■i^etseq. 
 
SPECIES OF DESiMIDS. 97 
 
 d. Basal lobe deeply notched; basal lobule broadly marginate; c<=,ntral 
 lobule obtsue.. . .... multilobatum, 98 
 
 d. Basal lobe undulate (;«). 
 
 d. " rounded or angular (f). 
 
 e. Margins smooth [k). 
 
 e. " cuspidate, spinulose or beaded (/). 
 /. Basal lobe undulate (w). 
 
 f. " rounded or angular (x). 
 
 g. Margins smooth (/) 
 
 g. " cuspidate, spinulose or beaded (j). 
 
 h. End lobes horizontal; diam. 45-50/* . . Nordstedtianum, 105 
 
 h. " " " diam. 35-40/* spitiosum, 106 
 
 h. " " upright, diverging ... . . . forinosum, 103 
 
 i. Basal lobes deeply notched (j). 
 /. " undulate (z). 
 
 j. Cytioderm rough with conic granules; semi-cells with one large 
 central inflation, a smaller one on each side, two on end lobe, 
 
 verrucosum, 100 
 d. Basal lobes undulate {cc). 
 k. " rounded or angular (ee). 
 
 I. A short spine on the angles of end and basal lobes divaricatum, 104 
 /. A small projection on each side near the apex . compactum, 107 
 m. Cytioderm more or less tuberculate («). 
 m. " punctate (0). 
 
 m. " smooth [r). 
 
 n. Tubercles basal, mostly 5 . . . circulare, loi 
 
 n. " 5 central, 4 marginal . . elegans, io6 
 
 n. " scattered; end lobe with a tooth on each side, 
 
 ornithocephahim. * 
 0. Semi-cell 5-lobed, basal lobe emarginate, the lateral small, entire, 
 
 pinnatiim, 98 
 0. " not 5-lobed (/). 
 
 /. Basal lobe with i lateral, subcentral tubercle, not emarginate, 
 
 ampullaceum^ 100 
 /. Basal lobe without lateral tubercle, slightly emarginate, affine, 100 
 p, " " " " not emarginate; diam. 22-25/^, 
 
 di delta, 99 
 p. " not emarginate; diam. 6o-6g/( . ventricosum. ** 
 
 *Journ. R. Micr. Soc, Feb., 1886. 
 
98 SPECIES OF DESMIDS. 
 
 r. Semi-cell subrectangular, basal lobe very broad, end lobe partly in- 
 cluded between the lateral . • . . crassum, 97 
 r. Semi-cell more or less pyramidal {s). 
 s. Diameter -j-i-j- in. or more (50-55/^) . . ... Everettense, 102 
 
 J-. Diameter less then -j-i-^ in. ; apical angles acute, 
 
 Porkornyanum, 104; erosum, 104 
 s. Diameter less than -g^ in.; apical angles rounded . elegans, 106 
 t. End lobe on a long slender neck; basal lobe with 6 protuberances, 
 
 mammillosuni, 102 
 /. " " " " " " " basal lobe without protuberances, 
 
 insigne, 102 
 t. End lobe not on a long neck [u). 
 u. Basal lobe much wider than end lobe (w). 
 u. " scarcely wider; diameter less than -g-J-j- in. {42 pi) 
 
 simplex, 106 
 V. Basal sinus narrow, basal lobes approximate (f) 
 V. " wide, basal lobes widely separated . intermedium, 102 
 
 f Diameter -j-^ in., (ioo/<) . . .... magnificum, ** 
 
 f " less than -^\j^ in.; no pits on the surface, 
 
 ansatum, gg\ purufn. ** 
 
 |. " " " " " 4 pits on semi-cell . scrobiculatum, ** 
 
 •w. End lobe beaded: angles of basal lobes beaded, ventricosum, 160 
 w. " dentate; angles of basal lobes dentate . simplex, 106 
 
 w. " smooth, its angles spinous or cuspidate, rostratum, 106 
 
 X. Angles of end lobe and margins of basal each with 3 diverging spines, 
 
 cuspidatum, 105 
 
 X. '' " with short spines, margins of basal dentate or 
 
 granulate ..... . abruptum 107 
 
 X. Angles of end lobe with one cusp or spine. . . rostratum 106 
 
 y. Basal and central lobules both slightly emarginate, oblongum, 98 
 y. Basal lobes slightly emarginate, central obtuse, multilobatum, 98 
 
 z. End lobe columnar, margins nearly parallel, end truncate, 
 
 attenuatiim, 103 
 
 z. End lobe not columnar, partly included between the lateral lobes, 
 
 oblongum, 98 
 z. " " not included (aa). 
 
 aa. Cell 2-3 times longer than broad; diameter -5^ in. (7SyM), 
 
 humerosum, 99 
 
 aa. Cell about twice longer than broad, diameter y^Vo ''^- (i4/<), 
 
 Lundellii. 
 aa. " " " " diameter -j-^ in. (75/^), 
 
 peciinatum.** 
 ** F.-W. Alg£E, p. 36 et. seq. 
 
SPECIES OF DESMIDS. 99 
 
 aa. Cell J^ or less longer than broad (pV). 
 
 bb. Semi-cells urn-shaped; diameter -j-J-j- in. (50/i) . urnaforme, loo 
 
 bb. " more or less quadrate; basal lobes horizontal, emargin- 
 
 ate; protuberances minutely granulate . . . gemmatum, loi 
 
 bb. Semi-cells more or less pyramidal, basal lobes emarginate, 
 
 insular e, 104 
 
 ic. Angles of end lobe acute . . elegans, io6 
 
 cc. " " rounded or obtuse (dd). 
 
 dd. Diameter -^ to ^^ in (32-38/^) inerme, 104 
 
 dd. " TsW'"- (14/^); length -5-I-5- (28/Y) . crassicolh, 105 
 
 dd. " yJj-5- to y^ in. {20-22 jS); length ^ (28/*), 
 
 compactum, 107 
 
 iff. Angles of end lobe acute (# ). 
 
 f(f. " " obtuse or rounded {gg). 
 
 ff. End notch broad, gaping, the apices upright . . . binale, 107 
 
 ff. " narrow, close, the apices horizontal . . simplex, 106 
 
 gg. End broadly rounded, continuous with the sides; diameter -j-^jj^ 
 
 (14//), .... obtusum, 107 
 
 gg. " " " " " " semi-cells wedge- 
 shaped; diam. 24-28/^ . . ameatum.** 
 
 gg. End elevated above the sides, a small projection near the apex on 
 €ach side .... . . cornpactum, 107 
 
 gg. End elevated, no lateral projections . . . pingue, 105 
 
 22. MICRASTERIAS. FIG. 22. FIVE FORMS. 
 
 § Cell more or less circular (i). 
 
 § Cell oblong (2). 
 
 I. End lobe narrow, lengthened into divergent arms {a). 
 
 I. " " not lengthened into arms, semi-cells 5-lobed [b)^ 
 
 1. End lobe broad, not lengthened mto arms [c). 
 
 2. Semi-cell 5-lobed, lobes horizontal; end lobe with 4 arms (d). 
 2. " " " " end lobe with 2 arms (z). 
 
 2. " " lobes not horizontal, approximate; no arms (aa).. 
 
 2. Semi-cell 3-lobed, lobes horizontal; end lobe with 4 arms (d). 
 2. " " " " end lobe without arms (/). 
 
 a. Semi-cell 5-lobed {k). 
 
 a. " 3-lobed, lobes radiate (/). 
 
 b. End lobe not or slightly exserted (/). 
 
 b. " conspicuously exserted (r). 
 
lOO SPECIES OF DESMIDS. 
 
 c. Semi-cells 5-lobed (111). 
 
 c. Semi-cells 3 or obscurely 5-lobed; lateral sinus shallow, obtuse; 
 
 lateral angles mucronate decemdentata, 1 1 3 
 
 d. Basal lobes with 3 linear processes on each side . muricata, 118 
 
 d. " without linear processes, but (e). 
 
 e. Forked once only, margins finely serrate, Mahabuleshwarensis, 112 
 e. " " " margins and surface spinous . . spinosa.** 
 e. " " " margins smooth . . . Nordstedtiana, 113 
 e. Forked twice (lobules forked); cytioderm spinous . . spinosa* 
 e. " cytioderm smooth; margins serrate, ^ifrOTfl;z;^za;z(3:, 112 
 
 e. " " " margins not serrate, ^;«^w3«a, 112 
 /. End lobe nearly as wide as the basal, apices deeply notched i^g). 
 
 f. ' " ■' " " " apices not deeply notched (A). 
 
 f. End lobe much narrower than the basal, end convex, oscitans, 116 
 /. " " " " " " end deeply emarginate, 
 
 foliacea, 118 
 /. " " " " " " end slightly concave, 
 
 Rabenhorstii*'^ 
 
 g. Basal lobes furcate (with lobules), (/). 
 g. " not furcate {J). 
 
 h. End lobe convex, without prominences . . . taticeps, 115 
 
 h. " truncate, with 2 small prominences . . . recta, 112 
 
 h. " retuse, basal lobe furcate ... . Baileyt, 118 
 
 i. " with 2 slender, transverse, bidentate projections, 
 
 quadrata, 117 
 /. End lobe without projections, convex; sinuses broadly rounded, 
 
 Kitchellii, 1 1 6 
 /. " without projections, concave; neck short; sinuses acut- 
 
 ish Rabeiihorstii, 118 
 
 i. " " " ■' neck long; basal lobes 
 
 curved upwards simplex* 
 
 j. Basal lobes horizontal, not curved . ... pinnatifida, 116 
 
 / " curved upward, narrow, 
 
 expansa, 117; arcttata, 117; simplex. * 
 k. Basal and lateral lobes deeply furcate (with lobules), furcata, iii 
 k. " " " shallowly furcate, surface smooth, (^) 
 
 k. " " " " " surface spinous; diam., 
 
 175-200/^ apiculata.** 
 
 h. " " " not furcate . . . pseudofurcata, iii 
 
 * Journ. R. Micr. Soc, Dec. 1885. 
 ** F.-w. AlgEe, p. 36 et se.j. 
 
SPECIES OF DESMIDS. lOI 
 
 ^[ Lateral and basal lobes separated by a deep acute notch, 
 
 Crux-Militensis, 1 1 1 
 
 H" Lateral and basal lobes separated by a shallow rounded notch, 
 
 speciosa.*^' 
 
 I, Lobules deeply furcate; borders not serrate . . dichotoma, iii 
 
 /. " not furcate, borders not serrate . . ringens, 112 
 
 /. " " borders serrate . . serrulata.** 
 
 in. End lobe remote from the lateral («). 
 
 m. End lobe not remote from the lateral {0). 
 
 n. End lobe triangular . . triangularis, 115 
 
 n. " not triangular . . . . hamata, 114 
 
 0. Lobes closely approximate, radiating (/ ). 
 
 0. '■ " " not radiating, end lobe truncate, 
 
 truncata, 114 
 /. End lobe triangular . . . . triangularis, 115 
 
 /. " cuneate, end concave . .... conferta, 114 
 
 /. " very broad, end truncate or convex . . crenata, 113 
 
 r. Cytioderm papillose . . .... . apiculata, no 
 
 r. " not papillose {s). 
 
 s. Basal lobes with 4 subdivisions, lateral with 8; apices of end lobe 
 
 furcate rotata, fimbriata, 109 
 
 J-. " '' " " apices of end lobe 
 
 not furcate . . . . . .... . cornuta. 
 
 s. Basal lobes with 2 subdivisions, lateral with 4 (u). 
 
 s. Basal and lateral lobes with the same number of subdivision (w). 
 
 t. End lobe with i row of pearly granules .... Minnesotensis.\ 
 
 t. " without pearly granules (_y). 
 
 u. End lobe exserted on a long neck .... brachyptera, 1 10 
 
 u. " exserted without long neck, its apices furcate, .f/OT//^*, no 
 
 V. Margins spinous ... . brachypiera, no 
 
 V. " not spinous bispinaia.\ 
 
 y. Sinuses deep, inwardly widened and rounded; subdivisions of 
 
 semi-cell 20-40; surface smooth radiosa, 109 
 
 y. Sinuses deep, inwardly rounded, surface with rounded elevations, 
 
 mamillafa.** 
 z. Lateral lobe deeply furcate, basal part perpendicular, furcations 
 
 horizontal; ends bifid alata.** 
 
 aa. A row of centrally larger basal inflations across each semi-cell, 
 
 verrucosa.''''''^ 
 aa. No basal inflations; minutely granulate Jenneri, 115 
 
 ** F.-w Algae, p. 38 et seq. 
 
 f Journ. R. Micr. Soc, Dec. 1885. 
 
102 SPECIES OF DESMIDS. 
 
 23. STAURASTRUM. FIG. 23. FOUR FORMS. 
 
 % With numerous processes, their ends more or less divided (§ §) 
 
 T[ Without processes, the angles in front view produced or not (§) 
 
 § Cytioderm smooth or finely punctate (i). 
 
 § Cytioderm verrucose or granulate (2). 
 
 § Cytioderm hirsute, spinulose or thorny (3). 
 
 §§ End view 2-armed, body broadly ovate; arms serrate, apices 
 
 finely toothed Minneapoliense* 
 
 §§ End view 3 or 4 angled (B). 
 
 § § End view 5 or 6-angled, apices of (6) rays rounded and spinulose, 
 
 Kissimmense* 
 §§ " 5 angled, apices spinous (G). 
 
 §§ End view 6-angled, apices of cylindrical processes slightly 
 
 notched, 4 processes within the margin; end view hexagonal, 
 
 Wolleanum.* 
 §§ " " apices of (5-6) rays trifid, distended, 
 
 distentum, 149 
 § § End view 8-angled; rays a whorl of 8 below, 4 above, 
 
 tetroctocerum, 151 
 §§ End view circular, rays a whorl of 9 below, 6 above, artiscon, 148 
 § § " " rays marginal, very short, usually 9, ends notched, 
 
 Eloiseanum, 149 
 r. Angles of semi-cell in front view, not produced; rounded and 
 
 smooth (a). 
 I. " " " " " mucronate, spi- 
 
 ous or notched (c). 
 
 1. Angles of semi-cell in front view produced more or less {K). 
 
 2. Angles of semi-cell in front view more or less produced (/). 
 
 2. " '■ " " " not produced {gg). 
 
 3. Angles of semi-cell in front view more or less produced {00). 
 
 3. " " " " " not produced {yy). 
 
 a. Semi-cell oval or elliptical, ends not inflated (T). 
 
 a. " " " ends inflated; diam. ^jVir in. (25/^), 
 
 bacillare* 
 a. Semi cell semi-circular, smooth, sinus narrow, linear, oriicu/are, 120 
 a. Semi-cell almost circular, sides finely dentate . Cosmarioides* 
 
 a. " " " sides smooth vesiculatum* 
 
 a. Semi-cell triangular, sides concave trihedrale, 123 
 
 a. Semi-cell cuneate; cell slightly longer than wide, 
 
 pseudopachyrhynchum, 125 
 *F.-w Algae, p. 41 et seq. 
 
SPECIES OF DESMIDS. IO3 
 
 Tf Diameter 60-1 12/< (^|^ to ^|^ in.) (6). 
 
 T" " 32/< (y|-g- in.); granulate-crenate . . . I'lteohmi* 
 
 1 " 13-16/t (yfo to T3V0 in-); 
 
 mulicum^ minor, 119; Bieneammi, 124 
 
 ^. Sides sliglitly constricted near the angles, especially in end-view, 
 
 tumidum, 120 
 6. Sides not constructed; diameter -5-1-^ to -^ in. (75-83//), 
 
 grande, 120 
 i. " " " diameter jj^ in. (6oyu) . inerme 122 
 
 ^. Angles mucronate (d). 
 
 c. Angles aculeate, spinous, awned or notched (e). 
 
 d. Mucros double on basal angles, none on the end in front view; 
 
 semi-cells truncated triangles paniculosum, 124 
 
 d. Mucros single on all angles, horizontal; diameter less than -^^ in. 
 (50/i); semi-cells not quadrangular . . . brevispina, 121 
 d. Mucros single on all angles, horizontal; semi-cells quadrangular, 
 
 quadra?zgttla7-e, 145 
 d. Mucros single on all angles, diameter larger than 3^^ (So/<), 
 
 magnum, 120 
 
 d. Mucros single, oblique downward and inward; diameter -,^ 
 
 (looyu) or more tnajuscuhmi, 121 
 
 d. Mucros single, oblique downward and outward; diameter -j|^ 
 
 (45 yu) or less Dickiei, 122 
 
 e. Aculei or awns i on each angle (/). 
 e. " 2 on each angle i^g). 
 e. " 3 on each angle [vv). 
 
 e. " 4 or more on each angle {ww). 
 
 f. Semi-cells elliptical, often angular, approximate; ends straight, 
 
 concave or convex; awns horizontal, diverging, converging or 
 upwardly oblique; diameter -^^ to y^jVo- in. (25-38/1), 
 
 dejectum, 121 
 /. " " diameter -^ to -^, (55-60/^), cornutum* 
 
 f. Semi-cells elliptical, separated by a long, narrow isthmus, 
 
 cuspidatutn, 123 
 /. " triangular-fusiform; awns long; diameter -^^ to j^ 
 
 (50-5 7/t) .... megacantimm, 121 
 
 /. Semi-cells triangular; sinus with a small spine on each side, 
 
 Lewisii, 122 
 /. " " sinus without a spine . . aristifcrum, 122 
 
 /. Semi-cell quadrangular, margins toothed or spinous, 
 
 quadr angular e, 145 
 *F.-w. AlgEE, p. 41. 
 
t 
 
 104 SPECIES OF DESMIDS. 
 
 g. Angles in end view trifid .... .... trifidum, 123 
 
 g. " " " simple or bifid {ss). 
 
 h. Arras trifid or bifid; end view 3-4 radiate; arms smooth, 
 
 brachiatum, 1 24 
 h. " " " end view 3-radiate; arms aculeate, rough, 
 
 asptnosum, 143 
 h. " " •' end view 5-6 radiate distentum, 149 
 
 h. " '' " end view 7-9 radiate .... Rotula, 135 
 
 h. Arms truncate, oblique, geniculate, short; end view 4-radiate, 
 
 inconspicu um, 125 
 h. Arms acute or aculeate, curved; end view3-radiate sudeticum* 
 
 i. Ends separated by a more or less elongated isthmus (/). 
 /. Ends approximate (z). 
 
 j. End view fusiform, with a central obtuse inflation, leptocladum, 136 
 j. " oval, a long arm on each side, 
 
 grallato7-ium, 136; ungulatum, 136 
 /. End view triangular or 3-radiate [k). 
 J. " quadrangular or 4-radiate (/). 
 
 J. " 5-radiate (»). 
 
 /. " 6-radiate (w). 
 
 j. " 7-8 radiate . , . ... Ophiura, 134 
 
 k. Isthmus basally inflated; cuspidate or spinous (/). 
 
 k. " not basally inflated; cuspidate not spinous {jii). 
 
 I. Isthmus basally inflated . elongatum, 130 
 
 /. " with a 1-4 cuspidate protuberance on each side; arms 
 
 short fasciculoides, 130 
 
 /. " with I notched spine on each side . . spinosum, 139 
 
 m. Diameter -g-i-j- in. (50/^) or less (n). 
 '"• " roir '"• (6oy") or wider {0). 
 
 n. End straightish, sides tapering into short, mostly obtuse processes, 
 
 tricorne, 126 
 n. End broadly convex; processes curved .... cyrtocerum, 128 
 n. " " processes straight, slender . gracile, 133 
 
 o. In end view the angles produced in long arms, 
 
 vestitum, iT)^; pseudosebaldi, 139 
 o. In end view the angles not produced in long arms, Sebaldi, 138 
 p. Isthmus basally inflated or cuspidate (r). 
 p. Isthmus not basally inflated nor cuspidate {s). 
 r. Isthmus basally inflated, corrugated ■d.nAA&n^icvi\aXe,tetragonum, 130 
 r. " with a short spine on each side . . odontatum, 134 
 
 *Journ. R. Micr. Soc, Dec, '85. 
 
SPECIES OK DESMIDS. I05 
 
 s. Diameter -j-J-^- in. (3i/<) or smaller (t). 
 s. " ^ in. {60/u) or longer («). 
 
 /. End straight, sides tapering into short, mostly obtuse processes, 
 
 triconie, 126 
 
 /. End convex; processes short, stout . . . . crenulatum, 126 
 
 /. End concave; processes short, upwardly diverging, 
 
 pusillnm, 130; Donnellii; 132 
 
 u. Processes short, robust, incurved; end of semi-cell truncate, 
 
 cerastes, 133 
 u. " long, narrow, incurved; end of semi-cell convex, 
 
 ankyr aides, it,i 
 u. Processes long, horizontal . . . . ' . tetracerum, 134 
 
 V. Processes curved, apices bifid . . pentadadum, 129 
 
 V. " " apices entire . .... incisum, 132 
 
 V. Processes horizontally radiating; ends of cell with bifid papillae, 
 
 pentaceruni; 134 
 V. Processes horizontally radiating; ends without papillae, 
 
 crenulatum, 126 
 V. Processes upwardly diverging, the apices bifid . franconium, 131 
 w. Diameter -g-l-j in. (40 /t) or smaller (x). 
 «'■ " -Fir in- (7°/^) or larger {y). 
 
 X. Isthmus centrally ribbed; rays curved downward . comptum, 129 
 X. " not ribbed; in end view rays basally separated by an 
 
 acute incision .... incisum, 132 
 
 X. Isthmus not ribbed; in end view rays separated by a rounded 
 
 sinus . .... . crenulatum, 126 
 
 y. End with prominent papillae; diameter ^^-j- to y^ in. (140-150/^), 
 
 ^ Ophiura, 134 
 
 y. End with prominent papillae; diameter -j-^j to -g-^-j in. (7S-85yu), 
 
 coronulatum, 135 
 y. End without prominent papilla; ray margins serrate, 
 
 macrocerum, 134 
 y. " " " ray margins granulate-crenate, 
 
 hexacerum, 137 
 z. End view oval, ends produced in a long, thin arm, ungulatum, 136 
 z. " fusiform . . fusiforme, 137 
 
 z. End view triangular or 3-radiate {aa). 
 z. " 4-radiate or angular [ee). 
 z. " 5-radiate {ff) 
 
106 SPECIES OF DESMIDS. 
 
 aa. Apices of rays obtuse; diameter -^ to -^ in. (40-50/^), 
 
 arachne, 129 
 
 aa. " " " diameter T^ to TiW in- (15-20/^). 
 
 iotanum, 137 
 ■aa. Apices of rays not obtuse {bV). 
 
 hb. End of cell in front view papillose or verrucosa (cc). 
 bb. " " " " not papillose nor verrucosa (dd). 
 tc. Diameter ,5-^^ in. (36/^) or smaller, arcuatum,T.T,o; subarcuatum, 140 
 ic. " -j-J^ to ^^ in. (6o-8o/<) ; arms diverging, anatinum, 139 
 ■dd. End view, sides straight, angles 3-4 spinous,, polymorphum, 126 
 dd. " sides concave; arms long, straight, in front view di- 
 verging paradoxum, 129 
 
 ■dd. End view, sides concave; arms short, Haabxliense, 131; nanum, 138 
 dd. " sides convex; arms short, tumid at base, .^if/^a;'««»z, 133 
 
 £e. Apices of arms inconspicuosly bifid or trifid, 
 
 Haabceliense, \j,\; paradoxum, 129 
 ■ee. Apices of arms prominently and deeply trifid . . . Osceolense.* 
 
 ff. Apices of arms obtuse; the arms mere lobes, very short, 
 
 silataium, 128 
 ff. " " " arrns long, narrow .... arachne, 129 
 
 ff. Apices of arms bifid; front yiew end with a crown of papillae, 
 
 Floridense, 135 
 ff. Apices of arms bifid; front view end without papillae, 
 
 pentacladum, 136 
 
 gg. End view 4, 5, 6, or 7-angular or radiate (lih). 
 gg. End view triangular (zV). 
 
 hh. Cytioderm rough with pearly granules; rays 4-7, short, obtuse, 
 
 maigaritaceum, 125 
 hh. " granulate; end view 4-6 angled, sides straight, 
 
 Meriani, 132 
 ////. " ■' end view 4 angled, angles with 2 spine^ 
 
 Novce CasarecB, 145 
 
 hh. " " end view 4-5 angled, sides concave, angles 
 
 without spines dilatatum, 128 
 
 a. Angles in front view notched or otherwise divided {jj). 
 
 a. Angles entire (kU). 
 
 *Bulletin Torrey Botanical Club, Dec. 1885. 
 
SPECIES OF DESMIDS. 107 
 
 jj. Surface granules emarginate or divided; semi-cells broadly elliptical, 
 
 asperum, 127 
 JJ. " not emarginate; semi-cells elliptic, truncata, 128 
 
 jj. " not emarginate; semi-cells subsemiorbicular, 
 
 angles truncate . . . muricatum, 127 
 
 jj. Surface scabrous, semi-cells elliptic . .... scabrum, 130 
 
 jj. Surface tuberculate; sides at base convex, spinous; a central, 
 
 spherical, spinous projection conspicuous . . . bullosum.* 
 jj. Surface tuberculate; sides at base concave; no central protuber- 
 ance . .... tuberculatum.* 
 jj. " " " " not concawt, pseudocrenatum.** 
 
 kk. End view sides concave (//). 
 
 kk. " sides nearly straight, very slightly convex (nii). 
 
 kk. " sides convex; semi-cells subsemiorbicular, 
 
 muricatum, 127 
 
 //. Semi-cells twisted; 2-3 times longer than wide, elliptic or oblong, 
 
 alternans, 128 
 //. Semi-cells not twisted (7m?i). 
 mm. Front view ends concave; end view angles rounded, 
 
 striolatum, 126 
 mm. " " end view anglesacute, Pringlei, 132 
 
 mm. Front view ends convex; end view angles crenate, sides smooth, 
 
 crenatum, 126 
 
 mm. " " end view angles not crenate, somewhat 
 
 truncate . . ... . dilatatum, 128 
 
 mm. " " end view angles granulate, rounded, 
 
 erasum.** 
 nn. Diameter j-jVo 'i^- (^5/^) O"" '^^^ • • pygmcBum, 128 
 
 nil. " greater than y^Vsr ''^- (^Sy"); end broadly truncate, 
 sides slightly convex or nearly straight, converging, 
 
 botrophilum, 131 
 nn. Diameter greater than y^iVir i"^- (^S/^); end rounded, sides convex; 
 semi-cell elliptic . . rugulosum, 127; punctulatum, 127 
 
 00. End view 3-radiate or angular, sides nearly straight (//). 
 00. " " " sides concave (;-r). 
 
 00. End view 4-radiate or angular {xx). 
 
 pp. Cells spinulose on the whole surface aculeatum. 140 
 
 pp. " on the margins only setigerum, 141 
 
 *Journ. R. Micr. Soc, Feb. 1886. 
 **F.-w. Algee, p. 42 et seq. 
 
Io8 SPECIES OF DES-MIDS. 
 
 rr. Cells spinulose, a short, irregular process on each side, 
 
 controversum, 143 
 rr. Cells spinulose on the margins of the long, colorless, diverging 
 
 arms ... aspinosum, 143 
 
 ss End view triangular or 3-radiate (iiii). 
 ss. " 4 or 5-angular or radiate (//). 
 
 ss. End view circular, with usually 9 short, marginal, notched pro- 
 cesses Eloiseanum, 149 
 
 tt. End view margins smooth; spines short; semi-cells in front view 
 
 twice as wide as long avicula, 123 
 
 tt. End view margins smooth; spines short; semi-cells in front view 3 
 
 or 4 times as wide as long . .... commutatum, 124 
 
 tt. End view margins smooth; spines on the angles only, very long, 
 
 longispinum, 145 
 tt. " spines on the margins and surface as well as on 
 
 the angles Mmnesotense.**" 
 
 tt. End view margins verrucose, the verrucse emarginate or not, 
 
 forficulatum, 144 
 //. " " denate, angles usually 3 . monticulosuvi, 144 
 
 uu. End view margins smooth, concave; angles notched, 
 
 quadr angular e, 145, 
 uu. " " crenate; spines long, divergent. 
 
 Nova Cmsarece, 145; 
 uu. " " spinous; angles produced, furcate, 
 
 forficulatnm, 144. 
 vv. End view triangular; aculei short, Hystrix, 142; trideniiferum, 142 
 vv. " " spines long, colorless, 
 
 tricornutum, 145; Iriquetrum.**' 
 vv. End view 4-angled, angles broadly rounded, spines scattered; 
 
 sides concave Hystrix, 142 
 
 vv. End view 5 -angled, sides concave . . . Brasiliense, 146 
 
 WW. Angles with numerous setae as long as the lobes; cells in front 
 view cruciform .... . cruciatum, 142 
 
 WW. Angles with 4 teeth, 2 projecting upward, 2 downward, 
 
 Cerberus, i^t 
 WW. ■' 2 spines; margins concave, spinous 
 
 quaternium, 144 
 XX. Sides unequally produced, spinulose or spinous, controversum, 143 
 XX. Sides equally produced, spineless; angles spinous aculeatum, 140 
 
 **F.-w Alg:e, p. 41 et seq. 
 
SPECIES OF DESMIDS. I09 
 
 V}'. Diameter -j^ in. (38/1) or less [zz). 
 yy. Diameter greater than (38yu) -^^ incli {A), 
 zz. Cytioderm aculeated, aculei larger and denser at the angles, 
 
 teliferum, 140 
 zz. Cytioderm aculeated except at the centre, echinatum, 141 \pecten, 141 
 zz. " spinous; margins dentate . convexum.* 
 
 zz. " " margins crenate , Ravenellii, 143 
 
 A. Cytioderm aculeated, aculei geminate . . sociatum, 142 
 
 A. " " aculei not geminate, densest at the angles, 
 
 Brebissonjiii, 141 
 A. " " aculei evenly covering the surface, 
 
 Saxonuutn, 141; hirsutum, 141 
 A. Cytioderm spinous, spines not notched . echinatiim, 141 
 
 A. " " spines or short processes notched, 
 
 spongiosu7n, 148 
 
 B. End view 3-angled; processes within the margin, 6 in number (C). 
 B. " " " " " ". 3 in number (Z)). 
 B. '' " " processes both on and within the margins i^F'). 
 B. " " " processes at the angles only (^). 
 
 B. End view 3-angled, angles broadly truncate, each with 3 promi- 
 nences . xiphidiophorinn .** 
 B. " " " •' " " each with 2 promi- 
 nences . . simplex.** 
 B. End view 4-aagled, body quadrangular, ends of arms trifid, 
 
 Osceolense.** 
 
 B. End view 3 or 4-lobed, emarginate or bifid; cell very irregular or 
 
 quadrate ... . . . ... . enorme.^ 151 
 
 C Front view lateral margins crenate; basal margins crenate, 
 
 eustephanum, 147 
 
 C. " lateral margins smooth . . . pseudofurcigerum, 147 
 
 C. " lateral margins with 3-6 sharp teeth; basal margin 
 smooth . ... cunealum, 148 
 
 D. Cytioderm granular , furcigerum, 146 
 D. Cytioderm smooth; end view angles produced into 2 processes, a 
 
 third above and between them . Pottsii, 151 
 
 D. Cytioderm smooth or finely punctate; end view angles notched. 
 
 Kite helm, 150 
 £. Processes 9, nearly as long as semi-cell diameter, ends furcate, 
 
 Tohopekaligense.** 
 
 *Jour. R. Micr. Soc, Feb., 1886. 
 **F. W. AlgK, p. 41 et seq. 
 
no SPECIES OF DESMIDS. 
 
 E. Processes shorter than semi-cell diameter, ends furcate, 
 
 furcatuva, 150 
 E. Processes 6, short, notched; semi-cell rectangular, twice wider 
 
 than long , . . . . duplex, 149 
 
 E. End view central radiating processes 6; marginal, including 
 
 angles, 9, . . . . senariam, 147 
 
 E. " central and marginal spines short, numerous, notched,. 
 
 spongiosum, 14& 
 G. Semi-cells saucer-shaped, margin with 5 divergent spines, 
 
 calyxoides .*" 
 
 *F. — w. Algfe, p. 46. 
 
GLOSS A.RY. 
 
 Aculeate: having one or more sharp points or prickles. 
 
 Acuminate: ending in a sharp point. 
 
 Antheridium, plural Antheridia: certain reproductive organs supposed 
 
 to have the function of the anthers of higher plants. 
 Annulate: ringed, marked with rings. 
 Articulate: jointed, formed of joints. 
 
 Bi.: in compound woods, meaning two or twice. 
 Bidentate: with two teeth or tooth-like projections. 
 Bifurcate: forked, separating into two branches or parts. 
 Bullate: blistered or puckered. 
 
 Cxnobium: a community of individual cells united in one body or 
 
 cluster. 
 Comiate: united at base, as two opposite branches around the stem. 
 Costa, plural Costce: a rib. 
 Costate: ribbed. 
 Crenate: scolloped. 
 Crenulate: with small scollops. 
 Crescentic: crescent-shaped, like the new moon. 
 Cruciform: cfoss-shaped. 
 Cuneate: wedge-shaped. 
 Cuspidate: with a short, stiff, sharp point. 
 Cytioderm: the membrane of the cell. 
 
 Decussate: in pairs alternately crossing. 
 
 Dentate: toothed. 
 
 Dichototttous: with the divisions in pairs; two forked. 
 
 Dioecious: having the male and female flowers on separate plants. 
 
 Dissepiment: a partition or division. 
 
 Dorsum: the back, here the back or curved portion of Closieriuni. 
 
112 GLOSSARY. 
 
 Filifortn: thread shaped, or thread-like. 
 Flexuose: bending in opposite directions. 
 
 Fusiform: spindle shaped, large in the middle and tapering to both 
 ends. 
 
 Geminate: twin, in pairs. 
 
 Geniculate: bent like a knee. 
 
 Gonidia: propagative bodies, not produced by any act of fertilization. 
 
 Granulate: with small or fine granules. 
 
 Hirsute: hairy. 
 
 Hyaline: transparent as glass. 
 
 Impacted: matted, the' whorls indistinct. 
 
 Lamellate, lamellose: formed of superposed layers or plates. 
 Lunate: crescent-shaped. 
 
 Mikron (/J.): the gg^o,, of an inch. 
 
 Monmcious: having the male and female organs separate but on the 
 
 same plant. 
 Monilijorm: like a string of beads, or necklace-like. 
 Mucronate: tipped with a short, stiff point. 
 
 Nucleus, plural Nuclei: in this case, one or more collections of chloro- 
 phyll in the cell. 
 
 Obovate: egg-shaped, but with the broader end upward. 
 Oogonium, plural Oogonia: the sac bearing the oospores. 
 Oospore: spores formed in the ovarian sac or oogonium. 
 Orbicular: circular, or nearly so, in outline. 
 
 Pellucid: transparent. 
 
 Piliferous: bearing short hairs. 
 
 Plicate: folded. 
 
 Polymorphus: haying several or many forms. 
 
 Pubescent: bearing fine, soft hairs. 
 
 Punctate: dotted with minute elevations or depressions. 
 
 Fyriform: pear-shaped. 
 
 Ramulus, plural Famuli: a small or secondary branch. 
 Feniform: kidney-shaped. 
 
GLOSSARY. 113 
 
 Saccate: sac-like, baggy. 
 
 Scabrous: rough. 
 
 Septate: with a partition. 
 
 Serrate: with saw-teeth, or teeth pointing forward. 
 
 Setiforni: bristle-like. 
 
 Setigerous: bearing bristles or setje. 
 
 Sigmoid: s-shaped. 
 
 Sinus: the depression between two parts of a cell. 
 
 Spermatozoa: active, thread-like bodies in certain cells. 
 
 Spermogonia: cells which give rise to the spermatozoa. 
 
 Spimclose: bearing short spines or prickles. 
 
 Stipe: the stem or stalk. 
 
 Stipitate: with a short stem or stalk. 
 
 Stratum: a layer, anything spread out in a layer. 
 
 Sub.: in compound words, meaning less than. 
 
 Subulate: awl-shaped. 
 
 Thallus: a mass of cells, consisting of one or more layers, often a 
 
 flat expansion. 
 Tortuous: irregularly curved, winding, twisted. 
 Truncate: as if cut off square at the end. 
 Tnberculose: with small rounded projections or tubercles. 
 
 Umbellate: the branches or parts beginning at the same point, like 
 the ribs of an umbrella, 
 
 Ventrum: in this case, the concave region of Closterium. 
 Verruca, plural VerruccB: rounded, wart-like elevations. 
 
 Whorl: m a circle round the stem. 
 
 Zoospores: spores with active movements. 
 

 INDEX. 
 
 
 
 Page. 
 
 
 Page. 
 
 A. 
 
 
 Chantransia 
 
 37 
 
 Anabaena 
 
 67 
 
 Characium 
 
 52 
 
 Anacystis 
 
 / 
 
 72 
 
 Chlamydococcus 
 Chlamydomonas 
 
 50 
 5° 
 73 
 44 
 55 
 45 
 72 
 83 
 
 Aphanizomenon 
 
 Aphanocapsa 
 
 Aphanochffite 
 
 Aphanothece 
 
 Apioc3'stis 
 
 Arthrodesmus 
 
 Asterothrix 
 
 68 
 
 73 
 44 
 72 
 
 55 
 96 
 
 71 
 
 Chroococcus 
 
 Chroolepus 
 
 Chytridium 
 
 Cladophora 
 
 Clathrocystis 
 
 Closterium 
 
 
 Coelastrum 
 
 51 
 
 B. 
 
 
 Ccelosphaerium 
 
 72 
 
 Bambusina 
 
 80 
 
 Coleochsete 
 
 38 
 
 Bangia 
 
 37 
 
 Campsopogon 
 
 38 
 
 Batrachospermum 
 
 37 
 
 Conferva 
 
 47 
 
 Beggiotoa 
 
 71 
 
 Cosmarium 
 
 87 
 
 Botrycoccus 
 
 54 
 
 Craterospermum 
 
 62 
 
 Botrydium 
 
 49 
 
 Crenothrix 
 
 68 
 
 Botrydina 
 
 54 
 
 Cylindrocapsa 
 
 42 
 
 Bulbochsete 
 
 41 
 
 Cylindrospermum 
 
 68 
 
 C 
 
 
 D. 
 
 
 CalocyUndrus 
 
 86 
 
 Desmidium 
 
 81 
 
 Calothrix 
 
 62 
 
 Dictyosphffirium 
 
 53 
 
 ChKtomorpha 
 
 47 
 
 Dimorphococcus 
 
 55 
 
 Chaetophora 
 
 44 
 
 Docidium 
 
 85 
 
 Chamfesiphon 
 
 68 
 
 Draparnaldia 
 
 43 
 
ii6 
 
 INDEX. 
 
 
 
 Page. 
 
 
 Page. 
 
 E. 
 
 
 Micrasterias 
 
 99 
 
 Enteromorpha 
 
 43 
 
 Microcystis 
 
 72 
 
 Eremosphaera 
 
 55 
 
 Microcoleus 
 
 69 
 
 Euastrum 
 
 96 
 
 Microthamnion 
 
 44 
 
 Eudorina 
 
 49 
 
 Mischococcus 
 
 55 
 
 Euglena 
 
 5° 
 
 Mougeotia 
 
 61 
 
 G. 
 
 
 N. 
 
 
 Genicularia 
 
 80 
 
 Nephrocytium 
 
 54 
 
 Gloeocapsa 
 
 73 
 
 Nodularia 
 
 68 
 
 Gloeocystis 
 
 54 
 
 Nostoc 
 
 66 
 
 Gloeothece 
 
 72 
 
 0. 
 
 
 Glceotrichia 
 
 63 
 
 
 
 Gomphosphaeria 
 Gonatonema . 
 
 72 
 62 
 
 GEdogonium 
 Olpidium 
 
 38 
 
 55 
 
 Gonatozygon 
 Gongrosira 
 
 80 
 44 
 
 Onychonema 
 Ophiocytium 
 Oscillaria 
 
 81 
 
 52 
 70 
 
 Gonium 
 
 50 
 
 
 
 H. 
 
 
 P. 
 
 
 Hapalosiphon 
 Hildebrantia 
 
 66 
 38 
 
 Palmella 
 Palmodactylon 
 
 54 
 53 
 
 Hyalotheca 
 Hydrodictyon 
 
 80 
 51 
 
 Pandorina 
 
 Pediastrum 
 
 Penium 
 
 49 
 50 
 82 
 
 Hydrurus 
 
 53 
 
 
 
 
 
 Petalonema 
 
 65 
 
 I. 
 
 
 Phymatodocis 
 
 81 
 
 Introduction 
 
 II 
 
 Pithophora 
 
 45 
 
 Isactis 
 
 63 
 
 Plagiospermum 
 
 62 
 
 
 
 Pleurocarpus 
 
 62 
 
 L. 
 
 
 Plectonema 
 
 65 
 
 Lemanea 
 
 37 
 
 Porphrydium 
 
 54 
 
 Leptothrix 
 
 71 
 
 Polycystis 
 
 72 
 
 Leptozosma 
 
 81 
 
 Polyedrium 
 
 53 
 
 Lyngbya 
 
 68 
 
 Prasiola 
 
 43 
 
 M. 
 
 
 Protococcus 
 
 53 
 
 Mastigoiiema 
 
 63 
 
 R. 
 
 
 Merismopedia 
 
 72 
 
 Raphidium 
 
 55 
 
 Mesocarpus 
 
 62 
 
 Rhizoclonium 
 
 47 
 
 Mesotsenium 
 
 8i 
 
 Rivularia 
 
 63 
 

 INDEX. 
 
 
 117 
 
 S: 
 
 Page. 
 
 
 T. 
 
 Page. 
 
 Scenedesmus 
 
 SI 
 
 Tetmemorus 
 
 
 94 
 
 Schizogonium 
 
 47 
 
 Tetraspora 
 
 
 54 
 
 Schizochlamys 
 
 54 
 
 Thorea 
 
 
 37 
 
 Schizomeris 
 
 45 
 
 Tolypothrix 
 
 
 65 
 
 Sciadiura 
 
 52 
 
 Triploceras 
 
 
 86 
 
 Scytonema 
 
 64 
 
 Tuomeya 
 
 
 37 
 
 Sirogonium 
 
 61 
 
 
 
 
 Sirosiphon 
 
 65 
 
 
 U. 
 
 
 Sorastrum 
 
 SI 
 
 Ulothrix 
 
 
 45 
 
 Sphseroplea 
 
 42 
 
 Urococcus 
 
 
 55 
 
 Sphaerozosma 
 
 81 
 
 
 V. 
 
 
 Sphserozyga 
 
 Spirogyra 
 
 SpirotEenia 
 
 68 
 
 56, 58 
 82 
 
 Vaucheria 
 Volvox 
 
 48, 49 
 49. 
 
 Spirillum 
 
 72 
 
 
 X. 
 
 
 Spirulina 
 Staurastrum 
 
 72 
 102 
 
 Xanthidium 
 
 
 95 
 
 Staurogenia 
 
 51 
 
 
 Z. 
 
 
 Staurospermum 
 Stephanosphsera 
 Stigeoclonium 
 
 62 
 43 
 
 Zygnema 
 Zygogonium 
 
 
 61 
 61 
 
 Symphyosiphon 
 
 64 
 
 
 
 
 Symploca 
 
 69 
 
 
 
 
 Synechoccocus 
 
 72 
 
 
 
 
Botanical and Entomological Supplies 
 
 QUEEN PLANT PRESS 
 
 No. Price 
 
 4003 The Queen Plant Press, with absorbent paper $2 00 
 
 4004a Handle for above, stout leather, very neat and convenient . . o 25 
 
 4004b Sling strap, ad justablei for same 6 25 
 
 Special rates will be quoted in quantities for class use. 
 
 COLLECTING CASES 
 
 4000 Large size, 1 5x8^x4 X 
 
 4001 Smaller size, 12x7^^x3 >^ . . 
 
 Special estimates made for any required quantity for class use. 
 
 MAGNIFIERS 
 
 $1 50 
 
 Pocket Magnifiers, 
 Coddingtons, Achro- 
 matic Triplets and 
 Doublets. 
 
 Prices from 
 25 cents to $5.00. 
 
 N. Y. OFFICE, 
 
 SEND FOR BOTANICAL AND ENTOMOLOQICAL CIRCULAR B. B. 
 
 QUEEN & CO., Inc. 
 
 loio Chestnut Street 
 
 .WllIIIIIMIl"""* 
 
 PHILADELPHIA