Marine Biological Laboratory Received. Accession No. Given By Place,_ ~iL 3.C. m m m cr m CD CD m a a ^^^^^^^^u&^^ FRESH-WATER OF THE UNITED STATES; (EXCLUSIVE OF THE DIATOMACEjE) COMPLEMENTAL TO DESMIDS OF THE UNITED STATES; WITH 2300 ILLUSTRATIONS, COVERING ONE HUNDRED AND FIFTY-ONE PLATES, A FEW COLORED, INCLUDING NINE ADDITIONAL PLATES OF DESMIDS. BY THE REV. FRANCIS WOLLE, Member of the American Society of Microscopists. BETHLEHEM, PA.: THE COMENIUS PRESS, 1887. TO DR. ANTON HANSGIRG, OF THK ROYAL-IMPERIAL UNIVERSITY OF PRAGUE, BOHEMIA, IN RECOGNITION OF HIS EARNEST RESEARCHES AND VALUABLE CONTRIBUTIONS TO THE LIFE-HISTORY OF FRESH-WATER ALG^E, THIS VOLUME IS RESPECTFULLY DEDICATED BY HIS FRIEND AND CORRESPONDENT, THE AUTHOR. PBEFACE. IN presenting the following memoir on the Fresh-water Alg*e of the United States, we are keenly sensible of the great task we have undertaken. The subject-matter is in an unsettled state, pass- ing through a period of transition. There is an Old School and a New School. The former accepts all forms as distinct plants, and the latter rejects a large portion of the forms, mostly unicellular, as only conditions of development. Suggestions for a new nomen- clature have been made. The latest by Dr. Anton Hansgirg, Pro- fessor in the Royal University of Prague ; but they seem premature. There are too many questions of life-history remaining undeter- mined. The most complete work representing the Old School, is Raben- horsfs Flora Europaea Algarum (1864-1868). An admirable work in its day, and indispensable for reference at the present time : but a very large number of forms therein described, making up many genera, some of which contain fifty or more species, are nothing more nor less than conditions of development. Thuret of France has claims for later suggestions. He does not reject the unicellular forms as mere conditions, but proposes to reverse the order of arrangement by placing those more highly developed, or those most nearly allied to the larger marine algse, first in rank ; and then gradually descend to the lower forms. The idea meets with favor. Dr. O. Kirchner in preparing a prodomus of the Fresh-water Algse of Silesia (1878) adopted the proposition. His work being imbued with the more modern ideas of the value, (or valuelessness) of many forms, and being quite in accord with my own observations and convictions, his volume has been a valued companion, and I am largely indebted to Dr. Kirchner for the order of arrangement followed in the preparation of the body of the vi FRESH-WATER ALGJE OF THE UNITED STATES. present volume. Many genera are still preserved which have liter- ally no worth, but they serve for reference. They will be noticed more fully under their various generic characters. We have added nine additional plates of Desmids illustrating one hundred or more species and varieties mostly new to the United States. In our ability to make this large addition we have had the kind co-operation of collectors and workers in various parts of the coun- try. Rev. H. D. Kitchel and his son H. S. Kitchel continued with us ; Miss E. Butler, of Minneapolis, Minn., made some good finds. Geo. B. Twitchel has been operating in a new field, Ohio. Professor F. W. Cregin is active in Kansas ; W. N. Hastings is working up the vicinity of Rochester, N. H., and G. M. Rafter, that of Rochester, N. Y. ; Mrs. Hanson and Miss M. S. Haggin, of San Francisco, Cal., have during the past Summer (1886) commenced opening up the Des- midial resources of that State ; as pioneers they have done a good work. G. v. Lagerheim, of Stockholm, Sweden, has published a list of American Desmids, partly from the island of Cuba, but mainly from Massachusetts. Mr. W. B. Turner, of England, also added a few American forms from Nova Scotia and the United States, all duly noticed under their generic heads. FRANCIS WOLLE. BETHLEHEM, PENNSYLVANIA, DECEMBER, 1886. AUTHOEITIES QUOTED, Mostly in addition to those already noted in Desmidx of the States; also the abbreviation of names used in the preparation of this monograph. AG. — C. A. Agardh. Systema Algarum, 12 mo. Lund, 1824. AG.— J. G. Agardh. Species genera et ordines Algarum. Lundse, 1848-lsi;:;. ALLM. — George James Allmaii. On a new genus of Algee, belonging to the family Nostochacese. Annals and Magazines of Natural History, 1843, etc. ARCH. — W. Archer. Various communications in Quarterly Journal of Microscopic Science. London, 1857-1880. BAIL. — John W. Bailey. Microscopic observations in South Carolina, Georgia and Florida. Smithsonian Contributions, Vol. II. BERK. — Rev. M. J. Berkley. Gleanings of British Algae, supplement to English Botany, 1833. BOR.-THUR. — Ed. Bornet, et G. Thuret. Notes Algologiques. Paris, 187(5- 1880. BORZI. — Antonino Borzi. Studi Algolgici : Note alia morfologia e biologia. Messina, 1883-1885. BORY. — Bory de St. Vincent. Memoir sur les genres de confervis nommes Thorea, Lemanea, Batrachosphermum et Draparnaldia. Paris, isos. BR. — A. Braun. 1. Ueber Chytridium, 1856. 2. Rejuvenescence in Nature. 3. Algarum unicellularum genera nova, etc. BREB. — A. Brebisson. Algues des environs de Falaise, 1835. CES. — Vincenzo barone Cesati. — Ueber die Vermehrung von Hydrodictyon. Hedwigia, 1852. CIENK.— L. Cierikowski Ueber Sphaeroplea, etc., Botanische Zeitung, 1H<>.~». Ueber meineri Beweis fiir die Generatio primaria, 1858. CLEVE. — P. T. Cleve. Monograph ofver de Svenska arterna af Algen, Fain. Zygnemacese. Upsal, 1868 ; Fam. Vaucheria. COHN. — Dr. Ferd. Cohn. — Beitrage zur Biologic. Breslau, 1870-1884. On Protococcus pluvialis ; translated and published I >y Ray Society, 1853. Vlil FRESH-WATER ALG^E OF THE UNITED STATES. COOKE. — British Fresh-water Algse, 1885. CORDA. — A. K. J. Corda. Die Algen. Sturm's Deutschlands Flora, 1829- 1832. D. C. — MM. Lamarck et de Candolle. Flore Francaise, 1805. D. BY. — A. de Bary. Ueber die Conjugaten, 1858. Ueber der Algengattung Oedogonium, 1864. DICK.— Dr. G. Dickie. The Botanists' Guide to the Counties of Aberdeen, etc., 1860. DILL. — J. J. Dillenius, M.D. Historia muscorum. Oxford, 1741. DILLW. — L. W. Dillwyn. British Confervse. London, 1809. DUCLUZ. — M. Ducluzel. Essai des Conferves de Montpellier. EHEB. — Dr. C. G. Ehrenberg. Die Infusioiisthierchen als vollkommene Organisnien, 1838, etc. FLOTOW. — J. v. Flotow. Beobachtungen iiber Heematococcus pluvialis, 1844. FRES. — Dr. G. Fresenius. Sphaeroplea in Bot. Zeitung, 1851. GAY. — Fr. Gay. Essai, monographie locale des Conjugacees. Montpellier, 1884. GIROD. — Girod — Chantrans. Recherches Microscopiqne sur les Conferves, etc., 1802. GREVA. — Grevillea. A quarterly record of cryptogamic Botany, 1872-1886. GREV. — Algpe Britannicse. K. Kaye-Greville, 1850. GRUN. — A. Grunow. Die Desmidaceen vind Pediastreen einiger Oester- reichischen Moore, etc., 1858. HARV.— Dr. W. H. Harvey. A manual of the British Algae. London, 1841. Phycologica Britannica, 1846-1851. HANSG. — Dr. A. Hansgirg. Polymorphismus der Algen, 1885. Bemerkungen zur Systematik einiger Siisswasser Algen, 1884; and other papers. HASS.— Dr. A. H. Hassall. British Fresh-water Algae. London, 1845. HICKS. — John B. Hicks. On Fresh-water Algse ; Sundry papers in Royal Mic. Journal. HILSE. — Dr. Hilse. Beitrage zur Algen und Diatomeen-Kunde Schlesiens, 1860. HILL. — Franz Hillebrandt. Ueber ein Chroolepus mit Zoosporenbildung. Bot. Zeitung, 1861. HOB. — J. Hobson. Notes on Indian Desmidese. Mic. Journal, 1863. HOOK. — Sir W. J. Hooker. — English Cryptogamia. 1833. HUDS. — Gulielnii Hudsoni. Flora Anglica, 1778. ITZ. — Dr. H. Itzigsohn. Skizzen zu einer Lebensgeschichte des Hapalo- siphon Braunii. Also frequent papers in Bot. Zeitung; Hedwigia; Annal. des Science ; Nova Acta, etc. JOSH. — W. Joshua. Burmese Desmidiese with descriptions of new species. KIRCH. — Dr. O. Kirchner. Kryptogamen Flora von Schlesien. Breslau, 1878. NAMES OF AUTHORS. IX KLEBS.— G. Klebs. Ueber die formen einiger Gattungen der Desmidiaceen, 1879. KG. — F. T. Kuetzing. Phycologia generalis ; 1843. 2. Phycologia Germanica ; 1845. 3. Species Algarum ; 1849. 4. Tabulae Phycologicse, 1845-1869. LAGS. — Lagerstedt. Monographia om Algslagt Prasiola. Upsal, 1869. LAGH. — G. Lagerheim. Bidrag till Kaennedomen om Stockholmstraktens Pediastreer, Protococcaceer, etc. 2. Algologiska och mykologiska anteckningar fran en botanisk resa i Lulea Lappmark. 3. Om Chlorochytrium Cohnii och dess foerhallande till naerstaende arter. 4. Ueber Phaeothamnion. Eine neue Gattung unter den Siiss- wasser-Algen, 1884. 5. Zur Algenflora der Wasserfalle von Lulea Elf. 6. Bidrag till Sveriges Algflora, 1883. 7. Bidrag till Amerikas Desmidieflora, 1885. LANDS. — D. Landsborough. British Seaweeds, with notices of some of the Fresh-water Algae. London, 1849. LECLERC. — Sur la fructification du genre Prolifere. Paris, 1817. LINN. — Car. Linnaeus. Species Plantarum, 1753. LYNGB. — H. C. Lyngbye. Tentamen Hydrophytologiae Danicae, 1819. MENEGH. — Prof. J. Meneghini. Monographia Nostochinearum Italicarum. Turin, 1841. MEYEN. — F. J. F. Meyen. Beitrage zur Physiologie und Systematik der Algen. Nova Acta Leop. Acad. 1828. MONT. — J. F. Camille Montagne. Exploration Scientifique de 1'Algerie. Paris, 1846, and occasional papers, 1845-1852. MOUG. — J. B. Mougeot et C. Nestler. Stirpes Cryptogamae Vogeso-Rhenanae. Spec, exsic. 1,500, 1810-1860. NAEG. — C. Naegeli. Gattungen Einzelliger Algen. Zurich, 1849. NORD. AND WITTR. — O. Nordstedt et V. B. Wittrock. Algae aquae dulcis exsiccatae. Upsal, 1877-1886. NORD. — O. Nordstedt. Numerous Papers, v. Des. U. S. p. ix. NOTA. — Notarisia Commentarium Phycologicum. Redattori, G. B. de Toni, E. David Levi. Venezia, Italia. PERTY. — Max. Perty. Benierkungen iiber die Bacillarieen. Bern, 1848. Ueber die identitaet einiger Algen — und Infusoriensippen, 1863. PETIT. — Paul Petit. Spirogyra des Environs de Paris. Paris, 1880. PRINGSH. — Dr. N. Pringsheim. Beitrage zur Morphologic und Systematik der Algen. Berlin, 1858-1860. Jahrbucher fiir Wissenschaftliche Botanik. 1858-1884. PRITCH. — Andrew Pritchard. A History of Infusoria, including the Des- midiaceae and Diatomaceae. London, 1861. X FRESH-WATER ALG^ OF THE UNITED STATES. RAB. — Dr. Ludw. Rabenhorst. Algen Europa Exsiccati. Dresden, 1850-1867. Flora Europsea Algarum Aqua dulcis et submarinae. Leipzig, 1864. Kryptogamen Flora von Sachsen. 1863. RALFS. — John Ralfs. The British Desmidiete. London, 1848. REINSCH.— F. Reinsch. Algenflora von Mittel-Franken. Nurnberg, 1867. Contributiones ad Algologiain et Fungologiam. 1874. RICH. — Paul Richter. Ueber die in den EntAvickelungskreis von Beggiatoa rosea-persicina, Zopf, gehoerenden seitherigen algen-species. Leipzig, 1884. Ueber den Wechsel der Farbe bei einigen Siisswasseralgen, insbe- sondere den Oscillareii. Bot. Central Blattes, 1880. Zum Fornienkreis von Glceocystis. Hedwigia, 1880. Frage tiber die moeglichen genetischen Verwandtschafts-verhalt- nisse einiger einzelligen Phycochromaceen. Hedw., 1880. ROSTAF. — J. Rostafinski u. M. Woronin. Ueber Botrydiuni granulatum. 1877. Hydrurus i jego pokrewienstwo. 1882. ROTH. — A. G. Roth. Catalecta Botanica. Leipzig, 1797. Neue Beitrage zur Botanik. 1788-1800. ROY. — John Roy and J. P. Bisset. Notes on Japanese Desmids, 1886. SCHAAR. — Dr. Julio Schaarschmidt. Klausenburg, Austro-Hungary. A number of Papers on Hungarian Desmids, Diatom es and other Algse. All in the Hungarian language, hence of little use to the general reader. SIRO. — S. Sirodot. Sur le development des Algues d'eau douce du genre Batrachospermum. Paris, 1875. De la familie des Lemaneacees. STEIN.— F. Stein. Die Infusionsthiere. 1854-1882. THITR. — Gustave Thuret. Sur la reproduction de quelques Nostochinees. Note sur la synonymic des Ulva. 1854. Recherches sur les zoospores des Algues. THWAIT. — G. H. K. Thwaites. On an apparently undescribed state of the Palmellese with a few remarks on germination in the lower plants. 1848. Mode of the formation of spores in a species of Vesiculifera. 1846. On the early stages of development of Lemanea fluviatilis. 1851. TURN. — W. Barwell Turner. On some new and rare Desmids. London, 1885. VAUCH. — J. P. Vaucher. Histoire des Conferves d'eau douce. 1803. VAUP. — J. P. Vaupell. Befrugtningen hos en Art af Slaegten Oedogonium. Copenhagen, 1850. WART. — B. Wartmann. Zur Anatomie und Entwicklungsgeschichte der Algengattung Lemanea. St. Gall, 1854. WEBER. — Weber and Mohr. Gross Britanniens Coiiferven : a reproduction in German of Dillwyn's Confervae. 1803-1805. NAMES OF AUTHORS. XI WILLS. — A. W. Wills. Life-History of Volvox globator, in Midland Natur- alist. 1880. WILLE. — N. Wille. Oni en ny endophytisk Alge, 1880. Om Hvileceller hos Conferva. 1881. Oni Svaerinecellerne og deres Copulation hos Trentepohlia, Mart. 1878. Oni Slaegteii Gongrosira, Kg. Stockholm, 1883. WITTK. — V. B. Wittrock. Dispositione Oedogoniacearum Suecicarum. Stockholm, 1870. Om Gotlands Soetvattens Alger. 1872. On the spore formation of the Mesocarpese, especially of Gonatonema. 1878. Prodomus Monographia Oedogoniearum. Upsal, 1874. On the development and systematic arrangement of the Pithophor- acese. 1877. Oedogoneacese Novae, in Suecia lectae, 1872. Om Snoens och Isens Flora. WOOD. — H. C. Wood. Contributions to the History of the Fresh-water Algse of North America. (Smithsonian Institution, 1872.) WOBON. — M. Woronin. Neuer Beitrage zur Kenntiiiss der Chytrideen, in Bot. Zeitung, 1867, INTEODTJCTION. THERE is a period in the life-history of Fresh-water Algse which has not received the consideration the subject deserves. We mean an intermediate period between the niicrogonidia or spore, or the first development from it, and the matured plant. It is a period unlike anything known among the higher forms of vegetation. The phamogauious plants blossom, and bear seed, some in edible masses known as fruits, some in hard-shelled envelopes as the nuts, others have the seeds in pods, and so on ; the seeds germinate and at once reproduce the original type. Cryptoganious plants are not usually so direct in the reproduc- tion ; they propagate from spores which in many, perhaps most, instances divide into parts, two or four, and these redivide often many times over, and then develop a prothallus, a peculiar sort of filamentous growth, from which the true plant grows. In the case of the Fungi this ante-growth is called mycelium. Under circumstances not favorable to reproduction this mycelium will grow into large masses. It is found in dark cellars and in neglected mines often filling the galleries scores of feet in extent, sometimes to a depth of two or three feet, yet never producing a single plant ; on the other hand, under favorable circumstances, the true plant will develop rapidly with scarcely a visible sign of a mycelium. Among the Mosses also, we find this prothallus, (ante-growth) ; sometimes it extends over many square yards of earth or moist rocks without an evidence of the plant that should be developed from it ; at other times the true plant abounds with scarcely an evidence of a prothallus. This growth of prothallus, and of mycelium constitutes a peculiar or abnormal production ; they are the true plants arrested in their normal course of development, XIV FKESH-WATER ALG.E OF THE UNITED STATES. In Fresh- water Algae, perhaps more than in any other class of cryptogamous plants, is this peculiar, arrested character of plant- life observed. It is found everywhere either in immediate con- nection with or independent of the more fully developed plants. Usually it presents itself in unicellular forms, embracing the forms of such old genera as Protococcus, Pleurococcus, Chloro- coccum, and others among the Chlorophycese, and Gloeocapsa, Aphanocapsa, Microcystis and many others among the Cyanophy- cese. The cells divide, and redivide many times over. To say that one single spore, or cell, will produce thousands of its own kind in the course of a few days, is no exaggeration, yet all of these, or nearly all, are merely single cells, serving apparently no purpose except to form a bed or stratum from which in due time, when the particular requirement of temperature and moisture are supplied, a plant, or plants, will develop, repro- ducing the original filamentous type. When we consider that in all vegetation the process of cell multiplication takes place by division of cells, that this is the process of growth in every stem and leaf, but differing ; in these the cells remain united to increase the size, whereas in alga) the cells separate — the process of multiplication and growth of the so-called unicellular forms is not so altogether singular. As in the growth of a leaf hundreds and even thousands of cells are evolved before a leaf is fully matured, so in algse many thousands of cells are produced before the true plant is developed. There is at least an analogy between the two in principle of development. P. H. Dudley, in a recent paper read before the New York Microscopical Society (see document of said Society Vol. II, No. I. p. 9), on Protococcus viridis, takes a philosophic view of this condition of plant-life. A few lines may be transcribed : i i As humble as our plant may seem from its classification, modern science is still unable to solve its mysteries ; it is one of the great manufacturing chemists among plants, converting crude materials into combinations which, upon decay, may be taken up by higher vegetation. Spread out upon trees and rocks, its gelatinous substance is ready to catch and imbed the floating dust and inorganic matter brought to it by the wind, some of which will be converted and used. The air also brings great carboys of carbon di- oxide and exchanges them for oxygen. Fumes of sulphuric, sulphurous, nitric and nitrous acids, and also ammonia come to be combined ; the rain brings chlorides and other chemicals to be utilized. Each of the individual cells of Protococcus viridis, only measuring from two to ten Micro- INTRODUCTION. xv Millenieters in diameter, can do more in its small laboratory than our chemists with all the room and appointments that science has suggested — it builds its own cellulose walls from inorganic matter. Chemists are hardly agreed upon the composition of cellulose and the protein compounds, and if they were, they could not introduce the life-principle to produce them." The polymorphism of Fresh-water Algse is not a new thought. It has received varied attention during the past half of a century. 0. A. Agardh (Swede) in the earlier part of the present century called attention to some peculiar observations made by himself. The ideas were new and called forth severe criticism. Turpin treated him severely as a false prophet. At the present day some of his notions appear crude, but others stood the test of later observations, and Agardh deserves commendation for the direction he gave to later studies. Later (1840) followed Kuetzing (Prussia) in high rank as an Algologist. He recognized a relation between some of the lower unicellular forms with more fully developed plants. Dr. H. Itzigsohn (Prussia, 1850) made a bolder stride in the. study of the life-history of Hapalosiphon, and after two years of close attention, jHiblished his observations in an exhaustive, illustrated prodomus, bringing out many new facts relating to the polymorphic character of this plant. Correctly and ably as his work was done1 it was not accepted but quietly ignored, appar- ently for no other reason than that it struck too severe a blow at the hitherto accepted theories of classification. At the same time that Itzigsohn did so much to throw light on the life-history of the Cyanophycea? (Schizosporese), I. B. Hicks did much in* the study of some of the Chlorophycese. He called attention to the work of Itzigsohn and to the contributions of Meyen, but instead of awakening an interest of inquiry into the true character of the unicellular forms, and their relation to more highly developed plants, a lethargy appears to have seized upon the minds of Algologists ; a calm prevails and more than a decade passes before other explorers enter the field more or less imbued with the spirit of the newer thoughts ; from time to time larger or smaller contributions made their appearance. At the present date we have valuable papers from Borzi, of Messina, Italy ; from Cienkowski and Faniinzin, of Eussia ; from Hansgirg, of Bohemia, and Schaarschmidt, of Hungary ; from Kirchner, Klebs, Eichter, Sachs, and others, of Germany ; from Eostafinski, of Poland ; from Sirodot, of France ; from Wille, Wittrock, Lagerheim, and others, of Sweden. Valuable as these papers are. few appear to have traced the progress of growth in 2 Xvi FRESH-WATER ALG^ OF THE UNITED STATES. individual plants from their earliest germination through their cycles of transformation to full maturity. They relate mostly to snatches of observation, but all tending to illustrate the poly- morphic features of Fresh-water Algae, and the relation of unicellular forms to the fully developed filamentous algae. There is no such thing as the changing of plants from one generic character to that of another. What we do see approaching the appearance of such transformation is simply an undeveloped condition changing to another condition before reaching maturity. Dr. Hansgirg, of the Eoyal University of Prague, one of the latest observers noted above, who for five years has been gather- ing specimens in all parts of Bohemia, and made them a study at all seasons of the year, giving special attention to their process of development, sums up his observations in the following seven theses^freely translated from the German. We may remark in advance, they are full of valuable hints, but need, in some instances, verification in as far as they relate to our species. THESIS I. Most of the Schizophyceae (Cyanophyceae), if not all, are polymorphic algae, which, in different stages of growth in the open air, assume unicellular vegetative forms, and often retain these forms through many generations, but their genetic relation may be readily traced. THESIS II. Most, if not all, of the forms hitherto classed with Chroococcaceae, as the genera Chroococcus, ^Taeg., Gloeocapsa (Kg) Naeg, Aphanocapsa, Naeg., Synechococcus, Naeg., Gloeo- thece, Naeg., Aphanothece, Naeg., and others, have a genetic connection with other more highly developed forms, that is, the most (if not all) of the so-called unicellular, aeruginous algae forms have their origin in, or result from, the decay, or separa- tion and dividing of cells of filamentous Schizophycece. THESIS III. Such genera of the Family Oscillariaceae Eab. , as Leptothrix Kg., Hypheothrix Kg., Spirulina Lk., Oscillaria Bosc., Phormidium Kg., .Chthonoblastus Kg., Lyngbya Ag., .Hydrocoleum Kg., Symploca Kg., Schizothrix Kg., and others, are often found intermingled with thinner and thicker filaments which are merely younger or older conditions of the same plant ; among them are also forms of the families, Nostochaceae Eab., and Chroococcaceae Eab., and forms of the Family Eivulariaceae Eab.; (Calotricheae Thr.,) ScytonemaceaeEab., and Sirosiphonia- ceae Eab., all of which are genetically connected. THESIS IV. The genera Nostoc Yauch., Anabaena Bory., Cylindrospermum Kg., Sphaerozyga Ag., and others of the Family Nostochaceae Eab., embrace many heterogeneous algae INTRODUCTION. XV11 forms which like the many Chroococcaceae forms, are arrested conditions of development resulting in many instances from sudden thermic and hygrometric changes, and should be treated as developing conditions of various species of the families Oscillariaceae Bab., Eivulariaceae Eab., and Scytonemaceae Eab. THESIS V. The forms of the genera Mastigothrix Kg. , Mastigo- nerna Swabe, Schizosiphon Kg., belonging to the Family Eivulari- aceae Eab. , and of the more recently added genus Calothrix, and also the forms of the genera Diplocolon Naeg., Scytonema Ag., Arthrosiphon Kg., Tolypothrix Kg., Fleet onema Thur., Glau- cothrix Kirch., and others of the Family Scytonemaceae Eab., are the higher, and the most highly developed Algae forms. THESIS VI. As the higher developed forms of Eivulariacea3 Eab. , (Calothrix Thr. ) and of Scy tonemaceae Eab. , may be devel- oped from forms of the Family Oscillariaceae, so are, or may be, developed from the genus Glaucothrix Kirch., forms of Toly- pothrix Kg., Scytonema Ag., or forms of the nearly related Family Sirosiphoniaceae Eab., as the genera Hapalosiphon Naeg., Sirosiphon Kg., Stigonema Ag., Fischera, Schwabe, and others. THESIS VII. As the most of the Schizophyceae, so also many of the Chlorophyceae are polymorphic algae. Most of the Chlo- rophyl-green filamentous algae as Microspora Thr., Conferva Link., Ehizoclonium Kg., Ulothrix Kg., Schizomeres Leib., and Schizogoniuni Kg. , stand in close relation to the higher forms as of the Family Clisetophoraceae Eab., Siphonocladiaceae Schmitz, Ulvaceae Eab., and others, which forms are produced by the widening of the single filaments and the dividing longitudinally, thus gradually producing leaf-like forms ; on the other hand, by the separation of the parts and division of the cells in one, two or three directions, the most of the so-called unicellular algae are produced, embracing forms of Protococcus Ag., Palmella Lyngb., Pleurococcus Menegh., Gloeocystis Naeg., Palmagloea Kg., Schizochlamys A. Br., Palmodactylon Naeg., Dictyosphaerium Naeg., Apiocystis Naeg., Polyedrium Naeg., Characium A. Br., Hydrianum Eab., and others. * Dr. Hansgirg does not in every instance demonstrate the posi- tion taken, but he does take up several species and follows them minutely through various polymorphic changes which occur in the process of multiplication ; he also describes phases which occur under the influence of different degrees of light, tempera- ture, moisture and the character of the soil on which they grow. It would not accord with the design of this work to follow him in all of his observations, which cover about 50 pages. Scyto- nema Hoffmanni, Ag. , is one of the plants which received special XV111 FRESH-WATER ALG^ OF THE UNITED STATES. attention. It is found on old walls, damp mossy earth, old wood, and is not infrequent in green-houses. The plant in younger and older conditions was found to represent the following forms : first, Lyngbya f onus, viz., Lyngbya foveolarum Mont., [Oscillaria (Leptothrix) foveolarum, Eab. ;] L. Calcicola (Kg.) Hansg. [Lep- tothrix calcicola Kg., Hypeothrix calcicola Eab.] Oscillaria Kuetzingiana Nseg. ; Oscillaria tennis Ag. ; Lyngbya vulgaris (Kg.) Kirch., (Phorinid. yulgare, Kg.) Lyngbya antliaria (Jurg.) Hansg.; Symploca niuralis Kg., Symploca melanocephala Kg., Microcoleus terrestris Desm. Stigonema-forms ; Stigoneina Bou- teilli (Breb. et Desm.) Hansg. (Sirosiphon Bouteilli Breb. et Desm.) Nostoc-forms ; Kostoc Sphseroides Kg., N". gelatinosum Schon., including N". Delphinii, Bor. Unicellular -f oy^ms ; Chroo- coccus minor Naeg. Chr. pallidus Naeg. Chr. aurantio-fuscus (Kg.) Eab., Gloeocapsa seruginosa Kg., Gl. didyma Kg., Gl. quaternata (Breb.) Kg., Gl. sanguinea Kg., Aphanocapsa cruenta (Ag.,) Hansg. [Porphoridium cruentum (Ag.) 2s"aeg.] Some pages are devoted to an account of the development of Ulothrix flaccida Kg. The following are forms or conditions through which this plant passes. It is made to include U. nitens Menegh., Conferva antliaria Kg., Psichohorinium antli- arium Kg., Gloeotila ealdaria Kg., and embraces the following unicellular forms, viz., Stichococcus bacillaris 2s"aeg., Dactylo- coccus caudatus, Hansg., D. bicaudatus A. Br., Dactylothece Braunii Lagh., Protococcus viridis Ag., Chlorococcum humi- cola Eab., Cystococcus huniicola Naeg., Pleurococcus vulgaris (Grev.) Menegh., PI. pulcher Kirch., PL miniatus (Kg.) K"aeg., PI. aureo-viridis (Kg.) Eab., Protococcus grumosus Eich., P. cinnamoneus (Menegh.) Kg., Gloeocystis fenestralis (Kg.) A. Br., (Gloeocapsa fenestralis) Gl. vesiculosa Naeg., Palmella hetero- spora, Eab.? and P. botryoides Kg. These two plants are quoted, the one a Cyanophycece and the other a Chlorophycece as instances of the multiform transfor- mations to be observed in the development of Fresh-water Alga3. Many others might be cited from personal observation as well as from the notes of Dr. Hansgirg and others, all demonstrating the position assumed, and often referred to in the body of this work, that the algee forms undergo many polymorphic changes before they come to a full development. It is evident that sooner or later the whole system of classifi- cation must be changed. The present system is altogether too artificial, separating as it does many forms not only into different genera, but into different families, and orders, which are geneti- cally connected. Our present knowledge is too imperfect for a INTRODUCTION. XIX complete rearrangement. It is important to understand the life- history of not only a few, but of all the generic forms. Much as has been accomplished in the past few years by the studies of such men of prominence as Borzi, Cienkowski, Hans- girg, Richter, Rostafinski, Sachs, Schaarschmidt, Sirodot, Wittrock, "Woronin and others, there remains much more to be done, and years may pass before the life-history of all the generic forms shall be fully understood. To the names adopted for the plants described in this work, we have added the synonymous names, with the names of their authors, but have not every time quoted the titles of the works in which the names occur ; this plan to economize space, and because of secondary importance. The titles of the papers or works of the various authors referred to, may be found immediately preceding this Introduction. As this volume is complemental to our Desmids of the United States and the first eight of the series of 150 plates represent additional Desmids, have made the numbering of them a succes- sion of those of the first volume, commencing with number LIY. DESMIDIE^E. APPENDIX TO DESMIDS OF THE UNITED STATES. Genus, GONATOZYGON. V. Des. U. S. p. 22. G. SEX-SPINIFERUM, Turner. Joints variable in length, ten to thirty times the breadth ; base swollen, apex either rotmido- truncate or quite rounded ; spines, or rather setae, very short and arranged longitudi- nally in six linear series. Forming long filaments. Min- nesota. Length of joints 88-191 ^ ; diameter 6-8 /*. Genus, HYALOTHECA. V. Des. U. S. p. 22. H. DISSILIENS, Yar. HIANS, n. var. Plate LIY, figs. 14-16. Differs from the typical form in having the lateral margins of the cells arched with an acute notch in the middle. Diameter 25-50 /*. The larger form from Budd's Lake, New Jersey; the smaller from ponds near Maitland, Kissimme and other localities, Florida, sometimes occurring in large masses. It is nearly allied to a New Zealand species described by Nord- stedt as If. hians. Often difficult to distinguish from par- tially developed forms of Desmidium quadratum. End view is circular ; has no evidence of a thickened border or a twist. Genus, BAMBUSINA. Y. Des. U. S. p. 24. B. GKACILESCENS, Nord. Plate LIX, figs. 13, 14. This form is described as a variety of B. Brebissonii. Whether viewed as such or as a distinct species, it was an interesting discovery to find it fruiting freely in a pond near Winter Park, Florida. Diameter of cells 14 // • length 23 ^ ; zygospores 15 ^ 22 FRESH-WATER ALG^ OF THE UNITED STATES. The plant conjugates not like one of the Desmidiece, but more like a Zygnemacece, in longer or shorter series ; often when the zygospores are nearly matured, the cells of one side separate and cause the other side to bend backward. Judging by these specimens the correctness of the generic position of Bambusina may be questioned. Genus, SPHAEBOZOSMA. V. Des. U. 8. p. 28. S. PULCHRUM, Bail., var. CONSTRICTUM, Wolle. Plate LIX, fig. 12. Cells half as long as wide with a decided constriction in each lobe between the axis and the apex. Diameter 70-75 yu. Lake near Kissimme, Florida. S. PULCHELLTJM ( Arch. ) Bab. Plate LIV, figs. 8, 9. Cells in outline oblong with the middle much inflated, sharply incised and angles rounded ; ends narrower because not at all or very slighted inflated ; apices square; varying in length from one to nearly two diameters. Diameter 9-10 IJL. Pond waters, not rare. Syn. Spondylosium bambusioides, Witt. S. pulchellum, Arch. S. MONILIFORME, Lund. Plate LIX, fig. 11. Series of cells often long, firm, somewhat twisted ; usually included in a mucous envelope. Cells average one-half longer than broad, deeply constricted, sinus obtuse out- wardly enlarged, back more or less produced ;^seen from the vertex triangular, sides somewhat retuse ; angles rounded, isthmus sub -elongate, membrane smooth. Diameter about 20 /*. Not infrequent in quiet waters, Florida ; less frequent in New Jersey, Minnesota and Pennsylvania. Genus, PENITJM. V. Des. II. S. p. 33. P. SPIROSTRIOLATUM, Barker. Plate LXI, fig. 17. Large, elongated ; single cells somewhat swollen in the center, and tapering slightly towards the rotundo-truncate ends ; the cell walls possessing a number of superficial, con- spicuous, rather coarse striae, running in a spiral direction ; these somewhat interrupted at a number of annular rib-like projections varying in number ; these projections most numerous towards the ends. CLOSTERIUM. 23 Mr. Turner of England who reports this form from Minne- sota remarks, "As I do not know of the publication of any measurements or authentic figure of this species, I may pos- sibly be in error in referring these American forms to it : the figures therefore must speak for themselves." Diameter of cells 23-31 ju ; length of double cell as figured 227-260 p. Another form, Plate LXI, fig. 19, which may for the present, be referred to this species, I found frequent in the Tocoi marshes, Florida. It is unlike the preceding in the absence of the transverse sutures or rib-like projections ; in the variableness of diameter and proportionate lengths. Diameter of smaller forms 15-18 /* and of larger form 37 yw. The smaller are 10-14 and the larger 7 times longer than broad. Chlorophyl usually thrice interrupted. P. CRUCIFERUM, (D.BY.) Wittr. Plate LXI, figs. 9-11. Cells cylindrical, nearly twice as long as wide, scarcely constricted, ends roundly truncate ; seen from vertex orbic- ular ; chlorophyl laminae arranged in form of a cross as seen in transverse section ; cytioderm smooth. Syn. Oosmarium cruciferum, D.By. Marsh pools, Florida. P. (Cylindrocystis ) TUMIDUM, F. Gay. Plate LVI, figs. 7, 8. Cells twice as long as broad; each semi-cell a broadly truncated cone. Cytioderm smooth. Diameter 28 JJL. Frequent in Tocoi marshes, Florida. Genus, CLOSTEEIUM. V. Des. U. S. p. 37. C. JUNCIDUM, (Des. U. S. p. 38,) forma GBACILLIMA-LOEVISSIMA, Breb. Plate LV, fig. 21. Very much smaller than the type-form and destitute of striae. Frequent in pond near Maitland, Florida. C. ENSIS, Delp. Plate LV, figs. 13, 14. Cell elongate about twenty times longer than broad, sub- linear, or lightly attenuated from the middle to the apices 5 ends not curved ; cytioderm smooth. Diameter 36 yw. Not rare in ponds, Minnesota, Pennsylvania and New Jersey, 24 FRESH-WATER ALG.E OF THE UNITED STATES. 0. BREBISSONII, Delp. Plate LV, fig. 17. Cells sublinear, ends attenuated, moderately curved, apices rounded ; about thirty times longer than broad ; cytioderm smooth. Diameter 18 yu. Observed occasionally, Minnesota and Pennsylvania. C. LANCEOLATUM, Kg. (V. Des. U. S. p. 39). Plate LV, figs. 18-20. Found hundreds of specimens of this species in a gather- ing made by Prof. F. W. Cragin, Kansas. Diameter 40-50 /*. C. LUNULA, (V. Des. TJ. S. p. 40,) var. STRIATUM. Plate LV, fig. 12. Differing from the ordinary form by having the cytioderm finely but distinctly striate. C. ACEROSUM. (V. Des. U. S. p. 41. ) Plate LXI, figs. 1, 2. Finely in fruit ; presenting the peculiarity of two forms of zygospores, single and twin, oval, the longer axis at right angles with the axis of the cells. Cell walls finely but dis- tinctly striate. C. TURGIDUM. (V. Des. U. S. p. 41.) Plate LV, figs. 3, 4. A form differing somewhat from that figured Plate VI, fig. 15. C. STRIOLATUM. (Comp. p. 42 Des. U. S.) Plate LV, figs. 5-8. Distinct from forms heretofore illustrated, Plate VI, figs. 8 and 20. Fig. 8 may be considered of doubtful value. C. PRELONGUM, (Breb.) Delp. Plate LV, figs. 15, 16. Cells somewhat linear, cylindrical, elongate, about thirty times longer than broad, slightly curved, apices obtusely rounded, sometimes slightly recurved ; cytioderm striated. Diameter 20-21 j*. Ponds, Pennsylvania and Minnesota. C. SUBCOSTATUM, Nord. Plate LV, fig. 11. Cells usually four to five times longer than broad ; back rather high arched, below nearly straight, may be either slightly concave or convex ; apices obtusely rounded. Mem- brane usually yellowish brown with 9-12 longitudinal costae. Diameter 50-60 >, DOCIDIUM. 25 Found this species most frequent in smaller pools in Florida. By specimens seen from Brazil, S. A., it is evident that this form is liable to great variation in size, having some as large as 125 fi diameter. C. DELPONTII, Klebs. (C. crassum, Delp.) Plate LV, fig. 9. Cells cylindrical, somewhat inflated in the middle, gradu- ally tapering to an obtusely rounded apex ; distinctly striate with one, two or three sutures about the middle ; cell twenty times (more or less) longer than broad. Diameter 35-45 ^. Delponte's name of Crassum having been previously ap- plied to another species by Rabenhorst, Klebs changed it. C. LINEATUM, var. COSTATUM, Wolle. (Comp. Des. U. S. p. 43.) Plate LXI, fig. 3. This variety differs from the usual form in having the striae very thick and few in number. The figure represents one of many fruiting specimens found by W. N. Hastings, Rochester, New Hampshire. C. DIANAE. Plate LV, figs. 1, 2. Two specimens, differing particularly in size from those represented in Des. TJ. S. Plate VII, figs. 8, 9. Not rare. C. PRONUM, Breb. Plate LV, fig. 22. V. Des. U. S. p. 46. Cells very small, sublanceolate, each end drawn out into a setaceous beak about half as long as the body; cytioderm finely striate. Diameter 7-12 /*. Ponds, Florida. C. DIDYMOTOCUM, (V. Des. U. S. p. 39). Plate LV, fig. 10. A large form and distinct variety corresponding to de- scription by Delponte. Cytioderm not longitudinally striate, but smooth and apices obtusely rounded. Diameter 50-60 /<. Minnesota and New Jersey. Genus, DOCIDIUM. V. Des. U. S. p. 47. D. ARCHERII, Delp. Plate LIV, fig. 2. Cells smooth, cylindrical about twenty times longer than broad ; scarcely attenuated from the middle to the ends ; apices broadly rounded or truncate ; base of semi-cells with 26 FRESH-WATER ALG^ OF THE UNITED STATES. one or two undulations. Chloropkyl usually arranged in numerous small parallel bands. Diameter 50-60 //. Numerous in pond, Luzerne Co., Pa. D. NODULOSUM, D. By. Plate LIV, fig. 3. Cylindrical, eight to ten times longer than broad, scarcely attenuated ; undulate with three or more distinct swellings in basal half of semi -cell ; apex truncate, angles rounded, furnished with three or four teeth in view, below the margin ; chlorophyl parietal. Diameter 40-50 ^. Pools near Minneapolis, Minn. D. BACULUM, var. FLORIDENSE, Wolle. Plate LIV, fig. 5. Differing from the typical form, Des. TJ. S. p. 49, in having the margins wavy from base of semi-cell to apex. Diameter 15-17 ^ ; length of cell often thirty times greater. Frequent in pond near Maitland, Florida, March, 1885. D. RECTUM, Delp. Plate LXI, figs. 20, 21. Cells cylindrical, straight, twelve or more times longer than broad ; slightly narrower at the truncate apex than at the base ; moderately swollen at the base of the semi -cells. Diameter 25-28 yw. The distinction which Delponte makes between this form and D. Baculum, to which it is very closely related, is, that it is perfectly straight, while the former is "straightish," some- what bent, although not so represented, Plate XI, figs. 3, 4, Des. U. S. The central inflations are usually larger in D. Baculum than in D. rectum. D. WOODII, Delp. Plate LIV, fig. 4. Cell cylindrical, six to ten times longer than broad ; apices rounded ; basal inflation of semi-cell large, wide and high ; cytioderm smooth. Diameter at ends 50 /* ; inflation 65 yw. Pond, Ocean County, New Jersey. D. GrEORGicuM, Lagh. Plate LXI, fig. 16. Cells large, twelve times longer than broad ; moderately constricted in the middle; suture none; semi-cells much swollen about the middle ; basal part with four larger and smaller undulations, alternating large and small j ends CALOCYLINDRUS. 27 somewhat attenuated ; apices roundly truncate ; membrane hyaline, punctate, thickest at the ends — 110 aculei nor teeth. Diameter of cells, basal parts 54 ^ ; middle 75 // ; apices 39 jw. Pond waters, Georgia. D. VERTICILLATUM, ( Triploceros verticiUatum, Bail.) V. Des. IT. S. p. 53. Plate LXI, fig. 18. This illustration given as another of many forms in which this species often occurs. The third diverging process of the apical termination not always evident. W. N. Hastings, Rochester, New Hampshire, reports this form frequent in the Cocheco River. Genus, CALOCYLINDRUS. V. Des. U. S. p. 54. C. DE BABYI, Arch. Plate LVI, fig. 12. A specimen from Minnesota, the typical form, unlike the one fig. 5, Plate XV, which is more like a form of C. Cu- cumis f the constriction is not deep, linear, but merely a shallow notch, hence De Bary classified it with Pleurotaenium. C. CORDANUM, Breb. Plate LX, fig. 28. Diameter about half the length ; gently and slightly con- stricted in the middle ; ends round or somewhat trun- cate ; cytioderm lightly granular or punctate. End view circular. Diameter 26-27 ^ • length 47-50 ^ ; isthmus 17-19 //. This form is reported by W. B. Turner, as found in Nova Scotia. Genus, COSMARIUM. V. Des. U. S. p. 57. C. INFLATUM, Wolle. Plate LVII, figs. 18, 19. Cells one-half longer than broad j semi-cell gradually en- larged from a narrow base to a broadly dilated end ; end view broadly elliptic ; lateral view circular, with somewhat flattened sides ; membrane finely punctate or smooth. Diameter 25-28 // ; length about 40 /*. Ponds, Minnesota. (7. pseudoprotuberans, Kirch., has something in common with this form, but the semi-cells are separated by narrow linear sinuses. (7. inflatum has wide obtuse angled sinuses. 28 FRESH-WATER ALG^ OF THE UNITED STATES. C. LOBATULUM, Wolle. Plate LVII, figs. 33, 34. Small, one-third longer than broad, end of semi-cell broadly truncate; sides convex with a slight contraction near the apex ; side view circular with end truncate. Mem- brane finely and closely punctate, or granular. Diameter 25 /* ; length 33 yw. Ponds, Minnesota. C. CIRCULATE, Eeinsch. Plate LVII, fig. 37. Cells nearly circular 5 present form slightly shorter than broad ; sinuses narrow linear ; lateral view ovoid, end view elliptic ; isthmus one-third of diameter of cell ; membrane finely punctate. Diameter 75-85 yw ; length 70-75 yw. Frequent in Marsh pools, Tocoi, Florida. This form is considerably larger than the one described by Keinsch, and not quite equal in length and breadth, but otherwise very near it and certainly nearer than the plant described by Lundell under the same name. C. PERFORATUM, Lund. Plate LVII, fig. 32. Somewhat circular, slightly longer than broad, moderately constricted in the middle, sinus acute angled, enlarging out- wardly, rarely linear ; semi-cells sub-semi-circular, back high convex with the middle slightly flattened or rarely slightly retuse ; end view broadly elliptical ; lateral view circular with base broadly truncate. Membrane distinctly but sparsely punctate often with larger granules arranged in triangular form on basal part. Isthmus fully half of the diameter of the cell. Diameter 57-63 ja ; length 60-68 jw. Ponds, Minnesota. *• C. RHOMBUSOIDES, Wolle. Plate LX, figs. 6, 7. Cell nearly as long as wide ; semi -cells in form of a rhom- bus, sides all equal, straight or slightly convex ; nearly half as long as broad ; sinus between, deep and wide; isthmus one- fourth of diameter; end view rhombus-like; membrane finely punctate. Diameter 55-65 ^ • length 50 /*. From collections made by Mrs. Hanson and Miss Haggin in pools near Lake Tahoe, California, August, 1886. COSMARIUM. 29 C. AMERICANUM, Lagh. Plate LX, figs. 15, 16. Cells small, sinus rather obtuse and widening outwardly ; semi-cells sub-circular, the center with seven larger granules (six peripheral and one central) and twelve, more or less distinct, around these ; vertical view elliptic ; lateral view sub -circular. Membrane smooth excepting the central granules. Diameter of cell 22 ju • length 40 ^ ; thickness 18 /i ; diam- eter isthmus 6 //. Pond near Tewksbury, Massachusetts. C. WOLLEANUM, Lagh., var. GRANULIFERUM, Lagh. Plate LX, figs. 1, 2. Syn. C. pseudogranatum, Wolle. Des. IT. S. p. 158. Cell rather large, one-fourth longer than wide ; sinus somewhat ampliated inwardly and outwardly 5 semi-cells sub - semi - circular, base subreniform, dorsum narrowly rounded, angles rounded, margins finely crenulate - dentate ; in vertical view oval ; in lateral view broadly oval. Mem- brane distinctly punctate. Diameter 54 yw ; length 66 yw. Tewksbury, Massachusetts. The author of the present name for a Cosrnarium, G. von Lagerheim, of Stockholm, Sweden, finds that we have dupli - cated the name pseudograiiatum, previously used by Nordstedt, hence re-names the form as above. The new variety granu- liferum reminds one of C. cymatopleurum, Nord. , C. de Notarisii, (Witt.) Nord., and C. capense, ]N"ord., but it is distinct. C. BRAUNII, forma MAJOR, Eeinsch. Plate LVII, figs. 28, 29. Cell small, one and one-half times longer than broad, sinus narrow linear 5 sides with two emarginations ; ends truncate, membrane smooth ; lateral view oval ; vertical view elliptic. Diameter 25-28 /* ; length 36-40 /*. Ponds, Still water, Minnesota. C. (Euastrum,) SENDTNERIANUM, Eeinsch. Plate LVII, figs. 30, 31. Cells nearly twice as long as wide ; sinus narrow linear ; semi -cells nearly as long as wide, ends rounded, lateral margins each with four or five crenulations ; lateral view of whole cell elliptic with more or less of a constriction in the middle ; end view oval. Diameter 25 /* ; length 44 //. 30 FRESH-WATER ALG^ OF THE UNITED STATES. Minnesota, not infrequent. This species reminds one of C. nasutum, Des. U. S. p. 89, but that is proportionately shorter and strongly granulate. C. LOEVE. Comp. Des. U. S. p. 62. Plate XV, fig. 10. Duplicate specimens are represented, Plate LYII, figs. 35, 36. From a fountain in Pottsville, Penn., where they occurred by thousands in gelatinous masses, August, 1880. C. OCULIFERUM, Lagh. Plate LXI, figs. 7, 8. Cells small, deeply constricted, sinus inwardly and out- wardly more or less dilated ; semi-cells semi-circular-trian- gular, ends retuse, sides slightly convex or straight, inferior angles obtuse ; above the middle a single large granule and below it a series of six small granules arranged in a semi- circle, ends tending towards the retuse apex ; viewed from apex oval, from sides sub- circular. Membrane smooth. Diameter of cell 24 /* ; length 32 JJL. Pond, Tewksbury, Massachusetts. C. NORDSTEDTII, Delp. Plate LVII, figs. 23-25. Cell somewhat longer than broad, constriction deep ; semi-cell rectangular-oblong about twice as wide as long, granulate around the margins, center usually nude. I adopt this name for a form widely distributed, but vari- able ; sometimes it resembles C. triplication in size and shape, but differs in the number and arrangement of the granules, which are not in series of threes, but in continuous eccentric rows. Sometimes they cover the upper half of the semi-cell, then again only one or two rows occur within but close to the margin; the center and basal half are usually nude. The sides are not so straight as figured by Delponte, but the front and end views are always more or less rectangular- oblong. Eeinsch has named a very different form C. Nordstedtii; it is nearly, if not entirely, identical with C. cyclicum, Lund. C. EXCAVATTJM. (Y. Des. U. S. p. 77.) var. TRIGONUM, Lagh. Plate LX, figs. 24, 25. Cells in vertical view triangular, sides straight, or some- what convex, angles rounded. Diameter of cells 18 JJL ; length 20 j^ ; thickness 18 /A. Tewksbury, Massachusetts. CALOCYLINDRTJS. 31 C. SPHALEROSTICHUM, Nord. Plate LVII, figs. 26, 27. Cells small, somewhat longer than broad, sinus narrow linear ; semi-cells subreiiiform-trapezoid, base straight ; in- ferior angles nearly right ; ends in middle truncate and nude, granulate, granules often in two or three vertical series, often scattered, inconstant as name implies. In ver- tical view elliptic, margins granulate ; in lateral view circu- lar, granulate. Zygospore globose or subglobose, smooth. Diameter 13-14 yw ; length 16-20 yu. New Jersey and Pennsylvania, Resembles C. orthosticum, Lund., but is somewhat smaller, ends truncate and granules not so regularly arranged. C. CONSPERSUM, var. RETUSUM, Wolle. Plate LXII, fig. 5. (Comp. Des. U. S. p. 75.) Unlike the true form in the depressed or retuse ends ; sides also incline inwardly from the base of the semi-cell to the end. Diameter averages the same as the type-forms. Ponds, Minnesota. C. PARDALIS, Cohn. Plate LX, figs. 3-5. Cells suborbicular or subquadrate, equal or slightly longer than broad, constriction narrow linear or often some- what dilated inwardly, and more or less ampliated out- wardly ; semi -cells transversely oblong, subreniform ; base and vertex truncate or concave, angles inferior and superior rounded ; lateral view suborbicular ; vertical view oblong, sides straight ; membrane verrucose, verrucae (papillae) obtuse, regularly arranged in diagonal rows. Diameter 54-57 ^ ; length 75-80 /* ; thickness 39 /* ; isthmus 18-20 //. Lagerheim reports this African plant from Tewksbury, Mass. It has not come under my notice. Looks like a close relation to some form of C. compersum. The figures repre- sent a front, a lateral and a transverse view, copied from Cohn's figures. C. POLYMORPHUM, Nord. Plate LX, figs. 31-33. Suborbicular, deeply constricted, sinus narrow linear ; semi-cells semi-circular, base straight, end truncate ; two granules above the base, three about the middle of the area ; punctate between the two series ; granulate near the margin : 3 32 FRESH-WATER ALGvE OF THE UNITED STATES. in vertical view broadly elliptic, granulate within the margin, center nude ; in lateral view suborbicnlar, end truncate. Diameter of cell 25 // ; length 33 //. Tewksbury, Massachusetts. C. TAXICHONDRUM, Lund. (V. Des. U. S. p. 71.) Var. BIDEN- TULUM, Lagh. Plate LX, figs. 17, 18. Cell sub-circular, semi-cell with one large verruca at isthmus ; five large granules in an arched series between the middle and the margin, and four below this in the form of a cross, or a series of three and one below ; in vertical view elliptic, somewhat contracted at ends, the angles bi dentate. Diameter 45 fj. ; length 48 ^. Tewksbury, Massachusetts. C. PSEUDOTAXICHONDRUM, Nord. (V. Des. U. S. p. 71.) G. von Lagerheim appears to give too much prominence to simple differ entiations— mere vagaries of the same species. They may be briefly noted. 1. C. taxichondrum, var. bidentulum, as above. 2. C. pseudotaxichondrum, cells more depressed. 3. G. pseudotaxichondrum, var. trichondrum, semi-cells ornate with a single row of three granules. 4. C. pseudotaxickondrum, var. quadridentidum ; in front view, the inferior angles bidenticulate. 5. (7. pileigerum. Merely a depauperated form of the above. Pond, Tewksbury, Massachusetts. C. QUINARIUM, Lund. Plate LX, figs. 10, 11. Cells subhexagonal, about one-fourth longer than broad ; constriction deep linear ; semi-cells subtrapezoid, narrowed toward the subtruncate apex, sides somewhat convex, inferior angles obtuse, margins obsolete granulate-dentate; within the margin a series of prominent granules, in center five obtuse granules arranged in two transverse series ; membrane punctate ; in vertical view elliptic granulate around the margin j in lateral view circular. Diameter 33-35 /* ; length 39-42 /*. Tewksbury, Massachusetts. C. MICROSPHINCTUM, Nord. var. PARVULA, Wille. Plate LX, figs. 20, 21. Cells small, elliptic, one-half longer than wide, moderately constricted, sinus narrow linear ; semi-cell subelliptic, apex CALOCYLINDRUS. 33 obtusely rounded ; sides somewhat convex ; in vertical view broadly elliptic, apices somewhat produced 5 in lateral view ovate. Membrane densely but distinctly punctate. Zy go- spore globose aculeate, aculei broad at base, apices 2-3 furcate. Diameter 25-26 j^ ; length 36 p. Tewksbury, Mass. Have given the figure of the type. The form is closely related to C. pseudopyramidatum (Des. U. S. p. 69); but the constriction is not so deep, the ends not truncate, and in vertical view not distinctly elliptic. C. OCTOGONUM, Delp. var. CONSTRICTUM, Lagh. Plate LX, figs. 34, 35. Cells in front view oblong- tetragonal deeply constricted ; semi-cells trapezoidal ; in vertical view elliptic with middle somewhat inflated; isthmus one-third of diameter of cell. Membrane smooth. Var. constrictmn is more deeply con- stricted, sinus wider, and semi -cell in vertical view not inflated. Tewksbury, Massachusetts. From these specimens the significance of the name is not evident. Instead of three crenulations or angles on each side of a semi-cell, Delponte describes "sometimes four," or eight to the semi-cell. Has some resemblance to C. Braunii, Reinsch, but is not so regular. C. SUBCRUCIFORME, Lagh. Plate LX, figs. 12-14. Small, somewhat circular, the constriction introrsely and extrorsely anipliated ; semi-cells reniform, the end rounded, not crenulate; angles rounded verrucose with margins denticulate ; a central inflation granulate ; in vertical view subcruciform, angles granulate ; in lateral view ovate- circular. Membrane punctate. Diameter of cell 32 // ; length 36 ^ ; thickness 25 //. • Reminds one of C. ornatum, Focke, and also of C. subreni- forme, Nord. Tewksbury, Massachusetts. C. ELOISIANUM, Wolle. V. Des. U. S. p. 85. A species hitherto found only in Minnesota, now turns up also in New Jersey, Splitrock Pond, and more recently, (October, 1886,) Mr. W. ST. Hastings has been collecting fine specimens near Rochester, New Hampshire. The specimen represented, Des. U. S., Plate XIX, is an old form and caused too many teeth to be illustrated. A single series on the periphery of a semi-cell does not exceed 23-25. 34 FRESH-WATER ALG^E OF THE UNITED STATES. C. LAGOENSE, Nord. Plate LX, figs. 26, 27. Semi-cell in vertical view, in the middle much swollen and the ends inflated, granules large 5 center smooth. It is an exaggerated development of C. ornatum and hence a variety of it. Tewksbury, Massachusetts, and not infrequent in New Jersey ponds. C. BIRETUM, Breb. V. Des. II. S. p. 86, var. FLORIDENSE, Wolle. Plate LXII, fig. 6 Differs from the typical form in its somewhat larger size, but principally in the retuse ends. Diameter 70 //. Frequent along the shores of lake at Kissimme, Florida. Genus, TETMEMORUS. V. Des. U. S. p. 90. T. GIGANTEUS. Plate LIV, fig. 1. Represents a specimen not infrequent with the ends somewhat contracted, differing in this regard from the form Des. U. S. Plate XX. Genus, XANTHIDIUM. V. Des. U. S. p. 93. X. FASCICULATUM, var. SUBALPINUM, Wolle. Plate LVI, fig. 9. Prof. Delponte, in his DESMIDIACEARUM SUBALPINUM, p. 168, describes this species differently from that described in Des. U. S. p. 93, the variation being mainly in the wider separation of the lateral spines. To distinguish the two I make the above variety. Not rare in ponds, New Jersey and Minnesota. X. COLUMBIANUM, Wolle. Plate LVI, figs. 10, 11. Cells about one-third longer than wide; divided by a deep constriction forming much ampliated, acute-angled sinuses; semi-cells oblong hexagonal, superior and lateral angles each produced into a firm aculeus ; within the margins, four, often indistinct, aculei ; end view more or less regular hex- agonal, each angle somewhat produced and surmounted by a firm aculeus ; within the margin are four aculei, the ends of which often extend over the margin ; cytioderm smooth. Diameter 60 JJL ; length 80 //, without aculei. Pond, Ocean County, New Jersey. ARTHRODESMUS. 35 X. TORREYI, Wolle. Plate LVI, figs. 13, 14. Nearly equal in length and breadth ; semi-cell somewhat hexagonal, half as long as wide ; superior and lateral angles slightly protruding and surmounted each by a firm, straight, or slightly bent aculeus ; in vertical view elliptic with one aculeus on, and another within, the margin of each end ; on each side a rounded prominence peculiar to the genus. Lateral view elliptic with a constriction in the middle, two aculei at each end and two short tips evident near the middle. Diameter 33 yw, without aculei; with them 65 //; length 75 /<. Ocean County, New Jersey. First found in Horicon Lake, near the home of the venerable brother of the late John Torrey, of botanical fame. Genus, ARTHKODESMUS. V. Des. U. S. p. 95. A. INCRASSATUS, Lagh. Plate LXI, fig. 6. A large form, deeply constricted, sinus largely ampliated outwardly ; semi- cells subellipsoid, sides convex, ends highly arched, superior angles surmounted each with a nearly straight aculeus ; in middle two series of granules arched, nearly parallel with the ends ; in vertical view rhomboid-elliptic ; in lateral view somewhat circular ; mem- brane in middle thickened and yellowish. Diameter of cells 40 ^ ; length 50 //, without aculei. Tewksbury, Massachusetts. Var. CYCLADATUS, Lagh. Somewhat smaller, eight granules in the middle of semi- cell, one central and the others in circle around it. This variety is near my XantMdium tetracentrotum, Des. U. S. p. 95. Tewksbury, Massachusetts. A. NOTOCHONDRUS, Lagh. Plate LXI, figs. 4, 5. In size and constriction like A. incrassatus; semi-cells sub- semicircular, sides convex, ends straight with margins mod- erately granulate ; angles armed with a long divergent spine; semi-cells in vertical view elliptic, with three longitudinal series of granules; in lateral view subcircular. Men> brane smooth, in middle somewhat thickened and Diameter of cells, without spines, 30 u: length 32 Tewksbury, Massachusetts. 36 FRESH-WATER ALG^ OF THE UNITED STATES. A. TRiANGULARis, Lagh. Plate LXI, figs. 14, 15. Sinus between the serai-cells wide, obtuse; semi-cells triangular connected by a cylindrical isthmus, ends some- what retuse in middle; angles subacute bearing a long straight spine, either parallel or slightly converging ; senii- cells in vertical view lanceolate- oval ; in lateral view sub- circular. Membrane hyaline, in middle not thickened. Diameter, without spines, 25 ^ ; length 30 //. Georgia. A. PACHYCEROS, Lagh. Plate LXI, figs. 13, 14. Cell small, constriction an acute-angled sinus ; semi-cells suboval, sides convex, end arched, angles obtuse, each bear- ing a firm spine, straight or slightly bent, diverging ; semi- cells in vertical view oval ; in lateral view subcircular. Membrane smooth. Diameter, without spines, 18 /< ; length 20 //. By an oversight this form was put on the plate ; do not know it to have been found in the States. It is a Cuba plant. Genus, EUASTBUM. V. Des. U. S. p. 97. E. INTEGRUM, Wolle. Plate XXVII, figs. 18-22. The same is described as E. simplex Des. U. S. p. 106. Since the publication of the diagnosis, F. Gay, of Mont- pellier, France, is found to have anticipated the adoption of the same name for another Hhiastrum form. Hence we sub- stitute E. integrum for E. simplex. E. PECTINATUM, Breb. Plate LIY, figs. 10-12. Semi-cell three-lobed, terminal lobe dilated, usually en- tire; lateral lobes broad, making the basal portion of the semi-cell somewhat quadrilateral, horizontal, at each side emarginate ; lateral view cuneate, with two swellings near the base and one at the apex ; transverse view oval with three lobules on each side and one or imperfectly two at each end. Diameter 40-50 yu ; length about 75 yw. Minnesota. A number of varieties of this species have been described by specialists in different countries. The present is not Ralfs' type-form, but a variety. It is common in England, but hitherto not found here. EUASTRUM. 37 E. PURUM, Wolle. Plate LVIII, figs. 9-11. Small, short ; semi-cell three-lobed, broader than long ; basal lobe much inflated, terminal lobe short, dilated and notched ; in lateral view the base and end are more or less inflated. Diameter 35-45 ^ • length 55-70 /*. The smaller form from Florida, the larger from New Jersey. E. CUNEATUM, Jenner. Plate LVIII, figs. 12, 13. Semi -cells cuneate, not lobed; terminal notch linear. Diameter of cell 24-28 ^ ; length abont 75 //. Not rare ; seems of rather doubtful value as a species. E. MAGNIFICUM, Wolle. Plate LVIII, figs. 6-8. The largest of our Euastra; about twice as long as broad : semi-cell five-lobed, the terminal lobe exserted ; dilated, end somewhat convex, connected by a short neck ; basal and intermediate lobes entire, with a deep obtuse notch between ; upper margin of the basal lobes nearly horizontal and par- allel with the base of the semi- cell ; no prominent tumors, but one large central undulate inflation shown in lateral view (fig. 7 ). End view (fig. 8) shows the terminal and in- termediate lobes notched at each side. Diameter 100 ^ ; length about 190 /^. Ponds, near Malaga and Manchester, New Jersey. E. WOLLEI, Lagh. Plate XXIX, figs. 1-5. G. von Lagerheim, of Stockholm, Sweden, has seen fit to change the name of our E. intermedium, Cleve, for the reason that he finds that it does not correspond with the Swedish plant so named by Cleve. It has much of the form, but is much larger, having more than twice the diameter and twice the length. Cleve states the diameter of the plant described by him at 44 /< ; and length 77-80 /*. Diameter of our form is 112-120 }A • length 160-170 // ; moreover the end of the semi-cell of the Swedish plant is te>-lobed, ours is/ow-lobed. An apology for the error in choosing the name is un- necessary. Will only remark, a full description of Cleve's plant was not convenient at proper time. Var. QUADRIGIBBERUM. Lagh. Plate LX, fig. 29. Semi-cells with four horizontal inflations ; in vertical view elliptic, apices acuminate, sides quadriundulate. Tewksbury, Massachusetts. 38 FRESH-WATER ALG^E OF THE UNITED STATES. E. VENTRICOSUM, Lund. Plate LVIII, figs. 1-3. Large, twice as long as wide, outline subelliptic, deeply constricted, sinus narrow linear ; semi- cell trilobed, base much dilated, polar lobe short somewhat dilated, incision narrow linear, sides sinuate, two-lobed, superior lobe obtuse tending upward, entire, not bifid in lateral view; basal tumors three, intermediate two, and two in end lobe ; in vertical view elliptic, four undulations on each side ; in lateral view narrowed toward the ends, sides undulate, apex subtruncate and dilated; shows the superior lateral lobule entire. Diameter 60-69 ^ ; length 105 p. Found this plant frequent in pond, Orange County, near Maitland, Florida. Zygospores not infrequent, as fig. 1. E. ORASSTJM, Des. U. S. p. 97, var. SCROBICULATUM, Lund. Plate LVIII, figs. 4, 5. In outline very nearly the same as the type-form, but differs in having in the middle of the semi -cell four scrobi- culae. Lundell represents only two ; our form has four ; besides these excavations the plant has four papilla-like prominences towards the ends of the semi-cells, which I do not find alluded to; they may give claim for a distinct species. Pond, Malaga, New Jersey. Genus, MICEASTEEIAS. V. Des. U. S. p. 108. M. SPECIOSA, Wolle. Plate LVI, figs. 1, 2. Small, somewhat longer than broad, five-lobed ; lateral lobes unequal, the basal pair usually with only half as many divisions as the intermediate ones ; each basal lobe consisting of one, and the intermediate of two lobulets, the angles of each section drawn out into two spine-like points; terminal lobe rather narrow, linear, the end ex- serted and much dilated, usually with three prominent mucros at each angle, center an obtuse angled notch, stand- ing free with a rather wide gap between it and the adjoining lobes ; a series of small spines often observed on the margins of the lobes. Diameter 95 yu ; length 110 /*, of specimens from Florida ; diameter 125-150 //; length 155-165 yw, of New Jersey specimens. MICKASTERIAS. 39 This species appears related to M. radiosa, var. ornata, Nord., but is smaller; the lobes are not so deeply, nor so often intersected, and the polar lobe is more exserted and more dilated at the end. M. APICULATA, Menegh. Plate LVI, fig. 3. Large orbicular or oblong, with the surface more or less densely covered with macros ; semi-cell five-lobed 5 lateral lobes equal in size, not close, bisected 5 lobulets bifid, each section emarginate, mucronate at each angle; polar lobe pro- minent, widely dilated, center notched, margins mucronate. Diameter 175-200 JJL. Ponds, Pennsylvania, New Jersey and Minnesota ; rather rare. M. MAMILLATA, Turner. Plate LXII, fig. 2. Semi-cells papilionaceous, five-lobed ; end lobe broad ; its ends and those of the other lobes divided into palmate shapes, with the points broadly rounded ; surface adorned with maniilliform processes radiately arranged ; provided with a process at isthmus, the purpose of which is ap- parently (?) to strengthen the segmental union. Only one specimen (semi-cell) seen. Seemingly related to M. apiculata. Diameter 198 p. Inasmuch as this semi-cell was found in collections made in a swampy part of Harvey Lake, Pennsylvania, in which M. apiculata occurs freely, the author would emphasize the last remark. M. DENTICULATA. V. Des. U. S. p. 109. A zygospore. Plate LXII, fig. 3. From a collection made by W. N. Hastings, Rochester, New Hampshire. M. AMERICANA. V. Des. U. S. p. 112, var. SPINOSA, Turner. Plate LX, fig. 30. A form not strictly from the United States, but near it, may be introduced. Mr. Turner describes it thus: A small compressed form. About one-eighth less in length and breadth than the type. Central portion of segments smooth; lobes ornamented with short stout spines ; the end lobe bearing near its extremity a species of annular rugoso- spinous coronet. Diameter 112 /* ; length 136 jw. Pictou, Nova Scotia. 40 FRESH- WATER ALGvE OF THE UNITED STATES. M. ALATA, Wall. Plate LXII, fig. 1. In anticipation of the possible discovery of this inter- esting and unique form in Southern Florida, I quote it from G. von Lagerheim's Bidrag till Amerikas Desmidie-flora. It is an India plant, but is now also found in Cuba. The figure is drawn direct from an India specimen in my herbarium. M. FURCATA. V. Des. U. S. p. Ill, var. SIMPLEX, Wolle. Plate LIX, figs. 6, 7. Cell equal in length and breadth, two-lobed, terminal lobe exserted, its divisions spreading and producing a wide, shal- low sinus ; lateral lobes usually simple, but sometimes divided into two narrow, linear diverging sections, furcate at apices. Length and breadth 140-150 yw. A singularly variable species. Of thirty-one fresh speci- mens examined during a stay at Winter Park, Florida, by Rev. H. D. Kitchel and myself, twenty were found of nor- mal form as upper half of fig. 6, 7, no arms divided ; five had all the lateral arms divided, like the lower half of figure ; one had two arms divided and two single, like figure ; two had only one arm divided, and three had each two arms divided. As two-thirds of the forms examined had all the arms single, this is considered the type ; the others, one- third, variable, are varieties. M. CRUX MELITENSIS. V. Des. U. S. p. 111. Two semi-cells, Plate LVI, figs. 4, 5, differing somewhat from those figures on Plate XXXV. From Minnesota. M. EABENHORSTII, Kirch. Plate LVI, fig. 9. Cells as long as broad, small, three-lobed ; terminal cell not much wider than the lateral lobes, widened from the base to the end, apex concave, angles terminating with two short teeth ; lateral lobes divided by a wide, almost right- angled sinus, each half somewhat narrowed towards the end 5 apex indented, a small tooth at each angle. Mem- brane smooth. Diameter of cell 85 /* ; length 88 //. Thus reads a free translation of Kirchner's diagnosis. The figure does not represent the type; merely a small form of it. Ponds, Minnesota. STAURASTRUM. 41 M. VERRUCOSA, Eoy. Plate LIX, fig. 10. Iii outline this species agrees with smaller forms of M. denticulate^ Ealfs, but differs from these and other described forms by the remarkable row of crenulated, circular or oval basal inflations, crossing from side to side, larger towards the center, gradually growing smaller towards the margins. The original type was found in Scotland. The first from this country is from a pond near Minneapolis, Minnesota, in collections made by Miss E. Butler. M. RINGENS, Bail. V. Des. U. S. p. 112, var. SERULATA, Wolle. Plate LIX, fig. 15. In size and form the same as the original type from Florida. Bailey describes it as " granular near the mar- gins," but not as serrated. This new variety has the margins distinctly serrated, besides having the granules or mucros near the margins. Diameter 115-130 ^ ; length 125-145 /*. Found in large numbers in White Bear Lake, Minnesota, by Miss E. Butler. Genus, STAUEASTEUM. V. Des. U. S. p. 119. ST. MUTICUM, var. ELLIPTICUM. Plate LX, figs. 41, 42. A form differing from that of Plate XXXIX, and more strictly elliptical, semi-cells in front view slightly con- tracted near the ends. Diameter 33-35 //. Pond, St. Anthony Park, Minneapolis, Minnesota. ST. ORBICULARE. V. Des. U. S. p. 119. A variety from Watertown, New York. Plate LX, figs. 36-38, not so distinctly orbicular as the form illustrated, Plate XXXIX, figs. 9, 10. Diameter 34-37 ju ; length about 44 yw. ST. BACILLARE, Breb. Plate LVII, figs. 5, 6. Cells small, deeply constricted, sinus a wide, acute angle ; semi -cell narrow lanceolate, base convex, ends inflated, head -like, in vertical view 3-4-5 - angled ; angles radiately produced with ends enlarged and rounded. Diameter 25-30 /<. Pond, Minnesota. 42 FRESH-WATER ALG^ OF THE UNITED STATES. Brebisson describes a French plant as St. globosum, which is somewhat stouter and partially granular, but otherwise nearly similar ; the two are considered forms of the same species by recent specialists. ST. BREVISPINA, var. INERME, Wille. V. Des. IT. S. p. 122. A Florida form, Plate LXII, figs. 9, 10, differing slightly in vertical view, but otherwise not distinct from figs. 3, 4. Plate XL. Diameter 55-60 /*. ST. COSMARIOIDES, Reinsch. Plate LXII, figs. 7, 8. Cells large, composed in front view of two orbicular semi- cells attached, forming an isthmus of one-third the diameter of the cell ; margins of sides finely dentate ; in vertical view triangular, angles rounded, sides slightly convex. Prof. Reinsch describes this form as found in Pennsyl- vania, about twenty years ago. To my knowledge it has not occurred since. ST. VESICULATUM, Wolle. Plate LIV, figs. 6, 7. Small, smooth, about one-half longer than broad, con- striction deep, sinuses acute-angled, much ampliated ; semi- cell subpyramidal, not as long as broad ; base wide, inferior angles round, sides convex and inclining to a rounded apex; end view triangular, angles rather broadly rounded, sides slightly convex or straight. Diameter 31 /* ; length 45 /*. Differs from St. cordatum, F. Gay ; in front view, sinuses are not narrow linear, but much ampliated, thereby giving the cell a more elevated appearance. Green's Lake, New Jersey. ST. PSEUDOCRENATUM, Lund. (ST. MAAMENSE, Arch.) Plate LVII, figs. 9, 10. Cells nearly one-fourth part longer than broad, suboval ends somewhat truncate, deeply constricted, sinus narrow linear; semi-cells subseniicircular, base straight, sides sub- crenate, crenae roughly truncate-emarginate ; end obsoletely erose-dentate, inferior angles subtruiicate ; in vertical view triangular, sides retuse, angles broadly subtruncate, dentate with three granules. Diameter 30-35 /i ; length 38-42 /*. Found this species frequent in ponds, Minnesota and Cali- fornia. This form is nearest to St. crenatum, Bailey, (in STAURASTRUM. 43 Ralfs' Br. Des. p. 215,) but differs in having a much narrower sinus between the semi-cells, and semi-cells are not cuneate flabelliform. ST. ERASUM, Breb., var. ESPINULOSA, Lund. Plate LVII, figs. 16, 17. Of medium size, as long as broad, coarsely granulate, sinus acute-angled, outwardly ampliated ; semi-cells some- what elliptic, back nearly straight, angles rounded, more or less dentate, with large granules; in vertical view trian- gular, angles broadly rounded, sides concave. Diameter 34-38 /£. Green's Lake, New Jersey. ST. LUTEOLUM, Lagh. Plate LX, figs. 22, 23. Cells rather small, nearly circular, deeply constricted, sinus narrow linear ; base of semi-cell straight, back arched, inferior angles obtusely rounded granulate-crenate. Mem- brane thick, punctate, yellowish. Diameter 32 /* ; length 33 j* ; thickness 32 /*. Tewksbury, Massachusetts. ST. CORNUTUM, Wolle. Plate LYII, figs. 3, 4, duplicated on Plate LXII, figs. 11, 12. Cells medium size, about one-fourth longer than broad, smooth ; semi-cell oval or broadly elliptic, with a prominent, somewhat inwardly curved aculeus at each angle ; end view triangular, angles rounded, each with a firm aculeus, sides straight or slightly concave. Diameter 55-60 yu; length about 70 yw, aculei not in- cluded. In front view resembles a large form of Arthrodes- mus convergens, but the triangular end views prove it distinct. Ponds, Minnesota, not infrequent. ST. MINNESOTENSE, Wolle. Plate LVII, figs. 7, 8. Cells large, punctate, spinous, about as long as broad; semi-cells broadly elliptic, twice as wide as long; lateral angles each with two large, straight or incurved spines or aculei, three more pairs of similar spines placed within the margin of the end, one of each pair on opposite sides of the" semi-cell ; six more, often inconspicuous, arranged around the center; end view triangular, with two spines at each angle and two pairs (near the margin) between the angles, 44 FRESH-WATER ALGJE OF THE UNITED STATES. 011 each side of the triangle ; around the center are nine more spines, often indistinct. Diameter 65-75 JJL without, and 90-100 /< with the spines. Frequent in Minnesota ponds. ST. XIPHIDIOPHORUM, Wolle. Plate LYII, figs. 21, 22, and Plate LX, fig. 19. Small, one and one-half to two times as long as broad, deeply constricted, sinus narrow, widening irregularly out- wardly ; semi-cells transversely oblong, with lateral margins notched ; the end margins drawn out into a sort of one-sided, hastate, poignard-like spines or slender points, usually nine in number ; membrane smooth ; with several verrucae j end view triangular, angles broadly truncate and usually each showing three prominences, the bases or supports of three spines, sides concave. Diameter 25-30 ju ; length 40 ju, and upward. Ponds, near Minneapolis and Stillwater, Minnesota. Var. SIMPLEX, Wolle, differing from the type-form in having less spines, usually six ; (Plate LX, fig. 19,) in end view the truncate angles have only two prominences each. Found this form frequent in material collected in small pools near Lake Tahoe, California, by Mrs. Hanson and Miss Haggin, of San Francisco. ST. WOLLEANUM, Butler. Plate LYII, figs. 1, 2. Medium size, membrane punctate, about one-half longer than broad, moderately constricted, sinuses obtuse-angled ; semi- cell broadly oval or subhexagonal ; superior and lateral angles produced into subcylindrical, somewhat swollen processes or arms, slightly notched at the apices ; four more similar processes within the margin ; in vertical view regu- lar hexagonal, each angle furnished with an arm in appear- ance as those in front view ; within the margin, arranged in a circle around the center, are six, more or less conspicuous processes. Diameter of body 40-50 /* ; with processes 65-83 //. This species was discovered, identified as new and named by Miss E. Butler, Minneapolis, Minnesota, where it was found. Var. KISSIMMENSE, Wolle. Plate LIX, figs. 1, 2, 3. Front, lateral and vertical views. A large, smooth and beau- tiful form fully one-half larger than the original type from STAURASTRUM. 45 Minnesota. The arms are similarly constructed and ar- ranged, but in proportion with the body, are much longer, nearly equal in length to the diameter of the body ; apices not notched but tipped with several small spines. Diameter, including arms, 100-125 /*. Grassy shores of Lake at Kissimme, Florida, March, 1885. ST. TOHOPEKALIGENSE, Wolle. Plate LIX, figs. 4, 5. Cell smooth, semi-cell in front view oval with radiating arms ; in end view triangular, each angle drawn out into a smooth arm nearly as long as the diameter of the body ; two similar arms on each side ; all at nearly equal distances and bifurcate at the apices. Diameter, including arms, 75 /*. This species occurs frequently in small coves of Lake Tohopekaliga, at Kissimme, Florida. It bears features in common with St. furcatum, Breb., but is about twice the size, has more arms, and has them differently arranged ; the description " one spine at each angle, with two accessory spines at the base," or "three spines at each angle," does not apply. ST. AKCTISCON, Y. Des. TJ. S. p. 148. In addition to the forms represented on Plate XL VI I, figs. 9, 10, I add another, apparently more highly developed, Plate LXI1, fig. 4, distinct in the large, wide-spreading points of the trifid apices of the arms. Green Lake and other waters of New Jersey. ST. PARADOXUM, V. Des. TJ. S. p. 129, var. OSCEOLENSE, Wolle. Plate LIX, figs. 8, 9. This variety differs from the typical form in its larger size, quadrangular body and in the large trifid, hooked, apices of the arms. Diameter of spread of arms 60-70 //. Lake Osceola, Winter Park, Florida. ST. MINNEAPOLIENSE, Wolle. Plate LYII, figs. 11-13. Small verrucose ; semi- cells in front view subcuneate with the two opposite superior angles drawn out into a short arm with margins serrate, and apices finely toothed ; arms diverging from the arms of the connected s.enii-cell ; in ver- tical view arms straight, body much elevated on each side ; 46 FRESH-WATER ALG^ OF THE UNITED STATES. in lateral view arms straight, short ; body puffed out high on each side, crenate on the apices. Diameter in front view, including arms, 50-58 yu; thickness of body 20-25 //. The front presentation not unlike other forms, but the vertical and lateral view are quite distinct in the unusual inflation of the body. The name indicates the habitat. ST. CALYXOIDES, Wolle. Plate LVII, figs. 14, 15. Nearly equal in length and breadth ; smooth or finely punctate ; deeply constricted ; senii-cells saucer- or calyx- shaped, bearing on the undulate margin five equally distant divergent spines ; end view pentagonal, each angle produced and bearing a strong aculeus. Diameter about 33 yw without, and 75 /* with, the aculei. Pond, near Manchester, Ocean County, and Green's Lake, Warren County, New Jersey. ST. BRASILIENSE, V. Des. U. S. p. 146, var. TRIQUETRUM, Wolle. Plate LX, figs. 39, 40. The form hitherto found here is pentangular in vertical view ; the form first discovered and described by Nordstedt, is quadrangular, found in Brazil. The present form from California is triangular in vertical view ; it appears so nearly related in character of cell, arrangement and character of aculei, think it best described as a variety of the same species. Diameter of cells, including aculei, 63-67 yw. Smaller than the pentangular form, but about the same size as the original quadrangular form. Collected in small pools near Lake Tahoe, by Mrs. Hanson and Miss Haggin, San Francisco, California. FRESH-WATER ALGJE. MARINE Algae are conventionally classified into four primary divisions, the BED, the OLIVE, the GREEN, and the BLUE. Tech- nically they are known as the BHODOPHYCE^E, the MELANOPHY- CE^:, the CHLOROPHYCE^: and the CYANOPHYCE^;. The arrangement proposed for the classification of onr Fresh- water Algae is in the same order in as far as it may be adapted. The MELANOPHYCE^E are not represented. Having disposed of the DESMIDIE.E, as supplemental to a previous volume, the DES- MIDS or THE UNITED STATES, we commence with the BED fresh-water plants; they are most nearly related to the more highly developed forms, the Marine plants ; from these we de- scend to the lower and lowest forms. The inductive system does not apply, because so many of the hitherto recognized sim- pler unicellular forms are not established factors — they are not well understood, and indeed have no value except as conditions of plant-life. The following is an outline of the order of arrangement ad- hered to in the following pages. CLASS I.— BHODOPHYCE^. ORDER I.— FLOBIDI^E. \ FAMILY I. — Lemaneacese. Genus 1. — Lemanea. " 2. — Tuomeya. FAMILY II. — Porphyracese. Genus 3. — Bangia. FAMILY III. — Batrachospermacese. Genus 4. — Batrachospermum. 5. — Thorea. 6. — Chantransia. FAMILY IV. — Hildebrandtiacese. Genus 7. — Hildebrandtia. " 8. — Coinpsopogon. 48 FRESH-WATER ALG.E OF THE UNITED STATES. CLASS II.— CHLOEOPHYCE^:. ORDER II.— CONFERVOIDE^E. Section.— O OSPORE^E. FAMILY V. — Coleochaetacese. Genus 9. — Coleochaete. FAMILY VI. — Oedogoniacese. Genus 10. — Oedogonium. " 11.— Bulbochete. FAMILY VII. — Sphaeropleacese. Genus 12. — Sphaeroplea. " 13. — Cylindrocapsa. Section.— SYNZOOSPOREJE et A8EXUALI8. FAMILY VIII. — Confervacese. Genus 14. — Prasiola. " 15. — Enteromorpha. Section.— CLADOPHORIN^E. Genus 16. — Draparnaldia. " 17. — Stigeoelonium. " 18. — Chaetophora. " 19. — Microthamnion. " 20. — Aphanoehaete. " 21. — Gongrosira. " 22.— Ghroolepus. " 23.— Cladophora. FAMILY IX. — Pithophoracese. Genus 24. — Pithophora. Section.— ULOTRICHINJE. Genus 25. — Ulothrix. " 26. — Schizogonium. " 27.— Conferva. 28. — Chaetomorpha. " 29. — Rhizoclonium. ORDER III.— SIPHONED. FAMILY X. — Vaucheriacese. Genus 30. — Vaucheria. FAMILY XI. — Botrydiacese. Genus 31. — Botrydium. ORDER IV.— PBOTOCOCCOIDE^E. FAMILY XII. — Volvocacese. Genus 32. — Volvox. " 33.— Eudorina. " 34. — Pandorina. " 35.— Euglena. " 36.— Gonium. ZYGOSPOREJE. 49 Genus 37. — Stephanosphaera. " 38. — Chlamydocpccus. " 39. — Chlamydomonas. FAMILY XIII. — Protococcacese. Genus 40. — Pediastruni. 41. — Hydrodictyon. 42. — Coelastrum. " 43. — Sorastrum. " 44. — Staurogenia. " 45. — Scenedesmus. " 46. — Sciadium. " 47. — Ophiocytium. " 48. — Characium. " 49. — Protococcus. " 50. — Polyedriuui. FAMILY XIV. — Palmellacese. Genus 51. — Dictyosphaerium. " 52.— Hy drums. " 53. — Palmodactylon. " 54. — Tetraspora. " 55. — Schizochlamys. " 56.— Palmella. " 57. — Porphyridium. " 58.— Botrydina. " 59. — Botry coccus. " 60. — Gloeocystis. " 61. — Nephrocytium. " 62.— Rhaphidium. " 63. — Dimorphococcus. " 64. — Mischococcus. " 65. — Eremosphaera. " 66. — Urococcus. " 67. — Apiocystis. FAMILY XV. — Chytricliese. Genus 68. — Chytridium. " 69.— Olpidium. ORDER V.— ZYGOSPORE.E. FAMILY XVI. — Conjugate. Genus 70. — Spirogyra. " 71. — Sirogonium. " 72. — Zygnema. " 73. — Zygogonium. " 74. — Mougeotia. " 75. — Mesocarpus. " 76. — Pleurocarpus. 77. — Plagiospermum. " 78. — Gonatonema. " 79. — Staurospermum. " 80. — Craterospermum. FAMILY XVII. — Desmidiese. V. Desmids of the United States. 50 FRESH-WATER ALGLE OF THE UNITED STATES. CLASS III.— CYANOPHYCE^E. ORDER VI.— SCHIZOSPOHE.E. FAMILY XVIII. — Nostocacese. Section a.—RIVULARIE^. Genus 81. — Calothrix. " 82. — Mastigonema. " 83.— Isactis. " 84. — Gloeotrichia. " 85. — Rivularia. Section b.—SCYTONEMEJE. Genus 86. — Scytonema. " 87. — Symphyosiphon. " 88.— Tolypothrix. " 89.— Plectonema. " 90. — Petalonema. Section c.—SIROSIPHONE^E. Genus 91. — Sirosiphon. " 92. — Hapalosiphon. Section d.—NOSTOCE^E. Genus 93. — Nostoc. " 94. — Anabaena. " 95. — Sphaerozyga. " 96. — Aphaiiizomenoii. " 97.— Nodularia. " 98. — Cyliiidrospermum. Section e.—OSCILLARIE^. Genus 99. — Chamaesiphon. " 100.— Lyngbya. " 101.— Symploca. " 102. — Mierocoleus. " 103.— Oscillaria. " 104.— Beggiatoa. " 105.— Leptothrix. " 106.— Spiruliiia. " 107.— Spirillum. FAMILY XIX. — Chroococcacese. Genus 108. — Gloeothece. " 109. — Aphanothece. " 110. — Syriechococcus. 111. — Merismopedia. " 112. — Coelosphaerium. •' 113. — Clathrocystis. " 114. — Gomphosphaeria. " 115. — Microcystis. " 116. — Anacystis. 44 117.— Polycystis. 118. — Gloeocapsa. 119. — Aphanocapsa. " 120. — Chroococcus. LEMANEA. 51 Class L— RHODOPHYCE^S. Order L— FLOKEDLE. Plants rosy red or purple, dark reddish brown or blackish; multicellular, various in form ; crustaceous, filamentous, fasci- culate, verticillately branched, etc. Propagation sexual. The female cell (carpogon) bears a longer or shorter appendage, called the trichogyne. This is fer- tilized by very small granules (spermatozoids or anthorizoids) derived from cells at the ends of short branches or from certain spots or nests (antheridia) in the thallus. These spermatozoids float about in the water, find their way to the trichogynes, attach themselves and fructify the carpogon. Asexual propagation takes place by means of gonidia which are evolved in cells similar in location and in appearance to the carpogons. Family I. —LEMANEA CEJE. Filaments simple or sparsely branched, hollow, more or less nodose, rigid, bristle-like, light olive-brown, gray, or with age almost black. Carpospores collect at intervals within the filament. Genus 1, LEMANEA. Filaments rather large, 1 to 5 inches long, nodose of dark olive or blackish color, forming tufts most frequently on rocky beds of streams whose current is rapid and cool. Carpospores numerous, collected in branched moniliforni series within the nodes. The fertile filaments are hollow except an axillary thread composed of a single series of cells held in position by trans- verse threads at regular intervals. The walls of the filaments are thick, composed of two distinct layers of cells. LEMANEA TOEULOSA (Eoth.) Ag. Fertile filaments curved like a sickle or a bow, sub-simple, cartilaginous and rigid, 1-2 inches long, light olive-green, changes to darker color, with age nearly black ; nodules not always well defined, approximate, papillae flattened and often almost obsolete, mostly 4-6 verticillate ; spores 52 FKESH-WATER ALG^E OF THE UNITED STATES. oval ; sometimes has an axillary thread with others twined • around it. Widely distributed in mountain and other streams of rapid and cold waters. It grows in masses firmly attached by a sort of discoid root to stones or rocks, often forming a turfy covering to them. Much more frequent than the following. Plate LXIII, fig. 1, natural size 5 fig. 2, somewhat magni- fied ; fig. 3, a section of a filament magnified showing the nodules and the almost obsolete papillae ; fig. 4, a transverse section showing the carpospores in moniliform branched series. . LEMANEA FLUVIATILIS, Ag. Filaments straight, simple or but slightly branched ; 4-5 inches long, often much contracted toward the base, nodules more remote than in the preceding ; usually three distinct verticillate papillae to each nodule. An axillary thread composed of a single series of cells is found in the fertile filaments. The specimens of this species in my possession are from Northern New Jersey, South Carolina, Alabama, Rocky Mountains, and California. All from rapid waters of low temperature. Plate LXIII, fig. 5, natural size. LEMANEA CATENATA, Kg. About five inches long, regularly constricted, simple, compressed, arcuate, in mass obscure violet ; papules want- ing 5 spores irregularly oval or subglobose. Dr. Wood in his Fresh-water Algre recognizes this species from the Rocky Mountains, "Mountain stream, Diamond Range, altitude 6,500 feet. He adds, " In the dried state they are closely interwoven into a dark purple, rigid, thin mass. When soaked out they preserve the same color as in mass, but each individual stem has a general light yellowish, neutral ground tint, with dark-purplish or greenish black bands at regular intervals. At the position of these bands the filament is nearly round and contracted, whilst between them it is compressed and enlarged. The spores are placed, not at the swellings, but at the constrictions. The filaments between the little knots of spores appear to be hollow. Their walls are everywhere very thin when compared with L. torulosa." TUOMEYA. 53 Genus 2, TUOMEYA, Harvey. Filaments cartilaginous, continuous, solid, at first transversely banded, afterwards annularly constricted ; composed of a longi- tudinal axis, and two strata of periplieric cells. Axis columnar, consisting of several longitudinal cohering filaments, beset with closely placed whorls of moniliform ramuli, whose branches anastomose horizontally and vertically into a cellular peripheric membrane, which is coated externally with moniliform filaments, gradually developed. TUOMEYA FLTJVIATILIS, Harvey. 1 ' Grows in tufts an inch or two in length, scarcely as thick as a hog's bristle, much and irregularly branched, bushy ; the branches alternate or secund, scattered or crowded, twice or thrice divided and set with scattered patent ramuli which are slightly constricted at the interstices and taper to an obtuse point. When young, the branches and the ramuli are perfectly cylindrical. "In old, fully developed specimens the branches and ramuli are annularly constricted at short intervals, the nodes becoming swollen, whilst the iiiternodes remain un- changed. When a young branch is bruised between two pieces of glass the axis may be readily extracted. It con- sists of several parallel longitudinal jointed threads com- bined together at closely -placed nodes, from which issue horizontal dichotoniose filaments, composed of roundish or angular cells. In the young plants a portion of the filament between the axis and periphery is hollow, but in older ones the cavity is quite filled up with cells. The color is a dark olive. The substance is brittle, rigid when dry. The ex- ternal habit, substance and color are those of Lemanea, and without microscopic examination it might pass for one, but, as may be gathered from the above description, it is very different from Lemanea in structure.'' -Harvey, Nereis Boreali Americana. Part 3, p. 65. On stones in rivers and streams, Alabama, Prof. Tuomey. Near Fredericksburg, Virginia, Prof. Bailey, 1844 and 1845. I have no knowledge of this plant, have simply copied Prof. Harvey's description. Plate LXVI, fig. 1. An ideal form of the plant. No sketches extant, and no preserved specimen to be found. TUOMEYA GRANDE, Wolle. (Eiitothrix grande, Wolle. Bull. Torrey Bot. Club, November, 1877, p. 17.) Filament simple, tubular, cartilaginous, light olive, to 54 FRESH-WATER ALG^E OF THE UNITED STATES. darker olive brown, nearly black, attached by a discoid prothallus, caespitose, rigid, curved, cylindrical with wavy outline, sublinear, apex obtuse ; at base thin and nearly colorless; irregularly somewhat swollen, or irregularly nodose. The outer wall thick, opaque ; within hollow with an axillary nodose cord composed of numerous simple fila- ments, usually 40-50, but sometimes 100-150 ; at regular intervals are horizontal branchlets supporting the column in position and bearing 10-15 or more spherical spores. Filaments 600-750 // diameter ; internal threads 7-10 yw ; spores 20-25 //. Attached to stones in shallow sluggish river water, Beth- lehem, Pa. Frequent 1876-1878. In consequence of artificial changes in the river the latter year, the plant disappeared. Have preserved specimens in Rabenhorst's Algae Exsiccates, No. 2538, and in my own herbarium. This plant is evi- dently closely related to the preceding of which we utterly failed to obtain a specimen, in our oft-repeated efforts ; but while it has much in common it can not be the same, being not in the least branched. Plate LXVI, fig. 2, a plant nearly twice the natural size ; fig. 3, a portion of a filament magnified about 40 diameters, walls broken and in part removed to show the axillary cord ; figs. 4, 5, 6, are the supporting threads of the nodes and the spores lodged in them ; figs. 7 and 8, an axillary cord entirely drawn out of the filament. Conviction after frequent observation induced the change of the family of the one, and of the genus of the other of these two species. There appears to be no doubt they are both nearly related to the Lemaneacece. Family IL—PORPHYEACE^E. - Thallus mucous, membranaceous or filamentous, formed from a single stratum of cells, most frequently purplish. Vegetation by division of cells in two or more directions. Propagation by tetraspores. Genus 3, BANGIA, Lyngb. Thallus filamentous, terete or flattened, nearly plane, simple or branched, usually purple, lubricose, formed from a single series of cells. Cell -membrane thick, colorless, sometimes lamellose. Multiplication by the repeated division of the cell- contents in all directions. BATRACHOSPERMUM. 55 BANGIA ATRO-PURPUREA, (Dillw.) Ag. Forming lax purple tufts ; filaments abbreviated, scarcely more than an inch long, not branched, varying in thickness according to age ; articulations nearly equal in length and breadth, sometimes only one-third as long as wide, more or less constricted at the joints. Diameter of filaments, 28-60 //. Syn. Conferva atro-purpurea, Dillw. Girardia fusco-purpurea7 Gray. Attached to wood and stones in streams more or less sub- ject to tides. In Europe this plant is found also in purely fresh water. Plate LXVII, figs. 9-11. Four sizes in different stages of growth and cell division. Family I1L—BATRACHOSPERMACEJE. Dioecious algse, violet, violet-purple or bluish green. Thal- lus filamentous, articulate, branched, composed of a single cen- tral series of cells and a secondary system more or less verticil - lately branched and densely covered with simple or forked branchlets. Sperniatozoids and carpogones at the ends of branchlets, usually in dense orbicular clusters. Tetraspores at the ends of branches. Genus 4, BATBACHOSPEBMUM, Both. Thallus moniliform, gelatinous, soft, slippery, composed of an axillary or medullary series of cells, and a cortical, accessory parallel series which is clothed with subglobosely clustered .fas- cicles of branches which are sometimes more or less scattered. Mon. S. Sirodot, of France, has published a monograph on LES BATRACHOSPERMES, on their organization, functions, developments, etc. He points out some extraordinary differ- ences of form, according to the influence of the season, the supply of water, the depth at which they live and the degree of illumination. According to the external conditions under which they are developed, the Batrachosperms are found in three different modifications, viz., I. A primordial condi- tion, or prothallium; II. a non-sexual condition or Chan- transia; III. a sexual condition or Batrachospermum. The prothallium, he says, which has hitherto been over- looked by observers, is a kind of crustaceous pellicle cover- ing the surface of stones on which the plant grows. It is 56 FRESH-WATER ALG.E OF THE UNITED STATES. composed of irregular filaments which are sometimes ag- glomerated into globular masses. This structure is of great importance since, in the perennial species, it is the part which renders the plant able to persist. It is capable of growth and of reproducing itself by sporules. The non-sexual form he calls Chantramia, and describes it as composed of broad tufts of filaments each consisting of a row of cells ramifying and producing sporules, altogether analogous to those of the prothallium. Since this form can reproduce itself through a number of generations it has long been regarded as a distinct genus under the name of Chan- tramia. That a larger non-sexual condition may exist, and that it may be somewhat similar to Chantransia, may not be con- tradicted, but that all the forms of Chantransia are condi- tions of Batrachospermum can not be admitted. The sexual generation the author (Sirodot), describes as including a vegetative structure composed of whorls and of primary and of secondary prothalli; but the author founds his primary divisions on the character of the tricho- gyne, according as it is pedicellate or sessile; in the latter case it may be ovoid or in the form of a club, or a truncated cone. In the process of impregnation, the author maintains the actual absorption of the wall of the trichogyne at the point of contact with the cell- wall, the passage of proto- plasm from the latter through the orifice thus formed and the appearance of a septum at the base of the trichogyne which separates the cystocarpic vesicle. The rejuvenescence of the protoplasm at the close of impregnation imparts a great activity to this cell which then begins to bud and to produce the carpospores or oospores. Mon. Sirodot describes thirty-three native and exotic species of JBatrachospermum. BATRACHOSPERMUM MONILIFOEME, Both. Very variable in size, from one inch to a foot in length, clothed with a more or less firm gelatinous mucus ; violet, fuscous, reddish brown, purple or bluish green, vaguely and profusely branched ; articulations of the branches similar, oblong-subclavate, the outer ones sometimes setigerous ; in- ternodes naked or furnished with a few scattered accessory braiichlets. Cellules measure about 10 /* by 20 yw. Syn. Conferva gelatinosa, Dillw. Batrachosperma ludibunda mon- iliformia, Bory. In fresh, cool rivulets, in springs of rapid limestone waters — rarely in ditches. BATRACHOSPERMUM. 57 Besides this typical form Plate LXIII, figs. 6 and 10, there are many varieties, varying in color, in size and other par- ticulars. The following may be noted as varieties. Var. PULCHERRIMUM, Bory. Violet or purple, internodes almost naked, branches elongated, whorls rather distant globose. Plant 3-5 inches long. Var. SETIGERUM, Eab. The extremities of the moniliform branchlets drawn out into a long -setiform thread. Var. CONFUSUM, Hass. Internodes short, robust and corticulate, whorls approxi- mate with numerous interstitial ramuli irregularly disposed. Var. KUEHNIANUM, Eab. Eather a small form, blue-green, or purplish-green, stern simple, almost naked, whorls distant and slender. Plate LXIV, figs. 4, 5. Mountain springs, Pennsylvania. Var. ATRUM, Harv. Internodes long, somewhat corticulate, whorls imperfectly developed, interstitial ramuli very short, often only t;\ro- celled, color very dark or black. Syn. Conferva atm, Dillw. Batrachospermum detersum, Eiig. Bot. Lemanea setacea, Bory. Rivulet, Catalina Mt., Arizona. Plate LXIV, fig. 6, natural size. Plate LXIII, fig. 9, specimens magnified. 4 BATRACHOSPERMUM VAGUM, Ag. Very variable, but a large and well -developed species, two to ten inches long, almost invariably bluish-green ; distin- guished from the preceding, besides the color by the density of the interstitial ramuli, , and the rather imperfectly de- veloped whorls of the main stems ; the ramuli are often so impacted that the whorls are not apparent except towards the ends of the stems and on the younger branches. Syn. Batmcliosperma turfosa, Bory. Plate LXV, figs. 1, 2, older fronds; figs. 3-6, younger branches. Only typical specimens from Maine and Canada, 58 FRESH-WATER ALGJE OF THE UNITED STATES. Var. KERATOPHYTUM, Bory. Separated from the typical plant mainly in having the whorls distinct. Plate LXIV, fig. 1, is the natural size. Fig. 2, a branched end of a filament moderately magnified ; fig. 3, two whorls of the last more highly enlarged. This variety occurs frequently in lakes and streamlets of New Jersey, often six to eight inches long. Genus 5, THOBEA, Bory. Thallus filarnentose, attenuated at the apex, branched, light purple or purple-brown, villose, mucose, with a solid cen- tral medullary stratum, surrounded by dichotomously divided branchlets. THOREA RAMOSISSIMA, Bory. From a hand's-breadth to a foot long, and rarely two feet long, very much branched ; about the thickness of a horse- hair, dark green or when dried of a beautiful purple- violet, ramuli spreading horizontally, long and short alternating, articulate; joints 1-3 times as long as broad, or twice that length. Syn. Batrachospermum Mspidum, De Cand. Found a mere fragment of a frond in lake at Winter Park, Florida ; enough to identify the plant, but not sufficient for the above description ; have taken it from Cooke's British Fresh- Water Algse, p. 293. Plate LXXI, fig. 1, natural size. Figs. 2, 3, fragments of filaments magnified. Figs. 4, 5, base of ramuli greatly enlarged. Genus 6, CHANTBANSIA, Fr. Found in small caespitose clusters or tufts, steel blue or pur- plish violet, of much more simple structure than Batraclwsper- mum. Filaments articulate, formed of a single series of cylindrical cells, branched ; branches simple or compound, not verticil- late, naked. Carpospores in small clusters on the ends of short branchlets. Sexual propagation takes place, according to Sirodot, by car- pogons attached to lateral branches, fertilized by means of tricho- gynes. Asexual multiplication by means of tetraspores devel- oped on the end of cells, in appearance similar to carpospores. CHANTRANSIA. 59 Sirodot finds that certain Chantransia-Iike forms represent undeveloped conditions of Batrachospermum,\)\\t he has by no means proved that all forms of Chantransia are such un- developed forms ; on the contrary, he admits that some of the species have a sexual existence. CHANTRANSIA MACROSPORA, Wood. Caespitose, about an inch long, usually of yellowish green color, or in younger condition, deeper blue green ; in dried state olive-gray to deep violet purple ; filaments much branched with the branches mostly straight and elongate; fertile branches very short ; articulations 3-6 times longer than broad. Spores single or geminate, few, often distinct, globose, or sometimes slightly oval. Diameter of cells, 20 yw, (15-25 ju). The plant originally described was from Aiken, South Carolina. Found it in profusion, July, 1879, in pond, Atsion, New Jersey, fringing sticks and rootlets of cypress and other trees extending into the shallow water along the shores ; formed also a thick carpet about ten feet square on the planks of the chute of the outlet of the pond. Since then found it frequent in many localities in New Jersey. The vegetative plants are furnished with seta3 (tricho- gynes) usually attached, singly at the base, or 011 the apex of a carpogon. Basal stems are sometimes found with smal- ler filaments entwined around them. Plate LXIX, fig. 1. Plants magnified 125 diameters ; figs. 2, 3, 4, carpospores fertilized; figs. 5, 6, 7, carpogons with trichogynes attached ; fig. 8, natural size. Fig. 9, an older stem corticulated ; figs. 10, 11, 12, matured carpospores in early stages of development. CHANTRANSIA VIOLACEA, Kg. Tufts bright violet, short, scarcely two mm long, fila- ments straight, branches more or less erect, ends obtuse ; articulations 3-6 times as long as wide, 8-9 /* thick. Para- sitic on Lemanea and other plants. Var. EXPANSA, Wood. The author describes this plant as " forming a dark pur- ple, slippery, indefinite stratum on stones ; filaments purple, moderately branched, almost two lines long, together with branches straight, often elongate ; fertile branches short, ascending, joints 3-8 times as long as their diameter, the 60 FRESH- WATER ALG^ OF THE UNITED STATES. final articles obtusely rounded; polyspores racemose, crowded on the fertile branches, oval or somewhat ovate. Var. BEARDSLEI, Wolle. In the Bull. Tor. Bot. Club, January, 1879, we described a singular form, remarkable for size, having a diameter of 25-50 yw, three to six times more robust than the typical C. violacea. It occurred as an undergrowth, intermingled with Lemanea, which was fringed with the parasitic C. violacea. It was sterile, and may be an abnormal development. « Collected by Dr. Beardslee, Painesville, Ohio. The var. expansa occurs frequently on stones in outlets of limestone springs, Pennsylvania. A favorable opportunity for the study of the growth of the typical C. violacea occurred in an aquarium supplied with flowing water. It flourished for several years. The plants developed on the glass-sides. Eeferring to Plate LXVIII, fig. 1, the plant, natural size on Lemanea; fig. 2, natural size on glass ; fig. 3, plants magnified 125 diameters ; figs. 4, 5, clusters of carpogons (polyspores or sporangia) emitting gonidia which float about in the water until they find a place for rest ; fig. 6, a scratch in the glass, with five gonidia lodged and multiplied by the process of cell division until at the end of two weeks, dark, sack-like forms were produced 8-15 mm in length. A single gonidia measures 2.5 yw, or one ten-thousandth part of an inch, hence in one of these groupings no more than one-fourth of an inch square there would be in a single layer 625, 000 small cells or gonidia. The purpose of this rapid cell multiplication appears to be a provision to make a bed for a new growth. Placing one of the larger groupings (fig. 6) under higher magnify- ing power, the development of a young growth becomes evident (fig. 7) and soon the whole space is covered with young plants, fig. 8. The violet color of the species is traceable in all the stages of growth. Plate LXVIII, figs. 9, 10, represent var. expansa; figs. 11, 12, groups of carpogons (polyspores), fig. 13, natural size of plant. Fig. 14, var. Beardslei magnified 125 diameters. CHANTRANSIA HERMANNI, (Eoth) Kg. Caespitose, pale, rosy purple, about 6 mm long, branches erect, patent with cuspidate or piliferous ends ; articulation 3-6 times as long as wide ; 9-12 yu thick. HILDEBRANDTIA. 61 Syn. Trentepohlia pulchetta, Ag. Conferva nana, Dillw. Not as frequent as the preceding ; in fresh running waters. Plate LXIX, fig. 13, natural size, fig. 14, two stems mag- nified 125 diameters. Figs. 15, 16, clusters of carpogons. CHANTRANSIA PYGMAEA, Kg. Tufts dark, steel blue or greenish, 2-3 mm long, radiating branches erect patent with rounded terminal cells. Diameter of cells, 11-14 ^ 2-3 times as long. On wood and grasses in spring water. Plate LXVII, fig. 1, natural size ; figs. 2, 3, stems magnified 125 diameters ; figs. 4, 5, cluster of carpogons ; (tetra-spor- aiigia. ) CHANTRANSIA VIRGATULA, (Harv.) Thur. Grows usually as a close fringe 1-4 mm long, on Zostem and various marine algae. Filaments about 46 yw diameter, articulations 3-4 times longer than broad ; sterns rather straight, branches alternate or secund, rarely opposite; tetra -sporangia on short branchlets, single or rarely twin ; terminal cells often piliferous. Syn. Trentepolilia virgatula, Farl. C. luxurians, J. Ag. ; C. pili- ferumj Kg.; C. Lenormandi, Suhr. Mostly in sheltered coves along the New England coast. More of a Marine than a Fresh-water plant. Plate LXVII, fig. 6, several plants magnified 125 diame- ters ; fig. 7, tetra-sporangia ; fig. 8, natural size as a fringe on Zostera. Family IV.—HILDEBRANDTIACEJE. Thallus crustaceous, extended and firmly adhering, composed of subcubical cells arranged in close vertical series. Tetraspores in excavations in the surface. Sexual propagation unknown. Genus 7, HILDEBBANDTIA, Nardo. Smooth, purplish, crustaceous, forms a firmly attached coating on stones. Propagation asexual by means of tetraspores which are imbedded in pear-shaped cavities under the surface of the thallus. HILDEBRANDTIA RIVTJLARES, Ag. Thallus forms a bright, purplish, smooth crust, on river stones. Tetra-sporangia pear-shaped. Cells of the thallus 62 FRESH-WATER ALG.E OF THE UNITED STATES. red, oblong, round or angular. Cells 3.5-4 /* diameter 5 often twice as long. The only locality in which we found, or know this plant to have been found in fresh-water is the bed of the Susque- hanna River at Harrisburg, Pennsylvania. Syn. H. fluviatiliSj Breb. 5 Erythroclathous rivularis, Liebm. ; H. rosea var. fluwaMis, Kg. Plate LXIX, fig. 17, thallus peeled from a stone, highly magnified/ Fig. 18, small transverse section, showing the spore receptacles. HlLDEBRANDTIA ROSEA, Kg. A marine plant common on stones along the New England coast, differs mainly in smaller size, and spherical form of the cells. Genus 8, COMPSOPOGON, Mont. Thallus filiform, terete, branched, articulate, cells more or less inflated, or slightly constricted at the joints ; filaments corti- cate, somewhat parenchyniatous. Spores, according to Mon- tague, contained in small verrucse in the cortical. COMPSOPOGON COERULEUS, Mont. Tufts loose, 2-6 inches long, dark, olive-green ; filaments stout and firm, much branched, branches erect patent, mostly alternate, decompound, stems and branches tapering. Diameter of lower part of stems often 250 yw, branches 100 // more or less, tapering to an obtuse point. Articulations of stems and of branches rarely more than half as long as wide ; of the thicker parts only about one-third as long. Older parts of stem corticate, primarily indicated by longi- tudinal threads over the articulations, then by an irregular and thicker reticulation. Plate LXX, fig. 1, natural size of plant, figs. 2, 3, younger part, and end of branched filament largely magnified. Figs. 4, 5, two short sections of older parts of filaments, showing the cortical, all magnified 125 diameters. Collected in fresh-water marsh pool about two miles inland from Green Cove Spring, Florida, March, 1885. About a month later Rev. H. D. Kitchel found the same plant fre- quent at Blue Springs, on the St. John's River. In a collec- tion made by Captain J. Donnell Smith, 1878, we recognized the same form but did not identify it until the gathering of fresh specimens. COLEOCHAETE. 63 Class II.— CHLOROPHYCE^S. Plants normally with cell contents of a chlorophyl-green color, aquatic or serial, one, two, or many celled, either single or asso- ciated in families ; branched or simple. Cell contents sometimes change to crimson, flesh-color or yellow-brown, often with a cen- tral or lateral nucleus. Vegetation by cell division. Fecunda- tion often sexual. Propagation either by oospores or zygospores or gonidia. Order II— CONFER VOIDED. Filiform algse, simple or branched ; vegetation terminal, un- limited ; sometimes united laterally ; cell contents chlorophyl- green. Propagation in some genera is sexual, there being female cells (oogoiiia) which contain one or sometimes more oospores, and male cells (antheridia) in which spermatozoids are devel- oped. In some cases copulation of zoogonidia (swarming spores ) has been observed (Cladophora and Ulothrix); the exact mode of propagation of other genera is not satisfactorily determined. Family V.—COLEOCHAETACE^E. Small, bright green water plants either sexual or asexual. The oogonium is a round cell resting 011 the end of a slender 'neck, the continuation of an end cell of the frond. The an- theridia, 2 or 3, are formed on a neighboring cell or on a separate frond, and emit the spermatozoids which by means of two cilise reach the oogonium and fertilize the oospore, which corticates and becomes a resting or winter spore, developing the following Spring. Asexual propagation takes place by zoogonidia which may be developed in any of the cells ; they are provided with two cilise, in appearance like the spermatozoids, but considerably larger. 0 Genus 9, COLEOCHAETE, Breb. Filaments articulated, branched, either conjoined into a little cumulated mass or parenchymatously concreted into a plain sub- 5 64 FRESH-WATER ALG.E OF THE UNITED STATES. disciform thallus ; articles oblong, anteriorly more or less di- lated, often furnished with a long seta on the back or superior angle. COLEOCHAETE SOLUTA, Pringsh. Forms small discs composed of radiating dichotoniously branched filaments lying closely side by side but not adher- ing, cells one and one-half to three times as long as wide ; . carpogons (oogonia) usually develop near the terminal cells, at first small, flask shaped, but gradually enlarging, be- coming orbicular by a cortical forming around them. Vegetative cells average 25 /i diameter. Carpogons fully developed about 200 /* diameter. Not rare in ponds ; frequent in New Jersey waters. Plate LXXII, figs. 1, 2, parts of fronds ; fig. 3, loose growth in fruit ; figs. 4, 5, two carpogons ; figs. 6, 7, young forms. COLEOCHAETE SCUTATA, Breb. In manner of growth similar to the preceding, but distinct in having the filaments adhering side by side, forming a kind of irregularly orbicular, parenchymatous disc; cells sub- quadrangular ; oogonia subglobose, near the margins, corti- cated above, naked below. Fronds and cells very variable in size. Syn. Phyllactidium setigerum, Kg. An aquatic plant, everywhere; much more frequent than C. sohita. Plate LXXII, figs. 8-13, young and older plants of several forms. COLEOCHAETE ORBICULARIS, Pringsh. Like C. scutata in structure and fruit, but always exact orbicular ; the size of the cells is usually smaller. The distinction does not seem sufficient for a good species ; probably a mere variety. Syn. Phyllactidium pulchellum, Kg. Plate LXXII, fig. 14. Localities similar to the other species. COLEOCHAETE PULVINATA, A. Br. Fronds orbicular, upper surface rounded, about 2 mm high in the middle, not thin, flat discs as C. scutata; the arrange- ment of the filaments not so distinctly radiating from a central cell or cells ; size of cells large, 35-40 // by 50-60 yw. CEDOGONIACE^E. 65 Syn. Phyllactidium Australe, Ces. Chaetophora tuberculosa, K. Mueller. Occurs in large limestone springs, Northampton County, Pa.; sticks and branches of trees dropped into the water, are often full of this form, as small dark, olive-green promi- nences or tubercles 4-8-20 mm diameter; the larger ones are usually the result of the confluence of two or more smaller ones. COLEOCHAETE IKREGULARIS, Prillgsh. Thallus bright green, filaments irregularly disposed — not parenchymatous and not with any system of order ; articu- lations longer or more frequently shorter than the diameter. Oogonia transversely broadly oval, usually at the ends of branchlets, nude. Filaments 15-20 ^ wide. Oogonia diameter 40-45 ^. On water plants, leaves dropped in water, etc. This spe- cies assumes many varieties of forms. The one figured was chosen for its good condition of fruit; from a marsh pool, Eastern Pennsylvania. Plate LXXII, figs. 15, 16, specimens of Coleocliaete irregu- H,SJ with carpogons. Family VL—CEDOGONIACEJE. Filamentous algae, simple or branched. Monoecious or dioa- cious. Basal cells mostly lobately divided or ending in a discoid foot by which in early stage the plant is attached. Plants articu- late, endowed with a peculiar mode of cell multiplication by transverse division, indicated by transverse striae usually at the apical end of the mother cell. Plate LXXIII, figs. 2, 2, 3. The oogonia are developed in the series of vegetative cells, singly or in chains of 2-5 or more, one contiguous to the other, and more or less tumid, with a single oospore in each, first green, then gradually changing to orange, to red or brown, and some- times almost black. The fecundated oospore breaks up before germinating into several, ordinarily four, zoospores. Male plants are of two kinds, dwarf and elongated. The dwarf males (nannandres} are found attached to the female plant ; the elongated males are composed of a series of short interstitial cells in an independent filament ; these constitute, the macrandrous forms, and the former the nannandrous forms. Asexual propaga- 66 FRESH-WATEU ALG^ OF THE UNITED STATES. tion takes place by zoospores which are evolved in vegetative cells ; two cells separate (v. Plate LXXIII), the chlorophyl con- tained in a membrane, escapes, producing a spherical cell, pro- vided with cilire aro*und a hyaline point, moves about rapidly, then conies to a rest and develops. Genus 10, CEDOGONIUM, Lk. Filaments simple, articulate. Terminal cell sometimes elon- gated and setiform. Either monoecious or dioecious ; when monoe- cious the oogonia and the sperniogonia cells (antheridia) are on the same filament ; epigynous or hypogynom as the latter are above or below the oogoniuni. Dioecious, when the sperm ogoiiia cells are on different (male) plants. The nannandres are dwarf males somewhat of the form of inverted flasks, the lower part, the stipe, and the upper part consisting of one or more short cells, spermogonia cells (antheridia) ; these dwarf males are located parasitically on or near the oogoniuni, and fertilize it by means of sperrnatozoids developed in the spermogonia cells. Another dioecious form has no dwarf males, but instead, has interstitial spermogonia cells, in independent filaments, like the female plant except usually slightly smaller; these develop and emit the spermatozoids which find their way to the oogonium and fer- tilize the oospore. These two kinds are distinguished, the former as na/nnandrous, and the latter as macrandrous species. The dwarf males are supposed to develop from male zoospores (androspores ) and these from small cells similar to the interstitial sperniogonia cells which are found in the filaments of nannan- drous female plants, or in the filaments of independent sterile plants ; the former are called gynandrosporous and the latter idioandrosporous plants. The androsporangia cells and spermo- gonia cells are barely separable when empty, as most frequently found, except by size, the former being usually considerably larger. The androspores are many times larger than the sper- matozoids. The fertilization of the oospore is effected through a pore or small spherical opening in the oogonium or through a split in the upper part of the oogonium. In some species the oogonium splits round the top and opens as by a lid. The spermatozoids, having matured and escaped from the spermogonia cells, enter and fecundate the oospore which ripens into a perfect, fertile, resting spore. CEDOGONIUM. 67 Plate LXXIII, fig. 1, filament of a female nannandrous plant with oogonium and nannandres or dwarf males. Figs. 2, 2, 3, 3, parts of filaments with transverse striae indicating the mode of cell multiplication peculiar to this genus. When a cell has reached maturity it splits immediately below the apex by a circular line around the cell and by growth the top is raised and a new cell formed ; this new cell may split again as before, below the apex, the top be pushed up by the growth of another cell, leaving two transverse striae The same process is often repeated five, six, or more times and thus producing as many stria?. Fig. 4, section of filament of a female alga showing androsporangia (fig. 5), and dwarf males, (figs. 18, 19). Fig. 6, female mono3cious plant with spermogonia cells ( fig. 7 '), hypogynous ; and oogonium with pore in superior part of it. Fig. 8, filament of monoecious plant with spermogonia cells which are hypogyuous, (fig. 9); sub- hypogynous, (fig. 10) ; epigynous, (fig. 11) ; subepigynous, (fig. 12); and apical, (fig. 13); pore of oogonium, (fig. 14), open cen- trally. Fig. 15, a male plant with androsporangia cells, (fig. 16). Fig. 17, androspores escaping. Fig. 18, dwarf males, stipe, and spermogonia (fig. 19), bicellular. Fig. 20, zoospore making its passage out of mother cell. Figs. 21, 22, 23, fully developed zoospores, furnished with cilia? and becoming very active. Figs. 24-26, zoospores come to rest and developing young plants. Figs. 27-30, advancing stages of development. Figs. 31-33, imperfect zoospores passed out of cell through a fissure and ad- hering. Fig. 34, an oospore surrounded by a multitude of active spermatozoids (!). Fig. 35, shows how some oogonia, destitute of pore, open by an operculuin or lid. Figs. 36, 37, oospore passing out of oogonium. in a vegetative plant. Figs. 38, 39, clusters of young plants, found on an entangled mass of old Oedo- gonium in a water trough, which was dotted with small radiating clusters barely visible to the unassisted eye ; many very small, others larger, containing each from ten to fifty shorter or longer radiating filaments in character the same as the mother, or older plants ; could not satisfy myself whether these clusters spring from gonidia breaking through the cell walls (compare Plate LXXXIII, fig. 6), or from oospores breaking up into niicrogonidia. The figures represent two clusters, like which there were hundreds seen under very low magnification. The old forms were identi- fied as Oe. pachyandrium, Found October, 1882. 68 FRESH-WATER ALG.E OF THE UNITED STATES. The following are the species of the United States as far as identified, arranged in accord with the plan of Wittrock's monograph. (EDOGONIUM. SECTION I.— MONCECTOUS SPECIES. OOGrONIA ALWAYS DESTITUTE OF MEDIAN PROCESSES. A. — Oospores globose or subglobose. a. — Oogonia globose or subglobose. Oe. crytoporum, Wittr. Oe. obsoletum, Wittr. Oe. fragile, Wittr. Oe. zig-zag, Cleve. Oe. vernale, Has*. Oe. crispum, Hats*. Oe. plusiosporum, Wittr. Oe. polymorphuin, Wittr. Oe. autumnale, Wittr. b. — Oogonia elliptic or egg-shaped. Oe. urbicum, Wittr. B. — Oospores elliptic or egg-shaped. Oe. paludosuni, Hays. Oe. crassum, Hass. Oe. gracillimum, Wittr. SECTION II.— DICECIOUS SPECIES. SUBSECTION I. — WITH DWARF MALES. A. — Species with dwarf males unicellular. a. — Oogonia furnished with vertical intersections. Oe. platygynum. b, — Oogonia destitute of vertical intersections. 1. — Oospores globose or subglobose. Oe. decipiens, Wittr. Oe. Areschougii, Wittr. Oe. undulatum, A. Br. Oe. cateractum, Wolle. Oospores subellipsoid. Oe. cyathigerurn, Wittr, GBDOGONIUM. B. — Dwarf males bi-multicellular. Spermogonia external. 2. — Oospores with smooth membrane. a. — Oospores globose or subglobose. Oe. inultispora, Wood. Oe. flavescens, Hasts. Oe. irregulare, Wittr. Oe. Braunii, Pringsh. Oe. Lundense, Wittr. Oe. macraiidriuin, Wittr. Oe. crassiusculum, Wittr. 6.— Oospores ellipsoid or egg-shaped. Oe. Borisianum, Led. Oe. concatenatum, Hass. Oe. sexangulare, Cleve. Oe. Wolleanum, Wittr. Oe. acrosporuni, D.By. Oe. obtruncatum, Wittr. Oe. ciliatum, Hass. Oe. Huntii, Wood. 3. — Membrane of oospores echinulate. a. — Oospores globose. Oe. stellatum, Wittr. Oe. Donnellii, Wolle. Oe. echinospermum, A. Br. Oe. echinatum, Wood. b. — Oospores ellipsoid. • Oe. Hystrix, Wittr. SUBSECTION II. — DIOECIOUS WITH ELONGATED MALE PLANTS; MACRANDROUS. c. — Oogonia not, or scarcely swollen. Oe. capillare, Kg. Oe. stagnale, Kg. d.— Oogonia manifestly swollen. 1. — Oospores globose or subglobose. Oe. capilliforme, Kg. Oe. pachyandrium, Wittr. Oe. rufescens, Wittr. Oe. Franklinianum, Wittr. 70 FRESH-WATER ALG.E OF THE UNITED STATES. Oe. cardiacum, Hass. Oe. earbonicum, Wittr. Oe. Pringsheiinii, Cram. Oe. punctato-striatum, I). B>/. 2. — Oospore-s ellipsoid or oval. Oe. Boscii, Led. Oe. Landsborouglii, Hass. Oe. rivulare, Led. SECTION III.— ORGANS OF FRUCTIFICATION IM- PERFECTLY KNOWN. a. — Oospores globose or subglobose. Oe. delicatuluni, Kg. Oe. moiiiliforme, Wittr. Oe. Fonticola, A. Br. Oe. princeps, Hass. Oe. Loiidiense, Wittr. Oe. vesicatnin, Lynyb. Oe. hexagonum, Hass. b. — Oospores ellipsoid or oval. Oe. giganteum, Kg. Oe. grande, Kg. Oe. pyriforine, Wittr. Oe. longatum, Kg. SECTION I.— MONCECIOUS SPECIES. A. — Oogonia always destitute of median processes. a. — Oospores globose or subglobose. OEDOGONIUM CRYPTOPORUM, Wittr. Oogonia single, elliptic, or somewhat depressed globose, opening by a median pore, almost filling the oogonium, sperrnogonia 2-7 celled, scattered. Diameter veg. cells, 7-9 // ; 4-6 times as long. Diameter oogonia, 24-25 ju by 26-27 jn. Diameter oospore, 22-23 /< by 19-21 /*. Diameter sperm, cells, 6-8 /< by 7-9 //. Var. VULG-ARE, Wittr. Oogonia 2-5 continuous, or single ; spermogonia siibepi- gynons or snbhypogynons or scattered. Measures all some- what less than the typical form, and much more frequent. Ponds, Pennsylvania and New Jersey. Plate LXXI V, figs. 1, 2, CEDOGONIUM. 71 OEDOGONIUM OBSOLETUM, Wittr. (Oe. vernale, Wittr.) Oogonia single, globose to depressed globose, opening by a pore above the middle ; oospore same form as the oogonium nearly filling it. Spermogoiiia 1-3 celled, subepigynous ; spermatozoids single. Diameter veg. cell, 9-14 ^ ; 3-5 times longer. Diameter oogon., 34-38 }JL by 34-40 //. Diameter oospor. , 31-34 // by 28-31 yw. Diameter sperm, cell, 8-9 // by 12-16 yw. Ponds, Pennsylvania — specimens imperfect, but probably of this species — needs farther research. Plate LXXIV, fig. 3. Plate LXXXI, figs. 6, 7. OEDOGONIUM FRAGILE, Wittr. Oogonia single or twin, globose or subegg-shaped-globose, opening by pore above the middle ; oospore fills the oogo- nium ; sperinogonia 1-3 celled, hypogyiious or subepigy- nous ; spermatozoids twin. Diameter veg. cell, 12-17 // ; 4-5 times longer. Diameter oogon., 42-47 /* by 44-50 //. Diameter oospor., 40-44 // by 39-44 }JL. Diameter sperm, cell, 12-15 yw by 10-12 //. Ponds and ditches, Pennsylvania. Plate LXXIV, figs. 4, 5, 6. OEDOGONIUM ZIG-ZAG, (Cleve.) Wolle. Oogonia 2-5 or single, opening by a pore above the middle, globular, oospore filling the oogonium ; spermogonia 2-5 , celled ; a series of spermogonia cells alternating with one, or a series of two or more ooonia. Diameter veg. cells, 17-18 /* ; 2-4 times longer. Diameter oogon., 50-51 ^ by 53-54 //. Diameter oospor. , 47-48 /* by 49-50 f*. Diameter sperm, cells, 17 ^ by 10-11 yw. Have changed the diagnosis slightly to suit the plant, frequent in Northampton County, Pennsylvania. Plate LXXIY, figs. 7, 8, 72 FRESH- WATER ALG^E OF THE UNITED STATES. OEDOGONIUM VERNALE, (Hass. ) Wittr. Oogonia single, obversely egg-shaped, opening with an operculuni, fissures narrow ; oospore globose not filling the oogonium ; spermogonia bicellular, subepigynous. Diameter veg. cells, 10-16 yu ; 4-6 times as long. Diameter oogoii., 39-45 yw by 45-51 yw. Diameter oospor., 34-38 yu by 34-39 yu. Diameter sperm, cells, 10-12 yu by 8-9 yu. Syn. Vesiculifera vernalis, Hass. ; Vesiculifera Candollei, Hass. Ponds, Pennsylvania. Plate LXXIV, figs. 9, 10. OEDOGONIUM CRISPUM, (Hass. ) Wittr. Oogonia single, obversely egg-shaped, opening with an operculum, fissure narrow, oospores nearly globose, not filling the oogonium 5 spermogonia 2-5 celled, hypogynous or subepigynous ; sperrna'tozoids binate, terminal cell obtuse. Diameter veg. cells, 12-18 yw ; 2-4 times as long. Diameter oogoii., 37-49 yu by 42-54 yu. Diameter oospor., 33-46 yu by 34-46 //. Diameter sperm, cells, 9-14 yw by 7-12 yw. Syn. Vesiculifera crispa, Hass. Oedog. rostellatum, Pringsh. Oedoff. pulchellum, A. Br. Ponds and pools, Pennsylvania. Plate LXXIY, fig. 15. ;_ Var. ROSTELLATUM. Pringsh. Agrees in all essential points with the type-form except the terminal cell, not obtuse but rostellate. Meadow pools, ponds, etc. Plate LXXIV, fig. 11, young plant with oogonium, etc.; fig. 12, first development from zoospore; figs. 13, 14, more advanced stages. OEDOGONIUM PLUSIOSPORUM, Wittr. Oogonia single, subelliptic-globose ; opens by pore slightly above the middle ; oospore globose, not quite filling the oogonium ; spermogonia 2-6 celled, subepigynous, rare ; terminal cell obtuse. CEDOGONIUM. 73 Diameter veg. cells, 14-19 yu ; 2-2-3'> times longer. Diameter oogon., 38-45 ^ by 42-50 //. Diameter oospor., 33-39 yw by 31-37 yw. Diameter sperm, cells, 12-14 u by 8-12 yw. Sluggish waters, Pennsylvania, New Jersey, California. Plate LXXIV, figs. 20, 21. V OEDOGONIUM POLYMORPHUM, Wittr. and Lund. Oogonia single, rarely twin, globose-egg-shaped, opens by pore above the middle ; oospore globose not filling the oogoniuni closely ; sperniogonia 1-10 celled, often terminal, subepigynous or vague and rare ; spermatozoids binate ; terminal cell, obtuse, or apiculate or setiform. Diameter veg. cells, 8-14 yw ; 4-10 times as long. Diameter oogon., 30-33 yw by 30-35 yw. Diameter oospor., 25-30 ^ by 25-30 yw. Diameter sperm, cells, 8 yw by 6-7 /-i. Brown's Mills and other ponds, New Jersey. • Plate LXXIV, figs. 16-19. OEDOGONITJM AUTUMNALE, Wittr. Oogonia single, obversely egg-shaped-globose, or globose, opening by an operculum, fissure narrow ; oospore subglo- bose filling the oogoniuni ; sperm ogonia 1-2 celled, subepi- gynous or hypogynous, or sparse ; spermatozoids binate ; terminal cell apiculate or rostellate. Diameter veg. cells, 16-19 yw ; li-2i times longer. Diameter oogon. , 39-43 yw by 45-51 yw. Diameter oospor. , 37-40 yw by 39-43 yw. Diameter sperm, cells, 15-18 yw by 9-10 yw. Ponds and streamlets, Pennsylvania. Plate LXXXI, figs. 1, 2, 3, parts of filaments in fruit. Figs. 4, 5, first stages of development from zoospores. Species ivith elliptic or oval oogonia. OEDOGONIUM URBICUM, Wittr. Oogonia single, elliptic, opens by a pore in superior part ; oospore globose, not filling the oogonium ; spermogonia most frequently only two celled ; spermatozoids binate ; the sup- porting cells of oogonia usually destitute of chlorophyl. 74 FRESH-WATER ALG.E OF THE UNITED STATES. Diameter veg. cells, 15-16 /.i ; 2 2—6 times longer. Diameter oospor. , 33-45 // by 33-45 }.i. Syn. Oe. tumidum, Pringsli. Plate LXXXII, fig. 10. Marsh pools, eastern counties of Pennsylvania. Species ivitti elliptic or oval oospor es. OEDOGONIUM PALUDOSUM, (Hass.) Wittr. Oogonia single, elliptic, sometimes subofolique, opens by a pore above the middle ; oospore elliptic, moderately filling the oogonium ; spermogonia 1-8 celled, sparse, usually in upper end of filament ; spermatozoids binate. Diameter veg. cells, 15-20 /* ; 3-7 times longer. Diameter oogon., 39-48 ^ by 66-84 //. Diameter oospor. , 36-45 /* by 54-63 yw. Diameter sperm, cells, 14-16 /< by 6-13 yw. Syn. Vesiculifera paludosa, Hass. Marsh pools, Northampton County, Pennsylvania. , Plate LXXY, fig. 1. OEDOGONIUM CRASSUM, (Hass.) Wittr. Oogonia single, rarely twin, obovate- ellipsoid, somewhat tumid, opening by a pore above the middle ; oospore ellip- soidal nearly filling the oogonium, spermogonia 2-4 celled, hypogynous or subhypogynous or epigynous; spermato- zoids binate. Diameter veg. cells, 33-35 // ; 2-5 times longer. Diameter oogonium, 65-70 ^ by 100-125 yw. Diameter oospore, 60-66 j.t by 80-110 //. Diameter sperm, cells, 30-33 // by 12-15 f-L Having found this species with spermogonia cells, not heretofore observed, the diagnosis is adapted to our form. Iowa and Kansas. Plate LXXYI, figs. 2 and 3. Two filaments with sper- mogonia cells. OEDOGONIUM GRACILLIMUM, Wittr. and Lund. Oogonia single or twin, oblong ; opening by an oper- culum, fissure narrow ; oospores oblong- elliptic, not filling the oogonium ; spermogonia uni-bicellular, subepigynous ; spermatozoids binate. CEDOGONIUM. 75 Diameter veg. cells, 3-5 yu ; 5-6 times longer. Diameter oogon., 14-16 yw by 34-42 yw. Diameter oospor. , 13-15 ju by 24-31 yu. Diameter sperm, cells, 3-3] yw by 4 yw. Ponds, Pennsylvania. Plate LXXV, fig. 2. SECTION II.— DIOECIOUS SPECIES. - SUBSECTION I. — SPECIES WITH DWARF MALES. A. — Species with dwarf males unicellular, a. — Oogonia vertically constricted. OEDOGONIUM PLATYGYNUM, Wittr. Gynandrosporous, oogoiiia single, rarely binate, depres- sedly obverse egg-shaped; constrictions 7-12, angles rounded; oogoiiia cut round (circumsclssile) below the middle, opening by a pore seated in the fissure, vertical view orbicular, margin sinuate with depressions corresponding with the constrictions ; oospore somewhat depressed-globose nearly filling the oogonium aiidrosporangia 1-3 celled; terminal cell obtuse ; dwarf males small, obverse egg-shaped, seated on the oogoiiia. Diameter veg. cells, 6-8 yw ; 2-5 times longer. Diameter oogon., 21-30 yu by 16-24 //. Diameter oospor., 17-24 yu by 15-20 yw. Diameter androsp. cells, 6-8 yu by 7-8 yw. Diameter of dwarf males, 4-5 yw by 8-9 yw. Frequent in ponds, New Jersey, Florida, Minnesota. Plate LXXVII, figs. 1, 2, filaments ; figs. 3, 4, transverse sections of oogoiiia. b. — Oogonia destitute of vertical constrictions. I.— Oospore globose or subglobose. OEDOGONIUM DECIPIENS, Wittr. Gynandrosporous, oogoiiia single or two or three in series ; depressed-globose, narrowly circumcised in middle, open- ing by a pore in the fissure ; oospore depressed-globose, not 76 FRESH-WATER ALG.E OF THE UNITED STATES. filling the oogonium ; androsporangia 2-6 celled, dwarf males obverse egg-shaped, situated on the oogonium. Diameter veg. cells, 10-12 yw ; 3-5 times longer. Diameter oogon., 32-38 /u by 30-40 yw. Diameter oospor., 29-34 yu by 25-28 yw. Diameter androsp. cell, 9-10 yw by 11-15 p. Diameter dwarf male, 6-7 yu by 14-15 yw. Syn. Oedog. vesicatum, D. By. Ponds, New Jersey, rare. Plate LXXYTI, figs. 5, 6. OEDOGONIUM ARESCHOUGII, Wittr. Gynandrosporous, oogonia 2-6 continuous, or single, rather depressedly globose, broadly cut round (circum- scissile) in the middle, opening by a pore in the fissure ; oospore exact globose, not filling the oogonium. Andro- sporangia 1-6 celled, hypogynous or subepigynous, or rarely scattered, terminal cell (which sometimes is the an drosporangium) obtuse, dwarf males obversely egg-shaped, seated on the oogonia. Diameter veg. cells, 9-12 yu ; 4-6 times longer. Diameter oogon., 38-39 yu by 36-40 //. Diameter oospor., 22-24 yw by 22-24 yw. Diameter androsp. cells, 10-11 yw by 10-12 /x Diameter dwarf males, 6-7 yu by 14-15 yw. Ponds, New Jersey. Oe. Areschougii is recorded with some hesitation ; it is very near Oe. decipienx, the one may be a mere variety of the other. Plate LXXVII, fig. 7, a filament with oogonia, dwarf males, etc. OEDOGONIUM UNDULATUM, (Breb.) A. Br. Oogonia single or twin, elliptic-globose or subglobose, opens by a pore below the middle ; oospore in form like the oogonium, nearly filling it ; vegetative cells four times undu- latingly constricted ; terminal cell (which is sometimes the oogonium) obtuse; dwarf males elongate-obconical, seated on the supporting cell. Diameter veg. cells, 15-17 yu • 3-5 times longer. Diameter oogon., 51-56 /< by 57-75 //. Diameter oospor., 46-50 yu by 48-60 //. Diameter dwarf males, 9-10 yw by 65-70 yw. tEDOGONIUM. 77 Syn. Conferva undulata, Breb. ; Cynatonema confervaceum, Kg. Filaments single, not massed, widely distributed. Plate LXXVII, fig. 8, filament with oogonium, dwarf male, and pedicel. OEDOGONIUM CATERACTUM, Wolle. Idio-androsporous 5 oogonia often terminal, single or twin, obovate globose, subglobose or broadly oval, opens by a pore above the middle ; oospore globose or obovate globose nearly filling the oogonium; aiidrosporangia 2-6 celled, dwarf males unicellular, considerably curved, seated on, or some- times below the supporting cell ; spermatozoids internal. Diameter veg. cells, 28-38 ju ; U-3 times as long. Diameter oogon., 55-60 // by 60-75 yw. Diameter oospor., 50-55 /u by 50-60 p. Diameter androsp. cell, 26-30 yw by 10-15 yw. Diameter dwarf males, 10 yu by 65 yw. Attached to rocks in rapids below water-fall, Pike County, Pennsylvania. Plate LXXXV, figs. 10, 11, 12. b. — Oospores subellipsoid. OEDOGONIUM CYATHIGERUM, Wittr. 5 forma AMERICANA, Wolle. Idio-androsporous ; oogonia single, or two to three seriate, oboviform or ellipsoid, opens by a pore above the middle ; oospores of same form, nearly filling the oogonium ; sup- porting cell slightly tumid ; terminal cells obtuse ; andro- sporangia pluricellular ; dwarf males cyathiform, somewhat curved, seated on the supporting cell or on the oogonia. Diameter veg. cells, 17-21 yu; l}-3 times longer. Diameter oogonium, 45-50 yw by 55-63 /x Diameter oospore, 39-40 /.i by 44-46 yw. Diameter dwarf males, 12-15 yw by 50-54 yw. Ponds, Pennsylvania. This form is somewhat more slen- der than the type-form ; dwarf males are seated on the oogonia, not on the supporting cells, and the vegetative cells are shorter; but we prefer to retain this name as appro- priate and until more numerous specimens are found. Plate LXXXI, figs. 20-22. 78 FRESH-WATER ALG^E OF THE UNITED STATES. OEDOGONIUM MULTISPORA, Wood. Oogonia single, bi- or tri seriate, globose with a distal lateral pore ; oospore globose about the same size as the cavity of the oogonium. Dwarf males (antheridia) bi- or tri -cellular, curved with the lower part much the largest, generally adhering in considerable numbers to all parts of the female plant. Dr. Wood remarks : " This species differs from its nearest European congeners, Oe. Rothii and Oe. tlepressum, very markedly in the bi-cellular antheridia," He gives no meas- ures ; the plant illustrated, Plate LXXX, figs. 6, 7, is from the vicinity of Philadelphia, and supposed to be the plant referred to. The oogonia are not only tri- but often MUL- TISPORA. Diameter veg. cells, 12-15 yu ; 2-3 times longer. Diameter oogon., 45-50 yw by 45-50 yu. Diameter oospor., 42-47 yu by 42-47 yw. Diameter sperm, cells, 11-13 yw by 40-50 yw. Plate LXXX, figs. 6, 7. B. — Species with dwarf males bi-multicellular, spermogonia external. A. — Oospores with smooth membrane. a. — Oospores globose or subglobose. / OEDOGONIUM FLAVESCENS, (Hass.) Wittr. Idio-androsporous, oogonia single, egg-shaped-globose or hexagonally globose, opening by a pore in the middle or a little above the middle, oospore globose, not filling the oogonium ; androsporangia 1-9 celled ; dwarf males slightly curved, seated on the supporting cell ; spermogonia usually one-celled. Diameter veg. cell, 18-21 yw ; 4^-6 times longer. Diameter oogon. , 49-52 u by 51-60 yw. Diameter oospor., 45-49 yu by 45-49 yu. Diameter androsp. cell, 17-20 yu by 8-18 yw. Diameter stipe dwarf male, 11-12 >w by 39-45 yw. Diameter sperm, cell, 9-10 // by 15-20 yu. Syn. Vesiculifera flavescens, Hass. Minnesota, near Minneapolis. Plate LXXVIII, figs. 1, 2, filaments with oogonia, dwarf males, etc. (EDOGONIUM. 79 OEDOGONIUM IRREGULARE, Wittr. Oogonia single, globose, opening by a pore above the mid- dle, oospore filling the oogonium, dwarf males seated near or on the oogonia, spermogonia 2-4 celled, terminal cells attenuated. Diameter veg. cells, 16-20yw; 2 5 -4 times longer. Diameter oogon., 37-45 yw by 36-43 /x Diameter oospor. , 30-40 yw by 34-38 yw. Diameter stipe dwarf males, 12-15 yw by 20-24 yw. Diameter sperm, cells, 10-12 /u by 6-8 yw. Marshes, Florida. Plate LXXVIII, figs. 4, 5. OEDOGONIUM BRAUNII, (Kg.) Pringsh. Gynandrosporous ; oogonia single, elliptic- globose, opens by pore in the middle ; oospore globose, nearly filling the oogonium ; androsporangia 1-2 celled ; dwarf males some- what curved, seated near the oogonium, usually on the sup- porting cell ; spermogonia unicellular. Diameter veg. cells, 13-15 yw ; 2-4 times longer. Diameter oogon., 30-33 yu by 33-36 yw. Diameter oospor., 27-29 yu by 27-29 yu. Diameter androspr. cells, 14-15 yu by 11-12 yw. Diameter dwarf male, 7 yw by 15 yu. Diameter sperm, cells, 5 /* by 9 /^. Pennsylvania, New Jersey. Plate LXXIX,.figs. 6, 7. OEDOGONIUM LUNDENSE, Wittr. Oogonia 2-4 seriate or single, subglobose, opening by an operculuni, fissure very narrow and indistinct ; oospore glo- bose, very nearly filling the oogonium ; terminal cell obtuse ; dwarf males seated on the oogonia, stipe curved ; spermo- gonia one-celled. Diameter veg. cells, 15-17 JJL ; 11-2J times longer. Diameter oogon. , 32-34 /u by 34-35 //. Diameter oospor. , 30-31 yu by 30-31 yu. Diameter stipe dwarf males, 12 yu by 27-30 yw. Diameter sperm, cells, 10 yw by 6-8 yu. Marsh pools, Eastern Pennsylvania. Plate LXXVII, figs. 9, 10. 6 80 FRESH-WATER ALG^ OF THE UNITED STATES. OEDOGONIUM MACRANDRIUM, Wittr. Oogonia single or 2-3 seriate, egg-shaped or globose egg- shaped, opening by an operculum, fissure very narrow ; oospore globose or egg-shaped globose, not filling the oogonium ; terminal cells apiculate ; dwarf males much curved, seated on the oogonium, stipes often 2-3 celled ; spermogonia two or more, often seven-celled. Diameter veg. cells, 15-16 yu; 3-5 times longer. Diameter oogon., 36-40 // by 43-54 yw. Diameter oospor., 31-34 yu by 33-39 yw. Diameter stipe dwarf males, 12 yw by 24-33 //. Diameter sperm, cells, 9 jn by 5-9 yu. Marsh grounds, Eastern Pennsylvania. Plate LXXXII, figs. 1, 2, 3. OEDOGONIUM CRASSIUSCULUM, Wittr. Idio-androsporous or gynandrosporous ; oogonia single or binate ; globose egg-shaped or nearly globose, opening by a pore above the middle ; oospore ellipsoid-globose or obverse egg-shaped globose, membrane thick, nearly filling the oogo- nium ; androsporangia 2-6 celled ; dwarf males straightish, seated on or about the supporting cells ; spermogonia 1-2 or more celled. Diameter veg. cells, 27-30 yw ; 31-5 times longer. Diameter oogon. , 54-60 yw by 60-75 yu. Diameter oospor., 51-57 yw by 52-63 yu. Diameter androsp. cells, 26-28 yw by 10-18 yw. Diameter stipe dwarf males, 13 yw by 60 yu. Diameter sperm, cells, 7-9 yw. Not infrequent ; had good fruiting specimens from Penn- sylvania, New Jersey and Minnesota, all idio-androsporous. No doubt widely distributed. A specimen from Northern New Jersey presented an unusual appearance, an oogonium swarming in the space be- tween the wall of the oogonium and the oospore with small spermatozoid-like cells, most numerous in the upper part of the oogonium, passing in and out through the pore. Their function was not evident; if spermatozoids, their number was extraordinary. In the course of 8-10 minutes they gradually disappeared. Plate LXXYII, figs. 14, 15, 16, sections of filaments. Fig. 17, the oogonium referred to in the last lines. CEDOGONIUM. 81 b. — Oospores ellipsoid or egg-shaped. OEDOGONIUM BORISIANUM, (Led.) Wittr. Gynandrosporous ; oogonia single, or in series of 2-4, obversely egg-shaped, opening by a pore above the middle 5 oospore obversely egg-shaped or subglobose, almost filling the oogonium ; supporting cells swollen and usually curved 5 aiidrosporangia 2-5 celled ; terminal cells obtuse ; dwarf males slightly curved, seated on the supporting cells ; sper- mogonia cells single or twin. Very variable in size. Diameter veg. cells, 15-33 JJL ; 3-5 times longer. Diameter supporting cells, 31-40 ^ ; 2 times longer. Diameter oogon., 45-50 ^ by 60-75 ju. Diameter oospor. , 40-60 ja by 40-80 yw. Diameter androsp. cells, .17-20 ^ by 10-12 /*. Diameter stipe dwarf male, 15-18 /* by 45-80 /*. Diameter sperm, cells, 8-10 // by 12-20 //. Syn. Prolifera Borisiana, Led. ; Oe. apophysatum, A. Br. ; Oe. setigerum, Vaup. ; Oe. miraMle, Wood. Ur. Wood says of this species (mirabile) that its oogonia have two pores of fecundation. But this statement, suggests Dr. Wittrock, is based on a misconception of facts as may be seen by Wood's own figures. No form of Oedogonium has more than one pore of fecundation on a single oogonium. » Frequent, and widely spread ; very variable in size, but readily distinguished by the large and more or less bent, supporting cells. Have made several slight changes in the diagnosis of the European plant to adapt it to our forms. Plate LXXVIII, fig. 6, an undeveloped oogonium ; fig. 7, a smaller form ; fig. 8, a large form ; fig. 9, the more fre- quent form. OEDOGONIUM CONCATENATUM, (Hass. ) Wittr. Gynandrosporous, oogonia 2-6 seriate, or single, egg- shaped or quadrangularly ellipsoid, opening by a pore above the middle ; oospore nearly filling the oogonium ; sporoderm delicately porose ; supporting cell somewhat swollen : andro- sporangia 2-6 celled ; terminal cell obtuse ; dwarf males moderately curved, seated on the supporting cells ; spermo- gonia two-celled. Diameter veg. cells, 25-40 ^ ; 3-6 times longer. Diameter oogon., 70-83 n by 90-105 yw. Diameter oospor., 65-76 IJL by 85-95 yw. 82 FRESH-WATER ALGJE OF THE UNITED STATES. Diameter androsp. cells, 26-28 /< by 30-36 p. Diameter stipe dwarf male, 20-25 ^ by 55-75 ^. Diameter sperm, cells, 10-12 /* by 22-25 //. Syn. Vesiculifem concatenate, Hass. ; Oe. a/pophysatum, Pringsh. Frequent in Pennsylvania, New Jersey and probably in every State. Plate LXXIX, figs. 1, 2, filaments with oogouia, dwarf males, androsporangia, etc. ; fig. 3, an outline of a series of quadrangularly ellipsoid oogonia. Var. SETIGERUM, (Vaup.) Wolle. A plant which bears a very close relation to Oe. concate- natum except that the terminal cell is not obtuse but bears a long seta. Ponds, Northampton County, Pennsylvania. Plate LXXIX, figs. 4 and 5, parts of two filaments show- ing the setae. OEDOGONITJM SEXANGULARE, Cleve. Gynandrosporuos ; oogonia single, rarely twin, sexan- gular- ellipsoidal, open by a pore slightly above the middle ; oospore nearly filling the oogoniuin; androsporangia 2-4 celled ; dwarf males somewhat curved, seated on the sup- porting cells ; spermogoniuni one- celled. Diameter veg. cells, 9-16 /*; 3J-7 times longer. Diameter oogon., 29-32 /u by 33-38 /«. Diameter oospor., 27-30 fA, by 31-36 //. Diameter androsp. cells, 13-14 /* by 10-14 /*. Diameter stipe dwarf male, 7-9 ^ by 21-27 p. Diameter sperm, cells, 6-7 yw by 9-12 yw. A widely distributed species. Plate LXXIX, figs. 8, 9, a filament with oogonia, dwarf males and androsporangia. OEDOGONIUM WOLLEANUM, Wittr. Idio-androsporous ; oogonia single, or 2-5, rarely ten, seriate, elliptic or oval; oospore oval, nearly filling the oogoniuni ; more or less densely, longitudinally, costate ; androsporangia 6-10 celled ; dwarf males somewhat curved, seated on the supporting cells — sperrnogoiiia 1-4 celled ; supporting cells somewhat tumid ; oogoniuin often terminal. OEDOGONIUM. 83 x • Diameter veg. cells, 18-36 yu 5 3-7 times longer. Diameter supporting cells, 60-65 ^ by 116-140 ju. Diameter oogon., 68-80 p by 78-92 /*. Diameter oospor., 64-73 yw by 74-84 p. Diameter anclrosp. cells, 24-30 /* by 18-25 yw. Diameter stipe dwarf males, 18-22 yw by 60-70 jw. Diameter sperm, cells, 12-14 yw by 10-12 ju. Very variable in size ; widely distributed — Pennsylvania, New Jersey, Minnesota, Florida, etc. Specimens are pre- served in Wittr. and Nord.'s series, Algae Exsiccatee, No. 107, Pennsylvania specimens; and No. 207, New Jersey specimens. Plate LXXXII, figs. 1, 2, filaments of larger form ; fig. 3, male plant ; figs. 4, 5, filaments of smaller form. Usually fringing rootlets along the shores of ponds, sticks and the like, but found also in quantity on the rocky shores of lakes in New Jersey. OEDOGONIUM ACROSPORTJM, D. By. Idio-androsporous ; oogonium single, rarely twin, always terminal, ellipsoid; opening by a small, apical deciduous operculum ; oospore manifestly filling the oogonium, mem- brane longitudinally costate ; supporting cell often swollen ; terminal cell of sterile plants, obtuse ; dwarf males curved, seated on the supporting cells, stem or stipe often bi-cellular, long 5 spermogonia 1-2-celled. Diameter veg. cells, 10-14 ^ ; 2-7 times longer. Diameter supporting cells, 15-18 // by 2-3 times longer. Diameter oogon. , 30-35 /* by 45-51 //. Diameter dwarf males, inferior cell, 9-12 jw by 24-32 /*. Diameter dwarf males, superior cell, 6-8 /* by 55-65 yw. Diameter sperm, cells, 6-8 ^ by 14-15 yw. The above is Wittrock's description of the European plant. Our United States plants are not altogether iden- tical. One form we may distinguish as Var. FLOEIDENSE, Wolle. It is nearest the European form, but differs in having the filaments more slender, and cells proportionately much longer, nearly twice the length. The long dwarf males are characteristic 5 they are seated about the middle of the sup- porting cell and extend beyond the top of the oogonium. 84 FRESH-WATER ALG-JS OF THE UNITED STATES. Found it in tangled masses floating in a pool in Florida, near Winter Park ; filaments a foot or more in length, almost devoid of chlorophyl ; oospores and supporting cells vegeta- tive green. Diameter veg. cells, 7-8 ^ • 5-11 times longer. Diameter oogon. , 33-35 j* by 45-50 yw. Plate LXXXV, figs. 1, 2. Var. BOREALE, Wolle. Is the form common in Pennsylvania and New Jersey ; it is short, more robust, articulations only 3-5 diameters, dwarf males short, with spermogonia one- celled. Diameter veg. cells, 14-16 // ; 3-5 times longer. Plate LXXIX. figs. 10, 11. OEDOGONIUM OBTRUNCATUM, Wittr. Oogonium single or more rarely twin, broadly elliptic or globose-ellipsoid, usually terminal, opens by an apical oper- culum ; supporting cells the same as the vegetative cells. Oospore filling the oogonium. Diameter veg. cells, 8-12 yw ; 2-4 times longer. Diameter oogon., 15-17 JJL by 17-20. Frequent in pools, parasitic on culms of water plants. Not quite identical with the India form described by Wittrock, but nearly related; may be considered a small form. Plate LXXIX, figs. 12, 13. OEDOGONIUM CILIATUM, ( Hass. ) Pringsh. Gynandrosporous; oogonia 2-7 seriate or single, oval, open- ing by an operculuni ; oospore oval, nearly filling the oogo- nium ; androsporaiigia 2-8 celled ; terminal cell setiform ; dwarf males curved, seated on the oogonium ; sperinogoiiia unicellular. Diameter veg. cells, 12-20 yw; 2 2 -5 times longer. Diameter oogon., 40-45 j* by 52-70 yw. Diameter oospor. , 38-44 yw by 45-55 yw. Diameter dwarf males, 10-15 yu by 28-30 yw. Marsh pool, Atsion, Ne\v Jersey. Not quite the same as the European form but near it. Syn. Vesiculifera ciliata, Hass ; Oe. piliferum, Auers. Plate LXXXIV, fig. 10, a filament (fern.) in fruit. GEDOGONIUM. 85 OEDOGONIUM HUNTII, Wood. Filaments mostly produced into a long apical seta ; oogonia mostly single, globose, now and then hexagonal ; somewhat tumid in the middle ; the lateral pore placed below the mid- dle ; oospore globose, not filling the cavity of the spore-case, its surface with four spiral elevated lines or ridges ; antheridia bi-cellular (sometimes tri-cellular. ) Diameter oospore, 50 //. F. W. Algse of U. S., Wood, p. 198. Hitherto have not identified any plant answering this description. Plate LXXXIY, fig. 9. 1 3. — Membranes of oospores echinulate. a. — Oospores globose. OEDOGONIUM STELLATTJM, Wittr. Gynaiidrosporous ; oogonia single or 2-3 seriate, oboviform globose, opening by a pore above the middle ; oospore glo- bose, nearly filling the oogoiiium, spinulose, spines conical, spirally disposed ; androsporangia 1-2 celled ; terminal cell somewhat slender and subhyaliue, apex obtuse ; dwarf males rather straight, usually seated on the supporting cell, some- times scattered 5 spermogonia bi-cellular. Diameter veg. cells, 15-35 ju ; 2J-5 times longer. Diameter oogon., 51-61 ju by 58-70 yw. Diameter oospor. , with spines, 50-58 /* by 50-58 yw. Diameter androsp. cells, 14-19 yw'by 20-27 p. Diameter stipe dwarf male, 11-13 /* by 45-52 //. Diameter sperm, cells, 6-9 /* by 8-10 //. Frequent in Florida waters. Plate LXXXIY, figs. 1. 2, two filaments. OEDOGONIUM DONNELLII, Wolle. Idio-androsporous ; oogonia single, rarely twin, quadran- gularly globose ; oospore globose, echinulate, spines conical, nearly filling the oogoiiium ; androsporangia 4-10 celled ; dwarf males somewhat curved, stipe two-celled, spermo- gonia two or more celled. Male plants moderately smaller than female. Diameter veg. cells, 55-62 yu ; 1-2 times as long. Diameter oogon., 70-75 // by 85-95 yw. 86 FRESH- WATER ALGJE OF THE UNITED STATES. Diameter oospor. with echinge, 70-75 jw by 70-75 yw. Diameter androsp., 40-45 ^ by 10-12 //. Diameter dwarf males, 15-18 u by 80-90 yw. Diameter sperm, cells, 10-12 // 5-6 jw. Coll. Capt. J. Donnell Smith ; v. Bull. Torrey Bot. Club, 1879, p. 48. A very distinct species. Plate LXXXIY, figs. 3, 4, female filaments with oospores and dwarf males ; fig. 5, male plant with androsporangia. OEDOGONIUM ECHINOSPERMUM, A. Br. Gynandrosporous or idio-androsporous ; oogonium single, ellipsoid globose or snbglobose, opening by a pore in the middle ; oospore globose, coated with subulate spines, filling the oogonium ; androsporangia 2-5 celled ; dwarf males rather short, curved, seated on the supporting cell; spermo- gonia unicellular. Diameter veg. cells, 18-30 yw; 2]-4i times longer. Diameter oogon. , 40-50 ^ by 42-57 /J. Diameter oospor., 38-47 /* by 38-49 /w. Diameter androsp. cells, 21-25 yu by 9-15 yw. Diameter dwarf males, 10-12 /u by 30-35 //. Diameter sperm, cells, 8-10 yw by 8-10 yw. Frequent in Pennsylvania, New York, New Jersey and probably everywhere east of the Rocky Mountains. A distinct form from Florida may be noted as Var. SPERMOGONIA MTJLTICELLTJLARIA, Wolle. Excels the ordinary form in fine development, larger size, densely spinulose oospores and most prominent, the many celled spermogonia. Plate LXXXIY, fig. 7, the ordinary form. Plate LXXXV, figs. 6-9, the new variety from Florida. OEDOGONIUM ECHINATUM, Wood, Gyiiandrous, very elongate ; joints 6-14 times longer than broad ; sporangia globose, mostly depressed, about 35 ^ diameter ; oospores of the same form as the sporangia whose cavity they fill, covered with sharp spines ; the lateral pore placed above the middle; antheridia bi- cellular. Dr. Wood remarks, "I found this distinct species in a little stagnant pool, in Centre County, Pa. The filaments are very long and were matted together into a sort of fibrous mass. The male plants (dwarf males) were few in number CEDOGONIUM. 87 and were attached to the female plant in the neighborhood of the sporangia. The spines are thorn-like, sharp at the points, but robust at the base." Wood, Fresh- Water Algse of the United States, p. 198. With the exception of the lateral pore above the middle, this plant might be identified as Oe. Aster, Wittr. Plate LXXXV, figs. 13, 14. b. — Oospores ellipsoid. OEDOGONIUM: HYSTRIX, Wittr. Gynandrosporons or idio-androsporous ; oogonia single, ellipsoid to globose ellipsoid, opening by a pore in the middle 5 oospore same form as oogoiiium, nearly filling it, coated with subulate spines ; androsporangia 2-3 celled ; terminal cell obtuse, dwarf male stipe 2-celled, moderately curved, seated on the supporting cell ; spermogonium one- celled. Diameter veg. cells, 17-28 //; 2J-4-i times longer. Diameter oogon., 38-44 yw by 45-65 yw. Diameter oospor. with spines, 37-42 yw by 43-55 yw. Diameter androsp. cells, 17-18 u by 13-18 yw. Diameter dwarf males, 10-11 ^ by 50-65 //. Diameter sperm, cells, 7-8 yu by 10-14 /u. Eastern Pennsylvania. Plate LXXXIV, fig. 8. SUBSECTION II. — DICECIOUS, WITH ELONGATED MALE PLANTS ; MACRANDROUS. c. — Oogonia not, or scarcely swollen. OEDOGONIUM CAPILLARE, (Linn.) Kg. Oogonia simple, not swollen, cylindrical, opening by a pore above the middle ; oospore globose or cylindrical-glo- bose (somewhat quadrangular in longitudinal section) not filling the oogonium ; male plants the same or almost the thickness of the female plants ; spermogonia 1-4 celled, alternate with vegetative cells ; spermatozoids binate. Diameter veg. cells, 25-55 yu ; 1-2 times longer. Diameter oogon. 25-55 yw by H times longer. Diameter oospor. 22-52 /.i by 38-62 //. Diameter sperm, cells, 24-48 jn by 5-6 //. 88 FRESH-WATER ALG^E OF THE UNITED STATES. Syn. Conferva capiUaris, Linn ; Oe. regular e, Vaup. One of our most common forms, at the same time one rarest in fruit. Variable in size from 25-50 yw in diameter j filaments often a yard or more in length. Plate LXXXIII, figs. 7, 8, female and male plant. OEDOGONIUM STAGNALE, Kg. Oogonium single, slightly tumid, subcylindrical, opens by a pore above the middle ; oospore subcylindrical or globose- ellipsoidal, sometimes slightly constricted in the middle, nearly filling the oogonium ; masculine plant slightly less in diameter than the female ; spermogonia 1-3 celled, alter- nating with vegetative cells. Diameter veg. cells, 42-46 yw ; 1J-2 times longer. Diameter oogon., 49-50 yw by 65-75 yw. Diameter oospor. , 47-49 yu by 50-66 yw. Diameter sperm, cells, 36-38 yu by 7-9 yw. Very near Oe. capillare, barely separable except by the somewhat swollen oogonia. Plate LXXXIII, figs. 3, 4, two filaments of female plant ; fig. 5, male plant ; fig. 6, a cell in a neutral plant, the chloro- phylous contents broken up into small spherical motile cells (gonidia) which are passing out by an aperture in the side. d. — Oogonia manifestly swollen. 1. — Oospor es globose or subglobose. OEDOGONITJM CAPILLIFORME, Kg. Oogonia single, obversely egg-shaped, opens by a pore above the middle ; oospore subellipsoid, globose or cylin- drical-globose, not filling the oogonium ; male plant slightly smaller than female"; spermogonia 2-10 celled; terminal cell obtuse. Diameter veg. cells, 32-38 yu ; li-3 times longer. Diameter oogon., 42-48 yu by 51-62 yw. Diameter oospor. 37-45 yw by 40-50 yw. Diameter sperm, cells, 20-25 yw by 8-10 yw. Stagnant waters. Plate LXXV, figs. 11, 13, filaments of female plants ; fig. 12, male plant with spermogonia cells. CEDOGONIUM. 89 OEDOGONIUM PACHYANDRIUM, Wittr. Oogonia single or twin, moderately swollen, obovate- ellip- soid, opening by a pore above the middle ; oospore ellipsoid nearly filling the oogonium ; male plant slightly thicker than the female ; spermogonia 1-4 celled ; spermatozoids binate. Diameter veg. cells, 31-36 yw; 2^-62 times longer. Diameter oogon. , 54-57 yu by 90-108 yw. Diameter oospor., 51-54 ju by 73-85 yw. Diameter sperm, cells, 35-43 yu by 11-20 yw. Stagnant waters, railroad ditches, Pennsylvania, New Jersey, frequent. Plate LXXV, fig. 9, female, and fig. 10, male plant. OEDOGONIUM RUFESCENS, Wittr. Oogonia single or 2-3 seriate, globose or obovate globose, opening by a pore in the middle ; oospore globose filling the oogonium ; male and female plants of same size ; spermogonia 6-12 celled. Diameter veg. cells, 8-10 yw ; 5-6 times longer. Diameter oogon., 22-24 yw tiy 24-30 yw. Diameter oospor. , 21-23 yw by 20-22 //. Diameter sperm, cells, 6-8 yw by $-12 yw. Plate LXXXI, figs. 16, 17, male and female plants. OEDOGONIUM FRANKLINIANUM, Wittr. Dioecious, macrandrous; oogonia single or rarely twin, subglobose, opening by a pore above the middle ; oospore globose filling the oogonium, membrane firm ; filaments of male plant slightly smaller than the female. Diameter veg. cells, fern., 9-12 /^ 3-6 times longer. Diameter veg. cells, mas. , 8-9 yu ; 3-5 times longer. Diameter oogon. , 26-31 yw by 29-41 /*. Diameter oospor., 25-29 ^ by 24-30 yw. Diameter sperm, cells, 8-9 yu by 5-7 yw. This species from pond, Franklin, New Jersey, stands between Oe. rufescens, Wittr., and Oe. Ltundellli, Wittr. Plate LXXXII, figs. 7, 8, two female plants ; fig. 9, male plant. V. specimens, Wittrock and Nordstedt's Algse Exsiccatse, No. 309. 90 FRESH-WATEU ALG^ OF THE UNITED STATES. OEDOGONIUM CARDIACUM, (Hass.) Wittr. Oogonia single, between heart-shaped and globose, open- ing by a pore a little above the middle ; oospores globose, not filling the oogonia ; male plants a little slenderer than the female ; spermogonia 2-10 celled ; spermatozoids binate, terminal cells obtuse. Diameter veg. cells, fern. , 18-30 yw • 2-7 times longer. Diameter veg. cells, mas., 15-25 yw; 2-6 times longer. Diameter oogon., 50-70 yu by 58-85 yw. Diameter oospor., 42-60 yw by 42-60 yw. Diameter sperm, cells, 15-21 yu by 10-13 yw. Syn. Oe. inequaUs, Wood ; Oe. pulchellum, Eab. In pools near Philadelphia, Pa. The description by Wood is imperfect, nevertheless the plant appears to belong to this species. OEDOGONITJM CARBON ICUM, Wittr. Oogonia single or twin, obovate, or ovate globose, opening by a pore above the middle ; oospores ellipsoid-globose or nearly globose, barely filling the oogoniuin ; male plants a little more slender than the female ; spermogonia 2-5 celled ; spermatozoids binate ; terminal cells obtuse. Diameter veg. cells, fern. , 16-30 yw ; 3-6 times longer. Diameter veg. cells, mas. , 14-16 yw ; 3-6 times longer. Diameter oogon., 43-52 /* by 50-72 /u. Diameter oospor., 42-50 yw by 46-56 yw. Diameter sperm, cells, 13-14 /t by 12-14 /u. The only specimens of this species identified were collected in Iowa. Plate LXXXII, figs. 14, 15, male and female plants. OEDOGONIUM PRINGSHEIMII, Cram. Oogonia single or 2-6 seriate, sub-obovate-globose, open- ing by an operculum, with a very narrow fissure ; oospore globose, not distinctly filling the oogonium ; male plants somewhat smaller than the female ; spermogonia 2-10 celled, often alternate with vegetative cells towards the ends of fila- ments ; terminal cells obtuse or shortly apiculate. Diameter veg. cells, 12-20 ^ 5 2-4 times longer. Diameter oogon., 30-43 V by 36-45 yw. Diameter oospor. , 28-35 /* by 28-34 yu. Diameter sperm, cells, 10-15 ^ by 6-9 yw. (EDOGONIUM. 9 1 Syn. Oe. Nordstedtii, Wittr. Plate LXXXII, figs. 4, 5, two male filaments ; fig. 6, female plant. Pennsylvania, New York, Florida, and probably every State. OEDOGONIUM PUNCTATO-STEIATUM, D. By. Oogonia single, depressed-globose, manifestly splitting round in the middle, opening by a pore in the fissure ; oospore depressed-globose, nearly filling the oogonium ; male plant slightly more slender than the female ; spermogonia 3-7 celled, sperniatozoids single ; membrane of the vegeta- tive cells and of the oogonia spirally punctate. Diameter veg. cells, fern., 18-22 yw; 2-6 times longer. Diameter veg. cells, mas., 16-19 /<. Diameter oogon., 48-55 p. by 38-48 yu. Diameter oospor., 44-51 yu by 35-43 yw. Diameter sperm, cells, 16-18 yu by 6-10 yw. Only specimens hitherto identified in the United States, from Winter Park, Florida, 1885. Frequent there. Plate LXXXV, figs. 3, 4, 5, two female and a male plant. 2. — Oospor es ellipsoid or oval. OEDOGONIUM Boscn, (Le Cl. ) Wittr. Oogonia single or rarely twin, oblong-ellipsoidal, opening by a pore above the middle; oospore ellipsoidal, by no means filling the oogonium ; longitudinally costate ; male and female plants nearly the same thickness; spermogonia 3-6 celled ; sperniatozoids binate ; terminal cell slender and somewhat hyaline. Diameter veg. cells, 12-20 yu ; 4-6 times longer. Diameter oogon., 40-45 yw by 80-100 //. Diameter oospor. , 36-40 ^ by 60-65 /x Diameter sperm, cells, 13-14 yw by 6-9 yw. Pennsylvania, New York, New Jersey, etc. Plate LXXXII, figs. 11, male ; 12, 13, female plants. OEDOGONIUM LANDSBOROUGHI, (Hass.) Wittr. Oogonia single or twin, obovate, opening by a pore above the middle ; oospore obovate, usually filling the oogonium ; 92 FRESH-WATER ALG^ OF THE UNITED STATES. male plant slightly thinner than female ; spermogonia 5-25 celled ; spermatozoids binate, terminal cell obtuse. Diameter veg. cells, fern., 33-36 yu; 4-6 times longer. Diameter veg. cells, mas. , 21-33 yw. Diameter oogon., 63-75 /u by 105-120 /x Diameter oospor. , 59-70 yu by 75-102 yw. Diameter sperm, cells, 27-30 yw by 9-12 /x Syn. Vesiculifera LandsborougM, Hass. ; Oe. gemelliparum, Hantzsch. Pond, near Elmira, New York. Plate LXXXI, figs. 8-11, two female and two male plants. OEDOGONIUM RIVULARE, (Led. ) A. Br. Oogonia single or 2-7 seriate, obovate, opening by a pore above the middle; oospore obovate, rarely ellipsoidal or subglobose ; very much smaller than the cavity of the oogonium; the male somewhat smaller than the female plant ; spermogonia 3-9 celled ; spermatozoids binate. Diameter veg. cells, fern., 35-45 yw; 3-7 times longer. Diameter veg. cells, mas., 30-36 yw; 4 times longer. Diameter oogon., 70-85 yu by 130-160 yu. Diameter oospor., 55-65 yu by 65-100 yu. Diameter sperm, cells, 21-28 yu by 14-16 yw. Syn. Prolifera rivulare, Led. Florida, Iowa. Plate LXXXIII, figs. 1, 2, female and male plants. Var. MAJOR, Wolle. Oogonia single, or in series of 2-3, broadly elliptic or oval, opening by a pore above the middle ; oospore oval, nearly filling the oogonium. Diameter veg. cells, 55-70 yu ; 2-5 times longer. Diameter oogon., 90-100 yw by 130-150 yu. Diameter oospor. , 70-75 // by 120-125 yw. The largest of our Oedogoniums, unlike the typical form ; not in matured fruiting condition ; occurring frequently in waters of Florida. Seems nearest to Oe. rivutare. Plate LXXYI, figs. 7, 8 ; Plate LXXXIII, fig. 9, prob- ably belongs to the same variety. CEDOGONIUM. 93 SECTION III.— SPECIES OF WHICH THE ORGANS OF FRUCTIFICATION ARE IMPERFECTLY KNOWN. a. — Oospores globose or subglobose. OEDOGONIUM DELICATULUM, Kg. Oogonia single, subglobose, inflated, ends somewhat drawn out, or extended, oospore perfectly globose ; usually affixed by a discoid base. Diameter veg. cells, 5-6 // ; 3-4 times longer. Diameter oogon., 17-18 // by 20 ^. Diameter oospor. , 12-14 // by 12-14 p. Often parasitic on larger forms of Oedogonia. Plate LXXXI, figs. 12, 13. OEDOGONIUM MONILIFORME, Wittr. Oogonium single or 2-5 seriate, subglobose, or obovate- globose, opening by pore above the middle ; oospore globose or obovate-globose, nearly filling the oogonium, membrane of oospore thick and often indistinctly verrucose. Diameter veg. cells, 9-11 yw ; 3-5 times longer. Diameter oogon., 24-28 /* by 28-35 //. Stagnant waters, not frequent. Plate LXXXI, figs. 14, 15. OEDOGONIUM FONTICOLA, A. Br. Oogonium single, rarely twin, globose-obovate, opens by pore above the middle ; vegetative cells often very variable in length and in breadth in different parts of the same fila- ment ; usually a deep -green. Diameter veg. cells, 16-38 /* ; 12-15 yu long. Diameter oogon. , 36-40 JLI by 44-45 yw. Frequent in stagnant or sluggish waters, also in spring water. The largest form figured was found fringing a basin hewn in slate rock for cold spring water. Plate LXXV, figs. 4, 5, 6. OEDOGONIUM PRINCEPS, (Hass.) Wittr. Oogonia single, subobovate-globose, opening by a pore above the middle ; oospore globose, not quite filling the oogonium. 94 FRESH-WATER ALGJE OF THE UNITED STATES. Diameter veg. cells, 37-45 //; l}-2.} times longer. Diameter oogoii., 61-75 yw by 68-80 p. Diameter oospor., 58-66 yu by 60-65 yw. Minnesota, near Minneapolis. Plate LXXVIII, fig. 3. OEDOGONIUM LONDIENSE, Wittr. Monoecious ? oogoiiia single or twin, globose, cut round in the middle, opening by a pore seated in the fissure ; oospore globose, almost filling the oogoniuni ; spermogonia, or andro- sporangia, 1-2 celled, hypogynous. Diameter veg. cells, 10-15 yw; li-5 times longer. Diameter oogon. , 33-35 yu by 33-43 yw. Diameter oospor., 27-32 yu by 26-32 yw. Diameter sperm, cells, 26-27 yw by 27-29 yu. Plate LXXV, figs. 7, 8, fruiting filaments found in New Jersey. OEDOGONIUM HEXAGONUM, Kg. Oogonia almost globose, inclining to hexagonal ; oospore globose, rufous-brown not filling the oogoniuni ; terminal cell obtuse or sometimes setigerous. Diameter veg. cells, 11-13 yw 5 2-4 times longer. Diameter oogon. 24-25 yu by 26-28 yu. Diameter oospor. 16-18 by 16-18 yu. Syii. Vesiculifera hexagona, Hass. Occasionally intermingled with other species. Plate LXXXI, figs. 18, 19. b. — Oospores ellipsoid or oval. OEDOGONIUM GIGANTEUM, Kg. Oogonia single, somewhat tumid, cylindrical -obovate, opening by a pore above the middle; oospore cylindric- ellipsoid or broadly obovate, nearly filling the oogoniuni (sometimes flask-shaped, short-necked,) epispore delicately scrobiculate*; supporting cell somewhat swollen. Diameter veg. cells, 30-42 yu 5 2-4 times longer. Diameter oogon., 57-69 ju by 78-106 yw. Diameter oospor. , 54-65 yw by 75-103 yw. A form very nearly related to Oe. capilliforme, Kg., and may be a mere variety of that species. Plate LXXVI, figs. 4, 5, 6. BTJLBOCHAETE. 95 OEDOGONIUM GRANDE, Kg. Oogonia oval, elliptic, considerably longer than wide ; oospores oval, elliptic, filling the oogonia ; terminal cell obtuse. Diameter veg. cells, 25-30 ^. ; 3-5 times longer. Diameter oogon., 50-55 /< by 75-80 /*. Diameter oospor., 45-50 /* by 68-72 //. Meadow pools, Pennsylvania. Plate LXXVI, fig. 1, filament with oogonium, and two zoospores having passed out through a fissure in the side of cell, remaining attached. OEDOGONIUM PYRIFORME, Wittr. / Monoecious, oogonium single, pear-shaped ; spermogonia 2-3 celled, subepigyiious or hypogynous. Diameter veg. cells, 13-14 // ; 82—6 times longer. Diameter oogon. , 40-42 jn by 54-60 yu. Diameter oospor. , 35-36 /* by 45-48 //. Diameter sperm, cells, 10-12 ^ by 5-6 yu. Branchville, New Jersey. Plate LXXVII, figs. 11, 12, 13, filaments with oogonia and spermogonia. OEDOGONIUM LONGATUM, Kg. Oogonia single (often solitary, terminal) rarely 2-3 con- tinuous, ellipsoid, opening by an operculum, with a narrow fissure ; oospores globosely-ellipsoid, scarcely filling the oogonia ; terminal cell obtuse. Diameter veg. cells, 5-6 fji ; 2-3 times longer. Diameter oogon., 16-17 }*. by 21-24 jn. Diameter oospor., 15-16 yw by 17-19 //. Stagnant waters, far and near. Plate LXXY, fig. 3, four short filaments. Genus 11, BTJLBOCHAETE, Ag. Filamentous plants, much branched ; terminal articulations, and almost all others thickened upward and bearing at or near the apex a long, thin, hyaline seta, bulbous at the base ; cell membrane often punctate ; reproduction sexual as in Oedogonium; oogonia opening by a lateral pore above the middle. Nearly all of our species are dioecious. 96 FRESH-WATER ALGJE OF THE UNITED STATES. The following arrangement of our United States species is near in accord with Prof. Wittrock's suggestion. BULBOCHAETE. SECTION I.— OOGONIA GLOBOSE OR STJBGLOBOSE, PATENT. OOSPORES THE SAME FORM AND FILLING THE OOGONIA. DICECIOUS. A. — Dwarf males unicellular. B. elacMstandra, Wittr. B. — Dwarf males bicellular. a. —Basal cell of the dwarf males shorter than the spermogonia. B. intermedia, I). By. B. crenulata, Pringsh. B. polyandra, Cleve. B. setigera, (Roth.) Ag. B. Brebissonii, Kg. b. — Basal cell of the dwarf males longer than the spermogonia. B. gigantea, Pringsh. SECTION II. -OOGONIA ELLIPSOID OB SUBELLIPSOID. OOSPORES OF THE SAME FORM, FILLING THE OOGONIA ; EPISPORE LONGITUDINALLY COSTATE ; COSTJE MORE OR LESS CRENULATE. SUBSECTION I. — SPECIES MONOECIOUS. B. mirabilis, Wittr. B. nana, Wittr. SUBSECTION II. — SPECIES DICECIOUS. A. — Dissepiment of supporting cells obsolete. B. pigmaea, (Pringsh.) Wittr. B. — Dissepiment of supporting cells present. B. insigiiis, Pringsh. B. minor, A. Br. B. subsimplex, Wittr. B. repanda, Wittr. B. rectangularis, Wittr. B. rhadinospora, Wittr. BULBOCHAETE. 97 SECTION I.— OOGONIA GLOBOSE OR SUBGLOBOSE. A. — Dwarf males unicellular. BULBOCHAETE ELACHISTANDRA, Wittr. Oogonia globose, beneath the androsporangia; dissepi- ment of the supporting cell about the middle ; epispore smooth ; androsporangia above the oogonia, or scattered ; dwarf males very small, obovate, extending downward to a thin point, nearly straight, seated on, or near the oogonia. Diameter veg. cells, 15-20 yu; H- 2i- times longer. Diameter androsp., 12-14 yu by 10-12 yu. Diameter oogon. , 40-45 yu by 40-45 //. Plate LXXXYI, fig. 5. B. — Dwarf males Hcellular. a. — Basal part (stem or stipe} shorter than the spermogonia cells. BULBOCHAETE INTERMEDIA, D.By. Oogonia snbdepressedly globose, seated under the andro- sporangia ; dissepiment of the supporting cell in the middle ; epispore delicately crenulate (rarely smooth); androspor- angia 1-2 celled, epigynous, rarely scattered ; dwarf males seated on the oogonia, stems slightly curved. Diameter veg. cells, 16-19 yw ; I* -3 times longer. Diameter androsp., 13 yu by 10 yw. Diameter oogon., 40-48 yu by 31-40 /x Diameter dwarf males, 9-10 yw by 24-30 yw. ( 'ommon in ponds and sluggish waters ; varies considerably in diameter of filaments, length of cells, etc. Plate LXXXVI, figs. 1, 2, 3, three forms. BULBOCHAETE CEENULATA, Pringsh. * 7 O Oogonia depressedly globose, seated beneath terminal setae, rarely beneath androsporangia or vegetative cells. Dissepiment of supporting cell in the middle or slightly below it; epispore distinctly crenulate; androsporangia scattered, rarely epigynous ; dwarf males seated on or near the oogonia, stems nearly straight. Diameter veg. cells, 16-19 yw; 2-3^ times longer. Diameter androsp., 12 yw by 10 yw. Diameter oogon. , 45-48 yu by 35-38 yw. Diameter dwarf males, 9 yu by 26 yw. Pennsylvania, New Jersey and probably in every State. Plate LXXXVI, fig. 4. 98 FRESH-WATER ALG^ OF THE UNITED STATES. BULBOCHAETE POLYANDRA, Idio-androsporous ; oogonia somewhat depressedly globose, seated beneath a terminal seta or a vegetative cell ; dissepi- ment of supporting cell usually much above the middle ; epispore delicately crenulate or nearly smooth ; audrospor- angia 4-10 celled ; dwarf males seated on the oogonia, stem curved. Diameter veg. cells, 15-20 }JL ; 3-6 times longer. Diameter oogon. , 36-46 ju by 32-38 yw. Diameter androsp. cells, 13-14 // by 12-15 yw. Diameter dwarf males, 8-9 /* by 20-23 //. Culms, margins of lakes, Florida, often full of this species; did not identify it farther north. Plate LXXXIX, figs. 6, 7, female and male plants ; 8, 9, the androsp orangia. BULBOCHAETE SETIGERA, (Roth.) Ag. Oogonium depressedly subquadrangularly globose, seated beneath a terminal seta, or beneath an androsporangium ; membrane of the oogonium thickened after fertilization, dissepiment of the supporting cell a little above the middle or at the middle; epispore granulated; androsp or angi a scattered or epigynous, bicellular ; dwarf males seated upon or about the oogonia, stems straight. Diameter veg. cells, 25-28 // ; 2i-5 times longer. Diameter androsp., 18-20 /* by 14-18 yw. Diameter oogon. , 75-80 ^ by 60-65 //. Diameter dwarf males, 12-14 /* by 34-36 yw. Syn. B. Canbyii, Wood. Cannot find sufficient distinction in this form described in Wood's Contribution, p. 202, to separate it from the European B. setigem. It bears also a resemblance to B. iliSj Wittr. Not infrequent in New Jersey, Florida, South Carolina. A peculiar form probably of this species found in quantity fringing willow rootlets, sticks and the like in pond, at Hammonton, New Jersey, August, 1879. It was destitute of fruit ; no oogonia, instead the plants were numerously fur- nished with distinct, sessile, oval, pod-like cells dehiscing at the top, making a lid (operculum) which opens, and soon a zoospore escapes. BULBOCHAETE. 99 Plate LXXXVI, figs. 6 and 7 represent this form ; figs. 8-11, zoosporangia, and zoospores in different stages of exit. Plate LXXXIX, fig. 1, a specimen from New Jersey pine barrens ; figs. 2, 3, var. Canbyii, Wood. BULBOCHzVETE BREBISSONII, Kg. Oogonia obcordiforni-globose ; truncate below, erect, seated beneath terminal setae or androsporangia ; dissepiment of supporting cell low ; epispore delicately crennlate ; andro- sporangia 2-3 celled, scattered or epigynous ; dwarf males seated on the oogonium or more rarely near it ; stems straight, or nearly so. Diameter veg. cells, 17-20 ^ ; 3-42 times longer. Diameter oogon., 42-50 ju. by 37-45 /*. Diameter dwarf males, 10-12 /* by 28-33 /x A plant found in pond, Hammonton, New Jersey, is re- ferred, with some hesitation, to this European species; it is not strictly identical, but nearer it than any other species. Fresh specimens are desirable for more definite determina- tion. Plate LXXXVIII, fig. 1, a filament with oogonia, and dwarf males. b. — Basal cell of stem of dwarf males longer than the spermogonia. BULBOCHAETE GIGANTEA, Prillgsh. Idio-androsporous? oogonia rather depressed obcordate- globose, seated beneath terminal setae, rarely beneath vegetative cells ; dissepiment of supporting cell at or a little above the middle ; epispore verm cose ; dwarf males a little longer than the oogonium and seated upon it ; stem twice as long as the spermogonium, arcuate. Diameter veg. cells, 24-27 ^ ; 2-3 times longer. Diameter oogon., 62-66 ^ by 51-58 yu. Diameter dwarf male stem, 11-12 /( by 40-45 yu. Diameter sperm, cells, 13-14 ^ by 20-22 yw. Sluggish river water, Pennsylvania. Plate LXXXVII, fig. 1, branched filament with four oogonia and one dwarf male, 100 FRESH-WATER ALG^ OF THE UNITED STATES. SECTION II.— OOGONIA ELLIPSOID OR SUBELLIPSOID. OOSPORES OF SAME FORM AND FILLING THE OOGONIA ; EPISPORE LONGITUDINALLY COSTATE ; COST.E MORE OR LESS CRENULATE. SUBSECTION I.— MONOECIOUS. BULBOCHAETE MIRABILIS, Wittr. Oogonia ellipsoid or oblong-ellipsoid, patent or more rarely erect, seated beneath a terminal seta or vegetative cell (or aiidrosporangium) ; spermogonia 2-4 celled, erect, rarely patent, subepigynons or scattered. Horizontal division of vegetative cells not infrequent. Diameter veg. cells, 16-20 yw; li-lf times longer. Diameter oogon., 27-35 /* by 46-56 yw. Diameter sperm, cells, 10-12 /* by 7-9 /*. Have illustrated two forms (Plate LXXXVII, figs. 2, 3), which I hesitatingly refer to this species, the former from Minnetonka Lake, Minn., and from ponds, New Jersey; the other (fig. 3) occurs now and then in ponds, New Jersey, always sterile, hence perhaps valueless, but too distinct to be entirely rejected. BULBOCHAETE NANA, Wittr. Oogonia ellipsoid, erect or patent, seated beneath terminal setae or beneath vegetative cells ; spermogonia 1-2 celled, subepigynous or scattered. Diameter veg. cells, 12-15 yw; 1-1 J times longer. Diameter oogon. , 20-25 ^ by 33-36 //. Diameter sperm, cells, 8-9 yu by 6-9 yw. Frequent in pond waters, New Jersey and elsewhere. Our plant is equally near to B. Honile, Wittr., and B. nana, Wittr. Have united the two and adapted the diagnosis. Plate LXXXVII, fig. 6. SUBSECTION II. — DIOECIOUS. A. — Dissepiment of supporting cells obsolete. BULBOCHAETE PYGMAEA, (Pringsh.) Wittr. Oogonia ellipsoid, patent, seated beneath a terminal seta or beneath a vegetative cell ; in longitudinal section rather quadrangular ; androsporangia scattered ; dwarf males seated near the oogonia. Filaments often short and curved. BULBOCHAETE. 101 Diameter veg. cells, 12-15 yu ; less than diameter in length. Diameter oogon. , 23-25 yw by 34-40 yu. Diameter dwarf males, 11-12 yw by 15-18 yu, Diameter sperm, cells, 7-8 by 7-8 yw. Not rare. Plate LXXXVII, fig. 4. a condition not infrequent. Have not seen a typical plant. B. — Dissepiment of supporting cells present. BULBOCHAETE INSIGNIS, Pringsh. Oogonia ellipsoid, patent or erect, seated beneath the an- drosporangia or terminal setae ; epispore delicately trans- versely striate ; androsporangia epigynous or scattered ; dwarf males seated on or near the oogonia. Diameter veg. cells, 20-25 //; 2i-4J times longer. Diameter oogon. , 46-60 yw by 70-100 yu. Diameter androsp. cells, 16-20 yu by 20-25 yw. Diameter dwarf male (stem), 17-19 yu by 29-31 yw. Diameter sperm, cells, 10-11 yw by 7-8 yw. Hopatcong and other lakes, New Jersey. Syn. B. S£>m'oprotonema, a prothallus of a moss. G. DeBaryana, Bab., is a condition of Ckroolepus. Plate CVI, figs. 1, 5, 6, are forms of protonema ,; figs. 2, 3, magnified filaments of G. Sclerococcus ; fig. 4, natural size of thallus of the same, found on moist rocks, submerged stones in shallow water, and on old wood ; figs. 7, 8, a growth sometimes found in large patches on moist earth, or moist rocks, has much of the appearance of Cladophora ; the. diagonal divisions, or septae, of the larger stems separate it. It is a prothallus of B-ryum, a moss 5 figs. 9, 10, from the trunk of a tree in Florida, is probably a prothallus of a fern. CHROOLEPUS. 121 These forms have not a proper place here ; they are intro- duced merely as illustrations of the pseudo-genus, Gongrosira, and as aids to the novice. Genus 22, CHKOOLEPUS, Ag. Filaments irregularly branched, often so closely interwoven that the branches are scarcely discernible. Stems and primary branches of the same thickness ; cell contents of a reddish brown, golden yellow, or olive color, sometimes with a tendency to green ; zoospores about thirty -two in a cell, also of reddish brown or golden yellow color, provided with two ciliae. These little motile bodies are produced in certain cells set apart for the purpose, usually on the end of a filament, sometimes on the side, seldom in the middle of a filament ; when these cells are sufficiently matured the endochrome breaks up into minute parts, the future zoospores. Wille, of Sweden, made these bodies a special study and found that- they copulate freely. After a mo- tile life of a few hours they grow sluggish, sink in water, divide, and soon commence to form new filaments. Plate CXV, figs. 18, 19, represent the individual zoo- spores (under higher power than figs. 16, 17), then the first stage of copulation ; next, the cells uniting more closely and finally the two running together form a perfect sphere with one head and four ciliae ; figs. 20, 21, similar progressive stages. CHROOLEPUS AUREUS, (Linn. ) Kg. Golden red or orange ; threads either collected in small tufts, or spreading in a soft silky stratum; sometimes in- tricately and densely matted and expanded ; very much branched. Cells as long, or two or three times longer, than the diameter. Diameter of cells, 10-12 //. Diameter zoosporangia, about 20 yw. Syn. Conferva aurea, Dillw. ; Byssus aurea, Eng. Bot. ; Ceramium aureum, Hook ; TrentepoJilia aurea, Ag. Affects moist places, walls, rocks, old wood, etc. Plate CXV, figs. 1-4, filaments of fruiting plants : figs. 5, 6, 7, another form ; figs. 8-15, zoosporangia ; figs. 16, 21, zoospores escaping from the sporangia; figs. 18-21, zoo- spores, some swarming singly, others in first stages of copu- lation ; others, spherical, united, completely fertilized. 122 FRESH-WATER ALG^ OF THE UNITED STATES. Var. CORTICULUM, Wolle. In size and form very near the typical plant, not golden yellow, but yellowish green with a seeming tendency to yel- low ; on the bark of trees, sometimes in firm mats of 3-4 inches in extent. Trees, Southern Florida. Plate CXV, figs. 18-21 ; figs. 22-25, sporangial cells, var. corticulum. CHROOLEPUS IOLITHUS, (Linn.) Ag. Stratum thin, scarcely 2 mm thick, glaucous or dirty greenish when dry, sometimes reddish orange; threads and branches elongated, rather dichotomous, variously curved, ascending ; cells 13-3 times as long as their diameter ; in the upper portion of the branches reaching double that length. Diameter filaments, 25-40 IJL. Diameter zoosporangia, 50 yw. Syn. Byssus lolithm. Linn. ; Olivia violacea, Gray ; TrentepohUa lolithus, Wallr. ; also familiarly known on the Alps as Veilchenmoos and Vettchenstein, the stones overgrown with it, emitting, particularly when moistened, a strong fragrance, of violets. Moist rocks, White Mountains, N. H. CHROOLEPUS ODORATUS, (Lyngb.) Ag. Stratum thin, rather tonientose, rufous-tawny ; when dry cinereous, becoming greenish. Filaments and branches short, erect, parallel, flexuously curved, torulose ; cells equal or twice as long as broad. Diameter of filaments, 9-14 /.i. Have copied this diagnosis from Rabenhorst's Flora Al- f/anun. It does not describe the plants figured in all details ; they appear to be young plants, not fully developed. They occur on the bark of shade trees along the highways. Syn. Conferva odorata, Lyngb. Plate CXVI, fig. 6. CHROOLEPUS LICHENICOLUS, Ag. Stratum reddish orange ; filaments short and thin, greg- arious, often confluent ; when dry, of light yellow color ; branches variously and flexuously curved. Diameter of filaments 7-9 /* ; articulations 1-3 times longer ; cylindrical CLADOPHORA. 123 or sometimes tumid ; sporangia most frequently terminal, more rarely lateral, somewhat globose. Syn. Conferva Uchenicola, Eng. Bot. ; Chroolepus abietinum, Rab. On the bark of pine and other trees. Plate CXVI, figs. 7, 8, filaments with sporangia. CHROOLEPUS UMBRINUM, Kg. Stratum thin, somewhat crustaceous and pulvereus, dull or brighter red, fades with age. Filaments with short branches, torulose. Diameter of cells, 14-22 //, nearly glo- bose, or broadly elliptic. Bark of various trees, old wood, etc. The form figured is from Florida. Yar. QUERCINUM, Rab. Stratum thin, red or yellowish, pulvereus ; diameter about 16 yw. Bark of oak trees. Syn. Protoeoccus umbrinus, Kg.; Chroolepus irregular e, Kg., Pleu- rococcus seriatuSj Wood. Plate CXYI, figs. 1, 2, Southern form ; figs. 4, 5, Penusyl- vanian form. CHROOLEPUS MONILIFORME, Kg. Crustaceous, pulvereus ; when dry, ash color ; filaments decumbent, short. Diameter of cells, 20-25 //, oval, or ovate, about twice as long as wide. From rocks, Shawangunk Mountains, N. Y. Saw this form only twice ; it appeared distinct in size, in color, and form of cells. Plate CXY, figs. 30-33. Genus 23, CLADOPHORA. Filamentous, much branched; the ultimate branches much thinner than the primary. Cell membrane usually thick, cells longer than broad ; cell contents green, containing numerous starch grains. Propagation by zoogonidia which develop in large numbers in the cells and afterwards escape by a lateral or terminal opening ; they are furnished with two or four vibratile ciliae ; after a short motile life they come to rest and germinate without fecun- dation. 124 FRESH-WATER ALG^J OF THE UNITED STATES. The following arrangement from Rabenhorst's Flora Algarum, will be useful in their identification. FILAMENTS COLLECTED IN FLOATING MATS, MORE OR LESS LAXLY INTRICATE. A. — At first attached as tufts, afterwards floating as mats. a. — Cell contents not spirally disposed. Fruiting cells not terminal. 1. C. FRACTA, Kg. — Cell-membrane smooth, articulation more or less swollen. b. — Var. gossypina, Kg. c. — Var. horrida, Kg. d. — Var. rigidula, Kg. e. — Var. viadrina, Kg. C. OLIGOCLONA, Kg. j" Articulations not swollen, cylindrical, C. FLOTOWIANA, Kg. ( filaments long, sparsely branched. 3. C. CRISPATA, Kg. — Cell-membrane delicately plicate-striate. b. — Var. vitrea, Kg. c. — Var. brachyclados, Kg. B. — Tufts attached for the whole life. b. — Cell-contents vaguely disposed in lax spirals. fruiting cells terminal or subterminal. 4. C. CANALICULARIS, Kg. — Cell-membrane even ; branches con- nate at the base. 5. C. GLOMERATA, Kg. — Branches not connate at the base. b. — Var. mucosa, Kg. c. — Var. rivularis, Rab. d. — Var. simplicior, Rab. e. — Var. subsimplex, Rab. f. — Var. clavata, Wolle. g. — Var. pumila, Bail. 6. C. FLUITANS, Kg. — Filaments long, sparsely branched. 7. C. FLAVESCENS, Ag. — Cell-membrane plicate. 8. C. ^EGAGROPILA, Kg. — Filaments radiating from a common center, aggregated in a more or less spongy globe. 9. C. BRACHYSTELECHA, Rab. — Doubtful species. CLADOPHORA FRACTA, Kg. Filaments irregularly branched, in clusters or turfy masses of dark green color. Zoogonidia are developed in CL ADOPHOR A . 125 cells of the filaments, not terminal, usually more or less turgid. Cells cylindrical or more frequently somewhat swollen. Cell-membrane strong and smooth ; cell contents green, covering the inside of the walls. Diameter of stems, 50-120 /* ; 1-3 times as long. Diameter of branches, 15-40 // ; 3-6 times as long. The following are some of the varieties enumerated by Rabenhorst, which agree with forms found here. a. — Var. NORMALIS, Eab. Corresponding with the diagnosis. b. — Var. GOSSYPINA, Kg. Filaments long and thin, sparingly branched ; articula- tions 6-10 times longer than broad, often of silky appearance, loosely interwoven into large masses. Another form has the articulations much shorter. c.--Var. HORRID A, Kg. Much branched, branches in most part, secund, robust, articulations short, 13—2-3 diameters long. Often in masses in limestone springs. d. — Var. RIGIDULA, Kg. Green, but more frequently a dull brown or nearly black ; in comparison with the last (horrida) not quite so robust; articulations longer and more swollen. Floating masses in ponds of spring- water. e. — Var. VIADRINA, Kg. Filaments elongated, numerously branched ; cells cylin- drical or somewhat swollen, densely interwoven ; forms largely expanded masses, which when dried have the appearance of a skin or very coarse paper, 2-4 mm in thick- ness. Frequent in pools of stagnant or sluggish, brackish water. Plate CVII, figs. 1, 2, filament var. normdle; figs. 3, 4, escape of zoogonidia. Plate CVII, figs. 5, 6, filament var. gossypina. Plate CVIII, fig. 3, filament var. horrida. Plate CVIII, figs. 4, 5, filament var. rigidula. Plate CIX, figs. 1, 2, filament var. viadrina-, fig. 3 illustrates how a filament out of the water, on moist ground, seeks to retain life by throwing out a sort of rootlets. 126 FRESH-WATER ALG^E OF THE UNITED STATES. CLADOPHORA OLIGOCLONA, Kg. Filaments sparingly branched forming pale or dull green mats ; primary branches somewhat dichotomous ; secondary branches often long with short one-celled branchlets ; articu- lations cylindrical, of primary branches 2-6 times as long as broad ; of secondary branches 4-10 times as long. Diameter of cells of stems, 40-55 yu. Diameter of branches, 28-40 /*. Stagnant waters. Plate CVIII, figs. 1, 2, three short sections of filaments. CLADOPHORA FLOTOWIANA, Kg. Forms loosely entangled mats ; branches remote dichoto- niose, thin, very long, nearly simple, about 15 // diameter ; frequently at joints, short papilliform, one-celled branchlets. Stagnant pond waters. Plate CYII, figs. 7, 8, parts of filaments. Very near the preceding (oligocfona), perhaps the same ; Kirchiier has united the two as C. oligoclona. CLADOPHORA CRISP ATA, Kg. Filaments sparingly branched below, more fully toward the upper ends, insertion, at least of the lower branches, apical 5 cells cylindrical, membrane rather thin, often deli- cately plicate- striate ; cell contents in part disposed in a lax spiral manner ; not observed in older filaments. Diameter of lower cells, 40-75 yu. Diameter of branches, 25-30 //. Frequent in large floating masses in ponds. Var. VITREA, Kg. Light green or colorless ; irregularly branched ; cells 6-20 times as long as wide. Yar. BRACHYCLADOS, Kg. Pale green, laxly interwoven ; dichotoniously branched, ultimate branches subulate, patent, mostly unicellular ; cells 3-6 times longer than broad. Plate CIX, figs. 4-6. C. crispata, var. vitrea; figs. 7-10, var. brachydados. CLADOPHORA CANALICTJLARIS, Kg. Dichotomously or trichotomonsly branched 5 branches connate at the base, often fasciculately branched above as CLADOPHORA. 127 C. glomerate. Fructiferous cells terminal. Cell -membrane often thick ; cells cylindrical, 5-8 times longer than broad ; those of the branches rather shorter. Contents of cells arranged somewhat lax-spirally. Diameter of stems, 80-110 //. Diameter of branches, 35-50 yw. Rapid waters, Niagara, Portage, N. Y. Plate CXI, figs. 1, 2, specimen from Portage. CLADOPHORA GLOMERATA, Kg. Branches and branchlets of the second and third order fasciculate or penicellate. The cell contents of the larger cells applied in a net-like, or somewhat spiral manner, to the interior of the walls. Walls of cells externally smooth. The zoospores, (zoogonidia) always escape from terminal cells ; lower cells are sterile. Diameter of cells of stems, 60-100 yu. Diameter of cells of branches, 30-50 ju. A variable species ; the lines between different varieties are difficult to determine; the following may be enumerated. a. — Var. GENUINA, Kirch. Bright vegetative green, 6-12 inches long, much branched ; the ultimate branchlets more or less penicellate ; cell -mem- brane firm ; articulations of the stems generally about 6-7, and of the branches, 3-6 times longer than broad. From rapid streams. b. — Var. MUCOSA, Kg. Bright darker green, somewhat mucous, not as long as (a), lighter structure and thinner membrane. Mountain streams. c. — Var. RIVULARIS. Eab. / 2-4 inches long, branches somewhat scattered, ultimate cells penicellate fascicles. Frequent on river stones, in character near (a) but much shorter. d. — Var. SIMPLICIOR, Eab. Dull green, sparingly branched ; the penicellate fascicles very thin. e. — Var. STJBSIMPLEX, Eab. Very sparingly branched, devoid of penicellate fascicles. 9 128 FRESH-WATER ALG^E OF THE UNITED STATES. /. — Var. CLAVATA, Wolle. Bright vegetative green, sparingly branched, articulations with ends usually rounded and swollen ; below about 100 /*, smaller branches 50 j* diameter ; 5-8 times as long as broad. Mountain stream, Colorado. g. — Var. PUMILA, Bail. Barely one inch long, corymbose-fasciculate, erect ; dark green (pale subglaucous green, Kab. ) membrane firm. In clusters on stones or wood at water-falls, frequent. Plate CX, figs. 1, 2, C. glomerata, an ultimate branch of a robust form from Florida, (magnified 125 diameters,) zoo gonidia escaping; fig. 3, fasciculate branch of (g} var. pumila; figs. 4-8, apparently young growths from nostoc- like cysts found with (g) var. pumila. Plate CXI, figs. 1, 2, parts of filaments of C. canalicularis, Genesee Eiver; figs. 3, 4, (/) var. clavata.; fig. 5, (c) var. rivularis. Plate CXII, figs. 1, 2, 3, 4, (d) var. simplicior. Diameter of cells from base to apices, 125-25-15 ,w. Ponds, near New York City. CLADOPHORA FLUITANS, Kg. Filaments elongated, forms clusters one to two feet and upward in length, rather sparingly branched, dark green color. Articulations of the branches proportionately longer than those of the stems. Primary branches furnished with short, 2-6 celled, erect branchlets; cells cylindrical, with thick membrane; those of stems 11-2 times, and of the branches 3-12 times longer than broad ; otherwise like C. glomerate. Diameter of stems, 120-135 ^. Diameter of branches, 43-86 yw. Found in Watkin's Glen, three feet long. CLADOPHORA FLAYESCENS, Ag. Pale yellowish, about six inches long, very much branched, fasciculate in a plumose manner, branches patent or in- curved ; cell membrane often distinctly plicate ; cell contents distributed in a reticulate manner. Diameter of branches, 70-80 ^ ; articulations 6-12 times as long as wide. CLADOPHORA. 129 Syn. Clad, glomerata, var. flavescens, Eab. ; Clad, flavida, Kg. ; Conferva flavescens, Dillw., and others. New Jersey shores, pools of brackish water. CLADOPHORA AEGAGROPILA, (Linn.) Kg. Dark green, threads rigid, very much branched, radiating from a common center, at length agglomerated into a more / or less dense spongy globe. Earnula erect, often quite obtuse, articulations sometimes incrassated upwards; cell- membrane now and then thickened. Diameter of filaments, 25-50 n ; cells 1-1 £ times longer than broad. Syn. Conferva aegagropila, Linn. ; Conferva globosa, Phil. Trans. Roy. Soc. 5 Cladophora glomerata, Hass. Occurs here in limestone springs, attached to walls, and to stones in streams of cold water, in small subspherical clusters, composed of radiating filaments irregularly and variously branched, every branched filament differing from the other ; diameter of clusters 6-8 mm. Not unlike some of the smaller forms which occur frequently in northern Europe; but our plants appear like small depauperated forms, when compared with some of the large specimens in my herbarium, from Sweden, compact, globular bodies measuring 3-4 inches in diameter. Plate CXII, fig. 5. CLADOPHORA BRACHYSTELECHA, Eab. This form recognized by Dr. Wood, as one of our Clado- phora species, does evidently not belong here. It is one of the forms referred to under Gongrosira, a pseudo-germs. It is nothing more nor less than a prothallus, & protonema of some moss. Subsection C. — PITHOPHORIN^:. (Family PUhophoracece,, Wittr.1) This new division is described by the author (Wittrock), as " Chlorophyliferous Cladophora-like Fresh-water Algae, consist- ing of cells formed by bipartitioii of the terminal cell. The thallus has two distinct parts, viz : 1st, the cauloid part, devel- oped from the germinated spore upward, propagative, and almost 1 Erroneously entered in the system of arrangement adopted for this work, page 48. 130 FRESH-WATER ALGLE OF THE UNITED STATES. always branched ; the branches placed a little below the top of their supporting cells ; 2d, the rhizoid part developed, from the germinating spore downward, almost always sterile and branch- less, commonly unicellular. Spores neutral, quiescent (agamo- hypnospores), generally cask-shaped, single, formed by division into two of the cauloid cells, of the chlorophyl -filled and com- monly widened upper parts of these cells ; in germinating, as a rule, dividing into two cells, the one giving rise to the cauloid and the other to the rhizoid part of the thallus. Prof. V. B. Wittrock has prepared an elaborate Mono- graph, " On the Development and Systematic Arrangement of the Pithophoracete ; a New Order of Algce." It is fully illustrated; contains 80 pp. For full and interesting details consult the Monograph. Genus 24, PITHOPHORA, Wittr. Character and features the same as of the subsection given above. PITHOPHORA OEDOGONIA, (Mont.) Wittr. Var. VAUCHERIOIDES, (Wolle) Wittr. The stem, or cauloid part of the thallus in fertile speci- mens on an average 65 ^ thick, with partly solitary, partly opposite branches of two and more, rarely three degrees ; sporal branches rather common ; spores usually single, but sometimes twin, partly inclosed, partly terminal; the in- closed spores cask-shaped, on an average 95 ^ thick and 220 /* long ; the terminal spores cask-shaped, on an average 80 /* thick and 220 ^ long, with the upper end conical, apex rounded. The type of this species was collected in Guiana, and all of the species of this genus were supposed to be tropical plants. The variety originally found in a sterile state, had the branching characteristics of a Cladophora, and the long unicellular divisions of a Vaucheria, hence the name. Later gatherings were full of cask-shaped spores, and changed the generic position of the plant. It was found in successive years in a small pond, here, Bethlehem, Pennsylvania, and in three localities within a circuit often miles around Plain- field, New Jersey. It is a somewhat near approach to P. Oedogonia, but differs in size, being slightly more slender, and in minor details. PITHOPHORA. 131 Syn. Cladopliora Vauclierioides, Wolle, 1878. Plate CXIII, figs. 1, 2, 3, parts of three fertile stems with inclosed and terminal spores ; figs. 4, 5, sporal branches ; figs. 6, 7, two parts of filaments as first found, in an im- mature condition. PITHOPHORA .EQUALIS, Wittr. Yar. FLORIDENSE, Wolle. Principal filament of the cauloid part of the thallus in fertile specimens on an average 175 /* thick (Wittr. 102), more or less swollen, either with branches of two degrees, (those of the first, few and long, those of the second, short) or with branches of only one degree, numerous and short ; spores single or more rarely double, inclosed in the prin- cipal filaments or in the branches of the first degree ; more seldom terminal ; the inclosed spores cask-shaped with somewhat rounded ends, on an average 120 /* (Wittr. Ill) thick and 215 ^ (Wittr. 250) long ; the terminal spores cask- shaped, with upper end conical and the apex somewhat rounded ; on an average 90 ^ thick, and 270 /* long. Collected by J. D. Smith, Florida, 1878. A character peculiar to this variety is noticed in the swol- len cells and in their larger diameter. Plate CXIY, figs. 1, 2, two fragments of fertile filaments ; figs. 3, 4, 5, three spores, simple and branched. PITHOPHORA KEWENSIS, Wittr. Principal filament of the cauloid part of the thallus in fertile specimens on an average 59 /^ thick, with solitary branches of only one degree, or rarely of two degrees ; spores single, partly inclosed, partly terminal ; the inclosed spores cask-shaped, but more elongated ; on an average 81 ^ thick and 205 // long ; the terminal spores cask-shaped, with upper end conical ; apex somewhat rounded, on an average 88 // thick and 219 ^ long ; the rhizoid part of the thallus as a rule unicellular. Found in Florida (March '85) on the planked sides of the outlet of the large sulphur springs at Green Cove Spring, growing just above the water line, a plant, in caespitose clusters one-half to one inch long; it has the size and the features of this Pithophora, but being sterile at the time of collection could not be identified with certainty. The diag- nosis above is from Wittrock's Monograph. 132 FRESH-WATER ALG^E OF THE UNITED STATES. Plate CXIV, figs. 6, 7, parts of two sterile filaments from living plants; figs. 8, 9, part of a fertile filament from Wittrock's Monograph. Subsection D. — ULOTRICHIN^:. Simple, unbranched filaments. Earely with short, lateral, rhizome-like branchlets ; zoospores of two kinds ; maerozoo- spores with four ciliae which do not copulate ; microzoospores with two ciliae of which eight or more are developed in a cell ; these may copulate, but without it they propagate the species vegetatively. Two microzoospores copulating produce a fertil- ized macrozoospore, which gradually develops a plant. Besting spores have not been observed. Kirch ner remarks, "filaments of plants of this section often divide, or break up irregularly; the chlorophylous granules of the contents enlarge, the cell walls break and decay and then the cell contents are dispersed and often pro- duce large colonies of spherical unicellular forms similar to Palmetto, or Protococcus. Inasmuch as the UtotricMnce forms develop from macro- zoospores and from microzoospores they are not always quite uniform in size or appearance. Some of the species enumerated below are of questionable value. Genus HOEMISCIA, (Fr.) Aresch. (Hormotrichum, Kg. Hormospora, Breb.) Three names which have been applied, and which con- tinue in use by some algologists, to represent a class of plants embracing a number of forms more or less nearly allied, possessing an outer investment of colorless mucus. Cienkowski and other modern observers consider them mere stages of growth, or perhaps rather, stages of decay. In illustration of some of the differentiations common to some of the Ulotrichinae compare some of the following references. Plate CXX, figs. 21-30 ; Conferva floccosa, first the vegeta- tive condition (figs. 21-25) ; next, may be termed a sporan- gial condition (figs. 26-27 ) and lastly (figs. 29-30 ) a true Hormistidj or Hormospom form. These and intermediate conditions are often traceable in the same plant. Turning to Plate CXXI, figs. 6, 7, and 10, 11, we have Conferva vul- ULOTHRIX. 133 garis ; with this species there often occur such filaments as figs. 14-17. First specimens seen were a puzzle to me and suggested names for new species of Hormospora, but repeated observations removed all doubt concerning the unity of the species ; these are not stages of development, but different forms approaching decay. Plate CXXIV, figs. 10-16, are parts of filaments of similar character, green cells dividing not only in one, but some- times in two directions. Figs. 17-20, a very distinct form, purplish red, or reddish brown, vely gelatinous ; found in quantity sufficient for mounting nearly two hundred cards ; in pool, Bethlehem, Pennsylvania. Many of the cells elongate laterally as in an early stage of growth, others divide transversely making short, lateral series. Unlike any known form ; and as all the filaments are apparently of nearly the same age, it was impossible to trace a positive relationship to either Ulothrix or Conferva, but there is little doubt they are merely a condition of one or the other. The plant in its present condition has the appearance of a small form of Bangia, but can not reconcile it to that genus. Diameter of gelatinous sheath, 15-17 ^ ; of cells, 7-8 /*. Figs. 21-23, same plate, yet another Hormiscia-likQ form, also red, or reddish brown, found on damp forest ground in Vermont. The cells primarily green, then yellow, then reddish brown ; evidently not a vegetative condition, or a normal form, but what it really may be, remains for future observers to determine ; perhaps merely a Zygnema. Diameter of sheaths, 25-30 //. Diameter of cells, 15-17 yw. Genus 25, ULOTHBIX, Kg. Filaments simple, articulate; articulations short, more fre- quently shorter than longer than the diameter ; cell membrane thin, often very thin, very rarely lamellose. Cell contents green, effused, or parietal, inclosing an amylaceous granule. Propagation by macro- and microzoospores. Copulation of the latter has been observed in U. zonata ; both are set free by the breaking of the walls of the mother cell. ULOTHRIX ZONATA, (W. and M.) Aresch. Eather bright green, mucous, from 2-3 inches to two feet in length , in vegetative state always attached ; sterile cells 134 FRESH- WATER ALGJ3 OF THE UNITED STATES. equal, or half as long as wide ; fructiferous cells usually a little longer than broad, slightly constricted at the joints. Diameter of filaments, 14-40 u. • Diameter of macrozoospores, 12-18 yu. Diameter of microzoospores, 4-7 //. In vegetative state of bright green color, affecting cold and rapid waters, firmly attached to stones, two to six inches long. Foreign authors describe it as found in floating, inter- woven masses. As such have not seen it. The largest growth and greatest quantity occurred later in the season, in sluggish and warmer water; had a dull yellowish green, faded color; it was attached to stones in the bottom, ascend- ing to the surface, one to two feet long. Syn. Hormiscia zonata, Aresch. ; Lyngbya zonata, Hass. ; Conferva zonata, Ag. Syst. ; Conferva lubrica, Dillw. Plate CXVII, figs. 1, 2, 3, filaments in ordinary vegetative condition ; fig. 4, part of a filament with one macrozoospore in each cell ; fig. 5, one escaping, and two free macrozoo- spores with four ciliae ; fig. 6, macrozoospores, one at rest germinating, and three having already developed a number of cells ; fig. 10, cells with ripe microzoospores, some in cells, others escaped ; fig. 11, microzoospores passing out of cells, in a cyst ; fig. 12, the same separated and at rest ; figs. 13, 14, part of a filament with microzoospores germinating in the cells, without having copulated ; figs. 15, 16, resting zygospores, the result of two macrozoospores conjugating; the three in different stages ; figs. 17-19, microzoospores con- jugating ; two fertilized. ULOTHRIX .EQUALIS, Kg. Filaments yellowish green, articulations as long or some- what longer than the diameter, (12-14 yu), not constricted at the septae ; cell-membrane rather thick. Attached to plants in shallow river waters. Very near if not identical with U. Juergensii, Kg. Plate CXVIII, figs. 3, 4, 5. ULOTHRIX TENUIS, Kg. Dark green, attached ; from half to two or three inches long, mucous, cells equal, to two, to four times shorter than the diameter ; cell-membrane thin, homogeneous. Diameter of filaments, 17-25 yw, Plate CXVIII, figs. 1, 2. ULOTHRIX. 135 Attached to stones in streamlets. A form not infrequent, but am not convinced that it may not be a young condition of U. zonata. ULOTHRIX SPECIOSA, Carm. Filaments robust, soft, straight when young, becoming curled at maturity, 2-4 inches long, growing in flowing or spreading tufts, attached to rocks ; cells about half the length of the diameter, at first nearly filled with chlorophyl which condenses into oblong, or nearly spherical, macrozoospores which then escape. Diameter of filaments including the gelatinous investment, 38-50 yw ; cells, 25-28 ju. Syn. Hormotrichum speciosum, Crouan. ; Lyngbya speciosa, Carm. ; Ulothrix flacca, Thur. Brackish and fresh-water. Plate CXVII, figs. 23-25, parts of filaments in ordinary condition ; fig. 26, partly empty cells from which the macro- zoospores escaped. Hormotrichum ( Ulothrix) Carniichaeliij Harv. , is very nearly allied to this species. ULOTHRIX YOUNGANUM, Dillw. Filaments of a bright green color, 1-3 inches long, erect, straight or curved, slightly gelatinous ; cells varying in length from nearly twice as long as wide, to one-half or one- third of the diameter. Filaments of irregular size, from 20-30 IJL in diameter. Smaller than the preceding. Syn. Conferva Youngana, Dillw. ; Hormotrichum Youngeanum, Kg. ; Ulothrix isogona, Thur. Plate CXVII, figs. 20-22, parts of a younger filament and two parts of older plants, having undergone two or three divisions of cells. From submarine waters, Massachusetts. ULOTHRIX SUBTILIS, Kg. Denizens of fresh -water, bright or paler green ; cells usually as long, to twice as long as wide. The following have been arranged as varieties of this species : a. — typica, Kirch. Cells, 5-6 ^ diameters ; as long or slightly longer, b. — subtilissima, Rab. Cells, 44-47 jn diameter ; 1-2 times as long, rarely 3-4 times longer. 136 FRESH-WATER ALG.E OF THE UNITED STATES. c. — variaMliSj Kg. Pale green, cells as long or a little longer, rarely twice as long as wide. Diameter, 5.5-7 yw. d. — stagnor-unij Bab. Dirty green, in soft, closely inter woven, floating masses ; cells as long or somewhat longer than broad ; membrane very thin. e. — tenerrima, Kg. Light green, or dull yellow, mucous; separated from var. C. by the brighter green cell contents ; cells quadrangular. f. — thermarum, Wartm. Articulations one to three diameters, filaments long, tenacious, affects warm water; flumes of waste water from steam engines and the like. Plate CXVIII, figs. 9, 10, the typical form; figs. 22-26, an unusual form, found attached to the wooden sides of a trout pond ; many of the cells swollen to double and some- times nearly triple the diameter of the filaments. For something similar see V. varia ; figs. 27, 28, U. flaccida ; figs. 11, 12, filament of var. subtilissima ] figs. 13, 14, var. stag- norum-, figs. 15, 16, var. va/riabUis] figs. 17, 17, var. tener- rima] figs. 18, 19, var. thermarum. ULOTHRIX RIVTJLARIS, Kg. * Light green, often constricted at joints; rather crisp; cells equal or half as long as wide ; diameter 9-10 ^ ; mem- brane rather firm. Usually found attached to grasses and plants near shores of rivers. Plate CXVIII, figs. 6, 7, 8, parts of three filaments. Var. cataracta, Wolle. Forming bright yellowish green tufts on small grassy water-falls, furnished with branchlets more or less hooked, serving as tendrils to hold their position in the rapid Avaters. Diameter of filament, 10-12 ^ ; articulations one to two times as long as wide. Plate CXVIII, figs. 29-33. ULOTHRIX COMPACTA, Kg. Yellowish green, mucous ; cells shorter than the diameter, which ranges from fe-7.5 //. Quiet waters. Plate CXVIII, figs. 20-21, parts of filaments. ULOTHRIX. 1 37 ULOTHRIX OSCILLARINA, Kg. Beautiful green, mucous ; diameter of articulations, 10- 12 yw, length one-half or one-third as much ; membrane thin, colorless. From lake, Wisconsin. Syn. Conferva oscittatoroides, Ag. Plate CXYIII, figs. 34-36. The similarity of character between this form, of which we received but few specimens, and such as are represented Plate CXXI, figs. 16, 17, and Plate CXXIV, figs. 11, 13, 15, 16, does not leave the position given to this plant without question of doubt. ULOTHRIX MURALIS, (Ag.) Kg. Filaments somewhat rigid, thickish, tortuous, very long, interwoven in a bright, grass green stratum ; almuli strongly defined (Harv.). Kuetzing found this plant often furnished with braiichlets and called it U. radicans. Diameter of fila- ments 7-9 ju. Articulations equal, to £ or £ as long as wide. Found on walls, shaded rocks or in flowing waters. Har- vey reports it from pools of fresh water, Whalefish Islands, Davis Straits. , Syn. Conferva velutina, Bory; C. muralis, Dillw. ; Oscillaria pari- etina, Yauch. ; 0. muralis, Ag. Terrestial forms, on shaded and moist earth ; Hormidium, Kg. ULOTHRIX (Hormidium) FLACCID A, Kg. Articulations equal, or twice as long as the diameter, membrane very thin, colorless ; filaments fragile. Cell con- tents usually on one side of the walls, hemispherically con- tracted. Diameter of filaments, 7-9.5 //. On exposed river stones, old straw, etc. Plate CXVIII, figs. 27, 28, represents this species as well as U. subtilis. ULOTHRIX (Hormidium) NITENS, Menegh. Filaments loosely or densely interwoven, dark green, sometimes forming a somewhat membranaceous, shining stratum. Diameter of cells 6-7 /*, as long as wide, or slightly longer. 138 FRESH-WATER ALG^E OF THE UNITED STATES. Damp walls ; shaded brick pavements, particularly abun- dant late in the season in cold, wet weather. Have gathered it in fine condition covered with snow and ice. Develops from cells known as Protococcus viridis. Plate CXIX, figs. 1, 2, germinating spores and young filaments. ULOTHRIX (Hormidium) VARIA, Kg. Yellowish green, filaments somewhat variable in thickness, averaging about 7 yw. Cells as long as wide or a little longer or shorter. Forms thin strata on moist clay soil ; found it also in large pieces, several feet in extent, on moist sandy soil. Fila- ments have here and there series of larger sporangium-like cells. Plate CXIX, figs. 3-7, simple filaments, and two with series sporangia, (?) ULOTHRIX (Hormidium) PARIETINA, (Vauch.) Kg. Bright yellowish green, flexuous and interwoven ; cells half as long as broad ; cell membrane thin, hyaline, homo- geneous. Diameter of filaments, 10-16 yw. Syn. Hormidium parietinum, Kg.; Oscillatoria parietina, Vauch. Shaded ground, at the base of trees, etc. Plate CXIX, figs. 8-10, young forms developing from spores, (Protococcus cells,) which usually abound with the filaments. Figs. 11-15, parts of filaments. ULOTHRIX (Hormidium) LENORMANDI, Kg. Bather dark green, mucous, attains a length of four inches, floating. Diameter of filaments, 17-25 /x, articula- tion one, to one-fourth diameter long; membrane rather firm, often distinctly lamellate, usually constricted at the joints. Collected by C. G. Pringle, Beam Lake, Canada. Plate CXIX, figs. 19, 20. Have quoted this diagnosis from Eabenhorst's Flora Alga- rum. It describes parts of the plant satisfactorily, but there is a feature not noticed ; the filaments divide repeatedly longitudinally. The specimen illustrated shows how a SCHIZOGONIUM. 139 filament of one row of cells may be changed to a filament of more rows ; in the mass some had two, some four, some eight rows of cells. Comparing with good specimens of European Prasiola crispa, as contained in Wittr. and Nord.'s Algae Exsiccatae, No. 47, filaments with a single row of cells occur which are in perfect harmony with mine ; these divide longitudinally, producing threads with two rows of cells, of four, of eight and so on until a leaf-like frond is produced- the matured Prasiola. Having had no opportunity to examine specimens of other collections, the question may reasonably be asked, is not the plant an undeveloped form of Prasiola, rather than an Ulothrix ? There is some analogy between this form and Schizogonium, but this is an air (exposed rock) plant, mine a water plant. Genus 26, SCHIZOGONIUM, Kg. * Filaments as in Ulothrix, more or less laterally connate, (dupli- cate or triplicate) or by cellular division in two directions form- ing narrow flat bands which are somewhat crispate. The relation between Schizogonmm, Ulothrix, and Prasiola is close and in some stages of development they do not admit of separation. As a rule UlotJirix is composed of simple filaments, with one row of cells ; Schizogonium has two or more filaments connate ; and Prasiola is frondose. The opinion has been ex- pressed that Ulotlirix is the young stage of growth ; Schizogonium a more advanced condition with collateral segmentation, and Prasiola the adult stage. However appearances may sometimes favor such opinion, am not yet convinced, nor ready to accept. SCHIZOGONIUM MURALE, Kg. Dark green, forming a broadly expanded, soft, velvety stratum ; threads sometimes free, sometimes two or three laterally united 5 cells 2-4 times shorter than the diameter, pectinate, often crowded, sometimes interrupted ; cell-mem- brane rather thick, colorless, slightly undulate and con- stricted. Diameter of filaments, 15-18 //. Moist cliffs, Colorado; the only good specimens hitherto observed. Plate CXIX, figs. 16-18. 140 FRESH-WATER ALG^ OF THE UNITED STATES. Genus 27, CONFERVA, Lk., including MICROSPORA, Thur. Filaments articulate, simple, like Ulothrix ; the two separated with difficulty in sterile state. Cell walls more robust, cells as a rule, longer, often swollen, and cell contents granular. Propagation by zoogonidia ; copulation has not been observed ; microzoospores are produced by the division of the cell con- tents; very numerous, small, ovate elliptical, cuspidate and colorless at one end, furnished with two, or rarely three or four ciliae, escaping by small pores, or ruptures of the cells. All denizens of the water. CONFERVA AMOENA, Kg. Cheerful yellowish green ; cells primarily two diameters in length ; after division equal. Cell membrane firm, often finely striate. Filaments frequently three feet or more in length, tenacious. Diameter of cells, 20-25 )J. ; the largest of our Confervae. Not frequent, but in quantity where it does occur. Stream- lets of spring waters. Plate £XXI, figs. 1, 2, 3, normal vegetative condition in different stages of cell division ; fig. 4, older cells in state of dissolution, separating and distributing the cell contents -the niicrogonidia ; fig. 5, microgonidia seen under much higher power. CONFERVA FLOCCOSA, Ag. Cells more or less swollen, twice, or nearly twice as long as wide ; variable in thickness. Diameter, 14-18 }JL. Syn. Microspora floccosa, Thuret; Lyngbya floccosa, Hass. ; Conferva fugacissima, Dillw. A common form. Plate CXX, figs. 21, 22, 24, ordinary condition previous to division of cells ; figs. 23, 25, after division of cells ; figs. 26, 27, cells of parts of filaments globular, formed into extraordinary sporangial cells; figs. 28, 29, filaments in a state of dissolution, membrane soft, mucous; cells green, assume the form of macrospores ; farther development has not been observed. Compare, Hormiscia, page 132. CONFERVA UTRICULOSA, Kg. Green or yellowish brown in soft mats ; cells before divi- sion often six times longer than the diameter, distinctly con- CONFERVA. 141 stricted at the joints. After division only one-half or one- third as long. Diameter, 16-17yw. Syn. Conferva ventricosa, Kg. Pools of stagnant water. Plate CXX, figs. 14-16, filaments in ordinary condition before cell division. CONFERVA FONTINALIS, Berk. Bright green, attached ; articulation 6-10 times as long as the diameter, slightly swollen, or moderately constricted at the joints; starch grannies single, scattered or seriate; cell membrane rather thick, homogeneous. Diameter of filaments, 15-18 yw. Hitherto only from fresh water ponds and lakes, Florida. Plate CXX, figs. 17-20, a usual condition. CONFERVA FUGACISSIMA, Eoth. Bather pale or yellowish green ; cells 4-5 times longer than broad, before division ; and 2-2 2 times as long after divi- sion ; not constricted at the joints. Often in large masses; filaments three or more feet in length, rather tenacious. Diameter of filaments, 10-12 yu. Quite fresh waters, Florida and northward. Plate CXX, figs. 31-33. Var. SALINA, Wolle. Another very common form from Florida, in brackish waters ; is similar in its growth, and features, rather darker green, somewhat thicker, diameter, 12-14 //, cells average 2-3 diameters, appears nearly related to the typical form, hence recognize it as a variety. * CONFERVA AFFINIS, Kg. Pale or yellowish green. Cells prior to division often seven times as long as the diameter, later three to four times as long ; slightly constricted at joints ; cell walls rather in- distinctly striate. Diameter of filaments, 6-11 //. Syn. Conferva subtilis, Kg. Plate CXX, figs. 11-13. Stagnant and sluggish water. 142 FRESH-WATER ALG^S OF THE UNITED STATES. CONFERVA FUNKII, Kg. Pale or light yellowish green, later of a faded aspect. Cells prior to division about four times as long as wide, later twice as long. Diameter of filaments, 6-8 ^. From stagnant waters, Colorado. Plate CXX, figs. 9, 10. CONFERVA VULGARIS, Eab. Bright green, articulations more or less swollen, 2-3 J times as long as wide ; cell contents usually very granular ; cell membrane firm. Diameter of filaments, 10-12 /*. Var. FARLOWII, Wolle. Cells 2-3 times as long as wide. Diameter of filaments, 7-9 yw. Syn. Conferva bombycina inaequcdis, Kg. ; Microspora bombycina, Thuret; Microspora vulgaris, Eab. Very common in pools, ditches, trenches of running waters, outlet of springs, etc. Plate CXXI, figs. 6, 7, the type form; figs. 10, 11, the variety ; fig. 12, microgonidia escaping ; fig. 13, young developing plants. CONFERVA BOMBYCINA, Ag. Yellowish or darker green, soft, silky ; articulations oblong- cylindrical, slightly constricted at joints ; before division five times as long as the diameter, later about three times as long ; cell -membrane rather thin ; in drying some of the cells collapse, sometimes alternately. Filaments of irregular thickness. Diameter, 6-12 yw. Syn. Conferva sordida, Dillw. ; vesciculifera bombycina, Jernier. Trenches, ponds, pools, etc., not rare. Plate CXXI, figs. 8, 9, two vegetative filaments, and one dried, having alternate cells collapsed. CONFERVA PUNCTALIS, Dillw. Forms dull green mats ; filaments sometimes single or scattered ; cells short, not longer than two diameters before division ; cell contents granular. Diameter, 6-7 yu. Generally in stagnant waters. Plate CXXI, figs. 20, 21. CONFERVA. 143 CONFERVA ABBREVIATA, Bab. Small caespitose tufts, attached, green, but often discolored, ferruginous ; articulations short cylindrical, not constricted at joints, nor swollen ; cells before division not exceeding two diameters ; usually as long as broad. Cell membrane thin, hyaline, homogeneous ; chlorophyl evenly distributed. Diameter, 6-7 \ ^ Syn. Conferva floccosa ochracea, Kg. ; Conferva ochracea, Kg. Character of this species very near that of C. punctalis, but as a rule the cells are shorter and slightly thinner. The color, often ochraceous, or ferruginous may be ascribed to the character of the soil of the basin, rather than to a character of the plant. Plate CXXI, figs. 18, 19 ; these figures drawn for C. punc- talis may also represent a state of C. abbreviata. CONFERVA TENERRIMA, Kg. Usually pale green, often in colorless masses ; articula- tions lij-2-3 times longer than the diameter. Diameter of filaments, 3.5-4 //, (3-5 //, Kirch.). Ponds, Florida; and northward, in smaller quantities. Plate CXX, figs. 1, 2. CONFERVA GLACIALIOIDES, Wolle. Very pale green, filaments long, laxly interwoven, prim- arily attached, thin, floating in cloud -like masses. Diameter of filaments 4-5. 5 ^ articulations 4-9 times as long as broad. Springs, Pennsylvania. Very near C. glacialis, Kg., but articulations average twice as long. Plate CXX, figs. 5-8. CONFERVA RHYPOPHILA, Kg. Green, often ferruginously colored, thin ; cells ante divi- sion, 3-4 times as long as wide. Diameter of filaments, 4.3-5 //. Small pools, from Pennsylvania to Florida. Plate CXX, figs. 3, 4. Genus 28, CHAETOMOBPHA, Kg. Articulate filaments simple, nearly equally thick, fixed by a discoid, or root-like, divided, base ; lower articulations always short ; before division equal or somewhat longer, after division 10 144 FRESH-WATER ALG^ OF THE UNITED STATES. shorter than the diameter ; upper divisions more or less elongated. Cell-membrane thick, firm subcartilaginous, lamel- lose. Cell contents green, finely granular. Species of Chaetomorpha are frequent on our Atlantic and Pacific coasts, rarely also in brackish water, but being so evi- dently marine plants, the names of species are omitted. Plate CXXY, fig. 11, the natural size and mode of growth of a smaller species ; fig. 12, part of a single filament of Chaet. sutoria, Berk., magnified; fig. 13. part of a filament of a larger species, (Chaet. litorea, Harv.,) enlarged, showing (fig. 14,) the escape of the zoogonidia. Genus 29, RHIZOCLCmUM, Kg. Articulate threads, the same as in Conferva, but somewhat con- torted, having, here and there, short rhizome-like lateral pro- cesses, seldom composed of more than three cells, often only one. KmZOCLONIUM HIEROGLYPHICUM, Kg. Vegetative green, or yellowish green, forming thin webs or mats of considerable extent on moist ground. Cells 14-3 times as long as the diameter. Diameter of filaments, 20-25 yw, rarely 29 /*. On moist or wet ground in vicinity of springs. Plate CXXI, figs. 29, 30. Yar. AMERICANA, Wolle. Filaments average rather stouter, and cells rather longer and more irregular in outline, than the typical plant. Forms close and crisped web-like growth on shaded garden soil. Lateral processes unicellular. Plate CXXI, figs. 31, 32. EHIZOCLONIUM FONTINALI, Kg. Bright green, loosely interwoven ; diameter -of filaments, 13-15.5 yw. Articulations ordinarily twice as long as wide; ante-division four times as long ; membrane thin. Rhizome- like processes usually 2-3 -celled. Syn. Wiizo. fontanum, Kg. ; BMzo. rivulare, Kg. Springs and flowing waters. Plate CXXI, figs. 22-25. RHIZOCLONIUM. 145 EHIZOCLONIUM FLUITANS, Kg. Caespitose, attached, bright green, filaments often long, three feet or more, in rapid streams. Diameter 18-20 (-32) /A articulations 1-1 2, rarely 2 times longer than wide; lateral processes rather sparse, single or bicellular. Syn. EJiiso. laeustre, var. fluitans, Kg. ; RMzo. Kuetzingiamvni, A. Br. Rapid streams, mill-dams, and the like, New Jersey. Plate CXXI, figs. 26-28. Filaments of different sizes in- termingle. The larger ones (32 /O much larger than the European form, but probably the same species. The name is appropriate, hence retained. EHIZOCLONIUM STAGNALE, Wolle. Dark green, large dense floating masses on stagnant water ; primarily attached. Filaments more or less tortu- ous ; many cells irregularly swollen, 25-30-33 ^ diameter ; 2-23-3 times as long as wide. Membrane firm ; cell contents granular. Plate CXXII, figs. 8-10. EHIZOCLONIUM HOSFOKDII, Wolle. Vegetative green, robust ; diameter of filaments 36-40 //. Cell walls thick ; articulations 3-4 — more rarely 6 diameters. Lateral rhizome-like processes, short, without divisions. Collected in Erie County, N. Y., by F. H. Hosford. Plate CXXII, figs. 13-16, four parts of filaments. EHIZOCLONIUM CASPARYI, Harv. Yellowish green, often faded, stratified interwoven, curved here and there, and angularly bent ; at the angles often emitting short processes, root-like; articulations l]-li-2-3 times as long as wide. In brackish and salt water, California. Plate CXXII, figs. 11, 12, processes omitted. • EHIZOCLONIUM SALINUM, (Schleich.) Kg. Pale or yellowish green, crispate, diameter of cells 20-25- 30 yw; length 1-1 i -2 diameters, after division; prior to division 2-3-4 diameters ; filaments long, in loose or more densely interwoven mats ; primarily attached, then floating in submarine waters along the Atlantic Coast. 146 FRESH-WATER ALG^E OF THE UNITED STATES. Absecom, Perth Amboy, and low grounds generally, New Jersey. Syn. Wiizo. riparium, Harv. ; RMzo. obtusangulum, Kg.; Con- ferva riparia, Ag. ; Zygnema litoreum, Kg. Plate CXXII, figs. 5, 6, 7. EHIZOCLONIUM MAJOR, Wolle. Stratum dark green, filaments densely interwoven, some- what rigid, lateral processes short, numerous, cell contents 3-4 parted ; diameter of articulations 33-48 //, equal, to twice as long ; cell membrane firm. This finely developed, large plant, was found growing on the wooden structure of the docks at Perth Amboy, New Jersey. It is nearest Rhizo. pannosum, Aresch., and may be a variety of it. It differs in having twice the diameter, in the character of the rootlets, and in habitat. Plate CXXII, figs. 1-4. % Order III— SIPHONED. Plants in vegetative state, unicellular, often prominently branched, tubular or utricle-shaped ; dwellers in water, and in air. This Order is represented by only two genera, widely different in appearance and in their mode of propagation. The one has sexual fertilization, and asexual zoospores ; the other has sexual oospores and asexual zoospores, beside other mode of propaga- tion by rnicrogonidia. Family X. — VA UCHEEIA GE^. Filaments caespitose, green, rather robust, unicellular, land and water dwellers. A plant consists of a single, elongated, tubular filament, ordi- narily more or less branched. The chlorophyl rather evenly distributed on the inside of the walls of the tubes with green granules and minute oil drops imbedded. Propagation either sexual, by oospores fecundated by sper- matozoids, or non-sexual by zoospores. Sporangium terminal, formed by the globosely clavate swelling of the tip of the thallus, cut off by a septum ; contents dark green, at length enclosing one large zoospore. VAUCHERIA. 147 Oogonium lateral, sessile, or borne on a more or less elongated, simple or partite pedicel ; cytioplasm at length converted into a large oospore. Antheridiuni lateral, sessile, or cut off by a septum from the upper portion of a lateral branch, in which numerous spermato- zoids are generated, which at length become free 5 spermatozoids oblong, furnished, except in one species, with two unequal cilia. Genus 30, VAUCHEEIA, D. C. The generative cells, the oogonia and the antheridia are devel- oped in various numbers on the same filament, or tube. They are either sessile or posed on short pedicels, and are usually in close proximity, but in various relative positions. The oogouia are somewhat globular, one side beaked, opening at the apex ; the antheridia are more or less cylindrical, curved, horn-like in the upper part, the ends usually so turned that the apices are directed towards the beak of the oogonia. The spermatozoids are developed in the curves of the anthe- ridia and ejected towards the mother cell and drawn in at the beak ; the oosphere is thus fecundated and becomes an oospore. Zoospores are developed, singly, in the terminal sporangium and ejected from it. They move with a rolling motion by means of cilia with which their whole surface is amply provided, but soon come to rest and germinate. Microgonidia are developed in large numbers in vegetative cells ; they are ejected but remain motionless, at rest, soon to germinate. The following list is in accord with an arrangement of Euro- pean species, proposed by Professor Nordstedt, of Sweden. A. — Antheridia not separated from the thallus by a short empty boundary cell. a. — TUBULIGER^E. Antheridia little or scarcely bent, oblong cylindrical, or lanceolate, with an opening at the top. Oogonia and antheridia almost steniless. • Oogonia nearly round. 1. V. dichotoma, Linn. Dioecious. 2. V. Thuretii, Woron. Monoecious. Oogonia not round, more or less oval, frequently rather oblique. 3. V. aversa, Hass. 4. V. siricea, Lyngb. 148 FRESH-WATER ALG.E OF THE UNITED STATES. b. — CORNICULAT.E. Antheridia bent in the form of a horn or a hook, placed on the short and bent side-branches of the thallus. Brown pigment in the middle of the mature oospore. aa. — tiessiles. Oogonia sessile (or with exceedingly short stems) beside the antheridia on the thallus. 5. V. Dillwynii, Ag. 6. V. sessilis, Vauch. bb. — Racemosce. Antheridia at the end of a fruit branch, which, somewhat lower down, carries the oogonium. Oogonia turned upward. i Antheridia and oogonia bending in opposite planes, forming an angle with one another. When the oospores fall they are surrounded by the oogonium membrane, which is not changed to mucus. 7. V. geminata, Walz. 8. V. hamata, Walz. Antheridia and oogonia (mostly) bending- in parallel planes, the oogonium membrane turns to mucus and dissolves. 9. V. terrestris, Lyngb. Oogonia turned downwards. 10. V. uncinata, Kg. (Not represented.) c. — Antheridia straight, with the top covered, and a pair of fruiting tubes standing out at the side. 11. V. DeBaryana, Woron. (Not represented.) t B. — Between the antheridia and thallus itself is found a shorter empty boundary cell. a. - - ANDROPHOR^E. Several horn-shaped, bent autheridia placed on a swollen cell containing chlorophyl, which is fixed to the side of the thallus, by means of the boun- dary cell. (Not represented.) b. — PILOBOLOIDE^E. Antheridia bordering immediately on the boundary cell. (ISTot represented in the United States.) c. — Place of the antheridia or boundary cell uncertain. 12. V. tuberosa, A. JBr, 13. V, JMlus, Mart, VAUCHERIA. 149 YAUCHERIA DICHOTOMA, Lyngb. Large, robust, loosely caespitose, dirty green or becom- ing brownish. Filaments thick, setaceous, nearly a foot long, remotely clichotoiiious. Oogonia sessile, globose or ovoid, single, scattered, or two or more approximating. Oospores, when mature, with a triple membrane, spotted with brown. Antheridia single, erect oval, subclavate or acute, on the same or 011 different filaments. Diameter of filaments variable, 100-200 /*. Diameter of oogonia, about 100 /*. In ditches, marshy places around limestone springs. Good fertile specimens rare. In similar localities there are other species growing in large dense mats, but short filaments ; V. dichotoma is dis- tinguished by its much longer filaments, usually 3-6 inches long, and more bushy growth. Syn. Conferva dichotomy Linn. 5 Vaucheria globifera, D.By. ; Vaucheria salina, Kg. ; Conferva dichotoma setis porcinis, Dill. Plate CXXVI, figs. 1-3, parts of dichotomose branching filaments ; figs. 4-6, sessile oogonia ; fig. 7, one of the swollen ends ejecting microgouidia. VAUCHERIA THURETII, Woron. Forms cheerful, deep olive green, velvet-like mats often feet in extent. Filaments upright, close, from a closely in- terwoven substratum, in salt marshes along the eastern shores of New Jersey ; dried it becomes dark brown or blackish. Size of filaments, 50 yw more or less ; oogonia large, globose or ovoid, sessile or subsessile 125-150 yw diameter. Anthe- ridia rare, 011 same filament with oogonia. Plate CXXVI, figs. 11-15, sections of filaments from New Jersey specimens. VAUCHERIA AVERSA, Hass. Loosely caespitose, sparingly branched, expanding in all directions, filaments thick ; oogonia erect or suberect, sessile or subpedicellate ; antheridia, cylindrical or subclavate, erect, ends more or less curved. (European forms not erect 5 sub-horizontal.) Diameter of filaments, 100 }JL more or less. 150 FRESH-WATER ALG^B OF THE UNITED STATES. Syn. V. ornithocephala, var. avers. Kg. Plate CXXVII, figs. 5-8, sections of filaments with oogo- iiia and antheridia, as found on thalli recognized as properly belonging to this species, although differing from the Euro- pean form, in the more erect and regular oogonia and the less inclining antheridia. Find this species intermingled with aquatic plants near river banks. Compare note, V. sericea, Lyngb. VAUCHERIA SERICEA, Lyngb. Aquatic or terrestrial, occurring in turfy mats, of a yellowish, dirty, or bright-green color ; filaments thin, densely intricate, laxly or vaguely branched ; often ascend- ing and erect together with the branches ; oogonia sessile or very shortly pedicellate, 1-6 seriate, unilateral, obliquely irregularly oval, their lateral mouths produced into a ros- tellum or beak ; antheridia sessile upon the filament (thallus) near the oogonia ; somewhat cylindrical, subclavate, deflexed, especially in age ; spermatozoids (according to DeBary) oblong and furnished with a single cilium at each end. Diameter of filaments, 50-75 ^. Dr. Wood, in his Contribution, page 181, remarks, "I can see no constant differences between V. sericea, Lyngb., and V. aversa, Hass. The extreme forms differ somewhat, but both are very common about Philadelphia, and everywhere grade into one another. The plant grows in springs and actively running water abundantly in this neighborhood; also on very wet ground, especially on that which is habitu- ally overflowed, such as the face of dams, neighborhood of springs, etc." Evidently the Doctor had but one species, V. sericea, in different stages of growth. The plant I figure for V. aversa is clearly not the same ; distinct in habitat, in form of oospores and in the more erect antheridia. Syn. V. ornithocephala, Ag. ; V. polysperma, Hass. Plate CXXVII, figs. 12, 13, apart of a filament thickly set with oogonia ; from a specimen from Iowa. The plant is common, but not always so abundant in fruit. VAUCHERIA DILLWYNII, Ag. Terrestrial, broadly expanded, forming a rather thin stratum, of bright or dark green color. Oogonia globose, or ellipsoid, rostrate, sessile, usually single, sometimes twin, enclosed in delicately punctate membranes. Mature VAUCHERIA. 151 oospores spotted with brown ; sporoderm very thick, com- posed of several strata. Antheridia somewhat bag-shaped or clavate, located near, or sometimes between two oogonia. Diameter of filaments and of oogonia, 50 ^ more or less. On damp or wet ground, shaded places, banks of rivers and similar localities. Syn. V. pachyderma, Walz. ; V. Hookeri, Kg. ; V. Ungeri, Thnr. Plate CXXVI, figs. 8, 9, 10, three sessile oogonia and three antheridia. VAUCHERIA SESSILIS, ( Vauch. ) D. C. Loosely intricate, pale or dull green. Thallus capillary, sparingly branched ; oogonia 2-3, approximate, rarely single, ovate or oblong-oval, more or less oblique, rostrate ; anthe- ridia intermediate, either short, hamate or straight and sub- ulate, or a little clavate, sometimes elongated and incurved, rarely circinate. Mature oospores punctate with brown, involved in a triple membrane. Diameter of filaments about 50 IA. Rabenhorst describes five varieties of this species. l.--Var. sporangifera. Sporangia terminal, ovate- clavate. 2.--Var. caespitosa, (Vauch. ) Ag. Oogonia usually twin, ovate, with antheridia intermediate, sometimes shortly uncinate. 3. — Var. ornithocephala, Hass. after Ag. Oogonia single or twin, oblique rostrate; antheridia cylindrical-sub- ulate, incurved, intermediate, longer than the oogonia. 4. — Var. trigemina, Kg. Oogonia usually by threes. 5.- -Var. pphaerocarpa, Kg. A marine plant. Syn. Ectosperma sessilis, Vauch. ; Vauclieria caespitosa, Ag. ; Vauch. ovoidea, Hass.; Vauch. Tovarensfa, Karst. Plate CXXVII, figs. 9-11, three ordinary forms of oogonia and antheridia. VAUCHERIA GEMINATA, (Vauch.) D. C. Dark or dull green in dense intricate tufts. Filaments capillary, tough, dichotomous. The fruiting on short lateral branchlets, usually with two oogonia, opposite ; the anthe- ridia between and extending above them, more or less re- 152 FRESH-WATER ALGJE OF THE UNITED STATES. curved. More rarely only one, or more than two oogonia. Mature oospore spotted with brown, sporoderm colorless, composed of three strata. Filaments variable in size, 50- 125 jJi in diameter. Oogonia vary in proportion. Asexual propagation by gonidia distributed by decay of the cell- membrane. Var. KACEMOSA, Walz. Oogonia shortly pedunculate, 3-5, sometimes 8-10, aggre- gated in a corymbose manner. Antheridia single, scarcely longer than the oogonia. Syn. Ectosperma geminata, Vauch.; Vaucheria Dillwynii, Rab. ; Vauch. ovoidea, Hass. ; Vauch. ovata, Gray ; Ectosperma ovoidea, Huds. In stagnant waters, ditches, ponds, etc. Frequently peculiar appendages known as Vaucheria galls occur on filaments of this and other species ; somewhat urn- shaped excrescences, cylindrical cells, outgrowths of the plants; swollen below the middle, contracted at the base and distended at the truncate apex. They measure 200- 350 fj- in diameter, length three times greater. These are Rotifer nests produced probably by a sting or other irrita- tion. The living creature is always seen in proper season near the bottom of the cell together with 10-20 or more, dull rose colored eggs. Rotifers (?) frequently make a home in the filaments of Vaucheria. G. Benko calls the parasite Notommato Werneckii. Plate CXXVIII, figs. 1, 2, 3, parts of plants of true V. geminate, ; figs. 4, 5, forms of variety racemosa from speci- mens from Iowa and Pennsylvania ; fig. 6, an abnormal but not rare form of fruiting; fig. 7, a gall, or Rotifer's nest. VAUCHERIA HAMATA, (Vauch.) Lyngb. Aquatic or terrestrial, thallus rather rigid, vaguely branched. Oogonia single or double, seated on short seg- ments of the divided end of branchlets ; when two oogonia, then a third intermediate segment develops the antheri- dium, which elongates and recurves. Mature oospores are involved in a sporoderm, formed of three or four membranes. Syn. Ectosperma hamata, Vauch. ; Vaucheria hamulata, Kg. The only satisfactory specimens hitherto discovered are from California. Plate CXXVIII, figs. 8-10, drawn from California speci- mens ; single and twin oogonia. VAUCHERIA. 153 VAUCHERIA TERRESTRIS, Lyngb. Forms densely interwoven, thin, rather dark green strata, on moist soil. Oogonia usually single, sometimes in clusters, pedunculate, attached by a flattened base on the back of the incumbent, elongated, curved, antheridium. Mature oospore enclosed in a hyaline colorless sporoderui, composed of several membranes, considerably inflated. Syn. Ectosperma terrestris, Yauch. ; Vaucheria drdnata, Kg.; Vaucli. polymorplm. Wood. Damp ground, clayey soil, green-houses, etc., often form- ing considerable patches. Plate CXXIX, figs. 1-5, parts of fruiting filaments variously developed with one, two and more oogonia on a peduncle ; figs. 6-8, oospores germinating. VAUCHERIA VELUTINA, Ag. 1 ' Filaments exceedingly tough, interwoven into a dense, velvety, green stratum, pellucid below and creeping over the mud ; branches near the extremity erect fastigiate, and more or less crooked ; oogonia solitary, globular, on short lateral peduncles." -Carmichael. Diameter of oogonia, 57-68 JJL. North Carolina, Schweinitz ; West Point, New York ; Waterville, Maine; Culpepper, Va., Bailey. Have quoted the above from Wood's Contribution, p. 180. I have not recognized a plant to correspond in all particulars ; appears to be near V. sericea in general character and also near V. Dittwynii in fruit. VAUCHERIA PILUS, Martens. Has the habitat and form of a very robust V. dichotoma. Filament simple or sparsely branched ; diameter 180-200 yw ; long ; often hyaline, and mucose to the touch ; apex rounded, sometimes slightly inflated ; cell contents mucilaginous, granular, dull green. When dried, ash-gray, silky. Oospore nearly twice the diameter of the filament. The only speci- mens of this form of extraordinary size are from a ditch near Charlotte, Vermont. — Coll. F. H. Hosford. The value of the species may be somewhat doubtful, as suggested by Rabenhorst. The specimens received were too limited and incomplete for a decided opinion ; nevertheless the parts examined were of gigantean proportions. Plate CXXVII, figs. 1-4, 154 FRESH-WATER ALG^ OF THE UNITED STATES. VAUCHERIA TUBEROSA, A.Br. Flagella subterranean, apices swollen, tuber-like. Fila- ments dichotonious, three or four, or more times divided ; branches regularly constricted at the base of the divisions and often intermediately ; lateral stolons not infrequent, repeatedly constricted, bead-like, much enlarged at the ends. Neither oogonia nor antheridia have been observed. Have three distinct varieties of this strikingly peculiar plant. The type, Plate CXXX, was dredged in Lake Michigan by Prof. S. A. Forbes, four miles from Chicago, from a depth of six fathoms. It accords well with plants collected in Swiss lakes. Var. INTERMEDIA, Wolle. Plate CXXIX, figs. 9-11. This form has not, as far as observed, the tuberose swellings of the type, but has the distinct manner of branching and the constrictions at the bases of the psewdo-branchlets. It is bright green. The former is duller green, tinted with red at the constrictions ; the swollen ends very dark, or bluish green. Was found in marshes in Georgia by Capt. J. D. Smith. Var. MINOR, Wolle. Plate CXXIX, figs. 12-14, another form with only about half the diameter of var. intermedia, light green color ; parts between the constrictions proportionately much longer and the dichotomous branching not so regular. From small pools on the banks of the Susquehanna, Harris burg, Pa. Family XL—BOTEYDIACE^E. Small unicellular plants, green, globose; on the surface of moist earth, with a system of colorless radicles, much divided, descending from the base of the cell into the earth. Propagation takes place by means of sexual zoospores ; these copulate and produce zygospores, which quickly develop and produce vegetative plants ; the cell contents of these finally di1 vide into an indefinite number of resting spores. These ejected, in turn germinate and again produce sexual microzoospores. Asexual multiplication takes place also, by means of macro- spores. BOTRYDIUM. 155 Genus 31, BOTRYDIUM, Wallr. Vegetative plants unicellular, multiplying by division of cells and by development of zoospores. Asexual zoospores furnished with one, and sexual zoospores with two cilia. Sexual isospores, sometimes globular, sometimes compressed, alike capable of germination, are clothed with several tuberculate thickenings. Rostafinski and Woromin's careful researches into this genus show that this plant has various modes of multiplication. Zoo- spores are produced in a fourfold way. 1. From the vegetative plant ; 2. from the ordinary zoosporangia ; 3. from the root cell, and 4. from the hypnosporangia. Further modes of increase are ; 5, by cell division ; 6, by formation of macrospores ; 7, by formation of zoospores. The plant possesses also fivefold resting stages : 1, of the asexual zoospores laid in water for months ; 2, of the root cells ; the year throughout in which they originated ; 3, of the hypno- sporangia ; the year throughout in which they originated ; 4. of the macrospores ; for years ; 5, of the isospores ; at least over the year in which they originated. In dry seasons, unfavorable to development, the cell contents are often scattered, and seemingly transmuted into forms which have been erroneously called Protococcus coccoma; P. palustris, and P. botryoides. In proper and favorable season, the same cells reproduce sexual microzoospores and these again the original form. BOTRYDIUM GRANULATUM, Linn. Usually gregarious, often aggregated, rarely confluent, cells globose-pyriform, size of a poppy seed, or more usually of a mustard seed, or larger ; leek -green, sometimes pulver- ulent. Syn. Hydrogastrum granulatum, Rab. ; Lichenoides fungiforme, Ray Syn. ; Tremella palustris, Dillen. ; Botrydium argilla- ceum, Grev. ; Vaucheria radicata, Hook. ; Viva granulata, Huds. Plate CXXXI, figs. 1, 2, cells (plants) about twice the natural size ; fig. 3, two empty cells with tops fallen in ; figs. 4-7, cells magnified, with the system of subterranean radicles ; fig. 8, the cell contents passing down into the radicles; fig. 9, the radicles developing zoospores; fig. 10, cell (zoosporaugiuni) contents dividing and developing and scattering microzoospores ; fig. 11, zoospores highly magni- fied, sexual ; fig. 12, asexual macrospores ; fig. 13, zoospores 156 FRESH-WATER ALG^ OF THE UNITED STATES. developing in the radicles, matured and ready to escape ; fig. 14, radicle cells, more highly magnified, producing zoospores under culture in water ; figs. 15, 16, zoospores 4-6 days old ; figs. 17, 18, seven to eight days old ; fig. 19, zoo- spores in radicles germinating, direct, on soil ; fig. 20, zoospores developing into vegetative plants; figs. 21, 22, zoospores enlarging and producing sexual zoospores ; figs. 23, 24, zoospores copulating; fig. 25, isospores, the result of the copulation of zoospores ; fig. 26, after a few days the same become stellate. Order IV.— PEOTOCOCCOIDE^E. Strictly unicellular algae, green, without terminal growth or ramification and without a vegetative generation of cells. Either single, segregate, or associated in families. Cells of the families either indefinitely increasing in number, then forming daughter families ; or of a definite number, then forming a coenoMum, some- times parenchymatously united, yet unicellular because each cell is possessed of power of reproduction. Propagation sexual by means of oogonia and antheridia, or by copulation of zoospores, bi-ciliate macrospores, or microspores. The life-history of many forms belonging to this Order of plants is not yet fully understood, but as far as known they develop zoospores of one or the other kind, or both, and are thereby separated from the CONJUGATE. Family XIL—VOLVOCACE^l. Coenobia mobile during the entire period of life, each cell being furnished with two cilia. Cells green ; common tegument of the coenobium more or less ample, usually hyaline. Propagation sexual or asexual. SEXUAL FORMS. Coenobia spherical which by means of the cilia of the indi- vidual cells are mobile with more or less of a revolving motion. Sexual propagation by means of oogonia and antheridia. The latter are developed from a vegetative cell of the coenobium ; this enlarges, the contents of the cell divide and form a cluster of small cells developing spermatozoids ; the cell-membrane breaks and these escape. The oogoniuni in like manner is de- VOL vox. 1 57 veloped from a vegetative cell ; this enlarges, and being enclosed by a single membrane, the spermatozoids perforate and enter it ; thus fertilized the membrane increases in thickness, and the spore becomes a resting spore which in due time germinates. Asexual propagation takes place by the division of larger vegetative cells ( Parthenogonidia ) which produce new families; these when sufficiently advanced separate from the mother cell and enter upon independent life. Genus 32, VOLVOX, Ehrb. Coenobium spherical, continually gliding along with a rota- ting motion ; looking like a hollow globe, the surface composed of very numerous cells, gonidia, estimated as high as 12,000, ar- ranged on the periphery at regular intervals, connected by a matrical gelatin, having the appearance of a membrane in which the gonidia are imbedded. Each gonidia is globose with an outwardly-directed process bearing on the apex two long ex- serted cilia extending beyond the common gelatinous envelope by which the coenobium is circumscribed. By the waving of the cilia the coenobium is kept in constant motion. The con tents of the gouidia are chlorophyl-green including starch gran- ules and often a red pigment spot. The oogonia are larger flask-like cells (gonidia) extending from the periphery inwardly — they are sustained by the neck-like process bearing the cilia. The spermatozoids are produced in cells similar in appearance and similarly located, as already de- scribed ; the spermatozoids are spindle-shaped, furnished with two cilia ; they fertilize the oogonium by penetrating the mem- brane. The oogonia after a resting period, produce usually eight zoogonidia ; the number is not regular, sometimes more or less. Asexual propagation takes place by the division of the larger and darker flask-like cells, the larger end visible on the inner surface of the walls of the coenobia ; the smaller neck-like end extending outwardly bearing the cilia. These divisions aver- aging about eight in number, soon round themselves and develop the young Volvoxes in the mother cell. Within these young spheres, almost immediately after their production, may be seen the selected gonidia for another genera- tion, they being the larger gonidia, of darker green color than the surrounding ones seen on the inside of the young coenobia. Viewing the vast multitude of the gonidia on the surface of the sphere they appear to be detached, but upon a very close observation under a high power and a carefully adjusted light, 158 FRESH-WATER ALG^E OF THE UNITED STATES. it appears that from each gonidium there runs to each of the six surrounding ones a fine thread, sometimes double, always of ex- treme tenuity, and often so delicate as not to be seen at all, except by the use of reagents which often bring these lines into view, where it had been impossible to detect them. VOL vox GLOBATOR, Linn. Larger coenobia with very numerous cells, (gonidia) always with daughter-coenobia enclosed within the maternal one, evolved without sexuality ; fructification monoecious ; oogonia and antheridia developing in the same coenobium. The oogonia are often numerous. Diameter of well developed coeiiobia, often 650 JJL. Diameter of vegetative cells, 2-3 jw. Diameter of oogonia about 50 //. Diameter of antheridia about 35 /*. Diameter of spermatozoids, 4-6 yu long. Plate CLI, figs. 1-4, different stages of development, the latter with encysted resting spores. Plate CLII, fig. 1, coenobium showing the fine threads connecting the gonidia ; fig. 2, enlarged figure of connecting- threads ; fig. 3, an ideal section of the wall of a coenobium, showing the gonidia, flask-like, imbedded, with ciliated ends ; basal parts often developing oogonia and antheridia ; fig. 4, coenobium with three stellate resting spores ; fig. 5, a stellate oogoniurn or resting spore ; fig. 6, an exaggerated ideal of a section of a coenobium illustrating the ciliated ends of the gonidia extending through the gelatinous en- velope ; two oogonia dividing, a stellate resting spore and two undeveloped oogonia ; fig. 7, a complete antheridium, after "Wills ; figs. 8, 9, spermatozoids. Much disparity of opinion and uncertainty prevail regard- ing the mode of fructification ; some maintaining they are monoecious and others dioecious. VOL vox AUREUS, Ehrb. These are larger spherical cells, surrounded by a thick, smooth, colorless, often lamellate epispore, found within a mother coenobium ; probably merely resting spores. Plate CLI, fig. 4, six such resting spores. VOLVOX STELLATUS, Ehrb. Stellate forms are sometimes very numerous in a coeno- bium, varying in number from ten to one hundred and more EUDORTNA. 159 in a single sphere. These are supposed to be fecundated oospores, originated in a female coenobium. Plate CLII, fig. 4, three stellate forms ; fig. 6 has one included ; fig. 5, one separated from the coenobium. SPHAEROSIRA VOLVOX, Ehrb. Some authors consider this form related to Volvox; others regard it as the male form ; that it is related to Volvox is certain, but whether any distinct functional relation exists between them has not been satisfactorily determined. Probably it is merely a peculiar condition of dissolution, cells enlarging somewhat after separation from the walls of the coenobium. A form by no means rare in ponds in which the Volvox prevails. It may be obtained also in vessels in which Vol- vox globator is kept for cultivation. Plate CLI, fig. 5, a part of a coenobium of Sphaerosira volvox. Description after Williamson in Cooke's British Fresh-water Algw ; fig. 6, protoplasmic mass from the coeuo- biurn containing granules ; fig. 7, mass divided into two ; fig. 8, mass divided into four parts, and fig. 9, into thirty- two parts, each with movable cilia ; fig. 10, discoid family revolving in the mother sphere. These discoid families have come under my observation, not in the sphere, but outside ; they were evidently parts of a broken, or partially decayed coenobium. Volvox globator is distributed over the whole length and breadth of the United States ; it is found in ponds and pools, most abundant in warm weather, but in good condition, also in midwinter. The specimens examined from many locali- ties, from Maine to Florida and westward, appear to be one and the same species. VOLVOX MINOR, Stein. I judge to be merely a variety of uncertain value. Genus 33, EUDOEINA, Ehrb. Coenobium somewhat ovate or spherical, involved in a more or less gelatinous hyaline tegument, composed of 16-32 globose green cells arranged around the colorless sphere at subequal distances ; each cell furnished with two vibratile cilia pro- truding through the tegument. Usually four of the thirty -two cells develop antheridia and others oogonia. In each antheri- l] 160 FRESH-WATER ALG^ OF THE UNITED STATES. diiiDi sixty-four spindle- or pear-shaped spermatozoids are devel- oped of light green tint with colorless beak bearing two cilia, (Kirch.). Asexual propagation takes place by the division of the cells into 16-32 parts, each of which produces a new coeiiobium. EUDORINA STAGNALE, Wolle. Coenobium spherical, usually composed of thirty-two globose cells arranged more or less regularly around the inside of the walls ; the cilia pass through the tegument and by constant vibration the coeuobium is kept in activity. They are very variable in size, due to age, reckoned by hours, from their escape from the mother cell. Diameter, 25-200 //. Diameter of cells, 5-18 //. This plant is easily confounded with Pandorina morum. The feature mainly to be relied upon is the arrangement of the cells ; in Eudorina they are more or less regularly placed around the inside of the walls ; in Pandorina they are more densely clustered, often grape-like, nearly filling the cavity .to the center. Found this plant repeatedly in pools filled by rains ; the water was green with the multitude of coenobia it contained, all spherical, ranging in size as indicated above. The mul- tiplication is asexual and very rapid. The plant is unlike the only European species E. elegans, Ehrb., in that it is not oval in form, and the cells are much smaller. Plate CLI1, figs. 11-21. Fig. 11, a coenobium of sixteen cells ; fig. 12, cells dividing, making thirty-two ; fig. 13, a matured sphere, ready to break and scatter the cells, devel- oping young coenobia ; figs. 14-21, various stages of develop- ment of cells, all in active motion ; figs. 22, 23, spermatozoids. Genus 34, PANDOBINA, Ehrb. Coenobium globose, or subglobose, invested by a colorless, gelatinous tegument ; cells green, granulose, globose ; 8-16-32-64 in a coenobium, each enclosed in a thin membrane and furnished at maturity with two cilia ; often crowded in the coenobium and for the time polygonal. Propagation sexual, by the conjugation of zoospheres. Cells of a coenobium divide into eight daughter cells, these are scattered and conjugate with similar cells from other coenobia ; they flow EUGLENA. 161 together and produce a zygospore, which after a season of rest develops 1-3 large bi-ciliate macrospores, and these in turn develop new coenobia. PANDORINA MORTJM, Bory. Coenobiuni spherical or somewhat oval, usually composed of sixteen cells ; may vary by multiples of 8, from 8-64. Zygospore with a smooth epispore. Diameter of coenobia up to 220 /<. Diameter of vegetative cells, 9-15 //. Plate CLIII, figs. 1-5, the most frequent condition ob- served ; figs. 6, 7, coenobia with more numerous cells densely clustered ; figs. 8, 9, very fugacious coenobia ; placed to this species with some hesitancy ; fig. 10, a matured coeno- biurn ; the cells in condition for independent existence- ready to escape from the maternal tegument. In larger or smaller pools of stagnant water. Genus 35, EUGLENA, Ehrb., Cells more or less fusiform or elongate, mobile, exceedingly flexible and changeable in shape, terminating posteriorly by a more or less developed tail-like prolongation; anteriorly fur- nished with a long flagellum by means of which they keep up a forward and rolling or rocking motion. Increasing by longi- tudinal division, and by the production of germs through the subdivision of the cell contents. Usually they have a red eye-spot. EUOKLENA VIRIDIS, Elirb. Cells elongate, subcylindrical or fusiform, exceedingly flexible and variable in shape, mostly rounded anteriorly, and with a short transparent tail-like posterior prolonga- tion ; cell contents usually bright green, but sometimes changing to dark orange or red. Flagellum slender, exceed- ing the body in length ; a red pigment spot generally pres- ent at the anterior extremity. After a longer or shorter period of activity the cells come to rest, contract and assume a spherical form and throw around themselves a gelatinous envelope which gradually becomes indurate. These cells under favorable circumstances divide into two and then into four green cells ; finally the Euglena form is reproduced. Cells 40-62 ^ long. Common in stagnant waters. 162 FRESH-WATER ALG.E OF THE UNITED STATES. Plate CLV, figs. 1-8, normal forms capable of polymor- phic contours at will ; figs. 9-15, cells contracting and com- ing to rest, forming encysted sporular bodies; figs. 16-19, encysted bodies in more advanced stages, dividing into two and four parts ; figs. 20, encysted forms often in great numbers; figs. 21, 22, sporaugial bodies ejecting microzoo- gonidia. The encysted forms are often very abundant, forming a thick scum, or floating crust. In this quiescent state the cells have been mistaken for independent forms of algse. Microcystis olivacea; M. Nottii; also Protococcus turgldus and P. chalybius, of Kuetzing, are now regarded as repre- senting variable phases of this resting condition of Euglena viridis. The forms included in this genus have been most com- monly classified with the Infusoria, but not without dissent. Such authorities as C. A. Agardh, Kiitzing, also Perty, Bergmann, Lenkhart and Carter, and more recently Cien- kowski, Hansgirg and others, refer them to plants, the Fresh- water Algae. Stein, the distinguished German au- thority on Infusoria, recognizes organs he takes for mouth and pharyngeal tract, which are essential to animal exist- ence, but acknowledges that no solid food has been seen to pass through these organs. Dr. Hansgirg thinks the organs observed are not really mouth and throat, but serve a respi- ratory office (respiration of water). They stand in connec- tion with the contractile vacuoles and serve the function of osmose and exosmose which in other algse, particularly some of the OscUlariece are supposed to facilitate the power of locomotion. Euglena have generally (not invariably) a red eye-spot which has been taken to indicate animal life, but such is not necessarily the case; the same red pigment spot is found more or less frequent in most of the forms of Volvocacece. Am aware that Kent in his Manual of the Infusoria, tells of some of the latest and perhaps most exhaustive exami- nations made by himself, by keeping Euglena specimens for a prolonged interval in water with finely pulverized car- mine, and then discovered, by submitting them to a magnifi- cation of 800 diameters, very small particles of carmine in the body; but the question arises, could not these have found entrance by absorption through the respiratory organs, as suggested by Dr. Hansgirg? However this may be, they are so frequently observed with recognized algse forms, we place them here until a more unanimous opinion may be formed regarding them. STEPHANOSPHAERA. 163 I Genus 36, GONIUM, Mueller. Coenobium composed of 4-16 cells, so arranged in a single flat stratum to produce a quadrangular, tabular form, with angles rounded. The whole enclosed in a colorless tegument. Cells globular or by mutual pressure somewhat polygonal, bright green, becoming with age disordered, granulose, connected by the produced angles ; chlorophylose vesicles central, furnished with colorless contractile vacuoles, and two long exserted cilia. Propagation by repeated division of the cytioplasm. GONIUM PECTORALE, Mueller. Coenobium flattened, quadrangular, composed of sixteen green cells, furnished with vibratile cilia, usually four cells in the center, and three on each side. Diameter of coenobia, 23-90 /*. Diameter of vegetative cells, 5-15 p. Stagnant waters, rare. The above diagnosis applies to the European plant. The very few specimens found, from New Jersey and Pennsyl- vania, were too limited for definite description ; they appear to be the same. Plate CLI, fig. 15, lateral view of a coenobium ; figs. 16, 17, two coenobia in front view ; fig. 18, a coenobium before division. Genus 37, STEPHANOSPHAERA, Cohn. Coenobium throughout its whole life rotating and moving, com- posed of eight green cells, bearing two vibratile cilia, disposed at equal distances around a circle, enclosed in a common color- less hyaline, globose vesicle. Propagation, both by macrogonidia arising from eight-fold division of the green cells, bearing two cilia, with a lateral red spot, congregated in families of eight ; and by microgonidia, very much smaller, produced by multiplied division, at first revolving within the common vesicle by the action of four cilia, afterwards free, escaping singly. STEPHANOSPHAERA PLUVIALIS, Cohn. Cells globose, elliptic or fusiform, often at each extremity spreading out in mucous rays. Diameter of coenobia, 30-60 /*. Diameter of vegetative cells, 7-12 /*. In hollows of rocks, and in pools after rain. 164 FRESH-WATER ALG^ OF THE UNITED STATES. • This interesting little plant was first observed in Germany in 1850, and since in many places including the British Isles. Presumably it will be discovered in this country also. In anticipation, have quoted the above from European works. Prof. Cohn made exhaustive examinations and studies of the life-history of Stephanosphaera and has prepared able memoirs, the first of which appeared in Liebold & Kolliker's Zeitschri/t fur Zoologie, 1852 ; the other in Nova Acta Acad. Leop. Cur., 1857, part I, vol. XXVI, to which the student is referred for full particulars. The same author has also given an excellent paper on the previous genus, Gonium, in the Xova Acta, vol. XXIV, p. 169. Plate CLI, fig. 11, polar view of family with globose primordial cells ; fig. 12, lateral view, with fusiform prim- ordial cells ending in mucous filaments ; fig. 13, commence- ment of formation of macrogonidia ; fig. 14, division of macrogonidia advancing so that each cell consists of eight cuneate segments. Genus 38, CHLAMYDOCOCCUS, A. Br. Cells globose, or subglobose, (4-8 joined in a very fugitive coenobium ) cell membrane thickish, firm ; cell contents granular, brownish red or vermilion, in certain stages changing into green, or partially green with red center. Macrogonidia 2-4-8 rounded, the frontal extremity bearing long cilia, containing 4-6 starch granules, (not always visible,) involved in an ample, hyaline, mostly ovoid tegument. Microgonidia much smaller, numerous, .yellowish or dull green, the apex reddish, biciliate, moving actively within the mother cell, and at last escaping by rupture of the membrane. CHLAMYDOCOCCUS PLUVIALIS, A. Br. Cells subglobose, very variable in size; brownish red, changing in some conditions to green. Diameter of cells, 7-40 yw. Perhaps no plant is more Proteus-like than this little form ; normally sometimes like a plant, and sometimes like an animal ; ordinarily it presents the appearance of small globules, with a thick, tough, granular or punctate cell- membrane; cell contents opaque, of a brown, reddish- brown, or red color ; found in small pools of rain water. Dr. F. Cohn devoted two years of his time to a full com- prehension of the life-history of this species ; he, adopting the name of Protococcus pluvialis, prepared an elaborate CHLAMYDOCOCCUS. 165 memoir, filling 160 pages in the Nova Acta Acad. Caes. Leop. Carol. Nat. Cur. Vol. XXIIr P. II, to which the student is referred for the full, original details. Transla- tions may be seen in A. Braun's Rejuvenescence, pp. 206-214, and "Memoirs," by the Ray Society, 1853. Dr. Colin ex- presses surprise that so simple a form should have evoked so many different views. Almost every botanist who made the plant a study suggested a new generic name. It is found in the writings of different specialists under the following terms, Chlamydomonas, Astasia, Gyges, Disceraea, Proto- coccus, Gtoiococcus, Haematococcus, Palmella, Sphaerella, Microcystis, Uredo, Torufa, Dematium, Byssus, and Lepraria. It would not be in accord with the design of the present work to enter upon lengthy details of the life-history of the plant under consideration, but for illustrating a few of the many forms a plant may assume in the round of its devel-: opment, we copy some of Cohn's illustrations, and add very brief explanations. After a contemplation of these figures, the diversified ideas expressed by the many generic names as above applied to this plant may not seem so strange. Plate CLIII, figs. 11-26, cells of resting forms of CM. pluvi- alis; figs. 11, 12, two cells, carmine red, as they appear after being dried for some time ; fig. 13, a large cell, lighter red around the margins with a light central spot ; fig. 14, a cell similar to last gradually changing to green with a light cen- tral spot; fig. 15, cell chlorophyl green, with illuminated spot surrounded by a halo of red ; fig. 16, a reddish brown cell, with the middle changing to green, membrane thin ; fig. 17, a cell kept for six years in a dried state, restored with moisture ; it divides, one-half being green, the other half reddish brown ; fig. 18, cell red, changes its form pre- paratory to division ; fig. 19, division progressing ; fig. 20, the same cell divided. The two daughter cells have a thin membrane each, and still enclosed in the maternal mem- brane ; fig. 21, cells divided a second time, producing four, partially green cells ; fig. 22, a cell divided at once into four spherical brown cells, somewhat motile in the maternal membrane ; fig. 23, similar to fig. 22, showing only three cells ; fig. 24, resting cell red and green within a wide color- less envelope ; fig. 25, a green cell, red in the center, at the point of changing into a mobile body ; fig. 26, another cell like the last, with light green margins, middle red, prepar- ing for mobility ; figs. 27-29, zoospores without envelope, green ; figs. 30-32, three forms of zoospores, each enclosed in a wide membranous envelope ; fig. 33, commencement of 166 FRESH-WATER ALG^E OF THE UNITED STATES. a division of a green cell into four parts; fig. 34, comple- tion of the division of a green cell into four, each part developing a complete zygospore with two cilia ; fig. 35, an abnormal division of a cell into six parts, producing four cells of normal size and two smaller ones ; fig. 36, same as last ; fig. 37,' a vegetative green primordial cell ; fig. 38, cell dissolving, the primordial cell breaking up into green and red granules ; fig. 39, a resting cell developing a colorless end ; commencement of germination ; fig. 40, division of a resting cell into two somewhat elliptical cells, center red, sur- rounded by light and then darker green ; fig. 41, elliptic cell, middle red, margins lighter or darker green ; fig. 42, divi- sion of a resting cell into eight. The maternal cell dissolves into a gelatinous mass containing eight cylindrical, red, mo- tile cells ; fig. 43, two cylindrical cells developed from the young forms in fig. 42, red, with margins green ; fig. 44, green cell, center red ; fig. 45, eight small, light green cells with red centers resulting from the division of a single cell ; fig. 46, grape-like cluster developed from an unsheathed form, resting without having passed through the usual swarming period of life; fig. 47, a large, deep green cell developed from a sheathed resting spore, containing many green granules ; fig. 48, cell similar to the last, but red, which during observation broke up into eight small sub- cylindrical parts, which soon broke through the membrane as active zoospores; fig. 49, similar to the preceding (48), breaks up into more numerous parts, but in consequence of previous dried condition the parts become resting spores; fig. 50, large resting spore, red, breaks up into a larger number of smaller parts; fig. 51, zoospore with hyaline membranous envelope, dark red. These 41 are selected from Cohn's 114 figures. Each a different condition of the same plant. CHLAMYDOCOCCUS NIVALIS, A.Br. Cells globose, red, at first with a hyaline border, which is the thickened epispore, but gradually disappears with age. Diameter of cells, 10-35 jw. Syn. Haematococcus nivalis, Ag. ; Protococcus nivalis, Ag. ; Pal- mella nivalis, Hook ; Coccophysium nivale, Link. ; Tremella nivalis, A.Br.; Uredo nivalis, Bauer. This plant, familiarly known as BED SNOW, is frequently found on the higher peaks of the Rocky Mountains. It is CHLAMYDOMONAS. 167 upon the snow and ice of the Arctic regions, the snow-capped peaks of the Alps and similar localities, that this little plant prevails. The notice of botanists was first drawn to it by Capt. Ross, 1819, on his return from Baffin's Bay, where it was found extending for miles giving a red tinge to the snow. Dr. Kane and other later explorers, report its fre- quent occurrence. Judging by the descriptions given, the arctic plant does not diifer essentially from the form found on the high peaks of our Western chain of mountains. If brought to a lower temperature and cultivated, it may be questioned whether it would prove specifically distinct from Chi. pluvialis. The plants as we receive them from the Rocky Mountains, or from the Arctic regions, are in a quiescent state (resting spores) which multiply rapidly by the simple process of division of cells and would seem to belong to the genus Pro- tococeus, but A. Braun and others who had more facilities to observe the whole process of propagation, find they pass through the various stages of a Chlamydococcus, forming fugitive coenobia, macrogonidia and microgonidia furnished with two cilia, etc. Plate CLIV, figs. 1, 2, simple cells ; figs. 3, 4, two cells dividing into two, and into four parts. Genus 39, CHLAMYDOMONAS, Ehrb. Macrogonidia ovate or oblong-rounded, green, delicately gran- ulated, involved in a rather narrow hyaline tegument, frontal extremity very obtuse, or somewhat truncate with a contractile vacuole, and two cilia ; posterior extremity with a large chloro- phylose vesicle and with or without a red lateral spot. Micro- gonidia arising from repeated division of the cytioplasm of the macrogonidia ; oblong or ovate, numerous, pale green or yellow, becoming brownish ; oospores globose, red or brownish ; con- tents firm, colorless, hyaline. CHLAMYDOMONAS TINGENS, A. Br. Macrogonidia small, ovate or oval, light green without a red pigment spot, membrane close. Diameter of cells, 7-8 yw ; length, 14-25 //. Pools and ditches. Plate CLIV, figs. 5, 6, a variety of sizes of macrogonidia. I CHLAMYDOMONAS PLUVIALE, Wolle. Macrogonidia spherical or nearly so ; bright-light green j 168 FRESH-WATER ALG^E OF THE UNITED STATES. polar vacuole often indistinct; membrane thin and close, cytioplasm divides into two, or more rarely four parts. Diameter of cells, 4-8 //. Pits of rain water, often in large numbers. Plate CLIV, figs. 7, 8, the normal appearance. CHLAMYDOMONAS HYALINA, Cohn. Macrogonidia oblong elliptical, ends more or less rounded, thin -green, or whitish-green, anterior end furnished with two long cilia. Diameter of macrogonidia, 14-22 ^ ; length fully equal to two diameters. Found countless myriads in lake, Wayne County, Penn- sylvania, near the shore and extending outward, giving the water a thin milky-green appearance. Dipped with the hollow of the hand, the motile cells were distinctly visible without the aid of glasses. Plate CLIV, figs. 9, 10, drawn too small in comparison with figs. 7, 8. CHLAMYDOMONAS PULVIUSCULUS, Ehrb. Macrogonidia ovate, nearly twice as long as broad ; deep green, with a bright red lateral spot. Diameter of macrogonidia, 6-13 yw (Eab. ) ; 12-19 ^ long (Kirchner). Syn. Diselmis viridis, Dujard. I quote this species so common throughout Europe, certain it must be found here, although hitherto escaped my notice. In size and form it is almost identical with Chi. hyalina, but deep green in color and possesses a distinct red, lateral pig- ment spot. Plate CLV, figs. 23, 24, a usual appearance of this species, the latter a zoospore indicating much activity by means of two cilia ; fig. 25, an encysted form divided into two ; figs. 26, 27, a similar form divided into four parts ; fig. 28, cell divided, forming new encysted cells ; fig. 29, two red resting cells ; fig. 30, a macrozoospore, contents dividing ; fig. 31, a cell with contents divided ; parts escaping as microzoo- gonidia. HYDRODICTYON. 1 69 Family XIIL—PROTOCOCCACE^E. Vegetative cells not provided with cilia, either single, or united, forming coenobia. Propagation by copulation of zoogonidia ; or by asexual zoo- spores. Division of vegetative cells does not occur. The plants of this Family may be divided into three sections. I. Cells which form coeuobia. II. Cells which form pseudo-coenobia,. III. Cells which remain detached. I. COENOBIA. — Single cells unite into regular, definite forms called coenobia. These are developed primarily from single cells, daughter cells from the same maternal cell. They are separated from multicelliilar plants by the fact, that the single cells are incapable of division and that each may develop the original form. Genus 40, PEDIASTRUM, Meyen. For the plants of this genus, refer to Desmids of the United States, page 152. Genus 41, HYDBODICTYON, Both. Coenobia formed by oblong-cylindrical cells united at the ends into a reticulated structure ; primarily saccate, later simple net work; cells all fertile, some producing macrogouidia, which join themselves into a coenobium within the mother cell, others pro- ducing microgonidia, which are furnished with two or four vibratile cilia, and a lateral red spot. These are motile for a time in the maternal cell and then escape through a pore in the cell wall. They continue active for a short time during which they copulate, then rest, assuming a spherical form and a firmer cell membrane ; they lie dormant, may become perfectly dried, but after being restored by moisture they develop 2-5 biciliate zoospores, which in turn, after a short season of mobile life, come to rest, develop into large irregular, somewhat square cells, cuspidate angles, which soon cast off the membrane and yield young saccate coenobia. 4 HYDRODICTYON UTRICULATTJM, Eoth. Size of the coenobia very variable, differing mainly ac- cording to age ; the younger ones so small that fifty or more 170 FKESH-WATER ALG^J OF THE UNITED STATES. could be arranged within the compass of a single mesh of an older plant. Often very abundant in sluggish, and stagnant waters. Plate CLIV, figs. 11-14, parts of coenobia of various de- grees of development ; figs. 15, 16, very young coenobia ; fig. 17, cell with microgonidia ; fig. 18, cell with macro-' gonidia; fig. 19, free n^icrogonidia ; fig. 20, active macro- gonidia or zoospores. The latter four are taken from Colin. Genus 42, COELASTEUM, Naeg. Coenobium globose, hollow within, formed of a single stratum of green cells, primarily globose ; later the coenobium appears reticularly pierced; in older growths the cells are sometimes polygonal from mutual pressure on the sides. Macrozoospores develop daughter coenobia within the ma- ternal cell, which escape by the rupture of the membrane of the latter. COELASTRUM MICROPORUM, Coenobium spherical, diameter, 40-100 //, consisting of eight, sixteen or thirty-two globose cells, with interstitial openings through which the interior of the coenobium may be penetrated. Diameter of the globose cells varies accord- ing to age ; sometimes as much as 25 yw. Var. SPECIOSUM, Wolle. A large and beautiful variety in which the green spherical cells appear to be joined in the center of the coenobium by gelatinous cords. Diameter of cells and of coenobium rather larger than the type-form. This beautiful form may be a distinct species, but have hitherto seen too few perfect specimens to pronounce it such. Ponds and pools. Plate CLYI, figs. 1-3, a fully developed form and two younger specimens ; fig. 4, var. speciosum. COELASTRUM CAMBRICUM, Arch. Coenobium spherical ; cells angular, rounded on the exterior margin, each bearing a single truncate tubercular process ; sometimes with, but often without interstices. The only description of this species at my command is very brief and without illustration. I infer my plant is the same and hence adopt the name provisionally. The plant is entirely unlike C. sphaericum and C. cubicum, Naeg. STAUROGENIA. 171 Diameter of well-grown specimens about 70 // ; often much smaller, cells of a coeuobium in view, usually only ten. Color light yellowish green, or colorless, except the young coenobia in each cell, bright green. Ponds, not infrequent. Plate CLYI, fig. 5, a coenobium near maturity, the time for yielding up the young plants. Genus 43, SOKASTRUM, Kg. Coenobium globose, solid within, free swimming, composed of four, eight, sixteen or thirty -two compressed wedge-shaped cells, which are sinuate, emarginate, or bifid at the apex and radiately disposed. Propagation unknown. SORASTRUM SPINULOSUM, Kg. Coenobium globose, spinulose ; apex slightly emarginate, angles obtusely rounded with two spines at each rounded angle. Coenobia vary in diameter from 25-75 //. Cells 12-22 yu wide. The distinctive feature between this plant and those of the last preceding genus is, that this forms a solid coenobium, the others are hollow. More frequent than Coelastrum. Plate CLVI, figs. 6-10, smaller and larger coenobia, as they differ in age ; fig. 10, differs more than the others, but not sufficiently distinct for another species. Genus 44, STAUKOGENIA, Kg. Coenobium cubical, hollow within, composed of four or eight or sometimes sixteen subquadrate cells. Propagation by quiescent gonidia, produced after the subdivi- sion of the cell contents. Syn. Orucigenia, Morren. STAUROGENIA CRUCIATUM, Wolle. Coenobium consisting of four equilateral rhomboidal cells, sides incurved, angles rounded, together forming a somewhat square or rhomboidal figure. Cells united by a mucilagi- nous deposit around or between them ; measure of coenobia, 172 FRESH-WATER ALGJE OF THE UNITED STATES. 22-24 }JL each way ; cells about 10 // ; each with a cruciform marking on the surface. Small pond, near Bethlehem, Pa. Plate CLVII, figs. 9, 10, 11, three different forms ; fig. 11 having dropped one cell. Genus 45, SCEKEDESMUS, Meyen. Cells elliptic, oblong, cylindrical, ovate, or spherical, equal or unequal at the ends ; often produced with a longer or shorter spine. Cells most frequently laterally united, forming coenobia. Propagation by means of the repeated segmentation of the cell contents into one or more brood families set free by the rupture of the maternal cell membrane. Cells armed, or unarmed. SCENEDESMUS CAUDATUS, Corda. Cells oblong- cylindrical, each extremity obtusely rounded, 2-4-8 closely united in a simple series (rarely also in double series) the outer cells of a series armed at each extremity with a recurved spine. Length of cells about 22 yw. Kirchner makes the following varieties, which occur freely with us also : Yar. TYPICUS, Kirch. Spines on the end cells only. Yar. SETOSUS, Kirch. Spines on intermediate cells also. Yar. HORRIDUS, Kirch. Spines on all the cells of a series. Yar. ABUNDANS, Kirch. Spines in the middle of a cell, beside those on the ends. Syn. Scenedesmus quadricauda, Breb. ; 8. quadricaudatus, Ealfs. Plate CLYI, figs. 11, 12, var. typicus; figs. 13, 14, smaller forms 5 fig. 15, var. horridus. SCENEDESMUS ANTENNATUS, Breb. Yar. RECTUS, Wolle. Cells fusiform, 2-4 usually joined in a single series 5 rarely a double series. Cells all somewhat curved and cuspidate at the apex. Yar. RECTUS is separated from the typical form by its universally straight cells and straight spines, not recurved. Diameter of cells, without spines, 13-14 yw. Diameter of cells of variety, 14-16 //. Exposed moist white sand, Florida. Sometimes made green with this variety. Have not identified the type-form ; have quoted the diagnosis from Babenhorst's Flora Algarum. Plate CLYI, figs. 16, 17. SCENEDESMUS. 173 SCENEDESMUS DIMOKPHUS, Kg. Cells fusiform, acute, four to eight placed evenly in a single row ; inner cells fusiform with ends often drawn out, thin and long ; outer cells externally lunate. Syn. 8. bilunatus et geminatus. Kg. ; 8. pectinatus, Meyen ; Ach- nanthes dimorpha, Turp. ; Arthrodesmus pectinatus, Ehrb. Smaller stagnant pools. Plate CLVI, figs. 18-21, four forms. Sizes about the same as the preceding species — all are liable to some variation. SCENEDESMUS ACUTUS, Meyen. Cells fusiform, acute at each end, spineless, two to eight united in a series, either single or double, straight and irregularly alternately locked together. Three to six times as long as wide. Transverse diameter of cells, 4-6 yw. Ponds and pools. Syn. 8. fusiformiSj Menegh. ; Arthrodesmus acutas, Ehrb. Plate CLVI, figs. 25, 26, two series of cells. SCENEDESMUS OBTUSUS, Meyen. Cells oblong or ovate, obtuse at the ends, four to eight loosely connected in a simple series, or two series side by side, the thinner ends of the cells interlocking. Cells three to five times as long as broad. Diameter of cells, 6-7 ^. Ponds and pools ; not as frequent as some of the other forms. There is however a small form of cells, 6-7 n long, in series of two to four or more, in basins of fountains, which may belong here. These occur in quantity. Plate CLYI, fig. 22, the typical form; figs. 23, 24, the forms from fountain basins. SCENEDESMUS POLYMOKPHUS, Wood. Cells fusiform, or oval or elliptic or globose, single or two to seven conjoined, furnished in most cases with a single spine, sometimes two at each end ; ends obtuse, subacute, or very acute ; spines exceedingly slender and acute, straight, moderately long, inclined. Diameter of cells, 4-12 yw. Dr. Wood remarks, "This plant was found in a quiet pool, filling the water in such numbers as to make it opaque and very green." To the present author this appears more like a hetero- geneous mixture than a species. 174 FRESH-WATER ALG^E OF THE UNITED STATES. . SCENEDESMUS ROTUNDATUS, Wood. Cells globose or subglobose, armed with three to five very long, slender, acute, straight spines, single or in pairs, or three to four closely conjoined in a two-fold rank. Diameter, 4-8 //. Plate CLVI, fig. 27. Dr. Wood's remark to this form, "It seems scarcely correct to place this plant in the germs Scenedesmus, but I do not know any other genus to which it is more closely allied." Wood's Contribution, p. 91. This form is not infrequently intermingled with other species of Scenedesmus; it certainly appears related, but whether a distinct species, or merely connected in some way in a process of development, has not been made clear. II. PSEUDO-COENOBIA.- -The single cells united into a coeno- biuni-like family, but separated from a true coenobium by the cells not all belonging to the same generation. Genus 46, SCIADIUM, A.Br. Family is composed of a number of cylindrical cells, each contracted at the base into a short slender stem by which they are united, causing the long cells to spread above. Gonidia six to eight, resulting from the division of the cell contents ; at length protruding from the ruptured apex, retained at the mouth and extending in the form of an umbel. This process is repeated to a third, or sometimes a fourth generation. Ultimate cells produce free biciliate zoogonidia. SCIADIUM ARBUSCULA, A. Br. Umbellate, cells straight, rarely falcate, obtuse at the apex ; contracted at the base into a short stem whose length is about the same as the diameter of the cell. Diameter of cells 4 yw, with exceptions 3-5 yw. Syn. Ophiocytium arbuscula, (Naeg.) Bab. Rather rare, but had single specimens from three or four States. In small pools. Plate CLVII, figs. 1, 2, young cells ; fig. 3, commencement of the first generation of daughter cells ; fig. 4, farther pro- gress of the progeny ; fig. 5, a second generation being evolved from the first ; fig. 6, a third generation developing from the last. OPHIOCYTIUM. 175 SdADIUM GKRACILIPES, A. Br. Simple umbels, in connection by means of a cell ; usually floating ; a loose and vague growth ; cells cylindrical, straight, rarely slightly curved (foreign plants sometimes spirally twisted ) ; apices obtuse ; stems slight, with stipe nearly twice as long as the diameter of the cell. Diameter of cells, 4-5 //. Only locality hitherto discovered, pool, Minnesota. Syn. Ophiocytium gracilipes, A. Br. Plate CLYII, figs. 7, 8, from a specimen, Minnesota. III. EREMOBiA.--The single cells do not remain together, but scatter, and live independent of one another; if not widely separated they may form clusters of irregular forms, but no coenobia. Genus 47, OPHIOCYTIUM, Naeg. Cells cylindrical, straight, variously curved or circinate, at- tenuate at one end into a thin, short stem or mucro ; sometimes both ends rounded bearing each a longer or shorter spine, and sometimes without spines. Foreign authors seem unanimous in declaring "One or the other pole attenuated into a thin, short stem ; the other pole rounded.'' Our forms, evidently belonging to the same genus, diifer in this regard. Propagation by means of zoospores as in Sciadium with this difference, that the daughter generations of the former remain attached, in the present they are set free. OPHIOCYTIUM COCHLEARE, A.Br. Cells cylindrical, slender, pale-green, often very long, fili- form, variously curved or circinate, one end attenuated into a spine-like process acute or truncate ; other end rounded ; contents homogeneous. Diameter of cells, 5-8 yu. Frequent in ponds of stagnant water. Syn. Ophiothrix apiculata, Naeg. ; Spirodiscus cochlearis, Eich. Plate CLYIII, figs. 8-14, the usual appearance of the plant. 12 176 FRESH-WATER ALG.ZE OF THE UNITED STATES. OPHIOCYTIUM CAPITATUM, Wolle. Cells short, five to six times longer than broad, nearly straight, or arched, with both ends more or less incurved and most frequently somewhat enlarged, rounded, a spine on each end. Diameter of cells, 6-9 //. Not infrequent in ponds, East and West. Plate CLVIII, figs. 3-7, different forms. OPHIOCYTIUM PARVULUM, (Perty) A.Br. Cells small, variously curved, and often interwoven into masses, both ends rounded, no spines. Near O. cochleare, but smaller and spineless. Syn. Brochidium parvulum, Perty. i OPHIOCYTIUM CIRCINATUM, Wolle. Cells cylindrical filiform, long, circinate, repeatedly coiled, ends obtusely rounded, no spines. Diameter of cells, 10-13 yw. Specimens frequent in pond near Minneapolis, Minn. — Coll. Miss E. Butler. Plate CLVIII, figs. 15-18, four cells of ordinary appear- ance. OPHIOCYTIUM CUSPIDATUM, (Bailey) Eab. Cells large, smooth, crescent-shaped, Closterium-like, ends mucronate. Four to five times longer than broad. Diameter 50 /* ; length 150-165 ^ • length of spines, 15 /*. Syn. Closterium cuspidatum, Bailey. Rather rare— Bailey found it in several localities ; person- ally collected it only in Gilder Pond, Massachusetts, but re- . ceived specimens from Minnesota and from California. Plate CLVIII, figs. 1, 2, after specimens from Gilder Pond, Massachusetts. Genus 48, CHARACIUM, A. Br. Cells always attached ; at one end usually distinctly stipitate, variable in form ; oblong, ovate, pyriform, fusiform, etc. Cell contents green, homogeneous or granular ; zoogonidia succeeding division of the cytioplasm, more or less numerous, occupying the whole of the cell, at length greatly agitated, escaping by a CHARACIUM. 177 lateral, more rarely terminal, pore or rupture ; oblong with two vibratile cilia. — A.Br. CHARACIUM SESSILE, Herm. Cell globose or broadly ovate, with apex somewhat pro- duced ; one-half longer than broad, green ; cytioplasm often concentrated or contracted in the middle. Diameter, 7-9 //. Frequent on filamentous algae. Plate CLIX, fig. 1, five cells nearly matured. CHARACIUM ACUTUM, A. Br. Cells straight, usually erect, ovate, tapering gradually at both ends, producing a short neck at the apex and a stipe at the base ; apex at first acute and closed, later open to admit the escape of the zoospores ; stipe short, dilated at the end, cytioplasm homogeneous, or granular, pale-green, contracts and then divides producing zoospores. Diameter of cells, 7-10 //. Syn. Hydrianum acutum, Eab. Parasitic on larger forms of the algae ; ponds. Plate CLIX, fig. 2, four cells scarcely separable from the preceding, C. sessile, except that it is shortly stipitate. CHARACIUM PRINGSHEIMII, A. Br. Cells erect or suboblique, upper end drawn out into a rather thick neck ; stipe brownish yellow, dilated at the base. Diameter of cells, 10-15 /* ; about twice as long as wide ; cell contents green, granular. Differs from the last two in larger size and longer stipe. The features of the last three forms are so similar, the pro- priety of separating them as species may be questioned. Farther observations are desirable. Plate CLIX, fig. 3, three cells on filament of Oedogonium. CHARACIUM AMBIGUUM, Herm. Cells erect, more or less oblique, narrow lanceolate, some- what sword-shaped, 4-6 times longer than broad, each end attenuated, apex cuspidate and sometimes curved ; cytio- plasm bright green. Diameter, 5-8 /*. Ponds and pools, rare. Plate CLIX, fig. 5, six cells on filament of Conferva. 178 FRESH-WATER ALG^E OF THE UNITED STATES. CHARACITJM NAEGELII, A. Br. Cells elliptical or inverted egg-form when fully developed, 2-3 times longer than broad, always with rounded apex, stipe short, not dilated at the base. Cytioplasm bright green, granular. Diameter of cells, 7-18 ^. This form approaches very nearly to C. Sieboldi, also of A. Br. Can scarcely be separated except by size. Thus governed, it is C. Naegelii. Ponds, not frequent. Plate CLIX, fig. 4, filament of Oedogonium full of the plants ; two of them more fully matured than the rest. CHARACIUM HETEROMORPHUM, Eeinsch. Cells at first globose-elliptical, attenuated below into a thin hyaline stem ; contents granular, then contracted in preparation for formation of the gonidia ; zoogouidia elon- gated, escaping at the broadly opened apex. Diameter of cells, 8-10 p ; 2-3 times as long as broad. &y \\.Hydrianum heteromorphum, Rab. The distinction between the present genus and Hydrl- anum, Bab., being somewhat uncertain in the progress of development, I have followed the example of Dr. Kirch - ner by uniting the two. C. heteromorphwn would be a de- cided Hydrwnum, but the first three on the list, C. sessile, C. acutum and C. Pringsheimii would hold a more question- able position between the two genera. Genus 49, PROTOCOCCUS, Ag. Spherical forms not attached, not branched, in the strictest sense unicellular, single or gathered into irregular clusters, primarily always filled with chlorophyl green cytioplasm, often changes to red by exposure and other circumstances. They multiply rapidly by the process of cell division. As plants they have no value in the system of classification. More modern observations show that, as a rule, they are merely an intermediate condition of growth of higher filamentous plants. Have included under this head also the old genus of Chlorococcum and Pleurococcum, thus embracing a heterogeneous variety, all with hyaline cytioderm, mostly without tegument, swimming free, forming a scum on stagnant waters ; or out of the water, on trunks of trees, old wood, moist or shaded rocks, PROTOCOCCUS. 179 or compact shaded earth, forming a pulverulent stratum. The cells are more properly niacrospores or microspores. Such Protococcus forms occur, however, not only in the process of development, but also in conditions of decay. Large masses are sometimes observed, resulting from the dissolution of fila- mentous algae. Have observed this process, particularly in Spiro- gyra, how cell walls fall to pieces and waste away ; the cell con- tents, Pro£ococcws4ike, are set free for a longer existence and possibly for an asexual mode of reproduction. Cienkowski, a close observer, made similar observations on Cladophora, Ulotlirix, Hydrodictyon, Botrydium, and others. As far as our present knowledge goes there is no appreciable distinction between the macrospores or microspores of different genera of Chlorophylous filamentous alga3, particularly in the early stages, after separation from the maternal cells ; later changes may and do occur. I repeat some of the thoughts already expressed in the Intro- duction (v. p. xiii) about the life-history of various genera of Fresh-water Alga3; they have an intermediate, or arrested existence. In this stage they not only exist, but multiply very rapidly. The unicellular forms, ( Protococcacece) under consid- eration belong to this class, and are among the most common, because some of them can be found everywhere and at all seasons of the year ; they exist equally well during the scorch- ing heat of Summer and the frigid cold of Midwinter, but the multiplication of the cells may be arrested during the extremes of temperature. Damp, warm weather is most favorable to increase. They multiply, ordinarily, by cell division in one or two directions, not only one or two or even ten times over, but hundreds of times. One cell, in the course of ten days has pro- duced a family of twice 600,000 cells, under my observation; I say twice, because a single layer on the glass on which they grew contained 600,000 cells by liberal calculation, but the clusters had the cells more or less piled two or three fold. In this condition they may exist for months forming green crusts on the trunks of trees, etc., as already indicated. Some of these under favorable circumstances, preferring cool and wet weather, suddenly develop into filamentous algre, the same as those from which they originated. Every cell may not develop, just as little as every seed from the pods of wild flowers, or the ears of grasses, or the spores from the capsules of mosses or other cryptogamous plants; how many millions of these are grown to die unseen; few ever come to perfection. These 180 FRESH-WATER ALG^ OF THE UNITED STATES. spores possess, however, a peculiarity entirely distinct from seeds and spores of other plants ; they multiply and renmltiply and yet retain the character of spores. The provision appears to be to prepare a bed, or soil, to sustain and nourish the forth- coming comparatively few which do develop. In a paper read before the New York Microscopical Society, by E. B. South wick (See Jour, of the Socy., Vol. 2, ~No. 1), the writer observes on the frequency of Protococcus viridis. He gathered it from the trunks of a hundred different species of trees in Central Park, New York, some of the woods appearing more favorable to the multiplication of the cells than others ; in some cases the green coating, mostly on the north side of the trees, extended up the trunk some distance ; on others it was confined to the base ; some had very little, because not so well adapted to its growth. He observes, "on the American Elm the growth is most luxurious, extending to a great height." 1 ' On the Hibiscus the growth was of the finest character, and hyphae were observed in a budding process having from 2-6 branching cells ; below, the hyphae were the large masses of Protococcus cells which had been produced by fission, mostly in twos and fours, standing out in projecting clusters. On the Hemlock it was very abundant and of a bright yellow- ish green, and the gelatinous mass was so strong that when placed under the cover-glass of a slide, in water, they were with difficulty separated." Have quoted these words to indicate some of the different con- ditions in which this arrested form of growth is found, and also to indicate how a commencement of development into filaments takes place. Had Mr. South wick continued his observations on the hyphae at the base of the Hibiscus, where there is more moisture, he would no doubt have discovered a development of Ulothrix parietitia, Kg. These polymorphic (dimorphic; forms of arrested growths, PROTOPHYTA, may, if at all deserving of a place in a system of classification, be divided into two sections; the AERIAL and the AQUATIC forms. It seems but natural that a plant-form developed in the water will assume features differing more or less from those growing out of the water. The land forms have usually thinner or some- times crustaceous membranes, but even these after a rain or during moist weather become gelatinous, thus indicating a character which, when in the water, often produces a wide hyaline envelope.. All the aquatic forms are larger than the aerial varieties. PROTOCOCCUS. 181 As a matter of historical interest we record a few of the more prominent forms with the names, partly as varieties, which obtained hitherto. I. — Aerial Forms. PROTOCOCCUS VIRIDIS, Ag. Cells small, segregate, accumulated in broadly expanded strata of yellowish or darker green color, usually pulver- ulent, but during moist weather and after rain somewhat gelatinous. Diameter of cells, 3-13 yw. Common everywhere, on trunks of trees, moist rocks, walls, timbers of shaded buildings, old fences, etc. Syn. Pleurococcus vulgaris, Menegh. ; Protococcus communis, Kg. ; Clilorococcum vulgare, Grev., etc. Plate CLXI, fig. 1, a simple cluster of cells evenly dis- tributed. Plate CLXII, fig. 2, the same, but often clustered by twos, fours, and more, the result of division in one or two directions ; the Pleurococcus form. Plate CLXIII, figs. 1-5, show modes of development into filaments of Ulothrix. b. — Var. ANGULOSA. Pleurococcus angulosus, Menegh. The same as the last, but in different condition; in the process of decay rather than of multiplication ; effected by alternate moisture and dryness; the cells sometimes form around themselves gelatinous envelopes; they divide dis- tinctly ; becoming angular by crowding. Plate CLXII, fig. 3, cells very gelatinous. c. — Var. DISSECTUS. Pleurococcus dissectus, Naeg. Another condition of the same, being a dark green vege- tative, developing form, with cells decussately dividing; membranes thin. Diameter of cells, 5-11 ^. Usually on old and moist wood. Plate CLXII, fig, 4. Plate C, fig. 5, cells commencing to develop. d. — Var. MINIATUS. Pleurococcus miniatus, (Kg.) Naeg. Cells often of an orange yellow, or reddish brown color, 182 FRESH-WATER ALG^ OF THE UNITED STATES. (more frequently yellowish green); cell membrane rather thick, colorless. Diameter of cells variable, 5-15 /*. This may be termed the conservatory form. It is com- mon on flower pots, walls, and ground floors of green-houses. Porphyridium cruenta is merely another form of the same polymorphous, arrested, growth. Compare Porphyridium,^ page 194. The change of color is due to abnormal conditions rather than to a normal characteristic. Plate CLXII, fig. 5. The usual condition of single cells ; sometimes 2-4 are seen in a family. II. — Aquatic Forms. e.--Var. INFUSIONUM. Chlorococcum infusionum, Bab. Cells spherical, very various in size; mostly 5-15 ^ in diameter, but larger ones are intermingled ; the largest measuring 75-100 //. Sometimes very abundant in early Spring in meadow pools, largely intermingled with filaments of Ulothrix; evi- dently the two are closely related. Syn. Protococcus Meneghinii, Kg.; Ewibryospliaera Meneghinii, Trevis ; Lepraria infusionum, Schrank. / Plate CLXI, figs. 2, 3, a range of sizes from the smaller to the largest cells. Normally the smaller cells greatly out- number the larger sizes. /,--Var. HUMICOLA. Cystococcus humicola, Naeg. Stratum effused dark green ; cells globose, variable in size, sometimes many united in families, involved in a com- mon hyaline tegument ; cell membrane thin ; cell contents at first homogeneous, later granular. A form recognized as belonging to this variety occurred in cask of rain water around the water line. Diameter of larger cells, 16-18 //. General appearance very near Plate CLXI, fig. 1, P. viridis. #.--Var. BOTRYOIDES. Chlorococcus botryoides, Bab. Cells spherical, irregularly clustered, somewhat grape - like. Cell membrane thin, hyaline, homogeneous, green; with age often brownish ; cells average 12 yw. Not rare in pools. Not a normal form — merely an adven- titious condition. POLYEDRIUM. 1 83 h. — Var. GIGAS, Kg. Chlorococcum gigas, Eab. Cells green, mucous, globose, large, either single or associated in small families, always involved in a broad, more or less lamellose, hyaline, tegument. Diameter of cells, without the hyaline membrane, 12-18 //. Frequent in small ponds. Plate CLXI, fig. 4, single cells without tegument; figs. 5-11, cells divided into two ; redivided into four or eight cells in a wide tegument ; fig. 12, four cells dividing ; fig. 13, a large tegument with sixteen cells, each redivided into four. i. — Var. WIMMERI. Chlorococcum Wimmeri, Eab. Cells single, globose with rather thick membrane, often lamellate, colorless ; contents of cells often yellowish red ; primarily green. Diameter of cells, 45-55 ^. Occurs occasionally in stagnant waters. Not a normal condition ; only another phase of the polymorphous forms of the present genus. Plate CLXI, figs. 14-20, two of the cells dividing. j: — YESTITUS. Pleurococcus vestitus, Eeinsch. Cells solitary or in small loose families; green, or later orange yellow ; cell membrane thick, densely invested with small hairs, or spines. Diameter of cells, 12-22 ju. Not rare in ponds. Syn. Acanthococcus vestitus, Lagh. Plate CLXII, fig. 1, a cluster of cells of this form. Genus 50, POLYEDEIUM, Naeg. Cells single, segregate, free swimming, compressed, 3-4-8 angled ; angles more or less produced, sometimes radially elon- gated, either entire or bifid, mostly armed, rounded or rather truncate at the ends. Cell membrane thin, even. Cell contents green, mostly granular, sometimes with one to four reddish oil drops. Propagation by means of gonidia, of which usually three or more are formed in a maternal cell ; they escape through a fissure in the membrane. 184 FRESH- WATER ALG^E OF THE UNITED STATES. IsTot unlikely that some of the forms under this head also belong to the arrested stages of development of higher forms. Pringsheim observed resting spores in the development of Hydrodictyon of polyhedron form, from which young Hydrodic- tyon plants were developed. POLYEDRIUM TRIGONUM, Cells somewhat compressed, three to five-angled ; angles obtuse mucronate, sides more or less concave. Kirchner suggests the following as names for varieties : a. — typicum, Kirch. Three-angled, mucronate. b. — minus, Eeinsch. Three or four-angled, sides concave, smaller than the last. c. — tetragonum, Eab. Four-angled, ordinarily one mucro at each angle, rarely two or more. d.—^pentagonum, Eab. Five- angled, otherwise as "c.': e. — -punctatum, Kirch. Four-angled ; each angle with a short obtuse process, membrane granularly roughened. f. — bifurcatum, Wille. Four-angled, angles bifurcate sharply tipped. Diameter of cells, 13-36 /*. More or less frequent in pond waters. Of the six varieties only such were identified as are illustrated. Plate CLIX, figs. 7-10, tetragonum; figs. 15-18, bifurcatumj figs. 25-27, minus. POLYEDRIUM GIGAS, Wittr. Cells irregularly four or five -angled ; angles obtuse, sides concave. Diameter of cells, 35-70 /*. Have reason to question whether this is not the form recognized by Pringsheim as related to Hydrodictyon — see note above, with generic character. In ponds where Hydrodictyon prevails. Plate CLIX, figs. 11-14, typical forms. POLYEDRIUM ENORME, (Ealfs) Eab. Cells irregularly four angled, with the angles produced, hyaline, deeply bilobate; sometimes repeatedly bilobed, with the ends of lobes acute, or mucronate. Diameter of cells, 25-40 ^. Syn. Staurastrum enorme, Ealfs. PALMELLACE^E. 185 A very variable plant, not rare in ponds, but every new cell found is somewhat unlike the previous one observed. Plate CLIX, figs. 19-23, five varieties. POLYEDRIUM MINIMUM, A. Br. Cells quadrangular; angles obtuse, sides more or less deeply sinuate ; lateral view oval. Cells break in the mid- dle and discharge gonidia. Diameter of cells, 8-10 /*. Often in large numbers in small pools. Plate CLIX, figs. 28-31, six cells in different positions ; figs. 32-34 cells discharging gonidia. POLYEDRIUM LONGISPINUM, (Perty) Eab. Quadri-radiate, radii thin, elongated ; scarcely thickened into a body in the center. Length of arms, 30-45 yw. A rare and peculiar species ; seems scarcely related to t other forms described. Stagnant pond waters, the habitats of Desmids. Syn. Phycastrum longispinum, Perty. Plate CLIX, figs. 35-38. POLYEDKIUM MUTICUM, A.Br. Cells triangular, somewhat compressed, angles rounded, spineless, sides moderately compressed, membrane smooth. Diameter of cells, 12-15 /<. Here and there in ponds. Plate CLIX, fig. 24, three cells. Family XIV.—PALMELLACE^l. Unicellular algae, cells either single, or numerous, consti- tuting families, imbedded in a jelly to form a gelatinous stratum which is amorphous ; tubular shaped ( Hormaspora ) ; variously divided and perforate, ( Tetraspora ) ; falsely branched, (Hy- drurus); or sometimes the jelly or mucus is wanting, (Ehaphi- dium, Dactylococcus). Cytioderm mostly thin, often furnished with a gelatinous, or homogeneous, or lamellate tegument. Cytioplasm homogeneous, mostly at maturity distinctly granular, green, or reddish or fuscous, always furnished with a chloro- phylous vesicle, except Ehaphidium. 186 FRESH-WATER ALG^ OF THE UNITED STATES. Multiplication takes place by a vegetative division of the cells; propagation by transitory goniclia arising by various divisions of the protoplasm from the last vegetative generation ; gonidia without integument, mostly furnished with two cilia at the anterior end, and moving about actively. — Rabenhorst. Genus 51, DICTYOSPHAEBIUM, Naeg. Cells green, egg or kidney-shaped, united into a somewhat globose, hollow family, involved in a gelatinous, more or less liquid tegument; sometimes wanting; swimming free. Cells furnished with a single chlorophylous vesicle and a lateral trans- parent spot, surrounded with thick coats which are confluent into a homogeneous jelly ; united by very fine filament, which are dichotomously divided and radiate from the center to the peripheral families. Division of the cells occurring primarily in all directions, later only radiately. * DlCTYOSPHAERIUM EHREXBERGIANUM, Naeg. Family subglobose or suboval ; cells somewhat ovate or subglobose, with thin smooth membrane. Diameter of cells, 4-7 f*. Diameter of family about 15-18 yw. Not infrequent in ponds. Syn. Dictyo. pulchellum, Wood. A form not to be separated from Dictyo. Ehrenbergii, as illustrated and described by Naegeli. It is indeed more like the typical form than the plant which has frequently oc- curred to me. Plate CLYI, figs. 29, 30, two families ; fig. 31, a family after Naegeli' s figures. DlCTYOSPHAERIUM RENIFORME, Bulnh. Cells reniform, nearly twice as broad as long. Families somewhat oval or irregular. Diameter of cells, 6-9 )JL by 10-20 ^ Diameter of families, 40-70 ^. Very variable. Ponds, now and then. Plate CLVI, fig. 28, a regularly shaped family. DlCTYOSPHAERIUM HlTCHCOCKII, Wolle. Cells green, broadly oval, nearly one-half longer than broad ; often constricted in the middle indicating the pro- HYDRURUS. 1 87 cess of division of the cells. Families irregularly spherical ; cells arranged in radiating branched series, held by slender, colorless, gelatinous threads ; cells with a , central many- rayed chlorophyl body containing a large starch granule. Diameter of cells, 10-13 p ; length, 18-20 jn. Frequent in Denmark, and Splitrock ponds, New Jersey, September, 1885. A distinct form, but whether a plant strictly of this genus or a mere condition of plant development may be ques- tioned. The cells are larger than those of other species, the form is different, the longer axis of the cells is parallel with the radiating series, not the shorter one as in other species ; the large central nucleus is another peculiarity, and the cells are not so entirely confined to the periphery. Plate CLVII, fig. 12, a normal, well-developed specimen. Genus 52, HYDBUKUS, Ag. Thallus gelatinous, fixed at base, cylindrical or compressed, elongated, 2-12 or more inches long; often variously divided, sticky, surface naked or densely covered with delicate gelati- nous, at times fasciculate, fibers. Cells in the beginning globose or subglobose, afterwards elongated or elliptic, one or the other pole colorless, arranged more or less regularly in longitudinal families ; tegument thick, at length diffluent ; cells divide first in one and then in two directions. HYDRURUS FOETIDUS, (Vill.) Kirch. Fronds gelatinous, attached at the base, about twelve inches long, one inch wide in the middle, tapering both ways ; very much and irregularly branched ; branches scattered or crowded, simple or divided, gelatinous at first, later more firm and elastic. Thallus solid, or rarely hollow, seinipellucid, light green, olivaceous, or ochraceous, the end simple or penicillate. Cells primarily globose or sub- globose ; later somewhat conoid or elliptic. Diameters of cells range from 6-9 yw, with exceptions larger and smaller. Syn. Conferva foetida, Villars, 1789. Ulvafoetida, Vauch., 1802. Rivularia foetida, DeCandolle, 1805. Tremella myosuruSj Lyngb. , 1801. Hy drums penicillatus, Ag. Hydrurus Ducluzelii, Ag. 188 FRESH-WATER ALG^ OF THE UNITED STATES. Have selected only these six synonyms out of a list of thirty-three by almost as many different authors. It is very evident that the credit of first naming this plant is due to Villars (1789), not to Vaucher, because he in his Histoire des Conferves, 1803, p. 245, quotes Villars as the originator of the name foetida. Most authors, since 1824, to within a few years, call the plant ff.penicillatus, after Agardh. However more expressive this name may be, it has no claim to priority. Dr. O. Kirchner, of Breslau, Prussia, 1878, and Dr. J. Rostafinski, of Cracow, Poland, 1882, have restored the original name. The following are given as varieties : a. — Yar. PENICILLATUS, Ag. Thallus long, three to twelve inches, tubular, simple at base, wider and much branched above. Branches slender and long as the main stem, thickly set with short branchlets of dull green color. The most usual form. 6. — Yar. OCCIDENTALS, Harv. Thallus very long, one to two feet or more, much branched; branches very irregular, scattered or crowded, worm-like, tapering to a fine point, naked or clothed with feathery, villous ramuli ; cells ellipsoidal or pear-shaped, twice as long as their diameter. On the rocky bottom of rivers and streams in a strong current, Santa Fe, New Mexico. Forma. CALIDAKIUM, (Wood) Wolle. Wood in his Contribution, p. 34, describes Nostoc calida- rium, from Benton Springs, California, developed in a temperature of 100°-120° Fahr., growing to a length of over two feet, and looking like bunches of waving hair of the most beautiful green, etc. He saw dried specimens only, and those very limited, and was evidently misled by them. There is no doubt the plant is the same as described by Harvey, but dwelling in warm water. c.--Var. IRREGULARIS, Kg., forma CONFUSA, Eab. Smaller confluent masses, gelatinous, obsoletely branched ; thin branchlets almost entirely wanting. Found it to occur on the margins of turbulent waters, at waterfalls, and margins of rapid mountain streamlets over rocky beds. Appeared more like olive green or brown con- fluent masses than like a filamentous plant. d.--Yar. DUCLTJZELII, Ag. Thallus 1-3 inches long, slightly branched, but clothed with shorter or longer thin branchlets, the latter often ex- HORMOSPORA. 189 tending from the base to near the apex, color light brown or dull green. Sometimes in abundance in exposed, stony, rapid moun- tain streamlets. Plate CLXIV, figs. 1, 2, thallus of H. penicillatus about half of normal size ; figs. 3, 4, small part of a branchlet greatly enlarged showing the scattered cells ; figs. 5, 6, two young plants ; figs. 7, 8, 9, three cells taken from branchlet (4, 5), much enlarged ; fig. 10, first condition of develop- ment ; figs. 11, 12, progressed condition, cells dividing in one direction ; fig. 13, cells dividing in two directions. After Eostafinski, figs. 14, 15, two small fronds of H. irregu- laris, forma confusa ; figs. 16, 17, two thalli of H. Duduzelii. Genus 53, PALMODACTYLON, Naeg. Cells dull green, small, globose, enclosed in a colorless cylin- drical bladder-like membrane, often diffluent ; sometimes with transverse septae, making a series of small cells. Two, four or many of these tubular bladders with rounded apices, connected at one end, spreading radiately. Division of internal cells at first in one direction, later in two. One, two or four series of cells in each membrane. PALMODACTYLON VARIUM, Naeg. Family composed of numerous cylindrical bladder-like cases, radiately disposed by being connected at one end, each containing one, two or more rows of small cells. Diameter of cells 4-7 //; cylindrical sacks average about 36 ,u wide and 100 yu long. Stagnant ponds. Plate CLXXXVII, figs. 8, 9. PALMODACTYLON SIMPLEX, Naeg. Family simple, without branches, more filamentous struc- ture, otherwise like the last. Habitat the same. Can not reconcile my mind to the value of these forms. They occur now and then, but always leave the impression of their valuelessness as true plants. Genus, HOEMOSPOEA, Breb. ( A pseudo-genus. ) To this genus were reckoned a number of forms with oblong cells arranged in a single series, surrounded by a wide, colorless tegument, floating in families or clusters. It has been shown 190 FRESH-WATER ALG^J OF THE UNITED STATES. that filaments of this kind are more or less frequently intermin- gled with UlothriXj Cylindrocapsa, Conferva, and others. The cell membranes soften and diffuse, producing wide colorless envel- opes, such as were made characteristic of this genus. Compare descriptions of these genera, and particularly the illustrations. Plate CLXXXVII, figs. 10-23. Genus 54, TETEASPOEA, Ag. Cells green, spherical, contained in a thick, gelatinous or sub- membranous thallus, which in the beginning is short, sack-like, afterwards expanded. Cells more or less by twos or fours, as they divide in one or more directions ; afterwards scattered. Tegument thick, very rapidly diffluent into a homogeneous mucus. Zoospores are developed singly, one in a maternal cell. These gelatinous structures are of questionable value, as true, fully developed plants ; they are evidently a mere condition of growth, but having hitherto failed to detect, with certainty, their relationship, they are allowed to retain their nominal positions. Older thalli often contain developing forms of filamentous plants, such as Scytonema, Sirosiphon, Hapalosiphon and others. One variety T. gelatinosa, as found several times, two or three years apart, contained filaments of OsciUaria cruenta, Grun., scattered through the very large gelatinous masses. Other varieties appear to be more nearly related to Spiro- gyra and other Chlorophycece. TETRASPORA CYLINDRICA, Ag. Thallus attached, attains a length of 6-10 inches ; 2-10 // thick, tubular cylindrical, simple, ends tapering to a fine point, rather firm, gelatinous, dull or brighter green color. Diameter of cells about 16 /*. Syn. Viva cylindrica, Wallenbg. Trenches of spring water. Plate CLXY, figs. 7, 8, T. cylindrica half the natural size, and cells magnified. TETRASPORA BULLOSA, (Eoth.) Ag. Thallus rnernbranaceous, saccate, obovate, sinuate, bullose, one to six inches long, dark green, smooth or more or less verrucose; cells nearly spherical, geminate, or quaternate, crowded, granular. Diameter of cells, 6-12 /*. TETRASPORA. 191 Syn. Ulva bullosa, Roth. ; Tetraspora minima, Desv. ; Monotrema bullosiim, Thur. In sluggish, shallow streams, attached to stones. Plate CLXV, figs. 1-6, three forms ; 1-4 about natural size ; fig. 5, about half, or quarter natural size ; fig. 6, the cells magnified. TETRASPORA LUBRICA, (Roth. ) Ag. Thallus elongated, tubular, erect, two to twelve inches long; splitting, undulate, sinuous, between gelatinous and menibranaceous, yellowish green, cells globose, or somewhat angular, green, tegument very thin. Diameter of cells, 8-10 yw. Syn. Ulva lubrica, Roth ; Tetrasporella lubrica, Gaill. In rather quiet spring water, sometimes in large quantity. Plate CLXV, fig. 9, only about half the natural size. Var. LACUNOSA, Chaud. Thallus elongate, tubular, but not erect, attached to stones, in not rapid mountain streamlet, light green, thallus numer- ously perforated, with large elliptical lacunae. Thallus 2-10 inches long. Plate CLXV, fig. 10, thallus half natural size ; fig. 11, cells magnified. TETRASPORA GELATINOSA, (Vauch.) Desv. Thalli large, irregularly expanded and divided, very gela- tinous, at first attached, then swimming free, colorless or edged with green; cells spherical, scattered or by twos; variable in size. Diameter of cells, 3-12 yw. Mountain springs, Broadtop Mountain, Pennsylvania. All the masses with scattered filaments of Oscillaria cruenta. TETRASPORA EXPLANATA, (Kg. ) Kirch. Thallus attached, or floating ; irregularly expanded, rather soft and slippery, green; cells somewhat elliptic, angular, or globose, usually small and by twos. Diameter of cells, 5-7 /*. The form recognized as of this variety most frequent on wet timbers about sluices at mills. Syn. Palmella terminates, Ag. ; Coccochloris terminates, Breb. Plate CLXY, fig. 12, most frequent form, less than natural size. 13 192 FRESH-WATER ALGM3 OF THE UNITED STATES. Genus 55, SCHIZOCHLAMYS, A. Br. Cells globose, either single or 2-4 associated in families, the same as Tetraspora, and separated from that genus by the divid- ing of the cell membrane into two or four parts. This splitting and peeling of the membrane of the cells either coincides with a division of the internal cell mass or it occurs without any such division. Having seen this form repeatedly, usually associated with Tetraspora, and of the same general structure, same color or shade of green, same size of cells, dividing in the same way, in the same water and side by side, it has become evident, it is nothing more nor less than a form of it. Plate CLXII, fig. 7, cells of different sizes and in different stages of peeling, and dividing ; fig. 9, another form, green, corresponding with Chroococcus dicorticans, A. Br. , among the Cyanophyceae, but doubtless also a Tetraspora. • Genus 56, PALMELLA, Lyngb. Cells globose, oval or oblong, chlorophyl-green, but sometimes changes to orange or reddish color, surrounded with a more or less thick integument, generally very soon confluent into firm or soft shapeless jelly masses. Division of the cells alternately in all directions. The forms under this genus, like those of the preceding genera, Tetraspora, Protococcus and others, belong to the uncertain con- ditions of the Protophyta, arrested polymorphous forms, all multi- plying rapidly by the process of cell multiplication without developing, for a protracted period, the true plant. What the particular plants may be to which these Palmetto, forms indivi- dually belong has not been determined. We hold farther opinion in abeyance, in hopes of more light, and meanwhile record such forms as occur. PALMELLA MUCOSA, Kg. Thallus expanded, irregular in form, rather soft gelatinous, dull or olive green, cells spherical or broadly oval. Spher- ical cells variable in size, 7-14 u in diameter ; oval cells 12-15 f* wide, about one-third longer ; cell contents more or less granular. The former most frequent on dripping rocks, the latter on wet ground. Plate CLXII, figs. 12, 14, the two forms. PALMELLA. 193 PALMELLA HYALINA, Breb. Thallus irregularly expanded, gelatinous, green, cells minute, crowded ; tegument almost homogeneous with the gelatinous thallus, very soon diffluent. Diameter of cells, 0.75-1.00 //. Syn. Coccochloris hyalina, Menegh. Pools of stagnant water. Plate CLXII, fig. 6, a well -filled part of thallus. PALMELLA MOOREANA, Harv. Thallus at first somewhat globose, tuberculate, dark green, gelatinous, firm; cells nearly equal, elliptical, lighter or darker green. L»iameter of cells, 5 p. by 8 yu long. The thallus at first firm and floating ; diffluent with age ; the cells often found 011 wet ground, marshes ; probably the same as Aphanothece prasina, A. Br., and PalmeUa dura, Wood. Syn. Coccochloris Mooreana, Hass. Plate CLXII, fig. 11, small section of thallus. PALMELLA UVAEFORMIS, Kg. Thallus thick, gelatinous, soft, surface irregular, rather bright green ; cells small oblong, elliptic or globular, often variable in size; membranes firm; cell contents chloro- phyl green. Diameter of cells, 3-7 yw. Wet timbers about mills. Syn. Cagniardia uvaeformis, Trevis. Plate CLXII, fig. 13, section of a large thallus. PALMELLA MINIATA, Leibl. Thallus indefinite, gelatinous, surface irregularly tubercu- late, often changes to yellow or reddish color ; cells spherical with membrane firm ; contents orange, or green. Two forms, the one with cells very irregular in size, from 4-40 ^ ; the other with cells equal, about 14 /^ in diameter. Syn. Merettia miniata, Trevis ; P. aequalis, Naeg. Moist and wet earth. Plate CLXII, fig. 10, the form Aequalis, Naeg. 194 FRESH-WATER ALG^E OF THE UNITED STATES. PALMELLA BOTRYOIDES, Kg., including P. heterospora, Bab. Thallus gelatinous, spreading, soft or firm, somewhat tubercular, green or yellowish. Cells mostly spherical and often very unequal in size ; membrane of cells thin, contents chlorophylous green. Diameter of cells, 2-4 yu. On old wet wood ; frequent after a rainy season. Plate CLXII, fig. 8, section of a thallus. ^ Genus 57, PORPHYEIDIUM, Naeg. The diagnosis which hitherto obtained for this genus, reads : Thallus between gelatinous and membranaceous, somewhat in- crusting, long and broadly expanded, composed of globose or many-sided cells. PORPHYRIDIUM CRUENTUM, Naeg. Thallus spreading, gelatinous, composed of a single layer of cells, sometimes two or more ; lighter or darker red, cells normally globose, but when crowded, angular. This is another vague genus ; has only one species and that, relying upon personal observations upon many speci- mens, is identical with Protococcus miniatus. The cells are the same in size ; color of the one as of the other is change- able, first green then orange or red ; habitats are also the same ; the one more frequent on the flower pots, or walls of conservatories, and the other on the ground floors, but neither are confined to these localities ; they occur on wet or shaded grounds, pavements, etc.; on a sultry summer's day side- walks are sometimes blotched with red as with blood stains ; on examination these are found to be com- posed of an almost infinite number of small spherical cel- lules, rarely with the sides compressed, or angular. Syn. Palmella cruenta, Ag. ; Tremella cruenta, Eng. Bot. Com- pare Protococcus miniatus, page 181. Plate CLXVI, fig. 1, a very small portion of thallus, which often extends for feet over moist earth ; younger portion green and older parts lighter or darker red. Seen under low magnifying power. Genus 58, BOTEYDINA, Breb. Cells spherical or oblong, involved in a very thick, gelatinous, partially diffluent integument, in large families, which are often numerous, enclosed in a mother cell which constitutes a subglo- bose thallus. GLOEOCYSTIS. 195 BOTRYDINA VULGARIS, Breb. Thallus minute, rarely larger than the head of a pin, glo- bose, green. Cells, 2-4 //. At the base of trees, moist ground, moss, etc. Plate CXXIV, figs. 5-7, younger and older thalli. Genus 59, BOTEYCOCCUS, Kg. Thallus botryoid clustered cells, irregularly lobed, mucous. Cells oval, spherical, or elliptic, united in families, which are densely packed within a thin diffluent tegument. BOTRYCOCCUS BRAUNII, Kg. Small, free-swimming clusters, green, or at length becom- ing pallid or brown. All the forms found approaching the characters of this germs, were vague, not normal conditions, hence place little value on the merits of it. The most distinct form discov- ered is illustrated, Plate CXXIV, figs. 1-4, a peculiar condi- tion with clusters connected by thin hyaline filaments. It occured in large masses of decayed Spirogyra; pond, New Jersey. Fig. 1, clusters connected; figs. 2-4, clusters single. Genus 60, GLOEOCYSTIS, Naeg. Cells globose or oblong, either single, or 2-4-8 associated in globose families. Common and special integuments gelatinous, lamellose. Divisions in alternate directions. The forms under this genus, like the unicellular forms of fore- going genera, are merely conditions of polymorphous spore multiplication. The distinctive feature constituting cells of this genus, is the same as of Gloeocapsa, except in color ; wide, lamellate, colorless teguments of the cells, one or more within the maternal tegu- ment. In Gloeoccvpsa the life-history can be more easily traced because material is often very abundant. The spore may be followed from its escape from the filament through its various transitions and transformations, until its development into a young plant. In Gloeocystis this is not so easy, because, in my experience, the cells are not so frequent and usually very much scattered. The analogy of the two will lead to the inference, that if the one is an intermediate development, the other must be the same. 196 FRESH-WATER ALGJE OF THE UNITED STATES. GLOEOCYSTIS AMPLA, Kg. Thallus gelatinous, rounded, lobed, dirty or bright green. Cells globose or rounded oblong, 2-4-6, or more, associated in families ; tegument colorless, gelatinous, distinctly con- centrically lamellose, contents green granular. Diameter of cells, 9-15 /x Diameter of families, 45-90 yw. Syn. Gloeocapsa ampla, Kg. ; Pleurococcus swperbus, Cienk. Attached to submerged plants, or free swimming. Plate CLXVI, figs. 2-8, varieties in size of cells, size of cysts and number of cells in cyst, and maternal cell. GLOEOCYSTIS VESICULOSA, Naeg. Probably merely a variety of G-. ampla; in all respects the same except size. Diameter of cells, 4-7 /u. Diameter of families, 35 //, more or less. & More frequently on old wood and stones in ponds. Plate CLXYI, figs. 9-15. GLOEOCYSTIS EUFESCENS, A. Br. Another form of G. ampla, differing from the last merely by a change of color, which is sometimes brownish yellow or reddish. Plate CLXVI, figs. 16-18. On water plants, pools and ponds. GLOEOCYSTIS RUPESTRIS, Bab. Cells smaller, as of G. vesiculosa, tegument not so wide and not so lamellate. Thallus dull green or olivaceous, gelati- nous, rather firm. Diameter of cells, 3-5 /u. Moist rocks and walls. Plate CLXVI, figs. 19-21. Genus 61, NEPHROCYTIUM, Naeg. Cells oblong, kidney -shaped, with a dorsal chlorophylose vesi- cle, 2-4-8-16 associated in free swimming families surrounded by an ample oval or kidney-shaped tegument. Very variable in size. RHAPHIDIUM. 197 / NEPHROCYTIUM AGARDHIANUM, Naeg. Cells 2-4 times as long as wide, arranged in families of 4-16, enclosed in a thin tegument ; families 2-3 times as long as broad. Diameter of cells, variable, 3-7 //. Not infrequent in ponds with Desmids, etc. Plate CLXIII, figs. 12, 13, mature cells ; figs. 14, 15, 17, younger forms. NEPHROCYTIUM NAEGELII, A. Br. Cells oblong, two or three times longer than broad ; two, four or eight enclosed in a rather wide subspherical tegu- ment. Cells bright green, at length set free by the dimuence of the membrane. Length of cells 33-38 ^ before division. Syn. Oocystis Naegelii, A. Br. Between the two genera Nepkrocytium, Naeg., and Oocys- tis, Naeg., there appears too slight and uncertain a distinc- tion for separation. Neither is likely to stand eventually. They have the appearance of intermediate life conditions, which are not yet fully understood. Genus 62, BHAPHIDIUM, Kg. Cells fusiform, or cylindrical, generally very gradually cuspi- date or acuminate at the ends ; rarely obtuse, straight or vari- ously curved, single, geminate, or fasciculately aggregate, decus- sate in the center, or radiately conjoined, rarely two laterally united at the end ; other cells free. Tegument thin, smooth. Contents green, very finely granular, furnished with a central, or rarely lateral, transparent vacuole. Division of the cells only in one direction. EHAPHIDIUM POLYMORPHUM, Fres. Cells single or from 2-16 or more associated in fascicles, acutely cuspidate at each end, straight or variously curved ; usually of yellowish green color. Cells 12-25 times longer than broad. Diameter, 1.5-4 //. The following forms may be selected, as distinct varieties : a.--Var. ACICULARE, A.Br. Straight or slightly curved, attenuated at each end, 15-20 times longer than the diameter. Sometimes in large numbers in stagnant waters. Syn. Closterium Griffiihii, Berk. Plate CLX, figs. 22, 23. 198 FRESH- WATER ALG^E OF THE UNITED STATES. b. — Var. SIGMOIDEUM, Eab. Cells fusiform, somewhat sigmoid, single or two to four connected. Syn. _R. duplex, Kg. ; R,. triplex, Eab. ; Scenedesmus duplex, Ealfs. Plate CLX, figs. 24, 25. c. — FALCATUM, (Corda. ) Eab. Cells slender, curved, or semi-lunar, single or four to six- teen congregated in fascicles. Syn. Closterium falcatum, Menegh. ; Staurastrum falcatmn, Ehrb. ; Micrasterias falcata, Corda.; Arihistrodesmus falcatus, Ealfs, etc. Plate CLX, figs. 6-10. d. — Var. CONTORTUM, (Thur.) Wolle. Slender, variously curved, but mostly somewhat falcate, 20-30 or more times longer than the diameter. Length 38-50 /*. Collected in clusters from a few to many ; sometimes very abundant, thousands of clusters in a small space in stagnant waters; among them, occur not infrequently, two, three, four or more long slender cells, contorted or twisted together forming a body averaging 6 p by 12-15 //, which apparently constitute a process of fruiting. These bodies soon break up into green spherical or subspherical cells, microspores? Beyond this stage have failed to trace the process. Syn. AnMstrodesmus contortus, Thur. Plate CLX, figs. 13, 14, 15, larger clusters from pool, Florida; figs. 11, 12, smaller clusters preceding the twist; figs. 16-21, ten forms of the contorted, or twisted, fruiting specimens from Pennsylvania and Florida. EHAPHIDIUM BRAUNII, Naeg. Cells thicker than the preceding and proportionately much shorter; only four to six, or rarely seven times longer than the diameter, straight or moderately curved, with ends attenuated ; light green. Diameter of cells, 5-7 ^. Plate CLX, figs. 26, 27. EHAPHIDIUM CONVOLUTUM, (Corda.) Eab. The type form somewhat larger than the last (R. Braunii); cells more curved; ends more acutely acuminate, green, homogeneous, single or two, three or four connected, usually DIMORPHOCOCCUS . 199 back to back ; other specimens, probably only other stages of development, are smaller ; again other families are com- posed of larger and smaller forms intermixed ; some have the ends more incurved than others. They occur in families of two or four, and again in more or less spherical masses, containing hundreds. The distinctions between the differ- ent forms are not sufficiently constant to admit of separation. Some of the larger forms agree well with Selenastrum Bibrai- anum, Eeinsch, ends rather more acute ; the smaller forms are _R. convolutum, var. lunare, Kirch., but evidently these with numerous intermediate stages belong to the same species. Length of larger cells, three to four diameters, smaller ones about two diameters. Plate CLX, figs. 1, 2, 3, a larger form corresponding with Selenastrum, Eeinsch ; figs. 4, 5, smaller form, often clustered in large numbers ; figs. 28, 29, from a mass of hundreds of the small cells and a comparatively few larger ones among them. The larger, three times the length and breadth of the smaller ones of the group. Genus 63, DIMOEPHOCOCCUS, A. Br. Cells united more or less in fours on short branches, the two intermediate contiguous cells oblique, obtuse ovate ; the two lateral, opposite and separate from each other, lunate ; families free swimming, in botryoid clusters. — A. Br. DIMORPHOCOCCUS CORDATUS, Wolle. Cells cordate, extrorsal reniform, obtusely ovate or oblong curved with ends rounded, and sometimes with a deep notch on one side ; singly, or united in rather irregular clusters of 2-4-8 cells conjoined ; sometimes forming coenobia, by smaller families of cells connecting by slender, colorless, radiating, gelatinous threads ; thread attached to the back or rounded side of the cells. Diameter of cells, 4-8 ^ usually twice as long as broad. Free swimming. Ponds, Pennsylvania, New Jersey, Florida. Plate CLX, figs. 30-35, coenobia in various stages of growth ; figs. 36-38, simple group, as they often occur in large numbers. Found the coenobia forms most abundant in small pools in Florida. 200 FRESH-WATER ALG^ OF THE UNITED STATES. The only plant-form hitherto described under this genus has been recognized in various parts of Europe. Our form is evidently distinct. The generic description was prepared with the European plant in view, but judging by the figures which accompany, it is very vague and barely applies to our form. It is given unchanged. There appears to exist a relationship between the Coeno- bium form and Dietyosphaerium, but single clusters, which are by far the most frequent, particularly north of Florida, are entirely distinct. Genus 64, MISCHOCOCCUS, Naeg. Thallus dichotomously branched, bearing the terminal cells. Cells globose, terminal, geminate or quaternate. Division of cells in one direction. Propagation by zoogonidia. MISCHOCOCCUS CONFERVICOLA, Naeg. Cells globose, even, geminate, ternate or quaternate, 011 the tips of the branches ; bright green, delicately granular, destitute of a chlorophylose vesicle ; stem hyaline, spuri- ously articulated, often swollen at the angles. Diameter of cells, 4.5-9 //. Plate CLV, figs. 36-41. Transcribed substantially from Babenhorst's Flora Alga- rum. No specimens having been found in the United States, this is given in anticipation. It appears to be common in many parts of Europe. Genus §5, EKEMOSPHAEKA, D.By. Cells large, globose, free swimming; cell walls firm, with a hyaline border. Cell contents green, granulose, sometimes con- taining green laminae, disposed in a radiate manner. Multipli- cation by division into two or four (or more) sister cells, which escape by the rupture of the cell-wall. EREMOSPHAERA VIRIDIS, D.By. Cells globose, large, of a bright green color. Diameter of cells, 100-150 yw. Occurs in small pools, sometimes in considerable numbers. The extraordinary size and usually somewhat isolated appearance makes it possibly related to some other algse APIOCYSTIS. 201 form, but hitherto all efforts failed to detect any such con- nection. The cells divide and redivide, produce resting spores, etc. Different conditions are illustrated. Plate CLXVII, fig. 1, a cell in normal condition shedding the outer membrane ; fig. 2, a cell dividing into two ; figs. ,3, 4, a cell divided into eight sister cells, five only visible ; still enclosed in the tegument; figs. 5-11, different condi- * tions of propagation, forming macrogonidia, resting spores, changing color to brownish or red, young forms, etc. Genus 66, UBOCOCCUS, Hass. Cells large, globose or oblong, reddish or blood-red ; tegument thick, gelatinous, concentrically laniellose Gloeocapsa-like ; stem thick, gelatinous, often ringed or annulate. — Edbenhorst. Babenhorst properly makes the parenthetical note " Gloeo- copsa-like," because it is to this genus that these so-called Urococcus cells belong. They appear to be merely an occasional condition, arrested development of Gloeocapsa cells; but Gloeo- capsa is an intermediate, or arrested, polymorphous spore con- dition of Sirosiphon ; therefore, Urococcus is a spore condition of Sirosiphon. Two of the forms recognized have been named by Hassall as UROCOCCUS HOOKERIANUS and UROCOCCUS INSIG-NTS. The former is described: "Cells globose, or elliptic, vari- able in size, blood-red, granular, stem more or less elongated, often divided, densely ringed. Cells, 13-60 /*." The latter : U. insignis, u cells larger, globose, blood-red; stem abbrevi- ated, remotely annulated.7' Frequent with Sirosiphon and Gloeocapsa, on dripping rocks, mountain ravines, Pennsylvania. Plate CXXIII, figs. 11, 12, lateral and polar views of U. insignis; fig. 13, cluster of cells of U. Hookerianus. Genus 67, APIOCYSTIS, Naeg. Thallus small, vesicular, fixed by a stem-like base. Cells glo- bose, scattered or sometimes eight disposed in a circle ; contents homogeneous, or delicately granulose, with a distinct colorless vacuole ; tegument thick, dissolving into a homogeneous gela tine, cells dividing alternately in all directions. Propagation by mobile gonidia, which are globose and fur nished with a pair of vibratile cilia. 202 FRESH-WATER ALG^ OF THE UNITED STATES. APIOCYSTIS BRAUNTANA, Naeg. Thallus pear-shaped, pallid green ; the cavity filled up by gelatinous matter, in which are imbedded the gonidia, at first few, increasing in number with age up to 1,600. Diam- eter of thallus, 20-100 ^ or more. Height nearly twice as much. Internal gonidia average 7-8 yu. Smaller pools or ponds, attached to water plants ; have had some good specimens, but never in large numbers ;'the finest were from Florida. Plate CXXIII, fig. 8, two young fronds ; fig. 6, a mature frond; fig. 7, another with cells undergoing segmentation; fig. 9, a larger frond with matured gonidia ; fig. 10, free, ciliated gonidia or zoospores. * Family XV.—CHYTRIDIE^J. Plants for the most part aquatic, parasitic, epiphytal or endo- phytal, very rarely terrestrial, one or two celled. Cells vesicu- lose, single or gregarious, either innate in the fostering plant, or penetrating its membrane; now and then numerous and densely aggregated ; cytioplasm mucilaginous, most frequently colorless, sometimes colored. Antheridia not yet observed. Propagation by oospores or zoogonidia. Among a number of forms of plants of doubtful generic posi- tion, perhaps more properly placed with the Lichens or the Fungi. I retain two of the eleven genera recorded by Eaben- horst in his Flora Algarum. The two are the genera Cliytridium and Olpidium, forms which may be retained, and classified with PROTOCOCCOIDE^:. Genus 68, CHYTKIDIUM, A. Br. Cells globose or somewhat pear-shaped, operculate above ; the root-like base usually innate in various algse, penetrating the membrane of the cells. Zoogonidia very numerous, globose, with a nucleus, bearing a single very long cilium, escaping through the orifice of the cell caused by the falling away of the operculuni. CHYTRIDIUM ACUMINATUM, A. Br. Cells small ovate- pyriform, or balloon -shaped, which pene- trate into the alga3 upon which they grow by a sort of root- like base. The inflated portion of the cell is filled with colorless mucilage from which are formed very numerous OLPIDIUM. 203 small globular germ-cells with a darker nucleus and a single long cilium. Length of cells, 56-64 //. On the oogonia of various Oedogonia. Plate CV, figs. 20-22, Chytridia seated on oogonia. CHYTRIDIUM MINUS, Lacost et Suring. Cells subgiobose or somewhat oblong, pale yellow with a low operculum, base wide above, penetrating the membrane of filamentous algae, and terminating in a point. Length 6-14 jw, without operculum and basal root-like process. Frequent on algse of various kinds. Plate CV, figs. 17, 18, different forms of C. minus. CHYTRIDIUM GLOBOSUM, A. Br. Cells usually perfectly spherical, single or numerously aggregated; devoid of operculum, of radicals, of elongated neck, but possess two or more orifices ; apparently of two varieties, a larger and smaller form. Parasitic on algse of various kinds. Syn. RMzophydium globosum, A. Br. Plate CV, fig. 14, the most frequent variety ; figs. 11, 12, 13, a larger form from New Jersey. Genus 69, OLPIDIUM, A.Br. Cells globose or subgiobose, parasitic, epiphytal or endophytal, not rooting ; mouth vertical, elongated into a cylindrical tube. OLPIDIUM AMPULLACEUM, A.Br. Epiphytal, gregarious, globose, small, sessile, rarely pedi- cellate, tubular, mouth erect, cylindrical, nearly as long as the cell, terminating in a conical apiculus. Diameter of cells, 6-8 yw. Frequent on filamentous algse. Plate CV, fig. 7, cells on a filament of Oedogonium. OLPIDIUM INTESTINUM, A.Br. Entophytal, usually gregarious in the interior of larger plants, depressedly globose, extending at the apex into a tubular neck which is globosely dilated in the middle; 204 FRESH-WATER ALG.E OF THE UNITED STATES. perforating the membrane of its host ; extending somewhat beyond, and often widened at its mouth. Diameter of cells, about 25 //. The only specimens found by myself were in Closterium lunula. They have been found also in other algae. Plate CV, fig. 16, five Olpidia in a semi-cell of Closterium. OLPIDIUM ENTOPHYTUM, A.Br. Parasitic in the interior of plants, perfectly spherical, somewhat smaller than the preceding (intestinum), the tubes perforating the membrane, straight, not inflated, often extending beyond the membrane of the cell they occupy. Diameter of cells, 15-20 /*. Plate CY, fig. 15, cells of a filament of Oedogonium each containing two plants. Diameter of larger cells, 12-15 yw ; smaller ones, 6-10 //. Order V.— ZYGOSPOREJE. An Order composed of green or brownish algse, sometimes single cells, but more frequently series of cells closely united, possessing a peculiar mode of propagation by copulation and conjugation. The contents of two cells, whether individuals or whether in series, flow together and produce a new cell termed a zygospore. As a rule only one, but rarely two zygospores are produced by the copulation of two cells. Sometimes spores are produced without copulation ; such are termed, azygospores. Family XVL— CONJUGATE. Simple filaments composed of a single series of cells, or inde- pendent single cells with chlorophyl-green contents. Chloro- phyl arranged in parietal bands, in axillary laminae, or twin, stellate nuclei. SECTION I. — ZYGNEME^. Cells cylindrical, united into filaments, green, often with a mucous covering, conferva-like. Zygospores are clothed with a triple membrane, the exterior one decidious. When fully developed, after a period of rest, these germinate, putting forth a single germ, in the same way as the seeds of phoeiiogamous plants. This germ elongates by transverse division of the cells. SPtROGYiU. 205 This section may be subdivided into two parts, the Zygneminae, and the Mesocarpinae. SUBSECTION I. — ZYGNEMINJE. Chlorophyl arranged in three ways ; in bands on the inside of the cell walls, in twin stellate nuclei, and in axillary laminae. The process of copulation is the union of two filaments ; they come into close proximity, then the cells put out short tubercle- like projections by which the cells of one unite with the cells of the other filament ; the ends open and thus a tubular passage is formed between each of two cells of a longer or shorter series of cells. Such copulation is termed scalariform. In some forms the cells become geniculate and unite at the angle ; this mode is termed geniculate copulation. A third mode is termed lateral copulation, signifying that the contents of two adjoining cells unite, producing the zygospore. In the other two modes the chlorophylous cell-contents pass out through the connecting tube from one cell to unite with that of the other, or through an opening at the point of junction to mingle with that of its mate, thus producing the zygospore; sexual distinction between the two filaments conjugated, has not been observed. Genus 70, SPIBOGYBA, Link. Cells with one to several parietal chlorophyl bands spirally winding to the right. Copulation scalariform (Spirogyra, Kg.) or lateral (Rliynclionema, Kg.). Zygospores always within the wall of one of the united cells. Copulating cells usually shorter than the sterile ones, and often more or less swollen. More recent observations have proved that the two modes of copulation are not constant, that both ways may be found in the same filament, according to circumstances, hence Rhynchonema is omitted as a generic character. The most essential and reliable characters are derived from the zygospore. The length and breadth of the cells, the character, and number of spirals, are features not to be overlooked, but in themselves not sufficient to determine species. One of the most recent and complete monographs of Sfpirogyra^ embracing almost all of our species is by Mons. Paul Petit, Spirogyra des Environs de Paris, 1880. In accord with his arrangement of the species of this genus, the following division is made of our United States species : 206 FRESH-WATER ALGvE OF THE UNITED STATES. SPIROGYRA. SECTION I.— MEMBRANE OF CELLS REPLICATE, OR FOLDED IN AT THE ENDS. A. — Chlorophyl band single, rarely double. a. — Membrane of zygospore smooth. 1. S. tenuissima, Hass. 2. S. inflata, Vauch. 3. S. Spreeiana, Rcib. 4. S. quadrata, Hass. 5. S. Weberi, Kg. 6. S. Grevilleana, Hass. b. — Membrane of zygospore punctate. 7. S. calospora, Cleve. B. — Chlorophyl bands two or more. Ends of cells replicate. 8. S. Hassallii, Jenner. 9. S. insignis, Hass. 10. S. Hanzschii, Kg. SECTION II.— MEMBRANE OF CELLS NOT REPLICATE AT THE ENDS. A. — Chlorophyl band single. a. — Membrane of zygospore smooth. 11. S. mirabilis, Hass. 12. S. flavescens, Cleve. 13. S. gracilis, Hass. 14. S. varians, Hass. 15. S. quinina, Ag. 16. S. com munis, Hass. 17. S. Jurgensii, Kg. 18. S. longata, Vauch. 19. S. Lutetiana, Petit. 20. S. fusco-atra, Rab. 21. S. condenaata, Vauch. b. — Zygospore with membrane punctate. 22. S. punctata, Cleve. B. — Chlorophyl bands, two or more. ZYGOSPOBES OVOIDAL. 23. S. decimina, Mull. 24. S. neglecta, Hass. SPIROGYRA. 1207 25. S. fluviatilis, Hilse. 26. S. nitida, Link. 27. S. subsequa, Kg. 28. S. jugalis, DHL 29. S. setiformis, Roth. 30. S. dubia, Kg. 31. S. adnata, Kg. 32. S. rivularis, Rab. 33. S. majuscula, Kg. 34. S. elongata, Berk. 35. S. parvispora, Wood. ZYGOSPORES LENTICULAR, ORBICULAR DEPRESSED. 36. S. orthospira, Naeg. 37. S. bellis, Hass. 38. S. maxima, Hass. 39. S. crassa, Kg. SECTION I.— MEMBRANE OF CELL REPLICATE AT BOTH ENDS. A. — One spiral, or rarely two in a cell, a. — Membrane of spore smooth. SPIROGYRA TENUISSIMA, (Hass.) Kg. Diameter of vegetative cells 9-12 /* ; 4-15 times longer than broad; ends inlaid; single spiral, making 3-6 turns. Spore, 24-30 /t by 50-58 /J. Sporiferons cells much swollen, about twice as long as the spore. Zygospore oblong-elliptic, yellow or brown at maturity. Syn. Zygnema tenuissima, Hass.; Rhynclionema minimum, Kg.; Spirogyra Naegelii, Kg. Ditches and pools. The smallest of our Spirogyra; varies considerably in size, even more than indicated by the measures given. Plate CXXXII, figs. 1-3, fruiting and sterile filaments, a Wiynclionema form. SPIROGYRA INFLATA, (Vauch. ) Rab. Diameter of vegetative filaments, 14-18 JJ ; cells 3-8 times longer than broad ; cells with spore very much inflated ; spiral single, makes 3-8 turns. Fruiting cells much inflated, zygospore fusiform-elliptic, diameter 30-36 yw ; twice as long as wide. 14 208 FRESH-WATER ALG^ OF THE UNITED STATES. Syn. Conjugaia inflata, Vauch. ; Zygnema inflatum, Hass. ; Spiro- gyra gastroides, Kg.; 8. ventricosa. Kg.; Rhynchonema vesicatum. Kg. Rather common in smaller ponds. Plate CXXXII, figs. 6, 7, two filaments in fruit — scalar! - form and lateral copulation. SPIROGYRA SPREEIANA, Eab. Diameter of filaments, 18-21 /*. Cells 10-25 times longer than wide, ends inlaid; spiral slender, loose, making l?.-4 turns; fructiferous cells inflated, 36-42 yw diameter; zygo- spores 36 ^ diameter, 2-3 times longer than broad. Mountain pools, Pennsylvania. Plate CXXXII, figs. 4, 5, two parts of fruiting filaments. SPIROGYRA QTJADRATA, (Hass.) Petit. Diameter of vegetative filaments, 24-30 ju ; cells 3-9 times as long as broad ; ends inlaid ; spiral single, good size, making 1 £-5 turns; fertile cells much swollen, often some- what quadrate, flattened in the middle, cylindrical ; one or rarely two spirals. Zygospores elliptical or fusiform, diam- eter 27-32 ^ ; 2-4 times longer than broad ; copulation most frequently lateral. Syn. Zygnema quadrafum, Hass.; Rliynclionema quadratum, Kg.; Spirogyra pulchella, Wood. Frequent in stagnant waters; Plate CXXXII, figs. 8, 9, 10, a sterile filament; lateral and scalar if or in copulation. Plate CXLII, figs. 7, 8, parts of two filaments having a sort of rootlets, sometimes observed on plants in a strong current of water, or .when partly out of the water on shores of ponds ; they are developed, apparently, as a means to sustain life in precarious situations. This feature is not peculiar to plants of this genus only. Compare Plate CIX, fig. 3, a Cladophom, and Plate CXYIII, figs. 29-33, a U lothrix. SPIROGYRA WEBERI, Kg. Diameter of vegetative filaments, 18-28 // ; cells 6-15 times longer than broad ; ends inlaid ; spiral always single, slender and lax, describing three and a half to six turns ; fructiferous cells not inflated or but slightly dilated ; zygo- spore oval, one and a half to two times longer than broad. Diameter, 26-30 //. • ^ SPIROGYRA. 209 Kirchner makes the following varieties of this species : a. — genuina, Kirch. Cells four to eight times as long as broad ; one spiral making 3-5 turns. Diameter of cells, 16-22 jw. b. — elongata, Rab. Cells 4-14 times as long as broad; one spiral, 2-5 2 turns. Diameter as the last. Plate LXX, figs. 1, 2. c. — Httseana.; Kab. Two spirals, otherwise like "a." d. — intermedia, Kg. Cells twice as long as broad; copulation usually lateral. e. — tennis, Eab. Filaments thinner than any of the other forms. Ehynchonema Jenneri, Kg. Syn. Spirogyra Hornschuchii, Kerst. ; Zygnema longatum ; Zygnema intermedia, Hass. ; Spirogyra elongata, Wood. Appears widely and liberally distributed in quiet waters. Plate CXXXII, fig. 11. % SPIROGYRA GREVILLEANA, (Hass.) Kg. Diameter of vegetative filaments, 28-33 // ; cells 3-10 times longer than broad ; ends inlaid ; spiral usually single, more rarely double, describing 4-5, or occasionally 6-9 turns ; when two spirals the turns are more numerous ; fructiferous cells considerably swollen. Zygospores oval, brownish yel- low when mature, 2-2 i times longer than the diameter, vary- ing from 30-36 JA. Var. DIDUCTA, Kg. ; Zygnema diductum, Hass. , and Z. vesicatum, Hass. Cells 3-4 times longer than wide ; fructiferous cells much inflated. This species is separated from S. Weberi by the larger size of filaments, usually shorter cells and especially by the in- flated spore-bearing cells. Syn. Zygnema Grevilleana, Hass.; AS. inaequalis, Kg.; Rhyncho- nema diductum. Kg. Occurs frequently in sluggish and stagnant waters. Plate CXXXII, figs. 12, 13, sterile and fruiting filaments. b. — Membrane of spore punctate. SPIROGYRA CALOSPORA, Cleve. Diameter of vegetative filaments, 36-40 /*; 6-12 times longer than broad; spiral single, slender, describing 4-5 210 FRESH-WATER ALG^ OF THE UNITED STATES. turns ; fruiting cells shorter, slightly or not at all swollen. Zygospores elliptic or cylindric-elliptic, ends rounded, yel- low or orange when mature ; two or three times longer than the diameter, 40-42 /*. Spore-membrane somewhat punctate or scrobiculate. Syn. Spirogyra protecta, Wood. Not rare in ponds, East, West and South. B. — Chlorophyl bands two or more; cells replicate at the ends. SPIROGYRA HASSALLII, (Jenn.) Petit. Diameter of filaments, 30-33 ^ ; cells 4-8 times longer than wide; two spirals, rather large, lax, describing l£-3 turns. Fructiferous cells considerably inflated, 48-50 yu diameter ; zygospores elliptic, ljj-3 times longer than the diameter, measuring 42-48 //, and changing to yellow at maturity. Syn. Zygnema Hassallii, Jenn.; Rhynchonema Hassallii, Kg. Only specimens identified, from Iowa. Plate CXXXIII, figs. 5-7, sterile filament, and lateral copulation. SPIROGYRA INSIGNIS, (Hass.) Kg. Diameter of vegetative filaments, 36-42 ^ • cells 4-12 times longer than wide ; three spirals, rarely two, describing one to three turns. Cells bearing zygospores much swollen, shorter than sterile cells. Spores elliptic, usually twice as long as wide. Smaller axis about 28 yu. Beside the typical form, Kirchner has two varieties : Yar. BRAUNII, Eab. Cells 8-14 times as long as wide and two spirals ; and Yar. ELONGATA, Sur. Cells 5-12 times longer than broad, with 2-4 spirals. Syn. Zygnema insigne, Hass.; jRhynchonema Gallicum, Rivet. ; Sirogonium retroversum, Wood. Inhabits small ponds, not frequent. Pennsylvania, New Jersey to Florida, probably also westward. Plate CXXXIII, figs. 8, 9, sterile, and fruit-bearing filaments. Plate CXLII, figs. 8, 9, parts of two filaments of 8. insigne, with sterile cells, and others having the chlorophyl bands destroyed, or transmuted into brown stellate forms. The physiological function of the stellate forms remains undetermined. SPIROGYRA. 211 \ SPIROGYRA HANTZSCHII, Eab. Diameter of vegetative filaments, 40-45 yw ; cells 3-5 times longer than broad ; spirals two, making two or three turns in shorter cells. Spore-bearing cells not at all swollen; spores twice as long as wide. This plant is near the preceding in size, length of cell and form of spore ; but separated by having only two spirals and by fruit-bearing cells not being inflated. Stagnant waters, Pennsylvania. Plate CXXXIII, figs. 10, 11, filaments conjugated, with spores, and sterile filaments. SECTION II.— MEMBRANE OF CELLS NOT REPLICATE AT THE ENDS. A. — One spiral in each cell, a. — Zygospores having membrane smooth. SPIROGYRA MIRABILE, Hass. Diameter of vegetative filaments, 24-27 /* • cells 4-10 times longer than broad ; spiral single describing 4-7 turns in cell. Fruiting cells considerably inflated. Conjugation lateral more frequently than scalariform. Zygospore li-2 times longer than the diameter. Shorter axis varies from 24-26 /*. Syii. Zygnema mirabile, Hass. ; Spirogyra mirdbilis. Kg. The only specimens had for examination were from Wis- consin. Plate CXXXIY, figs. 1, 2, sterile and fruiting filaments. SPIROGYRA FLAVESCENS, (Hass.) Cleve. Diameter of vegetative filaments, 13-20 ja ; cells 3-5 times longer than broad ; spiral single, yellow green, describing 2-3 turns. Fructiferous cell much swollen, spore 25 by 40 //. Syn. Zygnema flavescens, Hass. ; Zygnema affine, Hass. ; JRhyncho- nema affine. Kg. Picked up satisfactory specimens of this species, fre- quently in stagnant waters in Florida. It averages some- what larger than the French form, but conforms well with English specimens. Plate CXXXIV, figs. 3, 4, sterile and fruiting filaments. SPIROGYRA GRACILIS, (Hass.) Kg. Diameter of vegetative filaments, 18-22 // ; cells 3-5 times longer than broad ; spiral bright green, making i-3 turns ; 212 FRESH-WATER ALG^E OF THE UNITED STATES. fruiting cells swollen only on the side of conjugation, the opposite side straight. Zygospores oval, turning yellow at maturity, about twice as long as wide. Syn. Zygnema gracile, Hass. This form has been erroneously connected with 8. flaves- cens. It is distinct in size, and in spore-bearing cells, which are inflated on one side only, not on two sides. The figures are from specimens collected in Michigan. Plate CXXXIV, figs. 5-7, conjugation scalariform, and lateral ; fruits also without conjugation ; also sterile filament. SPIROGYRA VARIANS, (Hass.) Kg. Diameter of vegetative filaments, 25-33 yu; cells H-2i times as long as wide; spiral single, with margins more or less dentate, describing l*-3 turns; cells bearing spores much swollen on the conjugating side, straight on the outer side. Zygospores oval or elliptic, li-2 times longer than wide, often appearing polymorphous, changing with the position they have in the cell. Syn. Zygnema varians, Hass.; Ithynchonema Woodsii, Kg.; Zyg- nema abbreviatum, Hass.; 8. arcta, Kg.; S. nodosa, Kg.; 8. ventricosa, Kg. Of all the species of this genus this appears most poly- morphous, and in consequence has given rise to various terms descriptive of conditions in which it was found by different collectors, and by the same under different circum- stances; frequently inflated cells are observed in longer or shorter series; these no doubt gave rise to such names as nodosa and ventricosa. Often the cells are very short, hence abbreviatum. The peculiar one-sided swelling does not appear to have been noticed by Vaucher, and probably did not exist in the plant he saw and described as 8. condensata ; hence there appears no good reason for calling 8. varians a synonym for S. condensata. Most abundant in stagnant pools adjoining mountain streamlets. Plate CXXXIV, figs. 8-13, sterile filament ; fruiting fila- ments, cells inflated without conjugation ; and early stage of conjugation. SPIROGYRA SUBSALSA, Kg. Diameter of vegetative filament, 22-25 jw; cells 1-1? times longer than wide; single spiral, describing 1^-2-3 turns in cell, Zygospore ovoid, slightly longer than the SPIROGYRA. 213 diameter. Sporiferous cell slightly, or not at all swollen. Color of mass deep green, slippery to the touch. Not infrequent in wet places, Florida. Plate CXLI, figs. 3, 4, sterile, and fruiting filaments. SPIROGYRA QUININA, (Ag.) Kg. Deep green, slippery, diameter of filaments, 33-40 //. Sterile articles 1-2 or rarely 6 times longer than broad ; fer- tile cells 1-1 i diameters, scarcely or not at all swollen; spiral single, the turns in various stages of density or of laxity ; commonly 1 £ or 3 turns. The zygospores vary much in form, apparently, some of them being globose, others elliptic, and still others cylindrical with obtusely rounded ends. $yi\. Zygnema qmninum, Ag. ; Conjugata condensata, Yauch. One of our most common forms in sterile condition ; fruits in proper season very profusely ; occurs sometimes in masses, all fruit. Many spore-bearing cells without evidence of conjugation. Plate CXXXIY, figs. 14-17, sterile and fruiting filaments. SPIROGYRA COMMTJNIS, (Hass.) Kg. Diameter of vegetative filaments, 20-22 /* ; cells 3-5 times longer than broad ; spiral slender, lax, describing l*-4 turns. Fructiferous cells not dilated ; zygospores elliptic, changing from green to yellow at maturity, 2-3 times longer than broad ; diameter 19-23 /*. Syn. Zygnema commune, Hass. ; Zygnema reversum, Hass. ; Rhyn- chonema reversum, Kg. Ponds and ditches. Plate CXLII, figs. 1, 2, sterile and fruiting filaments. SPIROGYRA JURGENSII, Kg. Diameter of vegetative filaments, 24-26 yw; cells 2-i-5 times longer than broad ; spiral slender, light green. Spore- bearing cells gently swollen around the elliptic zygospore, which is twice as long as wide; diameter about 30 yu, changes color to golden yellow at maturity. Stagnant and sluggish waters. The distinction between this and.,& communis is slight, resting almost altogether on the swollen fructiferous cells. Plate CXLII, figs. 3, 4. 214 FRESH-WATER ALG.E OF THE UNITED STATES. SPIROGYRA LONG ATA, (Vauch.) Kg. Diameter of filaments, 25-30 ^ ; cells 2-12 times longer than broad ; fructiferous cells not swollen or rarely moder- ately inflated ; spiral rather large, bright green, describing 2-5 turns. Zygospore oval, ends rounded, twice as long as wide, filling the breadth of the cell, changes color from green to light yellow and chestnut. Syn. Conferva longata, Vauch. ; Zygnema longatum, Ag. ; Zygnema aestivum, Hass. The three preceding forms 8. commune, Jurgensii, and longata, seem closely related; 8. quinina is also near, but separated by features which have been deemed sufficient to mark distinct species. If the occurring varieties are taken as typical forms then a separation would prove impossible. Spirogyra filaments of the same species often vary very much in diameter, in length of cells, number of turns and width of spirals, and shade of color. The length of cells is constantly changing by division ; the number of spirals is not absolutely con- stant ; there are sports, so called ; conjugation of filaments of different species have been observed, but such occasional deviation from rule must not be taken as a guide in classifi- cation. The features as they appear in mass have been our guide. Occurs frequently in masses in ponds, mill-dams, etc. Plate CXXXV, figs. 9, 10, sterile, and conjugated fila- ments. SPIROGYRA LUTETIANA, Petit. Diameter of vegetative filaments, 30-36 fji (mine 40-43 /*). Cells 3-7 times longer than the diameter ; spiral single, large, dentate, deep green, describing 3-7 turns ; sporiferous cells irregular, always more or less inflated, sometimes cylindrical. Zygospores polymorphous, globose, elliptic, oblong, cylindric, pyriform or reniform, of yellow tint when mature, 2-4 times longer than wide ; diameter, 30-42 JA. A plant gathered in considerable quantity, mostly sterile, in lake at Kissimmee, central part of Florida, is not iden- tical with the one described above by Mons. Petit, but in size and proportions of cells and general appearance so much like it, and so unlike any other described form, have adopted this name for it. 8. fusco-atra, Rab., is closely related, but varies in length of cells, number of turns of spiral in cells, and less inflated fruit-bearing cells. Plate CXXXY, figs. 7, 8, a sterile, and fertile filaments. SPIROGYRA. 215 SPIROGYRA FUSCO-ATRA, Rab. Diameter of filaments, 40-55 yw ; cells 2-4 times longer than broad, one spiral, making 2-3 turns in cell. Zygospore polymorphous, globose, elliptic or oval, one to two times longer than the diameter ; color changes to lighter or darker chestnut. Found this form most abundant in good fruiting condition in sluggish and stagnant waters of Paxtoii Creek, near Harrisburg, Pa. Occasionally a filament with two spirals was intermingled. Plate CXL, figs. 4 and 7, two sterile filaments, one of them with two spirals ; figs. 5, 6, two fertile filaments. SPIROGYRA CONDENSATA, (Yauch.) Kg. Diameter of vegetative filaments, 48-54 // (var. 62-75 /u); cells 1-1* times longer than the diameter, spiral slender, making one to four (ante-division) turns in cell. Fruc- tiferous cells not, or but slightly swollen, not shorter than the vegetative cells. Zygospores broadly elliptic, about one-half longer than the diameter. Var. RUSBYI, Wolle. Not essentially different from the type-form or from the variety Fleclisigii described by Rabenhorst, except in size, being as much larger than Rabenhorst' s variety, as the same is larger than the type, measuring 62-75 yw in diameter. Collected by H. H. Rusby in New Mexico, January, 1881. A sterile form, probably this species, occurs in New Jersey ; frequent in vicinity of Hammonton, but found no fruit. Syn. Conjugata condensata, Vauch. ; Zygnema condensata, Ag. Plate CXXXIX, figs. 7, 8, 9, two sterile filaments, and two in conjugation of var. EUSBYI. b. — Membrane of the spores punctate. SPIROGYRA PUNCTATA, Cleve. Diameter of vegetative filaments, 24-27 yw; cells 6-12 times longer than the diameter ; spiral single, rather slender, containing some starch grains; describing 3 £-7 turns in a cell ; fructiferous cells much inflated and much shorter than the vegetative cells. Zygospore elliptic, yellow at maturity, about one-half longer than the diameter; the membrane punctate. The mode of conjugation of this species is somewhat pecu- liar; the connecting tube arises from one cell only and 216 FRESH-WATER ALGJ3 OF THE UNITED STATES. attaches itself to the surface of the opposite cell ; the chloro- phyl passing over, the spore is formed and the cell becomes much inflated. The only locality hitherto discovered for this species is Pleasant Mills, New Jersey. Plate CXLI, figs. 5, 6, 7, four fertile and one sterile fila- ment. B. — Tivo or more spirals. SPIROGYRA DECIMINA, (Mull.) Kg. Diameter of vegetative filaments, 32-40 /* ; cells 2-4 times longer than the diameter 5 two spirals (rarely three) rather large, describing 1-2 turns ; fructiferous cells not inflated ; zygospore broadly oval or nearly globose ; same diameter as filament. As a rule this species has two spirals, but occasionally three ; being found intermingled, and having a specific ap- pearance, the latter are not easily confounded with other species of the same number (three) of spirals. Often found in large masses, mucilaginous to the touch. Syn. Conferva decimina, Mull.; Zygnema deciminum, Hass. Plate CXXXV, figs. 5, 6, sterile and fruiting filaments. SPIKOGYRA NEGLECTA, (Hass. ) Kg. Diameter of vegetative filaments, 60-65 // • cells 2-5 times longer than broad; three spirals describing 1-2 i turns; sporiferous cells li-3 times longer than the diameter, slightly swollen ; zygospores oval, ends broadly rounded, yellow at maturity, about one-half longer than the diameter. Kiitzing notes a peculiar feature in the spirals of this species — he says they are cylindrical and possess a sort of central nerve. Rabenhorst and others consider this feature of uncertain and doubtful value. My specimens were collected in South Carolina and reaching me in a partially dried condition could form 110 opinion. Was governed in my identification chiefly by the proportions of cells and spirals. Syn. Zygnema neglectum, Hass. Plate CXXXVI, figs. 8, 9, fruiting and sterile filaments. SPIROGYRA FLUVIATILIS, Hilse. Diameter of vegetative filaments, 33-38 ^ ; cells 3-6 times as long as broad; four spirals; wide and usually dense, bright, rather dark green, describing 1-2 turns. Fruc- SPIROGYRA. 217 tiferous cells much inflated ; zygospore oval, about one-half longer than the diameter, which averages 55 ,u ; length, 80 yw. This is probably the first record of the fruiting of this species. Found it in large masses in meadow pools in this vicinity. Plate CXXXVI, fig. 1, a frequent appearance of sterile filaments ; spiral bands not universally so wide ; figs. 2, 3, fertile filaments. SPIROGYRA NITIDA, (Dill.) Link. Diameter of vegetative filaments, 72-78 // ; cells one to three diameters in length ; also longer and shorter before and after division. Chlorophyl bands about 4, making 1-4 turns of the spirals ; zygospores elliptic-ovoid, often almost almond shape, li times as long as broad. Germinating plant clavate. Syn. Conferva nitida. Dill. ; Conjugata princeps, Yauch. ; Zygnema nitidum, Ag. ; Zygnema rostratum, Hass. ; Spirogyra diluta, Wood. Ponds, borders of streams, forms dark green masses, slippery to the touch. Plate CXXXVII, figs. 7, 8, sterile and fruiting filaments. SPIROGYRA SUB^QUA, Kg. Diameter of vegetative filaments, 55- 60 /.i ; cells 1-2 times as long as wide ; slightly swollen ; spirals two, or more rarely three, making each 1-2 turns. Zygospores spherical or broadly ovate. Spring waters, Pennsylvania. Plate CXLI, figs. 1, 2, sterile and fertile filaments. SPIROGYRA BELLIS, (Hass.) Cleve. Diameter of vegetative filaments, 65-78 yu ; cells 1* times (rarely 3 times) as long as broad ; spirals 5-6, making £-1 turn each. Fructiferous cells not swollen. (Hass. and Cleve say swollen — Petit says, often not swollen on the side opposite the conjugated cell.) Zygospore orbicular, de- pressed ( lenticular) with the membrane punctate or porose ; chestnut color. Syn. Zygnema belle, Hass. The species has something in common with the preceding, 8. subaequa, but is separated by filaments slightly larger, spirals more numerous and spores lenticular, not globose. 218 FRESH-WATER ALG^E OF THE UNITED STATES. Submerged grassy shores, Budd's Lake, New Jersey ; brackish water, Egg Harbor City, N. J.; and shores of ponds, Pennsylvania. Plate CXXXVII, figs. 5, 6, sterile and fruiting filaments, Budd's Lake. Plate CXXXIX, figs. 1, 2, Pennsylvania specimen ; sterile filament with root-like processes ; occurring frequently when plants are only partially submerged. SPIROGYR.A ORTHOSPIRA, (Naeg.) Kg. Diameter of vegetative filaments, 58-65 ^ • cells 2-3 times longer than the diameter; spirals 3-4-5 (rarely 7), often nearly straight or describing T to i turn in cell. Fructiferous cells moderately swollen. Zygospores brown as they mature 5 lenticular, (orbicular flattened). Forms presented to the, eye change as the position of the spore changes in the cell. Marsh pools, Pennsylvania. Plate CXXXVI, figs. 10, 11, sterile and fruiting filaments. SPIROGYRA MAXIMA, (Hass. ) Wittr. Diameter of vegetative filaments, 118-125 /* ; cells a little longer than broad ; chlorophyl bands, 6-7, margins finely notched describing each i-l turn ; fructiferous cells not in- flated ; zygospores lenticular, appearing according to posi- tion in cell, spherical or elliptical ; diameter same as that of filaments. Syn. Zygnema maximum, Hass.; Zygnema orMcularis, Hass.; Spirogyra orbicularis, (Kg.) Petit. In large masses in streams, Bethlehem, Pa. Fruits very abundantly latter part of Summer. Plate CXXXIX, figs. 3, 4, sterile, and fruiting filaments ; figs. 5, 6, two spores germinating, from zygospores kept in glass jars from September to the following January and February. According to Petit this species often attains a diameter of 132-138 //. Var. IN^QTJALIS, Wolle. A singular variety of Spirogyra maxima; the one fila- ment having a much larger diameter than the other con- jugating with it. The larger measuring 125 //, the smaller 80 /^. The zygospore is most frequently in the smaller fila- ment, and in consequence considerably smaller than the zygospore of the typical form. The smaller filaments if seen independent of the others would pass for 8. nitida, or 8. bellis. SPIROGYRA. 219 Occurring in small coves, shores of river, Bethlehem, Pennsylvania. Syn. Spirogyra setiforme, var. incequalis, Wolle. Bull. Tor. Bot. Club, 1883. Specimens were furnished to Witt, and Nord.'s Algce Ex- siccatce; vide No. 541. SPIROGYRA CRASSA, Kg. Diameter of vegetative filaments, 150-156 yw; cells 1-1 2 -2 times longer than the diameter ; spirals numerous, four or more, dentate or tuberculate, often close, subtransverse, making 2 to 1 to more turns in cell ; fertile cells like the others, not inflated. Zygospores broadly oval, elliptic, ovoid or subglobose. The type-form has the cells £-2 times as long as broad ; var. Heeriana, Naeg., has cells li-2 times as long as broad. This, the largest of the genus, is common in ponds and sluggish river waters ; it forms in early Summer long lubri- cous masses, of a bright green color, easily distinguishable by the unaided eye ; later in the season it assumes a dirty green color ; in this condition it may be found very abun- dant in fruit. Syn. Zygnema serratum, Hass. ; Spirogyra Heeriana, (Naeg.) Kg. Plate CXL, figs. 1-3, two sterile and one fruiting filament. SPIROGYRA JUGALIS, (Dill.) Kg. Diameter of filaments, 90-100 //; cells 1-1 £ times longer than the diameter, somewhat constricted at joints; chloro- phyl bauds 3-4, each making 1-2 turns. Fructiferous cells somewhat inflated ; zygospore elliptical or oval ; membrane even, brown at maturity, one-half more in length than the diameter. Syn. Conferva jugalis. Dill.; Spirogyra setiformis, Petit; Spirogyra decimina. Kg. Pond waters. Plate CXXXVIII, figs. 7, 8, sterile and fruiting filaments. SPIROGYRA SETIFORMIS, (Both) Kg. Diameter of vegetative filaments, 102-110 ^ ; cells equal to 1^-2 times as long as wide ; chlorophyl bands four or more, up to eight, margins irregularly notched, describing ?-l turn each in a cell ; sporiferous cells not inflated ; zygospores elliptical, sometimes appearing ovate or globose as they change position in the cell ; diameter slightly less than the cell. 220 FRESH-WATER ALG^ OF THE UNITED STATES. S. jugalis and S. setiformis appear closely related, probably ought to be united; following the example of Mons. Petit their separate positions are retained. The one having some- what inflated fruit-bearing cells, the other not, they differ also in some degree in the form of the zygospores. Common in ponds and quiet river waters. Syn. Conferva setiformis^ Both ; Zygnema interruptum, Hass. Plate CXXXYIII, fig. 1, sterile filament ; fig. 2, fruiting filament approaching maturity, showing the spirals of the coming germs in the zygospores ; figs. 3, 4, two spores germinating. SPIROGYRA DUBIA, Kg. Diameter of vegetative filaments, 43-50 yu ; cells li-2* times as long as broad; chlorophyl bands two, or more rarely three, narrow, nodose, lax, making each 1-2 turns in a cell ; sporiferous cells slightly swollen. Zygospores oval- elliptic, or subcylindrical, as broad as long, or one-half longer. Ditches; fruiting abundantly in May; forming dirty, light yellowish-green masses. Var. LONGI-ARTICULATA, Kg. Cells five times as long as broad, spirals 2 or 3 ; turns in cell, 7-8. Plate CXXXV, figs. 11, 12, typical form, sterile and fertile filaments. SPIROGYRA ADNATA, Kg. Diameter of vegetative cells, 40-45 ^ ; cells 1-3 times as long as broad ; 2, sometimes 3, spirals, making 3-4 turns each ; spore-bearing cells moderately swollen ; zygospores oval-elliptical. Stagnant waters, New York, Iowa. Syn. Zygnema adnatum, Ag. ; Conjugata adnata, Yauch. Plate CXXY, figs. 3, 4, sterile and fertile filaments. Appears nearly related to /S. decimina, but vegetative cells are shorter and spore-bearing cells are more or less inflated. SPIROGYRA RIVULARIS, Eab. Diameter of vegetative filaments, 32-36 ^ ; cells of sterile plants 7-11 times as long as wide. Fertile cells usually about four times longer than wide ; cylindrical or slightly tumid. Three spirals (rarely 2 or 4), lax, making 2£- turns in a cell. Zygospores oval-elliptical. SPIROGYRA. 221 Distributed in flowing waters from New York to Florida, forming lubricous, darker or yellowish green masses. Syn. Zygnema rivulare, Hass. Plate CXXXVI, figs. 4, 7, sterile and fertile filaments. SPIROGYRA MAJUSCULA, Kg. Diameter of vegetative filaments, 54-62 /* ; cells 2*-10 times as long as broad; chlorophyl bands light green, 3-5, sometimes more, as many as 8-10 ; usually lax ; fruiting cells not inflated, 2-4 times longer than wide. Zygospore oval or subgiobose. Forming often large, lubricous masses in ponds or pools, pale yellow green, or light greenish yellow. Not rare. Syn. Spirogyra orthospira, Naeg. Plate CXXXVII, figs. 1-4, two sterile and two fertile fila- ments. Plate CXLII, figs. 5, 6, a singular and extraordinary freak. Two filaments of distinct species, the one 8. majus- cula, and the other 8. calospora (&. protecta, Wood,) in conju- gation. Prof. C. E. Bessey, in the American Naturalist for January, 1884, describes an instance of this kind observed by himself. Apparently a hybridism between two distinct forms ; the one with one spiral and infolded ends of cells, the other with numerous spirals and obtuse ends. SPIROGYRA ELONGATA, (Berk.) Kg. Diameter of filaments, 22-30 yu; cells 4-14 times longer than broad ; spirals two, or more rarely three, lax, describ- ing 3-4 turns in a cell. Fructiferous cells much inflated ; diameter of elliptic or oval zygospore somewhat greater than that of the vegetative cell. Pools and ditches, Pennsylvania. Plate CXXXY, figs. 1, 2, sterile and fertile filaments. SPIROGYRA PARVISPORA, Wood. Diameter of vegetative filaments, 75 yu ; cells 2-4 times longer than broad ; spirals four narrow bands, making each about 1J turns; zygospores very small, elliptical, li-2 times longer than broad, diameter 50 yw. Dr. Wood reports this form from the Pine Barrens, near Hibernia, Florida. It is remarkable for the comparatively small size of the spores. Plate CXL, figs. 8, 9, sterile and fertile filaments. 222 FRESH-WATER ALG^ OF THE UNITED STATES. Genus 71, SIBOGONIUM, Kg. Filamentous, composed of a series of cells with parietal longi- tudinal or somewhat spiral chlorophyl bands. Fructifying cells diverse, arising by unequal division of the cells of the filaments, bending knee-like towards each other and growing together ; united at the point of adnation ; zygospore elliptic. The sterile cells, with the chlorophyl bands, resemble those of Spirogyra, but differ in the genuflexuous conjugation. SlROGONIUM STICTICUM, Kg. Diameter of vegetative filaments, 45-50 /< ; cells 2-4 times longer than broad ; 3-4 chlorophyl bands ; zygospores broadly elliptical ; spore-bearing cells more or less swollen. Syn. Sirogonium breviarticulatum, Kg. ; Sirogonium Braunii, Kg. ; Conferva stictica, Eng. Bot. ; Zygnema curvatum, Ag. ; Choaspes serpentina, Gray. Ponds, Florida. Have seen no specimens found north of the Gulf States. Plate CXLI, figs. 8-10, copulating filaments, with two spores matured and one forming. Genus 72, ZYGNEMA, Kg. Cells with two axile many -rayed chlorophyl bodies standing near the central cell nucleus, each containing a starch-granule. Copulation scalariform or lateral ; zygospore in one of the united cells, the same as in Spirogyra. Intermedial membrane of the sporoderm scrobiculate, even, or punctate. Cells having densely granular contents, including the two starch granules and often surrounded by a cytioderm of several layers, are supposed to be resting cells. A. — The intermedial membrane of spores smooth. ZYGNEMA LEIOSPERMUM, D. By. Diameter of vegetative filaments, 20-22 /* ; sterile cells twice as long as wide ; fructiferous cells usually shorter ; equal to the diameter, somewhat swollen. Zygospores orbi- cular or broadly oval. Small pools. Plate CXLIII, figs. 1, 2, 3, parts of two sterile filaments and one fertile. ZYGNEMA. 223 ZYGNEMA INSIGNE, Kg. Diameter of vegetative filaments, 26-30 /* ; cells equal to twice as long as broad. Copulation usually scalariforni, or sometimes lateral, sporiferous cells usually slightly swollen. Zygospore brown, globose ; diameter about 30 yw, or some- what broadly oval, 26 by 32 /*. Syn. Tyndaridea insignia, Hass. ; Zygnema tenue, Eab. Plate CXLIII, figs. 4-6, sterile and fruiting filaments, the latter with matured spores in part, others forming. B.— Spor oder m punctate or granulate. ZYGNEMA STELLIUM, Ag. Forming loose interwoven masses, primarily light green, but later, in time of fruiting, dirty yellow, or brownish. Cells 1-6 times as long as wide. Fructiferous cells more or less swollen. Copulation scalariform. Zygospores oblong or globose. Very variable in size. Kirchner suggests the following separation of the different forms, all of them occurring frequently here in smaller ponds, pits, rivers, lakes, etc.: 1. — GENUINUM, Kirch. Diameter of vegetative filaments, 25-36 ^ ; cells 1-3 times longer than broad. Plate CXLIII, figs. 7, 8, sterile and fertile filaments. 2. — VAUCHERIA, Ag. Diameter of vegetative filaments, 22-26 yu; cells 2 £-6 times longer than broad. Same as Z. Brebiaaonn, Kg. Plate CXLIII, figs. 9-11, two sterile and two fertile fila- ments. 3. — TENUE, Eab. Diameter of filaments, 12-22 /* ; cells 1-3 times as long as wide. Plate CXLIII, figs. 12-13, sterile and fertile filaments. 4. — SUBTILE, Eab. Diameter of filaments, 15-19 yw ; cells 2-4 times as long as wide. Same as Z. ovale, Kg. Plate CXLIII, figs. 14, 15, sterile and fertile filaments. 5. — STAGNATE, Kg. Diameter of filaments about 10 yu ; cells 3-4 times as long as broad. Plate CXLIII, figs. 16, 17, sterile and fertile filaments. 15 224 FRESH-WATER ALG^ OF THE UNITED STATES. ZYGNEMA PURPUREUM, Wolle. Diameter of vegetative filaments, 20-25 // ; cells one, or more rarely two diameters in length. Primarily yellowish green, but soon changes to a dark purple ; fruiting filaments more or less geniculated ; zygospores spherical ; spore-bear- ing cells slightly, or not at all swollen. Common in ponds of New Jersey, floating in large, loosely interwoven masses, but very rarely in perfect fruit. Found it very abundant also, in Florida; ditches in the Tocoi marshes, near St. Augustine, literally covered with it, as a smooth, glistening dark purple mantle ; frequent in perfect fruit. The chlorophyl is usually more or less centrally con- tracted in each cell. There is no evidence of twin nuclei, a fact which, with the color and the geniculate feature of the filaments, make distinct specific characters. Plate CXLIV, figs. 3-7, sterile and fertile filaments. ZYGNEMA CRUCIATUM, Ag. Diameter of vegetative filaments, 35-50 yw ; cells one half to twice as long as wide. Fructiferous cells not swollen ; copulation scalariform ; zygospores spherical, dark brown ; sporoderm finely punctate. Mostly in stagnant waters. Mainly separated from larger form of Z. stellium by the spherical spores. Syn. Conjugata cruciata, Vauch. ; Tyndaridea cruciata, Hass. ; Conferva bipunctata, Dillw. ; Zygnema Dillwyni, Kg. Plate CXLIY, fig. 1, an early stage of spore-formation by the union of the two stellate nuclei in a cell ; fig. 2, fertile and sterile cells on the same filaments. ZYGNEMA ANOMALUM, (Hass.) Kg. Diameter of vegetative filaments, about 25 /* ; surrounded by a colorless gelatinous sheath, often twice the diameter of the vegetative cells; sometimes even, sometimes much in- flated, constricted at the joints. Cells equal or nearly twice as long as wide. Zygospores globose, olivaceous ; sporoderm distinctly punctate. Syn. Tyndaridea lutescens, Hass. ; Tyndaridea anomala, Hass. Var. CRASSUM, Wolle. Diameter of vegetative filaments, 40-44 fa without sheath ; with it 63 /* more or less ; cells primarily 3-4 times longer than broad ; after division 1-1 J times longer. Cells, and sheath of shorter cells, somewhat swollen. ZYGOGONIUM. 225 Received this plant repeatedly from the northern part of Vermont, collected by Dr. F. Hosford; all the specimens were in sterile condition, hence leaving- the generic position somewhat in doubt. Ralfs and Hassall, of England, report this species having the zygospores in the cells of the filaments; Kiitzing, of Germany, on the contrary, reports it as having the spore between the filaments in the canal of conjugation. While there can be no doubt about its belonging to the Zygnemince, it appears not decided whether it is constant as a Zygnema or may be a Zygogonium. A remark by Ralfs on a character of the species under consideration may be well to note: "In its usual state the sheath is very conspicuous, and the dense endochrome so fills the cells, that the plant looks like a Conferva, the con- tinuity being interrupted merely at the dissepiments. When about to conjugate the sheath has nearly, or altogether dis- appeared, and the endochrome is collected into the stella?, having the rest of the cell colorless." Plate CXLIV, fig. 9, part of vegetative filament as occur- ring most frequently with wide sheath ; cells densely filled with chlorophyl previous to its gathering into twin stellate nuclei ; fig. 13, part of a fruiting filament more enlarged tha^n fig. 9, may also represent an ideal fruiting filament of var. craswm ; figs. 10, 11, 12, three parts, vegetative filaments of var. crassum, in different stages of growth. Genus 73, ZYGOGONIUM, Kg. Filaments and arrangement of chlorophylous cell contents the same as in Zygnema ; zygospore not in one or the other of the conjugating cells, but in the bladder-like middle space between the united pairing cells. Copulation scalariform, or lateral be- tween cells of the same filament. Some modern authors have proposed classifying all of the fol- lowing forms of this genus with Zygnema, using the argument that the two modes of fruiting are not constant. Personal ob- servations do not lead to the same conclusion ; deviations from rule are rare, and then only with imperfectly developed fruit, hence prefer the old division. ZYGOGONIUM PECTINATUM, Kg. Diameter of vegetative cells, 30-38 yw; cells 1-2-2 £ times longer than broad, slightly constricted at the joints. Zygo- spores globose, or broadly elliptic ; diameter about 50 yw • 226 FRESH-WATER ALG^E OF THE UNITED STATES. when fully matured, dull -olivaceous ; sporoderm punctate or scrobiculate. In stagnant waters. Syn. Conjugata pectinata, Vauch. ; Conferva decussata, Dillw. ; Tyndaridea conspicua, Hass. Plate CXLV, figs. 1, 2, sterile and fruiting filaments, with three perfected spores and two forming. ZYGOGONIUM AEQUALE, (Kg. ) Wolle. Diameter of vegetative filaments, 30-33 // ; cells 1-2-3 times as long as wide; zygospores not as long as wide, measuring 25 by 30 yw, transversely oval. Marsh pools, Pennsylvania. Syn. Zygogonium saxonicum, Eab. Eabenhorst quotes this species in his Flora Algarum, but fails to give the size or form of the zygospore — the dis- tinguishing feature; we assume the name, however, at a hazard, as it agrees so well in proportionate length and breadth of cells. Plate CXLY, fig. 3. . ZYGOGONIUM DECUSSATUM, (Vauch.) Kg. Diameter of vegetative filaments, 18-20 /* ; cells 3-5 times longer than broad ; cell membrane thin ; connecting tube inflated, bearing a spherical zygospore; somewhat larger than the diameter of the filament. Ponds, sluggish or stagnant waters. Syn. Tyndaridea decussata, Hass. ; Conjugata decussata, Vauch. Plate CXLV, figs. 4, 5, conjugating filaments with cells partly sterile, partly with zygospores. ZYGOGONIUM AGARDHII, Eab. Diameter of filaments, 15-18 yu; cells 1J-2 times longer than broad, more rarely equal ; bright yellow green, cells not swollen; sometimes moderately constricted at joints; zygospore globose, rarely slightly oval, membrane firm, colorless, smooth ; diameter, 20-25 //. Wet ground, Florida, frequent. Plate CXLV, figs. 6, 7, fruiting filaments. In size the plants ascribed to this species are thinner than those of Z. compicuum, Kg., nearer Z. decussatum, Kg.; the articulations are longer than the average of the former, and shorter than those of the latter. MOUGEOTIA. 227 ZYGOGONIUM PARVULUM, Kg. Diameter of filaments, 22-24 // • cells 4-6 times longer than broad, not swollen ; zygospore globose produced in the con- jugative canal; diameter very little more than that of the cells. Pools and ponds. Syn. Zygnema ordinarium, Berk. The distinction between this form and Z. decussatum, is slight, hardly sufficient for a good species. We quote it without confidence in its value, probably a form of Z. de- cussatum. Plate CXLV, fig. 9. ZYGOGONIUM RALFSII, Kg. Diameter of vegetative filaments, 16-20 /<<; cells 2J-3 (rarely 4) times as long as broad ; zygospore compressed ellipsoid twice as long as broad, produced in the inflated conjugative canal ; sporoderm smooth. Syn. Tyndaridea Ralfsii, Hass. Pools, Pennsylvania ; rather rare. Plate CXLY, fig. 8, part of conjugated filaments. The above description is from European works and de- scribes our form correctly except the zygospores ; the differ- ence between the length and breadth of the spore is not near as great. Genus 74, MOUGEOTIA, D. By. Cells cylindrical with axile chlorophyl -plates. Copulation scalariform. Zygospores drawn together in the widely swollen, bladdery, persisting middle space. MOUGEOTIA SPHAEROCAKPA, Wolle. Diameter of vegetative filaments, 20-25 ^ ; cells 3-6 times longer than broad; zygospores large spherical, diameter about 40 /*. Ponds, New Jersey, Pennsylvania, Florida, etc. The nearest allied species of Europe is M. laevis, Arch. Fila- ments about the same diameter, but cells shorter (2 diam- eters, or before division 4 diameters). Zygospores elliptic or oval. Archer says, "conjugation takes place by short wide processes, which, along with the shortness of the cells, give the pair of conjugating filaments somewhat of the ap- pearance of a perforated ribbon-like structure." He adds, " The elliptic zygospore, within the inflated transverse tube, has the longer diameter of the spore placed vertically to the length of the filament." 228 FRESH-WATER ALGJE OF THE UNITED STATES. Judging also by an illustration in Cooke's British Algce, M. laevis, Arch., is entirely distinct from our plant. The conjugating connecting tube is comparatively narrow, the spore small, not wider than the diameter of the filaments and decidedly elliptic. Plate CXLVI, figs. 1, 2, two pairs of filaments conju gated ; zygospores forming, and matured. MOUGEOTIA MlNNESOTENSIS, Wolle. Diameter of filaments, 15-18 /-i ; cells 4-5 times as long as broad. Zygospores very large, spherical, diameter 60 yw. General appearance near the preceding, but proportions of cells and spores, and size of filament, all distinct. From the comparatively few specimens seen, judge it a different species from the preceding M. Sphaerocarpus. Pond, near Minneapolis, Minnesota. Plate CXLVI, fig. 3, two filaments in conjugation ; spores mature. MOUGEOTIA DIVARECATA, Wolle. Diameter of vegetative filaments, about 20 /* ; cells 4-10 times longer than broad ; zygospores average 45 yu ; cells more or less diverging between the spores. Ponds, Pennsylvania. Somewhat like the two preceding species in the spherical spores, but differing in size, also in length of cells, and in the recurving of the same. Plate CXLYI, fig. 4, two conjugating filaments with matured spores. MOUGEOTIA DELICATULA, Wolle. Diameter of vegetative filaments, 12-14 yu ; cells 4-6 times longer than broad ; zygospores spherical, diameter 25-30 yw. Shores of St. Lawrence River, Canada. Plate CXLVI, fig. 5, conjugated filaments with spores matured. These four species are introduced with some degree of hesitancy as new species of Mougeotia. They evidently be- long to this genus, but whether absolutely distinct species may riot be so certain. They were found in distinct, and widely separated localities, never in large quantity, and not all so frequently as to remove all doubt of constancy in the specific characteristic features given. They are unlike any European species known. Cooke's figures represent very different forms ; possibly incorrectly, because not strictly in MESOCARPIN^. 229 harmony with Archer's description, when he remarks of M. laevis, "the conjugation takes place by short, wide, processes." MOUGEOTIA GKLYPTOSPERMA, D.By. Diameter of filaments, 10-13 yw ; cells 6-12 times as long as broad. Zygospore large, oval, with a thick, firm, yellow- brown epispore, more or less radiately corrugated when fully matured ; sporiferous cells elongated. The position of the zygospore gives the appearance of a Mesocarpus, but the distinction between the two genera must determine its proper place. In Mougeotia the zygo- spore is the result of the complete fusion of the cell contents of the two conjugating cells, whereas in Mesocarpus the spore is the result not of the complete coalescence of the green contents of the two cells, but only of a part thereof; the spore is not a true zygospore, but rather a daughter cell of it. This plant has a true zygospore, hence is properly placed with Mougeotia. The only good specimens, from marsh pools, Florida. Plate CXLVI, figs. 6, 7, conjugating filaments with spores in different stages of advancement toward maturity ; figs. 8, 9, two sterile filaments. MOUGEOTIA VERRUCOSUS, "Wolle. Diameter of filaments, 13-14 yw ; cells 6-10 times longer than broad, somewhat recurved. Spores transversely oval, shorter diameter 20-25 yw ; and longer axis, 40 /*. Membrane coarsely granular, dark brown. Pools, near Mobile, Alabama. A very distinct form. Found only a limited number of specimens ; short fruiting filaments; no sterile cells ; farther observations may modify the above description somewhat. Plate CXLVIII, fig. 5, conjugated filaments with matured spores. SUBSECTION.— MESOC ABPIN^E. Green filamentous plants, with chlorophyl more or less axillary. Copulation similar to that of the ZygnemmcB, scalari- form, geniculate or lateral ; the spore formed, however, is not the result of the flowing together of the entire chlorophyl masses of the two cells united ; the chlorophyl does pass out from the two cells and conjoins, but it unites only in part, being separated by two or four partition walls. The spore thus formed is not prop- erly a zygospore, but a hypnospore, or a resting spore. 230 FRESH-WATEE ALG^ OF THE UNITED STATES. Genus 75, MESOCABPTJS, Hass. Spores spherical or oval, between two cylindrical, straight or slightly inbent cells. Copulation scalariform. Spore membrane smooth. MESOCARPUS SCALARIS, (Hass.) D. By. Diameter of vegetative filaments, 25-30 /t ; cells 2-6 times longer than broad ; spores spherical or broadly oval, mem- brane brown, smooth, nearly the same in diameter as the filaments. Syn. Mesocarpus intricatus, Hass. ; Sphaerocarpus intricatus, Hass. Frequent in marsh and meadow pools. Plate CXLVII, fig. 2, conjugated filaments with spores; fig. 3, a specimen from Plaiuville, Conn., 1879, noted at the time as variety M. scalciris. Have seen no specimens since, and question, may it be a Mougeotia ? MESOCARPUS PARVULUS, (Hass. ) D. By. Diameter of filaments, 8-10 yw ; cells 6-12-16 times as long as broad ; spores globose, brown at maturity ; membrane smooth. Filaments of fruiting cells usually straight, but sometimes arched between the spores. Syn. Sphaerocarpus parvulus, Hass. ; Mougeotia splendens, Kg. ; Mesocarpus angustatus, Hass. Ponds and pools, North, West and South. Plate CXLVIII, figs. 3, 4, ordinary form of fruiting fila- ments. MESOCARPUS MACROSPORA, Wolle. Diameter of vegetative filaments averages about 30 yw; cells 6-10 times longer than broad ; spores nearly or quite twice the diameter of the filaments ; filaments arched be- tween the spores. Membrane of spores smooth. Shallow waters, Susquehanna River, Harrisburg, Pa. Plate CXLYII, fig. 4, specimen of spores and filaments. MESOCARPUS CRASSA, Wolle. Diameter of vegetative filaments, about 50 ^ ; cells 4-5, or before division sometimes ten times longer than broad. Spores spherical, membrane smooth, diameter averages 65 yw, about one-third more than that of the filaments. In large light yellowish green masses, floating on stagnant waters in ditches in Tocoi marshes, near St. Augustine, Florida. Plate CXLVII, fig. 1, spores and cells of filaments. PLEUROCARPUS. 231 MESOCAEPUS EECUEVUS, Hass. Diameter of filaments, 10-18 //; cells 5-10 times longer than broad, more or less recurved. Zygospores globose, membrane smooth, diameter, 20-24 yw. Syn. Sphaerocarpus recurv us, Hass. Ponds and ditches. Plate CXLVII, fig. 6, conjugating filaments and spores. MESOCAEPUS EADICANS, Kg. Diameter of filaments, 22-29 ^ ; cells 3-8 times as long as wide. A sterile form scarcely to be counted a distinct species, possibly a variety, or condition of M. scalaris, pos- sessing the singular feature of short branchlets usually emitted nearly at right angles, about the middle of a cell. Plate CXLVIII, figs. 7-10, sterile, branched filaments. The arrangement of the endochrome and of the starch grains in the cells, are a good illustration of sterile filaments of nearly all species. Spore membrane punctate. MESOCABPUS NUMMULOIDES, Hass. Diameter of vegetative filaments, 9-15 /* ; cells 7-14 times longer than broad. Spores spherical. 17-23 /* in diameter, membrane punctate. Syn. Sphaerocarpus nummuloides, Hass. Meadow, or wayside pools. Plate CXLVIII, figs. 1, 2, sterile and fruiting filaments. MESOCAEPUS EOBUSTUS, D. By. Diameter of filaments, 25-32 // ; cells 3-8 times longer than broad, nearly straight ; spores nearly spherical, 40-50 yw diameter, membrane reddish brown, finely punctate. Small ponds and ditches. Plate CXLVII, fig. 5, copulated cells, with spores too nearly spherical for the typical form. Genus 76, PLEUEOCAEPUS, A. Br. Filamentous, cells the same as the cells of Mesocarpus; copu- lation not scalariform, but lateral, by the flowing together of the chlorophyl of two adjoining cells. Sterile filaments often bent nearly at right angles, and united at the angles, but producing no fruit. 232 FRESH-WATER ALG.E OF THE UNITED STATES. This genus has by some authors been incorporated into the genus Mesocarpus, but the method of fruiting is so absolutely distinct, prefer to keep it separated. PLEUROCARPUS MIRABILIS, A. Br. Diameter of vegetative filaments, 25-30 ^ ; cells 2-5 times longer than the diameter. Spores somewhat depressed globose, about the same diameter as that of the cells, hav- ing a lateral position, mostly on one side of the filament at the joint of the two copulating cells. Common everywhere; forms large, loosely interwoven light green floating masses, usually only one to two feet in diameter, but sometimes 20-30 feet across. The filaments are very fragile, breaking into short lengths ; almost always geniculately united, but never in fruit. Was familiar with this form for eight years, saw it constantly, but always sterile, and was coming to the conclusion that the story of A. Braun about the mode of fruiting must be a myth, when suddenly, in 1883, it wras found in three distinct localities; first by E. S. Cheeseman, Knowlesville, N. Y.; second by Miss E. Butler, in a swampy meadow near Maiden, Mass.; and third, by myself in a small pool on the border of a pond familiarly knowrn as Buckaberry Pond, in Northern New Jersey. Have not seen it since. Syn. Mougeotia genuflexa, Ag. ; Conferva genuflexa, Dillw. ; Zygo- goniumpleurospermum, Kg. Plate CXLIX, figs. 8, 9, two pairs geniculate filaments grown together. The form known by earlier authors as Mougeotia genuftexa. Fig. 10, the beginning of the formation of a lateral spore ; figs. 11-13, three matured spores, the result of lateral conjugation ; figs. 14, 15, sterile filaments. PLEUROCARPUS COMPRESSUS, Lyngb. This specific term, compressus, was applied by Lyngb., Gray and Bab., and others to the form figured, Plate CXLIX, figs. 10-13, and Mougeotia genuflexa to figs. 8, 9. PLEUROCARPUS COLUMBIANUS, Wolle. Diameter of filaments, 37-40 ^ ; cells 4-8 times longer than broad, geniculately joined. In the year 1879, we an- nounced this plant as a new species. Bull. Torrey Bot. Club, January, 1879. It is nearly one-half thicker and the cells are longer than those of P. mirdbilis ; would more properly be named a variety of that species. Plate CXLIX, figs. 6, 7, sterile filaments. GONATONEMA. 233 Genus 77, PLAGIOSPERMUM, Cleve. Cells cylindrical, united into filaments ; cell contents similar to other Mesocarpince. Spores spherical or broadly oval in one of the conjugated cells. The spore-bearing cell somewhat in- flated and shortened by distinct and thickened, suture-like, par- tition walls. PLAGIOSPERMUM TENUE, Cleve; var. MINOR, Wolle. Diameter of vegetative filaments, 17-18 }J. ; cells 4-8 times longer than broad. Spores spherical, 2-2 times more in diameter than the filaments. Spores dark green to brown or red. The filaments of the typical form found in Sweden and described by Cleve, measure 25-30 //, and cells 8-16 times longer than broad. Shallow pools, Bethlehem, Pennsylvania, and Florida. Plate CXLYIII, figs. 11-15, fruiting filaments ; the same are also found in series of fruiting cells on the same filaments. Genus 78, GONATONEMA, Wittr. Cells elongated, cylindrical, united into filaments with axile plates of chlorophyl. Agamospores produced without conjuga- tion, formed by biseptation of the mother cells, which latter are often bent angularly, and alternately, at the point of fructi- fication. GONATONEMA" VENTRICOSUM, Wittr. Diameter of vegetative filaments, 5-6 fj. ; cells 8-12 times longer than broad, somewhat geniculately bent ; spore- bearing cells inflated ; spores spherical or broadly oval. Prof. Wittrock, of the Academy of Science, Stockholm, made a thorough investigation of the spore-formation of the Mesocarpece and especially on the new genus Gonatonema. The paper is too long for transfer to these pages ; a few words may be quoted: "It appears that the spores are always formed without a preceding act of conjugation. The spore formation, therefore, may be regarded as neutral, or we may assume that, as in exceptional cases, spores may be formed by the instrumentality of a single cell ; in this case the ex- ception has become the rule, and the spores would then be regarded as parthenospores, and not as agamospores. " "Because this plant differs in such an essential respect in the spore from the other Mesocarpece, I have thought fit to form a new genus for it, to which I have given the name of Gonatonema, meaning geniculate filament." 234 FRESH-WATER ALGJE OF THE UNITED STATES. Collected this plant in small pool on margin of river, Bethlehem, Pennsylvania. It may not be absolutely the same plant as described by Wittrock, but it is too near to be separated as a new species. Plate CXLIX, figs. 1-5, sterile cells, cells forming spores, and bearing matured spores. Genus 79, STAUBOSPERMUM, Kg. Filaments geniculate, zygospores short cylindrical, in front view Quadrangular; in lateral view narrow elliptical, between the truncated corners of, usually, four sessile lateral cells. Cells often twenty times longer than broad. STAUROSPERMUM CAPUCINUM, Kg. Diameter of vegetative filaments, 14-20 yw ; cells 6-14 times longer than broad ; zygospores quadrate, angles obtuse, truncate or incurved, sides often deeply sinuate. Sporo- derm smooth. Filaments acquire a bluish tinge and with age a purple hue. Ponds, widely distributed, the most frequent of our species. Syn. Staurocarpus glutinosus, Hass. ; 8taurocarpus capucinus. Kg.; Leda capucino, Bory. Plate CL, figs. 1-5, sterile filament ; immature spore and three forms of matured spores. STAUROSPERMUM QUADRATUM, Kg. • Diameter of vegetative filaments, 8-12 ^ ; cells 8-18 times longer than broad, forming floating masses of considerable size. Zygospores quadrangular, sides straight, angles trun- cate, membrane punctate or porose. Spores, 28-40 yw. Ponds, New Jersey, frequent. Syn. Staurocarpus quadratus, Hass. Plate CL, figs. 6-8, three zygospores of different sizes. STAUROSPERMUM VIRIDE, Kg. Diameter of filaments, 6-8 // ; cells 6-10 or more times longer than broad ; zygospores mostly quadrangular, with sides more or less deeply incurved ; membrane smooth. Syn. Staurocarpus gracilis ; S. virescens; S. affinis, all by Hass.; Staurospermum franconicum, Beinsch. Small pools and ponds, Florida. Plate CL, figs. 9, 10, a quadrangular, and a triangular zygospore. SCHlZOSPOREvE. 235 Genus SO, CBATEBOSBEBMUM, A. Br. Filamentous, elongated, membrane thin. Chi arophyl -green cell contents primarily diffused, later more contracted into an axillary band. Copulation geniculate. Zygospore spherical, in- volved in a cylindrico-subquadrangular membrane, at the point of conjugation. CRATEROSPERMUM LAETEVIRENS, A. Br. Diameter of vegetative filaments, 38 /* ; cells 3-8 times longer than broad ; zygospores green, changing to oliva- ceous, or brown. Floating in rather light green interwoven masses. Syn. Mougeotia craterosperma, Itz. The only specimens recognized as possibly of this genus, were collected, July, 1880, in Green Bond, New Jersey. The conjugation was complete, but the spores were imperfectly developed, hence my hesitancy in calling it a pronounced species of this genus. Blate CL, figs. 11, 12, the conjugated cells as observed. Class III.— CYANOPHYCE^E. (BHYCOCHROMOPHYCE^E. ) Blants one or many-celled, living in water, or enclosed in a maternal jelly when out of it, mostly in families formed from successive generations of cells. Cell membrane (cytioderm} not siliceous, combustible. Cell contents (cytioplasm] variously col- ored by means of phycochrome, aeruginous, red, violet, orange yellow, brown, or olivaceous, but never chlorophyl-green ; desti- tute of nucleus and usually without starch granules. Order YL— SCHIZOSPORE^E. (CYSTIPHOR^:. ) Cells single or united in single or branched series ; they divide in one direction only. Cytioderm soft, smooth, immersed in a more or less liquid or firm mucilage, variable in color, for the most part irregularly disposed. The two families NOSTOCACE^: and CHROOCOCCACEJE are sep- arated by the former having the cells united after division into filamentous series, and the latter having the cells separated and scattered. 236 FRESH-WATER ALG.E OF THE UNITED STATES. Family XVIIL—NOSTOCACE^E. Filamentous, simple or rarely with spurious branches, fur- nished with heterocysts ; involved in a copious gelatin, more or less firm or diffluent. The plants of some of the genera develop spores, and are provided with heterocysts ; the former, usually dark green, granular ; the heterocysts yellow or lighter or darker yellowish brown, or nearly colorless, almost devoid of cytio- plasm; sometimes they are terminal, sometimes interstitial, between vegetative cells. The spores divide after a period of rest, before or after the rupture of the cytioderm, and then ger- minate and reproduce. The function of the heterocysts is not determined. The Family NOSTOCACE^; may be divided into the following five sections : I. BIVULARIEJE. II. SCYTONEME^. III. SlROSIPHONE^. IV. NOSTOCE^;. V. OSCILLARIE^E. SECTION I.— RIVULARIE^E. Genm 81, CALOTHEIX, (Ag.) Thur. Filaments rather rigid, nearly straight, branched; branches spurious, being younger trichomes, agglutinated at the base and part of their length to the parent stem, terminating at the apex in a delicate hair-like extremity. Heterocysts normally present, usually at base of branches ; often fasciculately branched ; grow- ing in small tufts, or forming a light turf of indefinite extent. CALOTHRIX ORSINIANA, Thur. Forming a pulviuate stratum, about 40 yu in thickness, dark brown, or reddish brown, lubricous, opaque ; trichomes elongated, branches of nearly equal thickness, cuspidate at the apex or obtuse, distinctly articulate ; sheaths thick, smooth or lamellate, light golden brown. Trichomes with sheath, 20-25 //; without sheath, 10-13 ^t. Syn. Scytonema cirrhosum, Berk.; Coenocoleus cirrhosus, Berk.; Schizosiphon cateractce, Naeg. On submerged stones, Florida. The measures quoted by Kirchner and by Cooke are less than given above, but otherwise the description seems to indicate a similar plant. Plate CLXYIII, figs. 1, 2. CALOTHRIX. 237 CALOTHRIX DILLWYNII, Hass. Flaccid, aeruginous (blue-green) or more rarely brownish ; sheaths inconspicuous, except sometimes towards the base ; articulations, 1-11 times as long as the diameter; heter- ocysts at the base of the spurious branches, ovate or sometimes cordate. Diameter of trichomes, 12-15 yu ; smaller forms, 10-13 jn. The latter sometimes with twin heterocysts. The larger from specimen from Garrett County, Maryland. The other from swamps, etc., New Jersey. Plate CLXVIII, figs. 3, 4. CALOTHRIX GYPSOPHILA, Kg. Brown, or almost black, smooth, shining, in small tufts, or extended strata on rocks at water's edge washed by the waves. Trichomes about one-fourth of an inch long, sub- dichotomously branched, somewhat attenuated at ends ; sheath rather close, brownish yellow. Articulations indis- tinctly a-1 diameter. Heterocysts the size of trichome, usually two or three in series. Diameter of filaments, 12-14 yw. Syn. Scliizosiplion gypsopliilus, Kg. Lake Hopatcong, New Jersey. Plate CLXVIII, fig. 5, two short filaments with spurious branches. Have adopted this name although our plant is not in every particular in accord with the diagnosis given in Raben- horst's Flora Algarum. Plate CLXVIII, figs. 6, 7. Smaller variety from Pennsylvania, and from Minnesota. CALOTHRIX GRACILIS, Bab. Small tufts, aeruginous, or later dull brown, usually fasci- culately branched ; branches closely attached ; sheath firm, close, colorless or light yellow, indistinctly lamellate, ends closed, attenuate, except in older, brown plants, then often open and fibrous. Heterocysts oval, yellow, same size as the filaments, single or twin. Diameter of basal parts of trichomes, 6-8 /*. Syn. ScMzosiphon gracilis, Eab. Occurs frequently in ponds; differs from C. Dillwynii mainly in size. Plate CLXXIII, figs. 2, 3. 238 FRESH-WATER ALG^ OF THE UNITED STATES. CALOTHRIX MENEGHINIANA, Kirch. Forming strata on partially submerged rocks, usually near the water line, composed of small, deep aeruginous or brown dense tufts ; trichomes short, somewhat prostrate, at first simple, later much and compactly branched. Cells equal or half as long as wide. Sheath distinctly lamellose, at the base yellow or brownish, at the ends colorless and torn into fine fibers. Heterocysts usually single, same thickness as the vegetative cells. Diameter of vegetative cells, 6-8 /x Diameter of sheath, about 13 //. Syn. Schizosiphon MenegMnianus, Kg. Plate CLXX, figs. 5-7, three plants in different stages of growth. CALOTHRIX RADIOSA, (Kg.) Kirch. Small tufts, sometimes gregariously extended on sub- merged rocks, waving, made up of radiating, fasciculate trichomes, about 40 // long, considerably branched ; stems and branches somewhat curved, the two adhering about half the length of the branches, ends free ; mostly of brownish red color. Vegetative cells, i- i as long as wide. Sheath close, golden yellow or colorless. Heterocysts single, glo- bose, size the same as filament to which it is attached. Diameter of internal trichomes, 12 //. Diameter of sheaths up to 30 // wide. Plate CLXX, figs. 1, 2, two plants drawn on a much smal- ler scale than the others on the plate ; figs. 3, 4, a variety, appears to stand between this species and C. Meneghiniana; figs. 8, 9, young forms of the last, (3, 4). CALOTHRIX BREBISSONII, Kg. Caespitose, bright aeruginous, or sometimes changing to light brown, spurious branches short, stout, quickly atten- uate to a hair-point, beautiful aeruginous ; distinctly and shortly articulate, sometimes interrupted ; articles with granular contents, 3-4 to diameter. Sheath usually close, widens with age, colorless or light yellow. Heterocysts glob- ular, single, at base of branches, colorless or light yellow. Diameter of trichomes, with sheath, 16-20-25 //. Submerged stones, ponds, New Jersey. Plate CLXIX, figs. 5, 6, 7, two characteristic forms. CALOTHRIX. 239 CALOTHRIX HOSFORDII, Wolle. Stratum olivaceous, trichomes aggregated, bright aerugi- nous, subdichotomously spuriously branched ; branches flagelliform, turgid below, tapering to a fine, colorless hair- point. Articulations 4-5 to diameter. Sheath wide, dis- tinctly lamellose, yellow toward the base ; colorless and hyaline toward the ends. Heterocysts depressed semi-glo- bose ; 3-4 times broader than long ; bluish tint, somewhat lighter than the vegetative cells. Diameter of internal trichome, thicker parts, 10-12 ju. Diameter of sheath, 25-28 yw. Collected by F. H. Hosford, in pond near Charlotte, Ver- mont. Bears some resemblance to the last, C. Brebissonii, but is particularly distinct in the form and color of the heterocysts. Plate CLXIX, figs. 1, 2, a long filament with numerous, young forms, spurious branchlets, attached ; figs. 3, 4, three young, isolated plants. CALOTHRIX LACUCOLA, Wolle. Floating, dull yellow or brownish, dichotomously branched ; branches somewhat patent, not concrete, mod- erately attenuated, apices obtuse, slightly bent. Internal trichomes thin, dull aeruginous or yellowish brown, homo- geneous or indistinctly articulate, subequal or less. Hetero- cysts globose, yellow, single or twin, at base of branchlets. Diameter of thicker parts, 15-20 //. Split-rock Pond, New Jersey, the only habitat hitherto found. This singular plant bears a resemblance to Tolypothrix, but is unlike the forms of that genus in having the filaments attenuated, beside the distinct branching. Plate CLXXII, fig. 1, one of the larger forms. CALOTHRIX CRUST ACEUM, ( Ag. ) Wolle. Plants densely caespitose, erect, somewhat regularly branched, branches free, with obtuse rounded apices, and each with a heterocyst at the base. Aeruginous endochrome annulated, increasing in diameter towards the apices of the filaments. Diameter sheath, 17-20 yw. Diameter of internal filaments, 8-10 yw more or less. This plant has been variously described in its different stages of development. 16 240 FRESH-WATER ALG^E OF THE UNITED STATES. The first condition is described as Zonotrichia minutula, Wood. Fronds very small, blackish green, semi -globose, not dis- tinctly zoned, rather soft, growing on mosses ; not impreg- nated with lime ; internal filaments shortly articulate, very distinctly fasciculately josew^o-ramose, etc. Second condition Zonotrichia parcezonata, Wood. Blackish green, irregularly semi-oval, to six lines long, hard, slippery, not fragile, impregnated (partially) with lime, internally distinctly radiate, sparsely and often obso- letely zoned ; filaments moderately long, straightish, etc. The author remarks, " I found this plant growing 011 rocks as glossy, blackish, very hard and slippery fronds or masses, which varied in size from that of a very small shot to nearly half an inch in length. The filaments (internal) are often very evidently and frequently pseudo-r&mose." Certain specimens which I obtained, growing with the others, instead of being blackish in color, are grayish, but agree in all other respects with their fellows. The gray color depends upon the deposit of lime salts, distributed in quantity with the spray of the falls. It is probably this condition which Prof. Bailey refers to as Rivularia calcaria. This stage would make the third condition. A fourth condition is well calculated to deceive the novice — with age the trichome contracts, and the ends of the wide sheaths become fibrillose. Syn. Besides the above three, may be added Schizosiphon crusi- formiSj Naeg. ; Sch. cataracta ?, Naeg. ; Petronema fructicu- losum, Thwaites ; Scytonema crustaceum, (Ag.) Cooke. Very abundant, particularly on the rocks subject to the spray of water falls, Niagara, Genesee River falls, Adiron- dack Mountains, etc. Plate CLXXII, figs. 4, 5, the gray crustiferous form, natural size, often forms a thicker crust ; fig. 3, a section of a glossy blackish frond, Zonotrichia parcezonata • fig. 6, section of a more advanced growth ; fig. 2, a single plant separated and more highly enlarged ; fig. 7, more advanced stage, ends of trichomes fibrillose. Plate CLXXVII, fig. 15, natural size of thalli, as some- times found in clusters ; fig. 14, a section of one of them showing the Zonotrichia form. MASTIGONEMA. 241 Genus 82, MASTIGONEMA, ( Fisher) Kirch. Filaments short, free, without gelatinous sheath, branchless, singly or sometimes in small mats. Heterocysts at the base of the filaments ; spores unknown. All the forms under this genus are probably merely arrested, or intermediate conditions of higher developments of plant-life, as will appear in the following list of forms, under the names of species. MASTIGONEMA ^ERUGINEUM, (Kg.) Kirch. Filaments straight, bent, or curved. Sheath thin and close, extended into a slender flagelliform end. In vegeta- tive state aeruginous, distinctly or indistinctly articulate ; cell contents more or less granular. Heterocysts variable in size and form, single or geminate, globose, oval, depressed globose, pyriform, etc., usually yellow of lighter or darker shade ; sizes indefinite ; with age the sheath widens and sometimes becomes fibrillose. Plate CLXXIV, figs. 3-9, three distinct forms ; figs. 3-4, having double heterocysts, a larger oval, connected with a smaller globose cell ; figs. 5-7, pyriform heterocysts, both forms with thin, close sheaths ; figs. 8, 9, spherical, single heterocysts, wider sheath, becoming fibrillose. Plate CLXXI, figs. 8-10, three forms in a gelatinous coat- ing on the sides of a pump trough, commencing to branch after the manner of a Scytonema. Plate CLXXVI, figs. 2, 3, 4, another form, indicating the same manner of branching as the last. Plate CLXXV, figs. 1-3, young stages, developed from spores, and more advanced conditions ; fig. 4, a long filament indicating a connection with Tolypothrix ; figs. 5$ 6, another form, developing after a manner of its own. The young filaments commencing growth in small clusters, like fig. 9 ; these changing to horizontal positions, so that alternate cells lie in opposite directions, ifig. 8) ; at first short, flagelli- form, then elongating and becoming linear (fig. 6), and much longer, having the appearance of Tolypothrix muscicola; fig. 7, is another specimen of the same ; the branching com- mences at some distance from the basal heterocysts. Penn sylvania. Figs. 9, 10, same mode of developing; Florida specimens ; figs. 12-14, a larger form, from New Jersey ; manner of arrangement the same ; figs. 15, 16, 17, more scattered filaments — showing a gradual increase in breadth 242 FRESH-WATER ATuGJE OF THE UNITED STATES. and length ; first flagelliform, then linear and much elon- gated. All indicating that these so-called Mastigonema forms are not fully developed plants. Plate CLXXVI, fig. 8, young conditions gradually devel- oping into larger forms ; figs. 6, 7, in mass producing a dark olive coating on old planks subject to inundation from marine waters. These forms I named some years since, Mastigonema velutina, but have now reason to believe they are the young condition of Lyngbya aestuarii. Compare L. aestuarii; figs. 9-11, a variety of sizes, similar to figs. 2-4, having the peculiarity of interstitial heterocysts not here- tofore noticed. Plate CLXXIII, figs. 4, 5. A variety frequently occur ring, from Florida ; juvenile and maturer forms, correspond- ing with Plate CLXXI, fig. 7, also from Florida ; figs. 5, 6, of latter plate, represent filaments from a large floating mass, heterocysts torn off; probably the same, but older con- dition of fig. 7. Filaments instead of being bright aerugi- nous many are partially changed to yellow or light brown, and others brownish red. Fig. 1-4, appear distinct in a process of fruiting ; the basal articulations develop niacro- gonidia which pass out through a rupture at the end. These trichomes also have interstitial heterocysts. The clinging of the young to two of the older trichomes indicates a relation to Calothrijc. The formation of the rnacrogonidia in the basal cell is worthy of a note. Prof. A. Borzi remarks in his Morfologia e Biologia, etc., p. 297, that nearly all, or quite all of the Rivulariacece multiply not only by ormogons, but also by the spores which originate in the basal portion of the trichomes. These are true spores capable of hiber- nation. Plate CLXXVII, figs. 1, 2, somewhat distinct in hetero- cysts and the fibrillose sheath ; from wet moss and rocks, Niagara ; figs. 3, 4, more usual forms of variable sizes ; fig. 11, more elongated form ; fig. 12, very turgid specimens ; fig. 13, heterocysts wider than the filaments. Plate CLXXVI, fig. 1, a parasitic form on Lyngbya WoUei, and probably a young development of it. MASTIGONEMA HALOS, Wood. In little tufts ; filaments simple, in mature state greatly elongated, and with the sheath truncate and open ; in the young condition shorter and often ending in a rather short MASTIGONEMA. 243 seta ; internal filament shortly articulate, minutely granular, continuous or variously interrupted ; sheath firm, rather thick, often distinctly lamellated, colorless ; heterocysts subglobose. Diameter with sheath, about 12 /u. An inhabitant of salt or at least brackish water. Have found its like in fresh water also. Plate CLXXIV, fig. 2, the growth, under low magnifica- tion ; fig. 1, the plant enlarged 250 diameters. MASTIGONEMA SEJUNCTUM, Wood. Thallus somewhat caespitose, soft, parasitic; filaments simple, mostly inarticulate, but sometimes shortly, some- times long articulate, attenuate at the apex, yellowish olive or greenish, sparsely granulate ; sheaths mostly ample and distinct hyaline, often strongly undulate, the apex mostly much amplified and dissolved into fibrillae ; heterocysts about equal to diameter of the filaments. Diameter of trichonie, 4 yw. Diameter of sheath, 12 yu. Growing on the edges of minute leaves, so as to form little prominences or thickenings of the margin. Carp River bog. Plate CLXXIII, fig. 9, a small tuft ; fig. 6, an isolated trichome. MASTIGONEMA ELONGATUM, Wood. Thallus at first subglobose, afterwards frequently fusiform, blackish green, slippery, firm ; filaments aeruginous, very elongate, sometimes not articulate, but more generally shortly articulate, sometimes strongly contracted at the joints ; apices sometimes truncate, but generally produced into long, flexuous, translucent hair-points ; sheath trans- parent, close, frequently truncate at the apex ; heterocysts globose or subglobose. Diameter of filaments, 6-7 yw. Was found growing in an aquarium on some brook moss. It forms little nodules of the size of a pin's head upon the wire-like stems, or sometimes longer fusiform masses which are apparently produced by the coalescence of the little glob- ules. The color of these fronds, which are very firm, is blackish green. The filaments radiate from the base in all directions, etc. — Wood. Evidently not a Mastigonema, but a Rivularia. Plate CLXXIY, fig. 9, a single filament, after Wood. 244 FRESH-WATER ALG^ OF THE UNITED STATES. MASTIGONEMA FIBROSA, Wood. Light bluish -green, or olivaceous-green, apex of the ma- ture filament prolonged into a long, distinctly articulated hyaline seta ; sheath transparent ; in the immature filament distally, broad, and distinct although hyaline ; below, rather thick and close ; in the mature filament below close, indis- tinct, above dissolved in fibrilla3 and wanting at the apex ; heterocysts globose, sometimes geminate. Diameter of filaments, 10-11 //. Found growing with other low algae in a thick jelly, which clothed some wet, dripping rocks. Appears to be only one of the many varieties of this genus, not worthy of a distinct name. Syn. Mastigotltrix fibrosa. Wood. Plate CLXXIV, fig. 8, four trichomes after W^ood. MASTIGONEMA FERTILE, Wood. Caespitose, intermingled with other algee ; filaments sim- ple, elongate, truncate at the apex ; internal filament green, often interrupted, sometimes articulate, sometimes not; joints 2-3 times longer than the diameter ; sheath moder- ately close, thick, firm, transparent and colorless, truncate and open at the apex ; spores ( ? ) cylindrical, scattered, each contained in a cell, frequently several in a filament ; hetero- cysts globose, sometimes compressed. Diameter of filaments, about 8 yw. Found in stagnant pool in Bear Meadows, Pennsylvania, forming a filamentous, felty mass with Oedogonia and other algre. "The variously curved and interlaced, flexible filaments are always simple and of uniform, or nearly uniform diam- eter through their whole length. All specimens seen were abruptly truncate. — Wood. Seems a singular fact ; not one of these five forms discov- ered by Wood came under our observation. Genus 83, ISACTIS, Thur. Filaments agglutinated by a more or less firm mucilage, often calcariously incrusted, forming strata of flat surfaces, not arched, filaments erect parallel, attached at the base. ISACTIS FLUVIATILIS, (Eab.) Kirch. Stratum turf or sod-like often extended, more or less with a calcarious crust and then of an olivaceous gray color; GLOEOTRICHIA. 245 usually olivaceous, brown or reddish ; filaments closely compacted and sometimes, apparently, one stratum on an- other, the result of interrupted growths. The ends of the trichomes suddenly acuminate ; cells, light aeruginous, sheaths close, colorless, light yellow or brown, widened at the ends and dissolved into fibrillse ; heterocysts colorless globose or depressed. Single trichomes, separated from a mass, have a wide sheath ; cells often distinct and rnoniliform. Diameter of filaments, 8-12 ju. Syn. Zonotrichia fluviatilis, Eab.; Mastigonema plana, Eab. ; Isac- tisplana, Thur. Frequent on rocky margins of the bed of the Genesee River, about Niagara Falls, and similar localities. Plate CLXXYII, figs. 5, 6, two small sections of the turf ; figs. 7-10, isolated trichomes separated from the masses. ISACTIS CAESPITOSA, (Kg.) Wolle. Trichomes erect, awl-shaped, forming dark brown or blackish, slippery coatings on submerged stones ; cells yel- lowish green or brownish ; sheath close colorless ; primarily closed, later open and often dissolved into fine fibrillae. Diameter of trichomes, 5-6 //, more or less. Syn. Mastigonema caespitosum, Kg. Plate CLXXVI, fig. 5, a very small section of a thallus. Frequent on river stones in shallow water. Forma tenuior viridis, Eab. Forms deep olive, or almost black spots, larger or smaller in size, with a smooth even surface, on pebbles and larger stones near the shore of ponds. No appreciable distinction between this and the type-form. Earely the trichomes are linear. Plate CLXXVIII, figs. 1, 2, 3, from specimens collected in northern Vermont and New Jersey. Plate CCV, fig. 6, section of thallus greatly magnified; fig. 7, thallus moderately enlarged. Genus 84, GLOEOTEICHIA, Ag. Trichomes radiate, sometimes spuriously branched, distinctly vaginate ; sheaths broad, often succate at the base, transversely plicate, involved in a rather firm, more or less spherical mucus ; spores originate in the lower part of the trichome. 246 FRESH-WATER ALG.E OF THE UNITED STATES. GLOEOTEICHIA NATANS, Thur. Globose or angular, tuberculose, variable in size and form, green, becoming brownish ; trichomes straight, toru- lose, flexuous and hyaline above, lower articulation more or less compressed. Sheath broad, here and there constricted, colorless or yellowish. Spores oblong, cylindrical ; hetero- cysts subglobose. N Kirchner divides the numerous forms of this species into the following four sections : a. — TYPICA, (Rivularia Boryana, Kg.). Thallus somewhat globose, firm; trichomes with upper part much elongated. Spores cylindrical, 10-13 times as long as thick. Diameter of sheath about 36 /*. Spores 11-17 ^. ; hetero- cysts, 9-11 /-/. b. — GIG ANTE A, (Rivularici gigantea, Trent). Thallus large, sometimes four or more inches in diameter. ( Had a case reported to me from Maryland, as large as a man's head.) Spores cylindrical, olive, 3-6 times longer than wide. Diameter of spores, 9-13 ^ : heteroeysts, 6-8 /*. c. — ANGTJLOSA, (Itivularia angulosa, Roth). Thalli the size of cherries. Spores ellipsoidal, aeruginous- •brown, 3-10 times as long as wide. Diameter of spores, 14 ^ ; heterocysts, 9-12 yw. d. — BRAUNIANA, (Eivularia Bmuniana, Kg.). Thallus less than cherries in size; trichomes ligulate, sheath narrower than of the preceding. Spores 8-12 times longer than wide. Diameter, 10-12 // ; heterocysts. about 9 //. Syn. Tremella natanSj Hedwig ; Rivularia gigantea, Trent. ; E. angulosa. Roth ; P. Boryana, Kg. ; R. Brauniana. Kg. , etc. Ponds and stagnant pools. Plate CLXXVIII, figs. 15-19, smaller and larger thalli. The larger corresponding with very small specimens of G. gigantea; figs. 4-7, progressive stages of the growth of a trichome; figs. 5, 6, 7, the appearance of the sheath, first simple then constricted; figs. 8-12, progressive stages of another form ; figs. 13, 14, trichomes, fertile and sterile in the same thallus ; fig. 20, a form from Colorado, trichomes peculiarly contorted. GLOEOTRICHIA. 247 Plate CLXXIX, fig. 10, two trichomes from a thallus apparently in a state of dissolution, without maturing ; fig. 11, two trichomes with long spores, narrow sheath and gonidia formed above the spores and passing out of the sheath at the ruptured ends. GLOEOTRICHIA PISUM, Thur. Thallus rather soft, as a rule spherical, of the size of mustard seeds to that of peas, attached to water plants, various in color, brown, aeruginous or olive-green. Tri- chomes elongated ; lower cells with a distinct sheath, cell contents aeruginous, 1-2 times as long as broad ; upper cells longer with sheaths indistinct. Sheaths always close simple, not inflated or contracted. Spores cylindrical, rarely as much as 30 times longer than the diameter. Heterocysts usually wider than the vegetative cells. Diameter of spores, 5-12 yu ; of heterocysts, 7-14 //. Syn. Rivularia Pisum, Ag. ; It. durissina, Kg. ; It. Lens, Kg. ; It. villosa, Eab. ; It. cartilaginea, Wood. Often very abundant, parasitic on water plants, but most frequently seen without having the sheath developed. A very peculiar and perhaps novel mode of fruiting was observed in specimens collected in a stagnant pool, Quaker- town, Pa., August, 1879. The spores were long, about twenty times longer than the diameter ; the contents of these passed down, breaking through the wall separating between the spore and the heterocyst, not only filling but greatly expanding the heterocysts to a capacity to hold the larger portion of the spore contents. Saw none quite empty, but many more than half vacated. The subspherical, inflated heterocysts were numerous, many separated from the spore and scattered loosely ; assuming a vegetative green appear- ance ; cell contents granular, forming possibly sporangia of some kind. Facilities failed to trace these bodies to farther development. The process of forming gonidia in the basal cells of plants of this family has already been alluded to (vide page 236 and Plate CLXXI). This appears to be another way, perhaps abnormal way of propagation. Plate CLXXIX, fig. 7, part of a thallus, filaments show the spore cases partly emptied ; the contents emptying into the enlarged heterocysts ; figs. 8, 9, small sections from other thalli which did not show the same process, because not in proper condition for it ; fig. 9, shows gonidia or cells, and ormogonia passing upward ; fig. 6, natural size of thalli ; 248 FRESH-WATER ALG-JE OF THE UNITED STATES. fig. 1, a young form of Gloeotrichia; fig. 2, half of a trans- verse section of a smaller thallus ; spores formed, but sheath not yet evident ; fig. 3, a half of a similar section of a thallus arrested in its growth and fading. • Genus 85, RIVULABIA. i Filaments radiately arranged, agglutinated by a more or less firm mucilage and unitedly forming hemispherical, or bladdery well-defined forms. Heterocysts basal. Forms of this genus, in my earlier experience, were supposed to be frequent, but now I question whether any of them can be separated from the genus Gloeotrichia. The form most familiarly known as Rivularia dura, Kg. ; with such synonyms as Limnactis dura, Kg. ; Rivularia radians, var. dura, Kirch. ; Limnactis flagel- lifera, Kg. ; Limnactis minutula, Kg. ; and others, is often very abundant in ponds, attached to water plants ; it is a true Rivu- laria, in accord with the diagnosis of the genus ; but gathered at a later period of the year the spores, and the sheaths, evidences of the genus Gloeotrichia, develop themselves. Of the thousands which may be quickly gathered many are found to have devel- oped the characteristic spores and sheaths ; while others retain their simple form, and yet others have the trichonies shrunken or partially withered, showing signs of a state of decay. It has been shown how young forms of G. natans, gradually develop the mature trichomes ; Plate CLXXVIII, 4-7 ; figs. 8-12, etc. In a collection of many thalli of Rivularia dura all possible stages of development may be found in proper season. Judging simply by personal observations on living plants, and by analogy, all Rivularia should be transferred to Gloeotrichia. There is one form, however, of which we have not seen living plants ; apparently the same, which was found in England, and reported in the English Botany as early as 1804, named by Smith, Conferva echimdata, (indexed as Rivularia echinulata). Since then it has been found repeatedly in England and on the Continent. Prof. Cohn reports it as Rivularia fluitans, covering a sluggish river for miles in extent. Prof. J. C. Arthur, of the Iowa Agricultural College, reported a. similar, or the same plant, found as a scum of large extent on "Western lakes. Bornet and Flahault, of France, made a careful examination of this form of Rivularia, but unfortunately had not living plants. Judging by the specimens they had, they reached the RIVULARIA. 249 conclusion, that Rivularia echinulata and Gloeotrichia Pisum are probably identical. These plants like most of the algse multiply very rapidly by means of spores and by hormogonia. One fila- ment gives rise to five or more hormogons, each of which in the course of several days gives rise to as many more thalli ; thus in a comparatively short time millions of thalli may be produced. The following two diagnoses may be preserved as matters of historic interest, and for reference : RIVULARIA ECHINULATA, Smith. Thalli globose, minute, dark olive-green or brownish. Trichomes fastigiate, attenuated upwards to the apex, closely cohering, articulate ; heterocysts basal, globose ; sheaths very narrow, inconspicuous. Diameter of trichomes, at base, about 7 ^ ; 250 yw, more or less, long. Syn. Chaetophora punctiformis, Kg. ; Echindla articulata, Eng. Fla. ; Conferva echinata, Eng. Bot. ; Conferva echinulata, Gray, etc. Plate CLXXIX, fig. 4, a thallus from the surface of lake, Minnesota, collected by J. C. Arthur, noted above, flattened under cover glass of slide ; fig. 5, natural size of thalli. RIVULARIA DURA, Kg. Thalli nearly globose, about the size of mustard seeds, sometimes larger, dark olive green, brownish or n^rly black. Trichomes aeruginous, gradually tapering from the base to the hyaline apex, or sometimes variable in the same thallus ; some apparently withered, others more swollen, some inarticulate, others torulose ; all with distinct sheaths. Lower cells as long as broad or nearly so, upper ones longer, all with cytioplasm granulated ; sheaths colorless or yel- lowish ; heterocysts rounded. Diameter of trichomes, 8-9 ^ at the base. Syn. Limnactis dura, Kg. ; Rivularia radians, var. dura, Kirch. ; Dasyactis mollis, Wood. Attached to aquatic plants in ponds. Plate CLXXIX, fig. 1, transverse section of a large thallus ; fig. 2, a section showing the development of spores ; fig. 3, a section with withered, or fading trichomes. 250 FRESH-WATER ALG^E OF THE UNITED STATES. SECTION II.— SCYTONEME^E. Filaments not terminating in a hair-point, enclosed in a sheath, branched ; cells divide transversely only ; ramifications produced by the deviation of the trichome and emerging through the sheath ; usually furnished with heterocysts. Genus 86, SCYTONEMA, Ag. Sheath enclosing a single trichome. Eamification usually twin, produced by a fold of the trichome which ruptures outside of the sheath and gives origin, usually to two, but sometimes only one branch, at right angles. Heterocysts scattered here and there in the trichome, without any evident relation to the ramifications. The branched filaments produce interwoven mats of greater or less extent. Propagation by microgonidia, which arise from the cells of the trichome after having passed out of the older sheaths. The microgonidia increase in size after separation from the maternal cell ; the contents divide and redivide producing larger forms (Microcystis), which again divide producing others of like kind. Finally the small cells of a cyst arrange themselves in series, JTostoc-like, and these encysting in the maternal tegument ( Hormosiphon-forms ) reproduce the original type of the species. In the process of the propagation of Scytonema species, perhaps not always strictly in accord with the successive steps in the plan briefly described, occur various forms of so-called unicellular t/ plants, heretofore known by such generic names as Microcystis, Polycystis, Gloeocapsa, Gloeothece, Hormosiphon, Nostoc. and others ; all the forms under these heads are doubtless merely intermedi- ate polymorphic conditions of development in higher alga3 life. Different observations made in the study of different species, will be illustrated with the description of the species. Some of these were given to the public in the Microscopic Journal, in 1878 and 1879. One article, UA Nostoc the matrix of Scytonema^' an- other, "Dubious Character of some of the Genera of Fresh-water Algce," etc. SCYTONEMA TOLYPOTRICHOIDES, Kg. Thallus turf-like ; filaments much interwoven, mucous, dark olive or brown. Filaments long; ^semZo-branchlets mostly geminate. Thinner, even to one-half that of the stem, usually close at the base ; cells two or three to the diameter, sometimes constricted at the joints, aeruginous when young ; later, brown. Sheath primarily thin, but later, thick and SCYTONEMA. 251 brownish yellow. In older filaments the internal trichome is often contracted to less than one-third of the diameter of the sheath. Heterocysts somewhat oblong or cylindrical, bright brownish yellow. The development of this species from JVostoc-forms has often become evident by such conditions as are illustrated. Syn. Sc. cdlotrichoideSj Wood. Most frequent on dripping rocks ; also on wet or moist earth on the banks of rivers, etc. Plate CLXXXII, fig. 4, a normal vegetative condition ; fig. 5, an older filament with the internal trichome greatly contracted ; figs. 6, 7, part of a filament with secondary branches; fig. 8, a young filament just developed from a JVosfoc-forni such as figs. 9, 10, corresponding with condi- tions of N. rupestre. Kg., and N. verrucosum, Vauch. ; fig. 11, a jVosfoc-form found mingled with the others, showing the tendency to geminate branching before assuming the strictly Scytonema character. SCYTONEMA CALOTRICHOIDES, Kg. Tomentose, aeruginous ; filaments more or less curved and interwoven, sometimes distinctly, sometimes indistinctly articulate ; articulations subequal or half as long as wide. PsS'. minu- tum, Hass., is a still more slender form which occurs also, not infrequently mingled with the larger forms. 8. crustaceus, (Ag.) Eab. ; 8. rugulosus, Kg.; 8. secundatus, Kg., 8. Heufleri, Menegh. ; 8. rMzoides. Breb. ; 8. hormioides, Kg. ; and others, appear to be mere conditions, or stages of development of the same species. Plate CXC, figs. 1-3, macrogonidia ( Gloeocapsa cells ) ; figs. 4-8, earliest development of filaments from macro- gonidia; figs. 9, 10, two elongated young plants with a solitary series of cells ; figs. 11, 12, older forms, with 2-6-8 series of cells. SIKOSIPHON PULVINATUS, Breb. Forma ALPINUS, (Kg.) Wolle. Bearing some resemblance to 8. Alpinus, Kg., and with habitat similar to the last ; it exhibits now and then a dis- tinct, yellow heterocyst, and possesses here and there a spine-like outgrowth, or attenuated apex, which is a young growth with very short cells. Associated with this plant there are, usually intermingled during the later Summer months, many solitary cells (Gloeocapsa, etc.), which are spores or macrogonidia. They may be found in many progressive stages of development. They imply two processes of propagation, which may be illustrated as follows: Plate CXCI, figs. 1, 2, are two ends of filaments with young growths, spine-like processes ; fig. 3, a broken-off part of a filament, the sporangia, or cells bearing the niicro- gonidia, are enlarging and passing out of the sheath ; figs. 4, 5, the same increasing in size internally and externally and producing such encysted cells as figs. 6, 7 ; the tegu- ments of these dissolve gradually and then set the daughter cells free ; these (figs. 8, 9, 10) pass through another similar cycle of evolution, and again another and so on often for 270 FRESH-WATER ALGJE OF THE UNITED STATES. a number of generations ; finally the young forms commence to develop as represented by figs. 11-14. Another process differing somewhat in the details may be illustrated. By the difflueiice of the walls of the filaments and of the membranes of the internal cells, the niicrogo- nidia are scattered ; from these large masses of small, almost colorless, thin meinbraued, circular cells are evolved (figs. 15, 16); gradually a nucleus is formed in them (fig. 17.); they enlarge, the nucleus divides, producing larger and more firmly constructed cells (fig. 18), which become en- cysted by lamellate membranes, dividing and redividing and enlarging (figs. 19, 20), resulting in cells of the true Gloeo- copsa-type. These cells often occur in such quantities on wet cliffs, that they may be stripped with the palm of the hand. Among them there are always some in an early state of development, others more advanced and some fully grown. Most of the cells are sterile. Plate CXCV, fig. 16, fragments of specimen of the same species, from wet rocks, Black Water Creek, West Virginia. Reddish brown with three bright aeruginous spots, indi- cating preliminaries for fresh growth. Associated with forms of this kind are young aeruginous filaments, 9-12 /* diameter, others yellowish 25-30 yw and the larger forms 38-62 yu ; fig. 15, a tuberculose specimen, however merely a form of 8. pulvinaim, which occurs occasionally in older masses. Kirchner denominates this form 8. mamittosum, and credits the species to Agardh; but Agardh's plant was, probably, no true Sirosiphon, but a Stigonema, a Lichen ; nevertheless we retain the name and call it Forma mamillosum. It is not identical with Agardh's form. SlROSIPHON CORALLOIDES, Kg. Strata more or less expanded, tomentose, greenish-black or fuliginous black, trichonies rather short, prostrate, rigid, sometimes very irregular in outline, much branched, tuber- culose, yellowish brown or greenish ; branches erect, poly- morphic, often short, sometimes papilliform, obtuse; two to eight or more series of internal cells ; cells round or sub- quadrangular, aeruginous green, granular ; sheath often yellowish brown or golden yellow. Diameter of filaments from 25-150 /*. The finest specimens are from stones along the rocky shores of Green Pond, New Jersey, constantly washed by SIKOSIPHON. 271 the waves. Unlike the last S.pulvinatus, this is firmly attached to the stones, or rocks. Have it also from other parts of New Jersey, and from wet rocks, Mt. Mansfield, Vt. The latter specimens have the filaments very irregu- larly inflated, tuber-like. Plate CXCI, fig. 21, represents a single, rather large stem from a tomentose mat on a stone, New Jersey. Plate CXCII, figs. 9-12, from specimens from Mt. Mans- field, Yt. SlROSIPHON COMPACTUS, Kg. Forming a more or less expanded, compact, tomentose, dark brown stratum, trichomes and branches ascending, a little attenuated at the apices, obtuse, internally formed of a single, rarely a double series of cells, which are torulose and sometimes almost moniliform; diameter and length nearly equal, filled with a pale blue-green, granular cytio- plasm ; sheaths firm, golden brown ; heterocysts subglobose or oblong. Diameter of filaments, 12-15 yw. Syn. Stigonema compactum, Kirch. ; Hassallia compada, Hass. ; Scytonema compactum. Eng. Fla. Sandstone rocks, South Carolina; shaded limestone rocks, Pennsylvania, etc. Plate CXCII, figs. 1, 2, several characteristic filaments. SlROSIPHON SCYTONEMATOIDES, ( Wood) Wolle. Filaments often closely intricate, flexuous or variously curved, not rigid, (sparsely) branched ; cells uniseriate, about equal in length to their diameter ; sheaths ample, not distinctly lamellate, (their surface rough and corrugate) transparent, (mostly) colorless, (sometimes light brown). Diameter of filaments, .00066" — 16-17 //. This species was collected in South Carolina by Mr. Rav- enel, growing on the limbs of Myrlca cerifera. There can be little doubt that the form seen by Dr. Wood is the same as already described (page 257) as Scytonema cortex, var. cor- rugata. Doubting the validity of the normal condition of our present plant, and not able to duplicate it for corroboration, we retain the name selected by Dr. Wood for a plant, or a condition of a plant, entirely distinct, but to which the diagnosis applies well, omitting the few words we enclose in parentheses. 18 272 FRESH-WATER ALG^E OF THE UNITED STATES. The plant was found on damp soil, not on trees, collected by Dr. Hosford, of Charlotte, Vermont. The sheath is col- orless, the trichomes light blue, about one-third as wide as the sheath. The macrogonidia were seen escaping at the broken ends of the rather short filaments. Plate CXCII, figs. 3-5, filaments ; fig. 6, macrogonidia. SlROSIPHON OCELLATUS, Kg. Stratum more or less expanded, woolly-tonientose, dark olive brown ; filaments elongate, irregularly branched ; branches, primary and secondary ; cells of the stems mostly biseriate, and of the branches commonly uniseriate, subglo- bose or oblong compressed, equal or one-half, or one-third as long as broad, normally aeruginous ; sheaths thick, often laniellose, golden brown, external layers now and then paler ; sheaths of the branches colorless, or yellowish, quite smooth. Diameter of filaments, 12-38 ^. Syn. Stigonema ocellatum, Thur. ; Hassallia ocellata, Hass. ; Con- ferva ocellata, Dillw. ; Scytonema ocellatum, Harv. ; Sirosi- phon pellucidulus, Wood. Most frequent in small pools, swamps; also in larger ponds. The finest specimens occurred in Bamber Lake, New Jersey, attached to submerged sticks in dark brown waving tufts about one-half inch in length. Samples of this are preserved in Wittrock and Nordstedt's Algce Exsiccatae, No. 668, A.D. 1883. Plate CXCIV, figs. 1-3, three fragments of branching fila- ments ; fig. 4, part of a broken filament ; fig. 5, the rnicro- gonidia bearing cells ; fig. 6, the same, sliding out of the sheath and developing ; figs. 7-10, young plants. SIROSIPHON CRAMERI, Bruegg. Forming a blackish, widely expanded, tornentose, turfy covering to rocks ; filaments with scattered branches ; branches mostly single, often elongate and clavate ; cells uniseriate about equal or shorter than long, sometimes sub- globose; in advanced age often strongly compressed and transversely oblong from mutual pressure, yellowish, or sometimes when young, greenish ; the apical cells coalescent into an irregularly cylindrical mass, (merely a condition of young growth, ) sheaths yellowish brown ; at maturity more or less opaque and distinctly lamellate ; in youth more or less transparent, and sometimes colorless. SIROSIPHON. 273 Diameter of filaments, about 50 yw ; branches 38 yw, more or less, with sheath ; without sheath, 20-25 /x On slopes of Mount Tahawas, in the Adirondack Moun- tains, N. Y., at an altitude of about 5000 feet, over which water is continually dripping, this plant nourishes, forming a turfy coating, yards in extent. The specimens agree well with the description of the European, Alpine plant, found at practically the same altitude. (Wood's Contribution Fresh- Water Algce, p. 71.) Plate CXCIV, figs. 11-16, taken from specimens found in New Jersey, answering the description, but given not with- out a suspicion that they are closely related to 8. ocellatus. SIROSIPHON LIGNICOLA, Wood. Occuring in small black spots, often aggregated, forming extended tomentose strata. Filaments much branched, green, golden, or brown ; branches straight or variously curved ; sometimes very much contorted and interwoven ; their apices obtusely rounded or subacuminate ; cells 1-2 or more seriate, light or deep aeruginous, irregular ; terminal parts of trichornes sometimes cylindrical; shortly arti- culate, granulate; sheaths somewhat ample, not trans- parent, fuscous or ferruginous. Diameter of filaments variable, from 12-30 yw. Most com- monly, 15-20 }JL. • Frequent on old wood and on the trunks of trees in South Carolina. During the past eight or ten years I have received scores of specimens collected by the indefatigable W. H. Ravenel, of Aiken, South Carolina. The collections \vere made in various seasons of the year, and from the trunks of many kinds of trees, in dry, and in continuous wet weather. Sirosiphon is at best a very polymorphic algse. A few speci- mens illustrate this fact, but when many of the same genus are brought together from the same habitat, it becomes utterly impossible to separate them into different species. We therefore unite the species 8. guttula, Wood ; and S. acervatum, Wood, with S. lignieola, Wood. Plate CXCIII, figs. 1, 2, two well developed forms ; figs. 3, 4, an occasional appearance of a distorted growth ; figs. 5-11, conditions of young developing plants. SIROSIPHON ARGILLACEUS, Wood. Stratum thin, expanded, blackish, sub-niembranaceous ; filaments short, densely intricate and frequently somewhat concreted, giving origin to numerous irregular branches ; 274 FRESH-WATER ALGJE OF THE UNITED STATES. branches short, variously curved, somewhat rigid, mostly ascending ; cells in simple or double or triple series ; sheath thick, firm ; in the mature filament deep reddish brown, in the branches yellow-brown, at the apices of the branches nearly colorless and transparent. Moist clay banks, moist rocks, and the like. Habitat dis- t/ / tinct from the last, 8. Ugnicola, but otherwise, could not be separated ; it is like it very polymorphic. Plate CXCIII, figs. 12, 13, two of the simplest forms from a cluster ; figs. 1, 2, are as characteristic of the plant. SIROSIPHON BRANDEGEEI, Wolle. A form of which no full description can be given, as the only specimen received was very limited. It was collected by T. S. Brandegee, on the shores of a soda spring, Colorado. Filaments short with apices subacute, reddish brown; cells one, two, or three seriate. Microgoiiidia-bearing cells en- large to form sporangia; these eject macrogonidia which de- velop into Gloeocapsa or CAroococews-forms, mostly simple, having but one nucleus which gives rise to a young plant. Diameter of filaments, about 20 ^ ; younger forms, 12-15 yw. Soda Springs, Cannon City, Col. Plate CXCIV, figs. 17-20, older and younger forms ; figs. 21-23, intermediate forms of development, of the character of Microcystis and Cliroococcus cells ; figs. 24-27, various con- ditions of young, developing forms. SIROSIPHON CRTJSTACEUS, (Ag. ) Eab. Stratum thin, sub-tornentose, fuscous-black ; trichom.es decumbent, densely intricate, branches longer or shorter, sometimes inclining to corymbose near the ends, erect flexuous, subtorulose, apices rounded or subacute ; cells in simple series, rarely two series, globose, loosely disposed, light aeruginous ; sheath rather ample, colorless, hyaline, more rarely light yellow. Diameter of filaments, 15-18 yw. Syn. Scytonema crustaceum, Ag. ; Scy. velutinum, Wallr. ; Sirosi- phon velutlnus, Kg. ; Sirosiphon rhizodes, Breb. Moist rocks, Charlotte, Vt. Had this plant from only one locality. It is very near to S. rhizodes, but larger ; S. crustaceus is so nearly the same, they are probably varieties of the same species. HAPALOSIPHON. 275 Genus 92, HAPALOSIPHON, Naeg. Forming tufts, attached or floating, olive green, aeruginous, or with age light or darker brown, branched ; branches ordi- narily simple, springing ,at right angles, or nearly so, from the prostrate stem ; sometimes with secondary branchlets. Cells in a single series, distinct, or sometimes continuous, granulate. Heterocysts occur not infrequently. Inhabits submarine, as well as fresh waters. Dr. Itzigsohn, of Prussia, made an elaborate study of the life- history of plants of this genus, particularly of H. Braunii, de- voting two years to it. He gathered fresh material from a pond near his home at least once a week. In the winter months he obtained his specimens from under the ice. He was abundantly rewarded for his labors, making many very important and val- uable observations heretofore unknown, and so new to science that the value of his work was not credited at the time. Even now, after a lapse of more than thirty years, it is only here and there that the correctness of his observations is accepted. Old theories, numerous genera and a multitude of species are ad- mitted, which have no value as species. In the life-history of this one plant, in its numerous polymorphic transition -forms of development, occur conditions of plant-life corresponding with such genera as Chroococcus, Naeg., Aphanotheca, Naeg., Aphano- capsa, Naeg., Microcystis, Kg., Nostoc, Vauch., Hormosiplion, Kg.. Rivularia, Ag., Gloeocapsa, Kg., ftynechococcus, Naeg., and others, each distinctly characteristic, and yet all of them only links in the chain of evolutions necessary to their propagation ; some of them may be abnormal conditions or freaks. Dr. Itzigsohn satis- fied himself that all of the many forms described are connected with the present plant, but he failed to find the precise relation of each to each. For full particulars consult "tiMzzen zu einer Lebensgexehichte des Hapalosiphon BrauniiJ' 49 pp. 5 Plates, by H. Itzigsohn. HAPALOSIPHON BRAUNII, Kg. Floccose caespitose, often parasitic, attached, or floating ; aeruginous, lighter or darker olive brown ; filaments loosely interwoven ; interior trichomes usually light aeruginous ; articulations of stems distinct, about as long as wide or shorter, granular ; sheath thin and close, colorless, rarely yellowish. Diameter of filaments, 10-12 /^. Primarily parasitic on submerged plants, later floating, sometimes in large masses. 276 FRESH-WATER ALG^E OF THE UNITED STATES. Plate CXCVI, figs. 2, 3, 4, three filaments 5 branches often very much longer than illustrated, and thinner than the the stem : cells of stem usually more moniliform than those of 7 «•• the branchlets ; heterocysts somewhat oval, scattered ; fig. 5, short section of a filament, cells dividing, enlarging, devel- oping large encysted cells, fig. 6 ; from these come Chroo- coccm, figs. 7, 8 ; Palmagloea cells, figs. 9, 10 ; Nostockopsis, Wood, figs. 11-15 5 Nostocs, figs. 16, 17 ; Hormosiphon, fig. 18. Fig. 19, a specimen developing secondary branchlets. HAPALOSIPHON BYSSOIDEUS (Hass.) Kirch. Stratum turfy, dull black, somewhat olive green ; fila- ments or branchlets ascending ; ^sewdo-branchlets rather short, rigid. Cells primarily as long as wide, later one-third or one-fourth as long, aeruginous or writh age brown ; sheath thick, often distinctly lamellate, smooth, ends slightly atten- uate, apices rounded, colorless or golden yellow. Hetero- cysts compressed oval usually between the cells of the stem only ; light yellow. Diameter of filaments, 20-25 /* • branches somewhat thinner. Syn. Hassallia byssoidea, Hass. ; 8irosiphon truncicola, Bab. On the trunks of trees, South Carolina and other Southern States. Plate CXCV, figs. 10, 11, 12, two younger and two more advanced, branching filaments. From trunks of trees near Aiken, South Carolina. HAPALOSIPHON TORTJLOSUS, (Bab. ) Kirch. Filaments apt to be solitary, rarely longer than 4 mm; sparsely branched ; cells ordinarily half as long as wide, torulose, pale aeruginous ; sheaths close and thin, indis- tinctly lamellate, smooth, brown yellow. Diameter of filaments, 22-27 ^ ; branchlets somewhat less. On moist rocks intermingled with Gloeocapsa cells, Kirch. From moist rocks, Prince Edward Island, Virginia. The specimen received did not indicate the presence of Gloeo- capsa noted by Kirchner. Their presence would imply a relation to Sirosiphon as originally placed by Rabenhorst ; the arrangement of the branchlets, however, is Hapalosi- phon-like. Plate CXCV, figs. 13, 14, a short section of a filament. HAPALOSIPHON BREBISSONII. Kg. Caespitose, 3-4 lines long, dull aeruginous, much branched, distinctly articulate, articles equal or somewhat longer than NOSTOCE^E. 277 broad, aeruginous ; sheath of stein rather ample, often yel lowish brown ; of branchlets, thin, close, colorless, hyaline. Diameter of filaments, 15 //, more or less. Very near H. byssoideus, but more slender, cells longer, and aquatic, parasitic on water plants ; appears to stand be- tween H. byssoideus and //. Braunil. Plate CXCVI, fig. 1, after a specimen from Dennisville, New Jersey. HAPALOSIPHON FUSCESCENS, Kg. Floccose caespitose, dull aeruginous, changing to lighter or darker olive brown, parasitic ; much branched ; usually internal trichome light aeruginous or light olive yellow, more or less distinctly articulate, granular ; articles equal, to two or more times longer than broad ; ends of branchlets often somewhat SAvollen. Diameter of filaments, 8-11 /* ; branchlets, 5-7 yw. Pond waters. Syn. Tolypoihrix pumila, Kg. ; T. fuscescens, Breb. Differs from If. Braunii in its more slender filaments, and longer cells. Plate CXCVI, figs. 22, 23, specimens from ponds, New Jersey. HAPALOSIPHON TENUISSIMTJS, Grun. Parasitic, floccose, irregularly, squarrosely branched. Branches internally, pale aeruginous, often interrupted, in- distinctly articulate, variously curved; sheath thin and close, colorless. Diameter of sterns, about 7-8 IJL ; branchlets about half as thick. Ponds and wet ground. Plate CXCVI, figs. 20, 21, specimens from pond, New Jersey ; not infrequent also in Pennsylvania, Minnesota, Florida ; no doubt widely distributed. SECTION IV.— NOSTOCE^E. Simple, branchless filaments, with or without a sheath, never terminating with a hair-point, always provided with heterocysts. Spores usually present in mature filaments. Multiplication takes place in a two -fold manner. First, by means of the spores which give rise to young plants ; and sec- ondly, by means of hormogons, or parts of internal trichomes which separate from the filaments and develop new plants. 278 FRESH-WATER ALG^E OF THE UNITED STATES. Genus 93, NOSTOC, Vauch. Filaments nioniliforni, enclosed in a thin gelatinous envelope more or less distinct, often invisible, flexuonsly curved, irregu- larly interwoven ; cells globose or elliptic, more or less closely connected. Heterocysts intercalated or more rarely terminal. Cells about the size of the heterocysts or a little larger, which occur in the older forms, have been considered spores. Clusters of such filaments form distinct bodies, thalli, which are usually surrounded by a firm membrane, variously colored, most fre- quently olivaceous, but sometimes dark bluish green, dark brown, or light yellow ; sometimes colorless. In form either globose or subglobose, irregularly divided or often indefinitely expanded. The value of Nostocs as algae has frequently been questioned ; they have been associated with the lichens ; however true, that in the life-history of some lichens a Nostoc-foTm may occur, there can be no doubt that the usual forms of Nostocs belong to the algae, but there may be a question, whether they are true, nor- mally developed, plants. Many observations and studies lead us to believe that they are merely intermediate life conditions, arrested growths of algae life. It has already been shown ( Plate CLXXXVII, figs. 1-15 ), that a Nostoc is the matrix of Scytonema; also, how Nostocs are developed into ticytonema; compare Plate CLXXXII, figs. 9-13, also fig. 8 ; Plate CLXXXVII, figs. 27-33, and Plate CLXXXIV, figs. 34-40. Dr. Itzigsohn in his studies of the life-history of Hapalosiphon found that Nostocs constitute a stage of development, Plate CXCVI, figs. 16, 17. Where Scytottema prevails to any extent, there Nostocs are sure to occur also. Sometimes one may greatly predominate over the other, but they are usually consociated. Nostocs form an intermediate life-stage, an abortive existence in which they grow and multiply, producing their like for a number of generations, as do many of the unicellular forms of algae, without developing the true plant. There appears to be a struggle for existence in which various forms are produced ; there may be thousands of them and only here and there one which is destined through its fertility, to propagate the species ; the others are abortive and soon fade away. Many of the varieties of Nostoc- forms have given rise to a host of specific names which have no value as fully developed plants. Nostocs constitute a condition of plant-life which occurs fre- quently ; they are objects which attract the attention of ama- teurs and older collectors, and must needs have a name to be NOSTOC. 279 able to distinguish them when they become the subject of pen or tongue ; we therefore treat them briefly and retain such names as are most familiar. The collector should bear in mind that Nostocs are liable to great variations both in size and color ; some may be microscopical in size to-day ; at a later season they will be as large as peas or cherries ; some may have thin colorless membranes, while others have firm teguments of yellow or brown color ; the trichomes of some may be very slender and almost colorless, others are thicker, light yellow, brown, or lighter or darker aeruginous, apparently so distinct and unlike one another they have been accounted different species, but in reality the changes merely indicate a variety of stages of development or decay. In a comparatively recent work (Italian) a number of Nostocs are described and illustrated as N. macrosporum, Menegh. ; N. rupestre. Kg.; N. coriaceum, Yauch. ; N. verrucosum, Vauch. ; N. tenuissimum, Kab. ; all of which forms occur together, here, in mass on dripping rocks, and evidently constitute but one species ; then there are some noted as having the filaments sheathed, others as unsheathed ; neither are such properly separated, be- cause in the younger stage of growth the sheath is not devel- oped; in older forms (and yet not always) the sheath becomes evident. Various stages of growth of another JVosfoc-form, found at different seasons of the year, and by different individuals, have given rise to a number of names for the same plant. In early Spring it is found as a soft, floating, gelatinous stratum, and is called N. comminutum, Kg. ; or N. piscinale, Kg. ; when the filaments are not surrounded by a soft gelatin, then they form N. tenuissi- mum, Kg. These moniliform threads soon separate and sink. Next they are found as very small thalli attached to submerged grasses or mosses producing the form of N. minutissimum. Kg., or N. de- pressum. Wood. These thalli grow, and when about the size of peas, pass for N. coeruleum. Lyngb. Later in the season, about September, all of those which were so numerously attached to the plants a month or two earlier, will have disappeared, but instead there will be found on the bottom of the pond, larger thalli, from the size of cherries to that of plums ; this is N. prnniforme, '• Both ) Ag., and is one of our most attractive Nostocs with its firm, smooth, glossy periderm and its dark aeruginous green color. Having attained this mature condition, they soon fade ; the cytioplasm becomes watery, the periderm breaks and dissolves and the contents are scattered. 280 FRESH-WATER ALG^E OF THE UNITED STATES. Specimens of this species have been reported to me from waters beyond the Rocky Mountains, as large as a man's fist. Have endeavored to cultivate this Nostoc to get it to develop the higher plant of which it is probably an intermediate stage or condition, but failed. They did separate, multiply, and re- multiply, merely reproducing, however, of their own kind in the various stages of growth indicated above. The idea suggested itself that water, possibly, is not a normal habitat ; they need an occasional exposure to make them develop, as on dripping rocks, moist wood or earth, trunks of trees in wet seasons, and the like. On the banks of ponds where N. pruniforme occurs, there Scyto- nema is also found, but did not succeed in tracing the immediate connection between the two. The form known as N. commune. Vauch., is widely distributed and appears in conditions as variable as the localities in which it is found. It has been described under numerous names ; some- times appearing on damp or wet ground in small thalli, but these soon enlarge, and then flow together forming a soft ex- panded stratum; sometimes bullate, membrane thickens and hardens ; have seen the surface of the earth, after a rainy season, acres in extent, dotted over with olive black, thin, dried mem- branes, somewhat coriaceous fronds, an inch more or less in diameter, a condition of this Nostoc; these membranes, after a good soaking, show their true character. A striking instance of personal observation occurred on the island of Anastatia, Florida. Capt. J. D. Smith, a faithful collector in Florida, sent me fresh specimens developed under favorable circumstances ; they were parts of thalli which were inflated even to the size of a man's head. Among the numerous specimens examined the majority gave more or less evidence of a disposition to develop a filamentous plant — a Scytonema. Have transferred a few of these to paper, Plate CXCVII, fig. 8, a not infrequent form of a thallus ; fig. 9, normal form of filaments ; figs. 10, 11, cells of filaments separated and forming young plants ; figs. 12-15, forms of newly developed plants ; figs. 16, 17, filaments, one part moniliform, unchanged, and the other part changing or already developed to twice the diameter. Two French algologists, Messrs. Bornet and Thuret, published a few years since a synopsis of the Nostocs. They were guided by the old notion that they are really fully developed plants. They made eight groups, which we transcribe somewhat modi- fied and adapted to our forms as still useful in our present im- perfect knowledge of the full life-history of these spurious forms. NOSTOC. 281 I.— INTKICATA. Aquatic species. Fronds soft, gelati- nous without determinate form, often floating. A. — Trichomes forming irregular masses deprived of the general mucilage. Circumvolutions of trichomes distinct J?.— Trichomes involved in mucilage more or less abundant, loosely interwoven, joints of equal diameter, rather distant ; spores subglobose. II. — GELATINOSA. Fronds soft and gelatinous, ad- herent, joints of trichomes cyliiidrically elongated in the young filaments. Spores oblong large. A. — Growing in watery or inundated places ; fronds thick, deformed. B. — Plant terrestrial. Frond plane, applied to the ground by the inferior surface III. — HUMIFUSA. Terrestrial species. Fronds at first globose, then confluent, and forming gelatinous cushions adhering to the substratum by their lower face ; spores smooth, oval ; sheaths confluent. . Spores measuring 4x6 /z or more; mucilage toler- ably firm ; trichomes olive ; spores oval. Mucilage soft, easily diffluent; trichomes aerugi- nous green. IV. — COMMUNIA. Terrestrial species, (sometimes in- undated). Fronds at first globose, then becoming tongue-shaped, plane, or irregular. Adult frond suborbicular, folded, undulate, entire or lobed, often perforated, and often expanded V. — SPHAEKICA. Fronds globose or subglobose (often becoming irregular when they grow large); limited by a firm and resisting peridermic coating. ^4. — Terrestrial species. a. — Fronds often large, firm, trichomes com- pact, joints compressed spherical, rarely cask-shaped ; close together, uniform. . b. — Fronds soft, trichomes much spread out, of unequal size, joints nearly spherical, sheaths often colored, contrasting with the generally uncolored mucilage c. — Fronds very small, punctiform, not attain- ing 1 mm diameter. Trichomes large, joints cylindrical, a little constricted at the point of junction ; spores globose smooth. . d. — Trichomes fusiformly swollen between the heterocysts. B. — Aquatic species (color approaching to blue). a. — Trichomes dissimilar, unequal; joints of two forms, the one (young) elongated, the other large spherical often filled with opaque granules • . 1. TKNUISSIMUM. 2. COMMINUTUM. 3. SPONGU.EFORME. 4. ELL.IPSOSPORUM. 5. MUSCORUM. 6. HUMIFUSUM. I. (JALCICOLA. 8. COMMUNE. 9. SPHAERICUM. 10. RUPESTRE. 11. MACROSPORUM. 12. SPH^ROIDES. 13. CO3RULEUM. 282 FRESH-WATER ALGJ3 OF THE UNITED STATES. b. — Trichomes homogeneous, regular. 1. — Frond very small ; trichomes very com- pact 14. MINUTISSIMUM. "2. — P^rond attaining 2-10 mm. . . .15. GREGARIUM. 3. — Fronds attaining the size of a large cherry 16. PRUNIFORME. VI. — VERRUCOSA. Aquatic species ; fronds rounded or discoid, at first full, then hollow ; periderm firm and tough ; trichomes thin, regular. a. — Fronds subglobose or warty; mucilage tolerably soft; trichomes medium, compact; sheaths not frequent. 17. VERRUCOSUM. b. — Fronds at first discoid, or tongue-shaped, a little ovoid, hard 18. ALPINUM. VII. — ZETTERSTEDTIANA. Aquatic species. Fronds spherical, hard, tuberculose, divided into radiating separable lobes. 19. ZETTERSTEDTII. VIII. — FLAGELLIFORMIA. Terrestrial species ; fronds forming thongs, linear, straight and long; subdicho- tomous; trichomes longitudinally parallel. . . 20. FLAGELLIFORME. Following the order of the synopsis a tew notes and references will be in place. NOSTOC TENUISSIMUM, Kg. Scarcely separable from the next except that the thallus is not so gelatinous — a young condition of N. pruniforme. ^OSTOC COMMINUTUM, Kg. Syn. N. piscinale. Kg. ; N. lacustre, Kg. ; N. agglutinum, Kg. Floating in ditches and smaller ponds. NOSTOC SPONGI^FORME, Ag. NOSTOC ELLIPSOSPORUM (Desm. ) Eab. Two forms not recognized. NOSTOC MUSCORUM, Ag. Usually found on wet calcareous rock, and on the mosses which cover them. Plate CXCYII, fig. 35, a gelatinous thallus formed by the confluence of a number of smaller subspherical thalli. NOSTOC HUMIFUSUM, Carm. A form described as globose, or subglobose, from the size of a pepper corn ; often aggregated and confluent ; have not identified it, but have suspected that the form alluded to above as N. commune on Anastatia Island (p. 280) may be this form. The same ground on which it occurs abounds also in a small form of ftcytonema, near 8. chrysochlorum, Kg. N08TOC. 283 NOSTOC CALCICOLA, Ag. Not separable from N. commune, Ag. ; a condition of it. Moist rocks, South Carolina. NOSTOC COMMUNE, Vaucll. In connection with this form, read note above under generic characters. Syn. Tremula nostoc, Linn. ; Nostoc ciniflonum, Born, and Thur. ; N. foliaceum, Ag. ; N. arctum, Kg.; N. littorale. Kg.; N. prismaticum, Ces. ; N. rugosum. Kg. ; N. salsum. Kg. Frequent on wet ground, rocks, etc. Diameter of filaments, 5-6 yw. Plate CXCVII, fig. 8, a not unusual form of a thallus ; fig. 9, filaments separated from the thallus and greatly en- larged ; figs. 10, 11, cells of filaments separated, and young filaments developing; figs. 12-14, filaments somewhat ad- vanced, commencing to branch ; fig. 15, young filaments uncoiling after the manner of some Oscillaria ; figs. 16, 17, two filaments with one part unchanged, moniliform, the other end widened and changed, in character with the others. NOSTOC SPHAEBICUM, Vauch. Fronds very variable in size from that of poppy and mus- tard seed to that of peas; gregarious, usually olive or yel- lowish brown, more rarely somewhat aeruginous ; periderm firm, brownish. Diameter of filaments, 4-5-6 //. Frequent on damp rocks, in large numbers. Plate CXCVII, figs. 18-20, sizes as they vary with age. NOSTOC RUPESTRE, Kg. Fronds same as the last ; the forms that receive this appel- lation appear to be merely another growth, or another gen eration of fronds ; primarily the moniliform filaments are sheathless as figs. 21-23, then they become sheathed as figs. 24, 25. Next the teguments dissolve, and the young are scattered, producing such forms as figs. 26-30, which con- stitute the N. rupestre, Kg. , a form which embraces also N. macrosporum, Menegh. ; N. coriaceum, Vauch. ; N. verrucosum, Vauch. ; N. tenuissimum, Rab. ; N. microscopicum, Carm. ; N. gregarium, Hantzsch. ; Hormosiplion farfuraceus, Kg.; H. macrosiphon, Kg. ; and others, all of which are merely differ- ent stages of growth. 284 FRESH-WATER ALGLE OF THE UNITED STATES. NOSTOC MACROSPORUM, Menegh. Fronds very small, merely a form of the last, rupestre, and often intermingled with it. Syn. Hormosiphon macrosporuSj Kg. ; Nostoc pyreniacum, Bipart ; Nostoc ichthyon, Rab. NOSTOC SPHAEROIDES, Kg. A form not recognized in the United States. NOSTOC C03RULEUM, Lyngb. Fronds small, globose or subglobose, 1-8 JJL in diameter, fixed or free swimming, blue or greenish blue. Diameter of filaments, 4-7 yw. On mosses and submerged plants. NOSTOC MINUTISSIMUM, Kg. Var. N. PRUNIFORME. NOSTOC GREGARIUM, Thur. Yar. N. PRUNIFORME. NOSTOC PRUNIFORME, Ag. Fronds from the size of a mustard seed to that of a pea, to that of a damson or larger ; olive or dark aeruginous green, when old becoming blackish brown ; periderm cori- aceous. Trichomes loosely interwoven, joints subglobose, compressed, closely connected. Heterocysts globose. Diameter of filaments, 4-5 yw. The two preceding forms appear to be merely younger conditions of N. pruniforme. Compare note under the generic description, page 279. Syn. Ulva pruniformis, Linn.; N. coccymelon, Kg.; Tremella pruniformis, Both. Plate CXCVII, figs. 3, 4, young forms (N. minutissimum, Kg. ; N. gregarium, Thur. ) ; fig. 5, well matured forms ; figs. 6, 7, moniliform filaments from a frond. NOSTOC VERRUCOSUM, Vauch. Fronds more or less warty, subglobose or nodulose, brown- ish green, limited at the circumference by a firm periderm. Trichomes slender, somewhat compact, spaced out, joints subglobose, closely connected ; heterocysts spherical. Diameter of filaments, 3-4 ^. ANAB.ENA. 285 Syn. Nostoc irregular e, Wartm. ; N. nivale. Kg. ; N. Peloponne- siacum, Kg.; N. sphwricum, Menegh. ; Tremella verrucosa, Huds. In limestone springs, streams, etc. Plate CXCVII, fig. 1, a frond ; fig. 2, filaments from a frond. NOSTOC ALPINUM, Kg. Growing attached by its margin to rocks in running water, also to dripping rocks. Frond suborbicular, erect, membranaceous, 3-8 lines high, and 1-3 lines thick, very tenacious 5 deep olive green, smooth, often rugosely plicate at the base ; trichomes laxly or somewhat densely inter- woven ; heterocysts spherical. Syn. N. Sunderlandi, Dickie : N. cristatum. Bailey ; N. parmeli- oides, Kg. From specimens from the rocky bottom of the Susque- hauna, Harrisburg, Pa., and from the Palisades, N. Y. Plate CXCVII, figs. 33, 34, fronds in front and in side view. NOSTOC ZETTERSTEDTIANA, N.N. A form not recognized here. NOSTOC FLAGELLIFORME, Burk. and Curt. Fronds dark olive, several inches in length, half a line in diameter, lying prostrate on the surface of the soil, much branched in an irregular dichotomous manner; branches linear compressed ; periderm firm and elastic, cartilaginous, densely filled with moniliform filaments. On naked aluminous soil, at San Pedro, Texas. Collected by C. Wright. Plate CXCVII, fig. 32, specimen in my herbarium from Texas. • Genus 94, ANAB^ENA, Bory. \ Filaments similar to those of Nostocs, moniliform, singly or clustered in gelatinous masses, with rare exceptions with a sheath ; cells globose, or subglobose, some of which change into globose or elongated spores, usually of a brownish color. Heter- ocysts intercalated in the filaments. There is considerable vagueness of character in this and three or four allied genera. Different modern authors have modified 286 FRESH-WATER ALG^E OF THE UNITED STATES. the diagnosis to suit their own observations ; they fail to agree. Thuret hoped to have reached a definite limit, but neither Borzi, Wittrock nor Nordstedt are in accord with him. Wittrock and Nordstedt suggest that the genus Anabcena be divided into four subgenera under the following designations : Sub-Genus 1. TRICHORMUS, spores globose or subglobose, heter- ocysts intercalated, distant from the spores. Sub- Genus 2. DOLICHOSPERMUM, spores subellipsoid, or sub- cylindrical, heterocysts as in Trichormus. Sub- Genus 3. SPHAEROZYGA, spores subellipsoid or subcylin- drical, heterocysts intercalated, proximate to the spores. Sub- Genus 4. CYLINDROSPERMUM, spores subellipsoid or cylin- drical, heterocysts for the most part terminal and proxi- mate to the spores. Entertaining doubts whether these forms are true, fully de- veloped plants, we continue, provisionally, the old arrangement as nearly as possible. That Anabcena-forms develop Lyngbya and that Cylindrospermum and Mastigonema forms do likewise develop Phycochromes, has been clearly elucidated in our observations of the living plant- forms. A very satisfactory example was found on ponds of stagnant waters, submarine, in the vicinity of Dennisville, New Jersey. In all directions there were seen, July, 1880, large floating masses, dull, pale greenish, tea color, or olivaceous, gelatinous scums, composed apparently of two distinct filamen- tous plants, the one moniliforin, the other with even margins. The former is an Anabcena although not strongly marked by heterocysts or spores, nor strictly in accord with any described forms, nevertheless appears to be a form of the genus. Plate CXCV1II, figs. 9, 10, two filaments, the one in normal, moniliform condition, the other with the cells in the process of dividing : figs. 11, 12, 13, progressive stages of development ; cells becoming square, adjoining walls resorbing and making a continuous, homogeneous filament ; figs. 14-19, cytioplasm di- vides, and forms septa ; articulations at first equal then dividing into two, four, or six to a diameter. For details of this plant see Lyngbya vermicularis. For reference to other developments see Gylindrospermum. ANABJENA FLOS-AQUAE, Kg. Free swimming, submembranaceous, aeruginous; trichomes more or less curved, often circinate. joints spherical, or ANAB^NA. 287 from mutual pressure transversely elliptic or quadrate ; heterocysts intercalated, elliptical ; spores globose. Diameter of filaments, 4-6 ^ ; heterocysts often twice the size ; spores, 8-10 ju. Syu. Nostoejlos-ciquce, Lyngb. ; A. gelatinosa, Wood. Yar. CIROINALIS, (Bab. ) Kirch. Trichomes more circinate and joints larger; spores and heterocysts not proportionately so much larger than the typical form ; sometimes very little larger than the cells. Diameter, 7-10 yu. Syn. Anabcwia circinalis, Eab. ; A. spiralis, Thompson ; Tri- chormns spiralis, Balfs. Plate CXCVIII, figs. 20-23, filaments of type-form ; figs. 24-26, var. circinales, from specimens from Minnesota, and from Chautauqua Lake, N. Y. Yar. AESTUARII, Wolle. Same in size as circinales, but filaments not so circinate, and heterocysts and spores very slightly larger than the cells. Plate CXCY1II, figs. 9, 10, specimens collected at Dennis - ville, New Jersey. See note under generic description. GIGANTEA, Wood. Filaments occur floating singly or in great numbers, straight, but in the young state often spirally convolute; articles mostly subgiobose, closely connected, granular ; heterocysts subspherical, intercalated, a very little larger than the vegetative cells, thickened at each end in a puncti- form manner ; spore subspherical. Diameter of vegetative cells, 9-11 //; heterocysts, 12 >. Found occasionally intermingled with Bother algse, or forming a part of a thick, dirty green, almost pulverulent scum. Plate CXCYIII, figs. 27, 28, two short filaments ; one in process of cell division. ANABJENA VAEIABILIS, Kg. Gelatinous, submembranaceous, deep blue green ; tri- chomes slightly flexuously curved, almost parallel, verdigris green ; joints globose or elliptic, compressed or depressedly subcylindrical, equal to one-half longer than broad ; hetero- 19 288 FRESH-WATER ALG.E OF THE UNITED STATES. cysts intercalated, paler ; spores numerous seriate, ellipsoid, golden tawny, with a rather thick membrane. Diameter of cells, 3.5—4^; heterocysts and spores, 7-8 jj. Syn. Sphaerozyga Thwaitesii, Harv. ; Sphaer. variabitis, Kg. ; Trichormus rectus, Ealfs ; Anahcena licheniformis, Hass. ; Trichormus Thwaitesii, Ealfs. In ditches and smaller ponds. Plate CXCVIII, figs. 29-32, four short filaments ; spores variable in size as they approach maturity. ANAB.ENA STAGNALIS, Kg. Forming a gelatinous stratum, dilute aeruginous, some- times turning to yellowish ; trichomes more or less flexu- ously curved, usually occurring in clusters ; joints globose and elliptic intermixed, closely connected, finely granular ; heterocysts few, elliptic, fully tAvice the diameter of the vegetative cells ; spores spherical, as large as the heterocysts. Diameter of vegetative cells, 3-4 yw. Margins of pools, ponds, etc. ANAB^NA OSCILLARIOIDES, Bory. Forming a bluish stratum ; trichomes elongated flexuous, joints subquadrate, distinct; heterocysts barrel-shaped or elliptic ; spores oval, catenate, somewhat larger than the vegetative cells. Intermingled occur filaments which have the appearance of Oscillaria. Diameter of cells, 4-5 /*. Syn. ftphaerozyga oscillarioides, Kg.; Trichormus oscillarioides, Ealfs ; A. gelatinosa, Wood. In brackish ditches, Southern New Jersey. The latter, A. gelatinosa, evidently an imperfectly developed plant. Plate CXCVIII, figs. 39, 40, filaments in different stages of growth. AN AB JEN A CUPRESSAPHILA, Wolle. Forming a gelatinous, submembranaceous, deep aerngi- n'ous, stratum on cedar trees. Trichomes nioniliform, en- closed in a delicate sheath, slightly curved, or nearly straight, more or less parallel, light aeruginous ; vegetative cells about half as long as wide, granular, sometimes sep- arated ; heterocysts intercalated, brownish yellow, com- pressed globose, homogeneous. Diameter of filaments, 7-8 yw. SPHAEROZYGA. 289 Syn. Trichormus incur vus. All man. On the trunks of trees, low down near the water's edge in swamps, New Jersey. Plate CXCYIII, figs. 1, 2, specimens of filaments. i Genus 95, SPHAEROZYGA, (Ag. ) Ealfs. Trichomes sheathless, singly, or agglutinated in an indefinite gelatinous stratum ; rarely a number enclosed in a definite tegu- ment ; cells spherical, elliptic or oblong, or transversely com- pressed. Heterocysts intercalated, binary or solitary. Spores proximate to the heterocysts. SPHAEROZYGA POLYSPERMA, Kg. Filaments subsolitary or associated and interwoven, light bluish green, straightish, or variously curved and flexuous ; articles, either subspherical or shortly cylindrical ; hetero- cysts globose or very broadly elliptical ; a little larger to twice the diameter of the vegetative cells ; spores more or less, elongate, cylindrical ; in the mature state dark bluish green, densely granulate and with rather thick membrane. Diameter of vegetative cells, 2.5-6 yw. Syn. Splwerozyga Carmichaelii, Harv. ; Cylindrospermum elonga- tum, Kg.; Sph. Flotomana, Kg.; Dolychospermum poly- spermumj Wood. Small pools, stagnant waters. Plate CXCVIII, figs. 37, 38, two short filaments. SPHAEROZYGA HASSALLII, Bab. Trichomes equal, curved, often circinate, interwoven into a thin aeruginous stratum ; joints globose or more or less compressed, delicately granular ; heterocysts spherical, color- less, intercalated without order ; spores oblong cylindrical, single or in pairs, sometimes in series, distinctly curved, dark aeruginous, densely granulated, 2-3 times longer than broad. Diameter of cells, about 8 /* ; heterocysts, 9-10 ju ; spores, 12 //. Syn. Anabama flos-aquae, Hass. ; Ana. Hassallii, Nord. and Wittr. ; Dolychospermum Thompson^ Ann. Nat. Hist.; Anabcena circinalis, Phillips. Plate CXCVIII, figs. 33-35, three specimens from many variable forms ; fig. 36, Oseillaria filaments resulting from the development of this Sphaerozyga. 290 FRESH-WATER ALG^E OF THE UNITED STATES. SPHAEROZYGA SACCATA, Wolle. Thalli forming elongated, vertical, submembranaceous tubes, closed at the apex, 2-4 inches long and about one- fourth inch thick, in clusters of 10-15 more or less, attached to pond weeds (Potamogeton? etc.,) in shallow water at mar- gins of pond, or to the bottom where the water is not more than a few inches deep. Each tube contains numerous fila- ments, erect, parallel or slightly curved, composed of ob- long or cylindrical aeruginous cells, closely connected ; het- erocysts oval or subglobose yellow ; spores numerous, cylindrical, dull aeruginous, nearly twice as long as wide. Diameter of filaments, 4-5 u. Diameter of spores, 7 /w. Diameter of heterocysts, 6 yw. Frequent in Cranberry Pond, New Jersey. Specimens, No. 397, Wittrock and Nordstedt's Algw Ex- siccatce. Plate CXOIX, fig. 1, a normal cluster of saccate forms ; fig. 2, detached tubes floating ; figs. 3-5, various specimens of filaments as contained in the tubes. SPHAEROZYGA SMITHII, (Thwaites) Wolle. Trichomes straight, included in a definite gelatinous sheath, usually single but sometimes two or three in a sheath ; joints subspherical, about as long as wide or a little longer. Heterocysts subspherical or oval. Spores cylin- drical, unequal in length, usually about twice as long as wide, with the ends rounded. Diameter of cells, 4-6 ^ • heterocysts, 8-9 // ; spores, 9-12 yu. Syn. Dolychospermum Smithii, Thwaites ; Anabcena timithii, Thur. This plant might also be placed to the genus Hilsia, Kirch., having often two or three filaments in a sheath, but in general character it is too much like a Sphaerozyga to be separated. It is not strictly in accord with S. Smith ii of Thwaites, but the deviation is more pardonable in a plant of this genus than it would be to make a new species of it. Other changes in the character of the cells are worthy of note. The cells instead of remaining as in the young state rather longer than broad, become about three times as broad as long, evidencing a tendency to change and develop an Oscillaria or a Lyngbya-form. Plate CXCIX, figs. 17-19, typical filaments ; figs. 20-22, filaments two or three in a sheath ; fig. 23, cells dividing and increasing in width ; fig. 24, two filaments more ad- vanced toward the character of Oscillaria. NODULARIA. 291 Genus 96, APHANIZOMENON, Morren. Thallus somewhat membranaceous, free swimming, aeruginous or light pure blue, or becoming olive; trichomes medium size, a little attenuated towards the apex, agglutinated parallelly and densely in fascicles ; articulations cylindrical, very closely con- nected, pale blue, nearly colorless, and delicately granular. Spores elongated, cylindrical, rounded at the ends, pale blue or somewhat olive, smooth. — Borzi. APHANIZOMENON FLOS- AQUAE, Allrnan. Fully described by the generic character. Diameter of vegetative cells 3.5-5.5 yu; 1-2 times as long as broad ; diameter of spores, 5-5. 5 /<*; 6-12 times longer than the diameter. Gathered this species only once ; from a reservoir of rain- water. Syn. Limnochlide jtos-aquae, Kg. ; Sphaerozyga flos-aquae, Rab. ; Byss-us flos-aquae, Linn. Plate CXCVIII, figs. 7, 8, agglutinated filaments, floating ; figs. 5, 6, specimens of spores. 0 Genus 97, NODULAR! A, Mertens. Trichomes usually distinctly vagi nate, with closely compressed disc-shaped joints, collected in a gelatinous or membranaceous, irregularly diffused stratum. Heterocysts intercalated at regu- lar intervals; vegetative joints nearly equal, transversely com- pressed. Spores fuscous, or golden yellow, globose, slightly compressed. NODULARIA PALUDOSA, Wolle. Filaments single or in smaller clusters on marshy grounds ; trichomes nearly straight, of a beautiful aeruginous color ; articulations short, about half as long as wide, granular. Heterocysts nearly globose, yellow. Diameter of cells or filaments, 6-8 ^. This plant is evidently very closely related to Anabcena\ sometimes it has a sheath, but this appears soon to dissi- pate. Anabcena cupressaphila can scarcely be separated from this Nodularia except that the former has not, usually, the heterocysts at regular intervals; they are distinct also in habitat. These forms are noted merely provisionally. The Nodular iae of Europe occur only in brackish waters and are 292 FRESH-WATER ALG^E OF THE UNITED STATES. found in considerable masses; can not be the same plant observed here. Syn. Earlier authors classified these forms as Spermosira. Plate CXCVIII, figs. 3, 4, after specimens from Colorado and from Pennsylvania. Genus 98, CYLIXDROSPERMUM, Kg. Thallus like that of Sphaerozyga, trichomes sheathless. Hetero- cysts terminal, single ; spores originate in the cell next the heterocyst. CYLINDROSPERMUM MACROSPERMUM, Kg. Trichomes curved or nearly straight, pale aeruginous, more or less interwoven; joints globose or elliptic, often mixed with others, somewhat cylindrical ; cell contents usually somewhat granular. Heterocysts terminal, globose or slightly oblong. Spores elliptic- oblong, or oblong cylin- drical ; dark green or yellowish brown, or darker brown when matured ; granular, twice as long as broad. Diameter of vegetative cells, 3-4 yw ; heterocysts somewhat larger ; spores, about 14 yw. Syn. Andbcena inipalpebralis, Hass. ; Cyl. splitter ospermum, Eab. Plate CXC1X, figs. 6-8, normal appearance of the fila- ments; fig. 14, Wood's figure. In ditches and on wet ground. CYLINDROSPERMUM LIMNICOLA, Kg. Filaments slightly curved, pale aeruginous, forming a thin membranous thallus ; on garden and other soils in damp, sultry weather ; very near the last, but slightly more slender in filaments and spores. Probably merely a variety of the same. Syn. Cyl. minutum. Wood. Plate CXCIX, fig. 11, cells often very close, with ends compressed, presenting the appearance of Oscillaria; figs. 9, 10, after specimens from an almost dried up shallow ditch ; many of the spores dropped off ; the filaments seem to be true Oscillaria; fig. 12, Wood's figure of his Oyl. minutum. CYLINDROSPERMUM FLEXUOSUM, Eab. Stratum gelatinous, aeruginous, indefinitely expanded; filaments equal, mostly flexuous and interwoven, often cir- cinately or fasciately convulate ; sometimes straightish and in bundles ; articles oblong, more or less contracted at the CRENOTHRIX. 293 joints. Heterocysts subglobose, rarely hirsute ; spores oblong-cylindrical, 2-3 times longer than broad, distinctly granular. Diameter of cells, about 4 ^ ; spores, about 10 jw. • On dripping rocks, and on wet ground, Pennsylvania. CYLINDROSPERMUM COMATUM, Wood. Growing on the ground, forming a gelatinous stratum of an aeruginous color ; filaments nexuous, equal, intricate, not spiral ; joints shortly cylindrical, equal to or more than twice as long as wide; mostly separated; pale aeruginous, obscurely granular, terminal cells subglobose ; spores oblong- cylindrical, about twice as long as wide, granular, yellowish- brown ; membrane thick, distinctly granulate. Diameter of filaments, 3 // ; spores, 10 //. There appears to be but little to commend this plant for a new species, but in a supplementary remark the author adds, "The terminal cells are remarkable for being abundantly provided with long, flexible, hair-like processes, upon the ends of which are minute globular bodies. These appendages are so minute as to make it difficul^ to determine their struc- ture." If these hair-like processes are anything more than the result of the contraction of the gelatinous covering of the cell, they will constitute a good distinguishing feature. Plate CXCIX, fig. 16, a copy of Wood's figure. SECTION V.— OSCILLARIE.E. Simple filaments with or without sheath, singly or forming extended strata, without heterocysts and without spores, not terminating in a hair-point. Multiplication takes place, first by hormogonx, parts of internal trichomes which slide out of the end of a sheath, or which are scattered by the dissolution of the sheath ; each small part, con- sisting of but a few cells, quickly starts a new growth, develops new filaments like the one from which it was separated ; this applies particularly to Oscillaria, Lyngbya and tiymploca; secondly by means of gonidia developed usually in the cells of the parent plant. Genus 99, CBEXOTHRIX, Conn. Filaments distinctly articulate, colorless, surrounded by a gelatinous envelope. Propagation by means of microgonidia, and macrogonidia ; the former developed by the longitudinal division of the cytio- 294 FRESH-WATEK ALG^J OF THE UNITED STATES. plasni into two or three series of cells, and scattered by the diffluence of the sheath ; the latter formed in single series in the filaments and ejected. CRENOTHRIX POLYSPORA, Colin. Filaments slightly increased in thickness towards the apices; colorless, or sometimes changed to reddish or ochraceous as the result of incrustation by solutions of iron. Attached, or floating in small mats. The only plant of this genus hitherto recognized is near, if not identical with Hypheothrix Kuehniana, Bab. It re- ceived prominence through Prof. Colin, 1870, who was inter- ested in the examination of the water-supply of the city of Breslau, Silesia, and wrote a detailed history of the mode of its development. Later, 1879, Dr. Zopf, searching into the causes of complaints of impurities in the water furnished by the city of Berlin, Prussia, took special pains to cultivate this plant, and added more facts relating to its life-history and rapid growth. It was found to prevail to an alarming extent, developing in dark places, in deep wells, in water- mains and in smaller pipes. The peculiar colorlessness, and the gelatinous consistency of the plants, suggest a relation- ship with some of the forms of filamentous fungi. Cohn and Zopf retain it as an Algae. We are not aware that the plant was recognized in this country until recently, 1886. It was found in somewhat limited quantity, near the inlet to Lake Chautauqua, N. Y., whence part of the water-supply to the city of Jamestown is taken. Plate CCIX, figs. 1-3, a part of a filament with cytioplasm divided longitudinally, turning into microgonidia, and de- veloping in part, from the gonidia before separation from the filament, two groups or clusters of young typical plants 5 figs. 4-9, niacrospores, or resting spores, single, or dividing into two, and these in turn each dividing, and so on, doubling the length of the filament at each division, indicat- ing the process of growth ; fig. 10, part of filament under higher magnification showing the arrangement of the cells ; figs. 11, 12, cells, niacrospores, sliding out of the sheath ; fig. 13, microgonidia gather in masses, imbedded in gelatin- ous mucus, PaZwe7ta-like ; fig. 14, a small Palmetto, mass, gonidia developing into plants ; figs. 15-17, three parts of filaments with cytioplasm dividing longitudinally, magni- fied about 600 diameters ; fig. 18, a caespitose cluster as of common occurrence. LYNGBYA. 295 Genus 100, CHAM^ESIPHON, A. Br. and Grun. Short, tubular, parasitic, aeruginous cells witli thin, color- less, but distinct sheath. Propagation by means of one-celled gonidia. CHAMAESIPHON INCRUSTANS, Grim. Tubes short, contracted at the base, forming a short stipe ; younger plants have apex closed, rounded ; later open ; sheath indistinct. Diameter of tubes, a"5out 4 yw ; length, 16-17 yw. • In ponds, parasitic on submerged plants. Plate CC, fig. 3, young plants often thickly clustered, forming an incrustation. CHAMAESIPHON CONFERVICOLA, A. Br. Tubes from the base narrow cylindrical, or sometimes slightly swollen, solitary or in clusters. Diameter of cells, 3-4 // ; length, 25-35 /*. Parasitic on larger forms of algse, ponds. Plate CC, figs. 1, 2. Genus 101, LYNGBYA, Ag. et Thur. Filaments enclosed singly in a sheath, simple, or only excep- tionally exhibiting the appearance of the beginning of ramifi- cation where the trichonie issues from the side of the sheath ; often combined, forming a membranaceous stratum. This genus, as it now stands, emended by Thuret, includes all the plants of the genus Phormidium, Kg. ; Siphoderma, Kg. ; and the sheathed forms under Lepothrix, Kg. ; Hypheotlirix, Kg. ; AmphithriXj'Kg.; Leibleinia, Kg. Propagation takes place by means of hormogons, which slide out of the sheaths ; the disc-formed cells, singly or in short series divide and multiply and then develop sheaths, thus repro- ducing the plant. Another mode appears to be that the single disc-forms pro- duce gonidia from which spring Mastigonema-forms, which de- velop Lyngbya filaments. Compare Plate CLXXVI, figs. 6, 7, 8, and description. Forms like fig. 1, (same Plate) are of frequent occurrence, parasitic on Lyngbya Wollei, probably young growths of the plant. Perhaps these statements should be made with some degree of hesitation. Some of the Mastigonema- forms have been shown to be young conditions of different varieties of 296 FRESH-WATER ALG^E OF THE UNITED STATES. Phycochromes (Cyanophycece) ; it can not therefore be considered incongruous to suppose that the same or similar forms may develop Lyngbya ; nevertheless more evidence is sought. A third method of' propagation is a direct development of Anabcena-forrns. See notes under the description of the genus Andbcena. LYNGBYA AESTUARII, Liebm. Trichonies rigid, flexuously curved, blue green or with age brownish, densely interwoven in aeruginous tufts, or extended strata floating on brackish water, or spreading on moist earth near the sea shores. Joints 3-4 times shorter than their diameter ; scarcely constricted ; sheaths pellucid, hyaline, becoming brownish; at first scarcely lamellose, later distinctly lamellose. Diameter of trichomes, 20-28 yw. Forma MINUS. Smaller forms on soils with less moisture, but evidently the same species. Diameter of filaments, 12-15 //. Plate CCII, figs. 1, 2, after specimens from Absecom, and Perth Amboy, New Jersey. Syn. Lyngbya aeruginosa, Ag. ; L. curvata, Kab. ; L. majuscula, (British Seaweeds. ) In brackish water, abundant near the eastern coast of Jersey. Plate CC, figs. 11-16, from specimens collected in various places near the coast of New Jersey, and in Florida. LYNGBYA CINCINNATA, Kg. Filaments floating in loosely caespitose cluster, or often singly in marshy places ; in masses greenish black, often faded, brownish. Trichonies aeruginous, interrupted ; ar- ticulations short, 3-4-6 to diameter. Older plants distinctly lamellose. Diameter of trichomes, with sheath, 25-30 yw. Has much of the appearance of the last, but is purely a fresh- water plant and occurs at high elevations in Colorado ; on Mt. Mansfield, Vt., and similar localities. It is not the plant known by the same name which occurs in ditches and pools, sometimes as a Scytonema, sometimes as a Chrysostigma, and sometimes assuming the character of a Lyngbya. Compare Scytotwma cincinnata. LYNGBYA. 297 Syn. Calothrlx lanata, Kg. 5 I/yngbya discolor, Krypt. Badens. Plate CC, figs. 4, 5, after specimen from Mt. Mansfield, Vt. LYNGBYA MAJUSCULA, Harv. A marine plant, densely intricate, crisp ; trichomes rigid, flexuously curved, frequently interrupted, dull olivaceous or pale steel-color 5 sheath close, articulations 6-8 to diam- eter. Sheath distinctly lamellate in older plants. Diameter of filaments, including sheath, 30-38 yu. Collected in the vicinity of the City of New York, but it has a wide range. Plate CC, figs. 9-10, New York specimens. LYNGBYA WOLLEI, Farlow. Forms smaller or larger tufts attached to river stones ; the more sluggish the water the larger the extent of the growth, even to masses yards in diameter and a foot or more in thickness. Usually brownish black ; but when older some- what faded, more olive or brown or yellowish. . Articulation primarily about 4 to diameter, after division 6-8. Sheath firm, and lamellate in older forms. Diameter of filaments variable, from 40-4^w to 50-60 yw. Widely distributed from Massachusetts to Florida, and westward to Minnesota. The largest masses occurred to personal observation, in ponds, New Jersey. In one in- stance in pond near Stanhope, the floating mass was fully ten yards long, 2-3 yards wide, a foot or more in thickness, and so densely matted, it was impossible to break through with a row-boat. Plate CC, figs. 6, 7, 8, fragments of filaments which were a foot, more or less, in length. LYNGBYA VERMICULARIS, (Kg. ) Eab. A marine plant, forming extended floating mucose strata on ponds filled by the flow of high tides. Color dull or dingy tea green, or olivaceous ; often faded. Trichomes very unequal in size, flexuously curved, often vermicular, pale aeruginous. Articulations of smaller filaments, 2-4, of larger forms, 6-8 to diameter. Sheaths very thin, not lamellate, often gelatinous, colorless. Diameter with sheath, very variable in the same cluster, 13-32 //. This is a distinct form in the disparity of sizes, some more than twice as thick as others ; in the gelatinous strata, and in the thin and close sheaths. 298 FRESH-WATER ALG^ OF THE UNITED STATES. It does not strictly represent the plant of (Kg.) Bab., but has so much in common, have adopted the name for it. i It is near L. aestuarii, but separated by the thin and often gelatinous sheaths ; in the mixture of sizes of filaments, and color of strata; not deep aeruginous; neither is it sub-mem- branaceous, as that plant. The features may be largely characteristic of young devel- opments from Anabce,na-\ils& filaments, as explained under the description of the genus Anabcena. LYNGBYA PAIXIDA, (Naeg. ) Kg. Forming a firm niembranaceous stratum, pale rose or darker red color. Trichonaes rather straight or slightly curved, subparallel, or sometimes flexuously curved and in- terwoven; in older condition faded, or yellowish brown. The filaments at first bright aeruginous, but soon change ; usually they occur intermixed in color; aeruginous, pink, darker red, yellow, and almost colorless. Articulations equal to half as long as wide. Sheaths ordinarily rather wide, widen with age, finally lamellate and fibrillous. Diameter with sheath varying from 40-80 yu. Syn. Hypeoi/irix pallida, (Naeg.) Kg.; Phormidium pallidum, Naeg. Exposed wet soil, old roadways, old meadow grounds, New Jersey, Virginia, Florida, Pennsylvania. Plate CCII, figs. 26-31, various stages of growth. LYNGBYA NAVEANUM, GTUII. Occurs in thin strata, dull green, or olivaceous brown. Trichomes dull aeruginous ; articulations often indistinct, i-i as long as wide. Sheaths close, but widen with age; firm, colorless. Filaments more or less parallel, internal trichomes frequently interrupted. Diameter of filaments, with sheath, 15-18 yw. Marsh grounds, Florida; Crystal Bay, Canada; pools, Pennsylvania. Plate CCI, figs. 1, 2, from Pennsylvania specimens ; figs. 3, 4, Florida specimens. LYNGBYA OBSCURA. Free swimming in solitary filaments, but frequently form- ing a thin dark aeruginous, almost black, stratum. Articu- lations distinct, i-i as long as wide ; primarily bright aeru- ginous, later some shade of brown. Sheath in younger LYNGBYA. 299 plants colorless and thin ; older plants thicker, yellowish or yellow brown, and lamellate. Diameter of filaments, 12-18 j*. Appears closely related to the submarine forms of L. aeru- ginosa, Ag., L. pannosa, Kg1., and L. aesfnarii, Liebm., but beside electing fresh-water, it is thinner. According to Kirchner the sheath is often very much wider than lias come under my notice. L. bieolor, Wood, is the same plant. Plate CGI, figs. 5-10, from specimens from Bean Lake, Canada ; ponds, Vermont ; Pennsylvania ; New Jersey ; Alabama, and Florida. LYNGBYA PHORMIDIUM, Kg. Filaments much interwoven, forming mats of considerable size, of dirty aeruginous color ; articulations nearly as long as wide, light aeruginous, or turning yellowish brown. Sheaths colorless, moderate in thickness, not lamellate. Diameter of filaments, 7-9.5 yw. Syn. Phormidium Lyngbyaceum, Kg.; Symploca phormidium, Thur. On wet marsh bottoms. Plate CCI, figs. 22-26, filaments somewhat variable in thickness. Yar. EIVULARIS, Wolle. Filaments in larger or smaller tufts, from 1-6 inches long. Attached to river stones in shallow, flowing water, waving with the currents. Filaments often six inches long, the ex- tremities bright blue-green, lower parts changing to yellow- brown or fading entirely, becoming colorless. Articulations usually indistinct, sub-equal in length and width. Diameter of trichomes, including the narrow sheath, 8-9 yw. River Lehigh, Bethlehem, Pa. LYNGBYA ARENARIUM, (Kg.) Eab. Forming a thin membranaceous stratum, beautiful green, not lamellose, trichomes lightly curved, pale aeruginous. Articulations 3-4 to diameter. Apices of filaments obtuse conical, straight. Sheaths often soft, gelatinous. Diameter of filaments, 8-10 yw. Moist low grounds near Atlantic Coast. Plate CCI, figs. 27-29, specimens from New Jersey, near Atlantic City. 300 FRESH-WATER ALG^E OF THE UNITED STATES. LYNGBYA RUPESTRE, ( Ag. ) Kg. Stratum compact, rather velvety, gelatinous, shortly radi- ating, bright blue green, or becoming dark steel blue, the lower strata becoming discolored and fibrillose ; trichomes rigid, rather flexuous, a little torulose towards the apex ; articulations equal, or nearly equal in length and breadth ; very finely punctate, extreme apex paler or colorless. Diameter of filaments, 7-8 /^. Syn. Phormidium rupestre, Kg. ; Oscittaria rupestris, Ag. Plate CCII, figs. 5-8, from specimens collected by J. D. Smith, on rocks, falls of Deep Creek, Maryland. LYNGBYA SUBTORULOSA, (Breb.) Wolle. Forming a firm, aeruginous- steel color, membranaceous stratum; trichomes ' rather straight, subtorulose, pale aeru- ginous ; articulations nearly equal in length and breadth, the joints somewhat contracted and hyaline. Sheath firm, granulate and niucose. Diameter of filaments, 7-8 /*. Syn. Phormidium subtorulosa, Breb. ; Ph. lacustre, Naeg. From moist grounds, Florida. Plate CCII, figs. 3, 4, Florida. LYNGBYA MEMBRANACEA, (Kg.) Thur. Forming a firm leather-like expanded stratum, blackish brown or olivaceous color. Filaments distinctly articulate. Articulations before division as long or one-half longer than wide ; light aeruginous or light brown ; end cells slightly attenuate, sheath colorless and thin. Diameter filaments, 4-9 /u. .Kirchner finds two forms which he denominates — genuina and inaequalis. The former, with filaments of nearly uniform thickness ; the other verv variable in size. / */ Syn. Phormidium membranaceum, Kg. Collected by F. Hosford, Charlotte, Vermont. Plate CCI, figs. 11-13. LYNGBYA VULGARIS, (Kg.) Kirch. Stratum thin, inore or less expanded, mucilaginous, dark steel blue, purplish, olive, brown or turning yellow, opaque or shining ; by age becoming thickened ; trichomes straight, rigid, distinctly sheathed, joints as long as broad or shorter ; r LYNGBYA. 301 dissepiments delicately granulated, apex somewhat atten- uated, now and then somewhat curved. Diameter of filaments variable, 5-9 //. Kirchner makes the following four of Kuetzing's species, forms of Lyn. vulgar is ^ viz. : Myochroa, Kg., stratum blue-black 5 fusca, Kg., stratum dark-brown; lutea. Kg., stratum yellow-brown; publ'n-d, stratum aeruginous. Syn. Phormidium vulgare, Kg. ; Osettlaria autumnalis, Eng. Fla. ; Conferva decorticans, Dillw. ; OscUlaria decorticam, Grev. Fla. Edin. ; Humida decorticans. Gray. Frequent on moist soil from Maine to Florida. Plate CCI, figs. 14-20, parts of filaments from various localities. LYNGBYA JULIANA, Menegh. Fasciculately caespitose, blackish green, dull violaceous or pale steel color ; more or less radiating ; trichomes some- what flexuously curved ; internally frequently interrupted ; articulation *-i as long as wide ; apices attenuated, straight, obtuse. Diameter of filaments, 5-6 ^. Syn. Phormidium Julianum, Bab. Sandy soil, somewhat influenced by marine waters, Florida; Alabama. Plate Oil, figs. 20, 21. LYNGBYA TINCTORIA, Kg. Forming a purple stratum ; or dried, violet steel ; substra- tum ineinbranaceous, lamellose, faded. Trichomes fascicu- lately congested, long, waving ; apices more or less atten- uated ; articulations primarily twice as long as wide, later subequal ; cytioplasm granulate aeruginous. Diameter of filaments, 8-9 /*. This properly represents a river plant of Sweden and Norway. It has much in character with our L. Phormidium, var. rivularis. The plant here represented is from Arizona and was identified from a dried specimen, having for guide merely diameter of filaments, length of cells, and color. Needs farther observation. Plate CCII, figs. 22, 23, filaments from Arizona specimen. 302 FRESH-WATER ALG^ OF THE UNITED STATES. LYNGBYA CATARACTA, (Eab. ) Wolle. Forms a thick, firm gelatinous, extended stratum, meas- uring one-half inch, more or less, in thickness ; pachyder- mate ineinbranaceous, bluish-green, velvety ; trichomes slightly curved, articulations shorter than the diameter. Apices straight, obtuse or rarely barbed. Diameter of filaments, 3-3. 5 yw. Syn. Phormidium cafaractum, Eab. Frequent at waterfalls, mill dams, etc., sometimes in cushion-like masses, two or more inches in thickness; ordi- narily not so thick, but 6-12 inches in extent. Plate CCII, figs. 18, 19, from a Pennsylvania specimen. LYNGBYA EETZII, (Ag.) Kg. Stratum broadly expanded, rather compact, green-blacjt or deep olive, shining, parts changing to brownish, shortly radiating ; trichomes rather straight, bright aeruginous, indistinctly articulate ; articles about half as long as wide ; apices slightly attenuated, obtuse, straight. Diameter of filaments, 4-5.5 yw. Syn. Oscillaria Retzii, Ag. ; 0. laevigata, Yauch. ; Phormidium Retzii, Kg. Wet soil, South Carolina; wet rocks, Charlotte, Vermont. Plate CCII, figs. 15-17, from marsh grounds. LYNGBYA PAPYRINA, (Kg. ) Kirch. Stratum thin paper like, sometimes shortly radiating, with a pallid or brownish fibrillose substratum, formed from the interlaced empty sheaths; trichomes equal, joints nearly equal or a little shorter than their diameter ; granulated at their junction, apex obtuse, straight. Diameter of trichomes, 5-7 yw ; with sheath, 7-9 yw. Syn. Oscillaria papyrina, Bory ; Phormidium papyrinum. Kg. ; Ph. papyraceum, Eab. ; very near also to L/yngbya vulgaris. Plate CCII, figs. 9-11, specimen from the vicinity of New Haven, Connecticut. LYNGBYA INTERRUPTA, (Kg. ) Forming a membranaceous, aeruginous-green, mucous stratum, scarcely radiating ; substratum somewhat membra- naceous, decolored ; trichomes flexuously curved, yellowish green, interrupted; sheath continous firm; articulations half as long as wide, homogeneous or finely granulate at joints; apices straight, obtuse. Diameter, 5-7 yw. SYMPLOCA. 303 Plate CCII, figs. 12-14, specimen from Charlotte, Ver- mont. Habitat not furnished by the collector. LYNGBYA INUNDATA, Kg. Stratum deep blue green, with a whitish grumous mem- branaceous substratum ; trichomes curved, rather rigid, pale blue green, rarely fasciculate, sheaths narrow, joints shorter than their diameter, dissepiments not granulated, extreme apex straight, obtuse. Diameter of filaments, 4 n. Syn. Phormidium inundatum, Kg.; Oscillaria autnmnalis, Carm. Margins of wayside ditches and the like. Plate CCII, figs. 24, 25. Not infrequent. LYNGBYA OCHRACEA, (Kg.) Thur. See Leptothrix ochracea. LYNGBYA MUBALIS, Ag. Filaments somewhat rigid, thickish, tortuous, very long, interwoven into a bright, grass-green stratum, annuli strongly defined. See Ulothrix murale. This plant, originally classified (1824) as a Lyngbi/a, does not, by the term grass-green, belong to this division of algte. It is evidently a Ulothrix, and was so acknowledged by Kuetzing. He called it Hormidiwn murale. Nearly all of Agardh's other species were identified by Harvey (1857), and obtain at this time ; they are marine plants and hence not quoted here. Genus 101, SYMPLOCA, Kg. Trichomes articulate, simple or only exhibiting the begin- ning of ramification, more or less distinctly sheathed, ascending from a prostrate base, agglutinated together in erect or anasto- mosing fascicles or wick-like clusters, often involved in a matrical gelatin. SYMPLOOA LUCIFUGA, Harv. Dark aeruginous green, or more frequently dark olive, fascicles 3-4 mm high, approximate, subuliform ; apex at length pennicillate ; trichomes single or twin in a sheath, aeruginous 5 articulations equal or a little longer than broad, granulate ; sheaths broad, pellucid, colorless, smooth, soon disappearing. Diameter of trichomes, 3-4 }JL • including sheath, 8 yw. 20 304 FRESH- WATER ALG^E OF THE UNITED STATES. Syu. Oscillatoria lucifuga, Hass. ; Calotlirix luclfuga, Carm. MSS. Not infrequent on shaded clay banks ; affects cooler weather; Pennsylvania and New Jersey. No doubt widely distributed. Plate CCV, fig. 8, two vertical fascicles greatly magnified ; figs. 9, 10, natural size and usual growth ; figs. 11, 12, single filaments in sheath. SYMPLOCA FRIESIANA, (Ag. ) Kg. Stratum dull green or blackish, composed of vertical, subuliform fascicles, 10-15 mm high ; trichoines pale blue- greeii, distinctly articulated ; articles about as long as wide. Sheaths rather wide, colorless. Diameter of trichonies, 4-6 yu • with sheath, 8-12 //. The only habitat for this species was discovered by Colonel Macoun, on old wood, Canada. Plate COY, fig. 13, a caespitose cluster; figs. 14, 15, two single filaments. The trichomes are often twin in a sheath. SYMPLOCA FUSCESCENS, Kg. On earth and stones, aeruginous, changes to dull yellowish or brown. Trichomes with age pale olive or yellow-aerugi- nous. In every respect very near 8. lucifuga, except in size ; fascicles only 2 mm high. Diameter of trichomes, 2-3 //. Plate CCV, figs. 8-12, drawn for 8. lucifuga ; for the present plant, one-half the dimensions may be imagined. Probably it is a mere form of former. Genus 102, MICROCOLEUS, Desm. et Thur. Trichomes similar to Lyngbya, but two or more, and often many included in a sheath, which is primarily closed at the end ; later it opens and sometimes divides into shreads. Sheath ample, colorless, rarely indistinct. Have included under this genus Chthonoblastus, Kg.; Hydrocolewm, Kg.; Dasygloia, Thwaites. MICROCOLEUS ( DASYGLOIA ) AMORPHA, (Thwaites; Wolle. Forming a thin gelatinous membrane on dripping rocks, amorphous ; sheaths of the trichomes at first thin, then more gelatinous and thicker, cohering. Internal trichomes aeru- ginous, slender, simple. Sheath variable with age. First barely discernible, then twice the diameter of the trichomes. MICROCOLETTS. 305 Most frequently only one in a sheath, but sometimes two or three. Diameter, without sheath, 10-13 ^. Unlike the European, "coalescing in a solid gelatinous mass as large as a swan's egg;" this plant forms a thin, olive, or dark aeruginous green membrane, skin-like, on trickling rocks, Glen Onoko, Pennsylvania. Have gathered it here, always in the same condition, a number of succes- sive summers. Syn. Dasygloia amorplm, Thwaites ; Microcoleus variecolor, Kirch. ; Schizothrix variecolor, Bab. Plate CCIV, figs. 1, 2, several simple filaments ; figs. 3-6, young plants spirally coiled, gradually opening as they de- velop into forms as figs. 1, 2 ; figs. 7, 8, 9, sheaths with one or more trichomes included. MICROCOLEUS PULVINATUS, Wolle. Thallus large cushion-like, often 6-8 or more inches in diameter ; about two inches thick, somewhat hollow in the center ; dark olive brown ; gelatinous membranaceous ; readily lifted from the water without breaking. Trichomes one, two or three in a sheath. Diameter of trichomes, 5-6 yu ; sheaths, 12-20-30 /-/. The thalli, of all possible sizes from one to ten inches in diameter, are attached to stones and grasses, looking like boulders in the bottom of a mill race with rapidly running water; Bamber, New Jersey. This peculiar growth oc- curred on repeated visits to the locality in different years. Plate CCIV, figs. 13, 14, two small thalli; figs. 10-12, sheaths with one, two, and three trichomes. MTCROCOLEUS TERJRESTEIS, Desm. Stratum more or less expanded, deep blue-green, or steel blue, or changing to olive and then to a brownish red ; niem- branaceous, mucilaginous; trichomes equal, collected in filiform fascicles, sometimes much elongated, extruding from the opening of a common sheath in a penicillate man- ner, articulations equal in length and breadth. May be divided into two varieties, viz.: 1. repens, Kg., trichomes, 5-6 ju in diameter, ends of sheath open. 2. Vaucheri, Kg., trichomes, 4-5 yw, ends closed or torn. 306 FRESH-WATER ALG^ OF THE UNITED STATES. Syn. Chthonoblmtm repens, Kg.; Microcoleus repens, Hass. ; Vaginaria vulgaris. Gray ; V. chthonoplastes, Grev. ; Chtho- noblastus Vaucheri, Kg. Plate CCY, figs. 16, 17, var. repens. Plate CCIII, figs. 7, 8, 9, var. Vaucheri. MICROCOLEUS ANGUIFORMIS, Harv. Stratum thin, skin-like, aeraginons ; trichomes flexuous, often twisted in dense fascicles ; articulations nearly twice / */ as long as wide, sometimes indistinct ; often attenuated near the apices, special sheath very delicate ; universal sheath narrow, thin, colorless, ends open. Diameter of trichomes, 3.5-4; fascicles, 30-40 yw or more. Syn. Chthonoblastus anguiformis, Kg.; Ch. lacustris, Rab. ; Mic. chthonoplastes, Thur. Both affect moist earth, borders of pools and the like. Plate CCV, fig. 1, a peculiar coil from small pool, Atsion, New Jersey. Plate CCIII, figs. 5-9, different conditions which represent alike the present and the preceding species (M. terrestris). When the trichomes measure 3.5-4.5 //, the plant is recognized as of the present species, and when they measure 5-6 //, it would be termed M. terrestris. They run together, and are often not separable. MICROCOLEUS GRACILIS, Hass. Thallus membranaceous, skin-like, expanded, green, aeru- ginous, or with age dark olive green, blackish. Trichomes many included in a general sheath, which is usually wide, yellow or colorless, articulations variable, one to three times as long as wide. Kirchner suggests three varieties, viz: Var. SALINUS, Kg. Thallus thin, blackish green. Var. LYNGBYAI, Eab. Thallus bright aeruginous, often lamellose. Var. AERUGINEUS, Eab. Diameter of trichomes, 2.8-3/t; general sheath of fas- cicles often 140 //. Syn. Microcoleus marinus, Harv.; Chthonoblastus salimis, Kg.; OsciUatoria chtJionoplastes, Eng. Bot. Plate CCIII, figs. 10, 11, from specimens from swamps, Dakota. MICEOCOLEUS. 307 MICROCOLEUS HYALINUS, (Kg.) Kirch. Stratum pale aeruginous, thin, sometimes encrusted, ex- panded, also in solitary fascicles among other algae. Tri- chonies slender, single, or a few in a sheath ; articulations about as long as wide, light aeruginous, sheaths compara- tively wide, colorless, hyaline ; often divided at the ends leaving the impression of a branched filament. Diameter of trichomes, 1-1.5 yw; sheaths, 7-10 yw. Syn. Schizotlirix hyalina, Kg. Plate CCIII, figs. 3, 4, specimens from wet ground, South Carolina, from ponds New Jersey, on Sphagnum; wet rocks, Pennsylvania, etc. Not infrequent, but question whether it is a normal, vege- tative condition of a plant. Has the appearance of a faded, dried and contracted form. Measures are often considerably more than quoted, but the character of the plant remains the same. MICROCOLEUS EAVENELII, Wolle. Forming a stratum on old pasture grounds, dark violet or aeruginous. Trichomes of equal thickness, solitary, or two or three somewhat twisted, in a common sheath, aeru- ginous, changing to golden brown or chestnut color. Sheaths of younger plants close and colorless ; of older plants thicker and firmer, of golden brown color, lamellate ; ends usually empty and coming to a sharp point ; articula- tions subequal, or two to three to a diameter, distinct. Diameter of trichomes, 12 yw ; with sheath, about 15 fj. ; sheaths with two or more trichomes proportionately wider, Plate CCIII, figs. 12-14, specimens from pasture grounds near Houston, Texas, collected by H. W. Eavenel. This form is nearest Hydrocoleuni Brebissonii, Kg. But beside being a larger plant it affects moist ground, not flow- ing river waters. MICROCOLEUS HETEROTRICHUM, (Kg.) forma AMERICANA, Wolle. Forms a dense gelatinous stratum on large, partially sub- merged, stones in swamps ; deep olive black ; trichomes more or less twisted; two forms in the same sheath. Primarily the diameter of the main internal trichome is 12-14 /* ; with sheath, 18-20 /* ; later the sheath widens to 25-38 n ; then more slender moniliform trichomes become evident, entwining the larger one. The diameter of the 308 FKES1I-WATER ALG^E OF THE UNITED STATES. smaller ones is 3.5-4 /<. Color of larger tricliome aeruginous granular ; smaller ones the same as sheath, which is light yellow to brownish red, smooth when young, becomes fibril- lose with age. Syn. Hydrocoleum heterotrichum,JLg. •, Inctctis homceotricha, (Kg. Thur.) Kirch. Plate CCV, figs. 2, 3, two younger filaments : fig. 4, an older filament showing the two forms of trichonies ; sheath smooth ; fig. 5, more advanced in age, the sheath becomes lamellate and fibrillose. From swamp near Bethlehem, Pa. Genus 103, OSCILLAKIA, Bosc. Filaments straight, or slightly curved, rarely circinate and spirally convolute except in very young condition ; branchless and without a discernible sheath. Color mostly bright aeru- ginous, but often changes to violet or steel blue. All, in good vegetative state, are more or less motile and involved in a thin matrical mucilage ; joints disc-shaped in front view. The mystery of the oscillating and creeping movements of the Oscillaria has evoked many theories, but none, hitherto, have re- ceived a general approval. Some of the most recent thoughts come from Dr. A. Hansgirg, Professor in the Royal University of Prague, several of which we quote, before adding a simple idea of our own, and that perhaps not quite original. His first experiments were made to obtain the relationship of the move- ments to light. The filaments of OsciUaria FroeUclm^ placed in complete darkness were found to have lost on the second day their mucilaginous envelope and to have sunk to the bottom of the vessel. The twisting and creeping movements, however, continued until the seventh or eighth day, becoming gradually weaker. The more sensitive filaments of 0. aerugmeo-coerulia lost their power of motion more rapidly. In direct sunshine the movements were more lively than in diffused day-light. An increase of temperature of the water also promoted the rapidity of the movements. The separate filaments of the same cluster move with different degrees of rapidity, depending not only on the warmth and light but also on the age of the filament. The quality of the water, whether river, spring, or stagnant water has also an effect. The twisting, oscillating or nodding movements, the author believes to be due, not to their growth, but to osmotic changes OSCILLARIA. 309 in the cell contents. The creeping movements, he holds, can not be due to protrusions of the internal protoplasm, since each filament is enveloped in a gelatinous sheath, which is not com- posed of protoplasm. The cells also exhibit motion when the envelope itself is at rest. The movements must originate in the protoplasmic contents of the cells themselves and are prob- ably of the same nature as those of the sarcode in the so-called pseudo-podia of rhizopods and other protozoa." Life, whether vegetable or animal, is a mystery to the philo- sophic niind ; to attempt a detailed explanation of cause and effect would be presumptuous, but a remark or two may not be out of place. By the careful observation of living plants the process of cell-multiplication can be readily detected in the larger forms. Ordinarily the split of a cell commences on one side and then continues from the opposite side ; a number of cells dividing at the same time will have the tendency to throw the end of filament (Kit of line, first on one side and then on the other, thus producing the. vibratile motion. The process of creeping may be conceived in connection with growth, and yet it may not satisfactorily explain every movement. The appar- ent correspondence between the rapidity of growth, and that of the creeping filaments is not without significance. Larger forms of Oscillaria are found to grow by cultivation at the rate of about one-half inch in an hour. The creeping of the same fila- ments progresses at the same rate, age of the filaments and other circumstances corresponding, hence the reasonable inference of relation between the two movements. A. — Articulation of filaments often indistinct. OSCILLARIA SUBTILISSIMA, Kg. Filaments often solitary, but also forming a yellowish green stratum, sometimes convolute ; cell contents light yellow-green. Diameter of threads, 1-1.5 p.. Not infrequent on wet, marsh grounds. Plate CCVI, fig. 1. OSCILLABIA TENERRIMA, Kg. Filaments thicker than the preceding; ends somewhat attenuated and bent ; cell contents light aeruginous or with tendency to olive. Diameter, 1.8-2. 5 jw. In ditches, among decayed vegetable matter. Plate CCYI, fig. 2. 310 FRESH- WATER ALG;E OF THE UNITED STATES. OSCILLARIA DETERS A, Stiz. Forming reddish olive, diffused strata ; trichomes rather rigid, densely intricate, oscillating freely ; slightly curved, rule-scent ; articulation distinct or indistinct, equal to one- half longer than the diameter ; apices somewhat bent, obtuse. Diameter, 2 jn. Stagnant waters, Rochester, New York. OSCILLARIA AMPHIBIA, Ag. Filaments straight, forming a membranous stratum, light green, apices obtuse, straight, vibrating actively, articula- tion equal or subequal ; cell contents light blue-green. Diameter of trichomes, 1.8-2.8 //. Coating wood subject to hot waste water from steam engines. Plate CCV, fig. 3, from hot water, temperature of about 110° Fahrenheit. B. — Articulations about as long as wide. OSCILLARIA ELEGANS, Ag. Filaments slender, straight or slightly curved, forming a dense floating stratum ; threads radiating, bright aeruginons green, or with age somewhat olivaceous ; apices attenuated, curved. Articulations about equal in length and breadth ; cell contents light aeruginous. finely granular or homo- geneous. Diameter of filaments, 2. 8-3 j^ ; rarely 3. 5 //. Plate CCVI, fig. 4, from specimens floating on spring water ; also attached to water grasses. OSCILLARIA ANTLIARIA, Juerg. Thallus gelatinous, broad, submembranaceous, dark steel blue or turning to olivaceous ; filaments rather rigid, straight, often tranquil, sometimes oscillating, curved at the attenuated apex, articulations indistinct, about as long as wide; cell contents pale steel blue; nearly homogeneous. Diameter of filaments, 4.5-5.5 yw. Syn. Oscillaria parietiua, Vauch. ; 0. autumnalis, Kg. Around pumps, cisterns, etc. Plate CCVI, fig. 8, rather frequent. OSCILLAR1A. 311 OSCILLARIA CHLORINA, Kg. Sometimes swimming on the water as a dirty greenish stratum, sometimes diffused in the water ; filaments straight, actively moving, either articulated and having the cytio- plasm filled with blackish granules, or else neither articu- late nor granulate ; cytioplasm hyaline, almost colorless, or with a faint greenish tint 5 ends of filaments straight, ob- tusely rounded ; joints about equal to the diameter. Diameter of filaments, about o /^. Collected by Dr. H. C. Wood, on brick-ponds, near Phila- delphia. OlSCILLARIA GRACILLIMA, Kg. Trichomes straight, curved and sometimes coiled, solitary, or forming a thin membranaceous stratum. Threads ob- tusely rounded at the apex, often bent. Cell Contents light aeruginous, articulations not always distinct, about as long as wide. Diameter of filaments, 2.7-3.2 //. Plate CCVI, fig. 6, from specimen floating on pond. OSCILLARIA LEPTOTRICHA, Kg. Trichomes scattered, or collected in a very thin blue green stratum, slender, slightly curved, indistinctly articulate, joints twice as long as wide, or after division equal; very minutely punctate at the periphery ; attenuated at the ends, which are straight, curved or defiexed ; cell contents pale blue, or green. Diameter of threads, 3 yw. Plate CCVI, fig. 7, filaments collected in ditches of brack- ish water, New Jersey. Prevails in fresh-water also. C. — Articulation one-half as long as wide. OSCILLARIA VIOLACEA, Wallr. Filaments long, straight, radiating, forming a gray-violet membranaceous stratum, ends of filament somewhat reduced, and often drawn out to a thin point; articulations 2-j. to diameter, which is, 4-4.7 /*. Most frequent in green-houses. Plate CCVI, fig. 10. OSCILLARIA AERUGINEO COERULEA, Kg. Forming a submembranaceous, mucous stratum, bright blue-green ; filaments long, nearly straight, radiating, oscil- 312 FRESH-WATER ALG^E OF THE UNITED STATES. lating, articulations as long or half as long as the breadth ; dissepiments finely granulate ; apices obtuse or slightly at- tenuate ; cell contents bright aeruginous. Diameter of filaments, 4-5 //. Plate CCVI, fig. 9, not infrequent in stagnant or sluggish waters. OSCILLARIA CRUENTA, Gl'Un. Filaments light aeruginous imbedded in gelatinous masses which are hyaline or somewhat tinted with green or purple. Filaments primarily closely coiled, but soon unroll, remain- ing somewhat tortuous. Articulations often indistinct; after division about one-half longer than broad. Diameter of trichomes, 5 yw, a little more or less. Plate CCVII, figs. 1-3, parts of ordinary trichomes ; figs. 4-7, young coiled trichomes. Plate CCVI, fig. 5, parts of filament of a gathering of a previous season, varying from 4-6 jn. Unlike usual forms of Oscillaria, this was gathered sev- eral successive years (1882 — 1885) imbedded in large sub- merged, almost hyaline, firm, gelatinous masses of irregular form, averaging about the size of a man's head. These oc- curred in a mountain spring at about 1500 feet elevation. Beside the filaments, there are scattered through the masses spherical cells by twos and by fours, constituting them Tetraspora gelatinosa, Desv. An effort to identify a rela- tionship between the filaments and the Tetraspora cells was not successful, although there is a striking similarity in the purplish tint of the two. OSCILLARIA SUBFUSCA, Vauch. Forming a somewhat dense stratum, dark olive or nearly black, short rayed. Filaments nearly straight, with ends sometimes attenuated and furnished with two short cilia. Articulations, *- 1 times as long as wide. Cell contents light aeruginous. Diameter of filaments, 4.6-6.6 //. Plate CCVI, figs. 11-13, several varieties of filaments. OSCILLARIA BREVIS, Kg. Forms a thin, aeruginous stratum, filaments longer or shorter, somewhat attenuated near the ends, and slightly OSOILLARIA. 313 bent ; cells •>, or 2 as long as broad ; cell contents bright aeruginons. Diameter of filaments, 4.5-5 /*. Plate CCVII, fig. 8, filaments from an extended stratum on a shaded deposit of mud after an inundation ; Buffalo, New York. OSCILLARIA TENUIS, Ag. Forming a bright green or aeruginous or with age brownish stratum, short or elongate, radiating ; filaments straight, rather rigid, more or less endowed with active motion ; articulations usually distinct, half as long as broad or before division twice this length ; apex slightly atten- uated, obtuse, curved or straight ; cell contents light or darker aeruginous, finely granular. Diameter of filaments, 5. 5-6. 5 /v. Syn. Oscillaria viridis, Kg.; 0. contexta, Garni. ; Oscillator ia tennis, Hass. Babenhorst quotes nine varieties of this species, depend- ing mostly on color of stratum, habitat, length and diameter of cells, but all comprehended in the diagnosis above. Dripping mossy rocks, pools, margins of ponds or free swimming. Plate CCVI, fig. 14, sample of filaments which make up the stratum. OSCILLARIA CORTIANA, (Pollini) Kg. Forming dark aeruginous extended, floating strata on hot water, 110-120° Fahrenheit. Dries with a bright luster. Filaments straight, fragile, apices slightly attenuated, obtuse ; articulations equal or subequal ; three to five end joints somewhat curved ; cell contents light aeruginous, granular. Diameter of filaments, 6-7 /*. Plate CCVI, fig. 15, from specimens found in quantity floating on hot waste-water at a large steam mill, near Beth- lehem, Pa. OSCILLARIA LIMOSA, Ag. Affects limous grounds and forms an extended, thin, mucilaginous, radiating green stratum ; filaments rigid, straight, actively oscillating, aeruginous or with age olive or brownish ; articulations usually as long as wide, but later only half as long; apex obtuse, straight or curved, cell 314 FRESH-WATER ALG^E OF THE UNITED STATES. contents light aeruginous, homogeneous or slightly granular. Diameter of filaments, 6-7. 75 ^ ; more rarely 8-9 //. Syn. Conferva limosa, Roth ; Oscillaria Adansonii, Vauch. ; 0. tennis, var. limosa, Kirch. Babenhorst enumerates ten varieties, differing chiefly in color; as laete aeruginosa, Kg.; rufa, Kg.; fuscescens, Bab.; chali/bea, Kg.; subfmca, Kg.; amethysteo-chalybea, Kg.; others in form and habitat, as luic'utata, Ag.; fontana, Kg.; animalis, Kg.; and circulate, Bab. Plate CCVI, fig. 16, merely a few ends of trichomes of which thousands are interlaced to compose a stratum as usually observed on moist, muddy soils. OSCILLARIA NATANS, Kg. Filaments often interwoven into a bright aeruginous stra- tum, but more frequently, (var. eryptarthra, Kg.,) solitary and long, twining around water plants ; or free swimming in ponds of quiet waters ; ends of filaments somewhat atten- uated, apices obtuse. Articulations distinct, nearly as long- as wide, more rarely only half as long. Sometimes slightly contracted at the joints. Cell contents light aeruginous or changing to olivaceous. Diameter of cells, 6.5-8.2 yu. Plate CCVI, fig. 19, parts of filaments, frequent in many ponds of New Jersey. OSCILLARIA CHALYBEA, Mertens. Free swimming, long radiating ; stratum broadly ex- panded, obscure blue-green or steel blue color. Filaments pale steel blue, changing to olivaceous, lightly flexuous ; articulations distinct i-l as long as wide ; ends of filaments somewhat curved, apices usually obtuse, rarely rostellate. Cell contents light steel blue ; granulate. Diameter of cells, 7-8 /*. Plate CCVI, figs. 17 and 21, fragments of filaments col- lected from wet grounds, Florida. OSCILLARIA ANGUINA, Bory. Stratum thin, membranaceous, green or dark blue-black, filaments thicker than the last, straight or curved ; cells usually about half as long vas wide, slightly contracted at the joints; contents light aeruginous; apices bluntly rounded. Diameter of filaments, 9-11 //. OSCILLARIA. 315 Our plants are nearest, var. duJeis, Kg. This diagnosis includes also O. subsalsa, Ag. Plate CCVI, fig. 18, three parts of filaments from a gath- ering made in Florida. OSCILLARIA NIGRA,- Vatich. Stratum more or less compact, ample, broad, mostly float- ing, but frequent also on planks surrounding ponds and on wet earth ; blackish green with long radii. Trichomes straight or slightly curved, obtusely rounded, or more rarely attenuated and sometimes bearded. Color of articulations usually blackish blue, or dilute black ; length same as breadth before division ; later I or £ as long as broad ; dis- sepiments usually distinctly granular. Diameter of filaments, 9-10 yw. Plate CCVI, fig. 20, one of our most common forms. D. — Articulations less than half as long as wide. OSCILLARIA PERCURSA, Kg. Trichomes solitary, scattered, or united, forming a thin stratum, blue-green ; filaments radiating, straight or curved at the apices ; dried filaments longitudinally plicate. Ar- ticulations S-T as long as broad, here and there interrupted ; dissepiments distinctly, ornately granular; cytioplasm di- lute aeruginous. Diameter of cells, 15 JA, or slightly more or less. Plate CCVI, figs. 22, 23, four parts of trichomes from a collection made in Central Florida. OSCILLARIA FRCELICHII, Kg. Stratum dark steel blue, or dark olive green, often elon- gated, radiating, opaque, shining. Trichomes nearly straight, even, not attenuated ; cells 2, 3, or 4 times shorter than the diameter, after division 6-8 times shorter; aeru- giuous, brown or green. A frequent and variable species. The following have been suggested as varieties : 1. — Var. genuina, Kirch. Stratum dark aeruginous; fila- ments with ends nearly straight ; diameter 15-18 ^. 2. --Var. viridis, Zeller. Stratum green, diameter 15 /*; ends somewhat curved. 3. --Var. dubia, Eab. Stratum bright aeruginous, diameter of filaments, 13 //, ends straight. 316 FRESH-WATER ALG^E OF THE UNITED STATES. 4. — Var. ornata, Bab. Stratum dull steel blue ; diameter of filaments, 10 yw. 5. --Var. fusca, Kirch. Very dark olive brown, cell contents olive green, otherwise like first form. 6. --Var. caerulea, Kg. Trichomes light -blue. 7. --Var. violascens, Eab. Stratum dark steel blue, shining; trichomes beautiful violet steel, articulations 2-4 to diameter. 8. — Var. neglecta. Wood. Near the latter. Filaments di- lute purplish lead color, or leaden -gray. Stratum blackish purple. Plate CCVII, figs. 9, 10, from forms most frequent. Com- mon on sluggish waters, pools, and the like. OSCILLARIA MAJOR, Vauch. Stratum aeruginous or dark steel blue. Filaments thicker than the preceding, straight, ends slightly attenuated ; cells i-jj as long as wide, with ends bluntly rounded ; contents steel blue. Diameter of filaments, 19-22 ^. Plate CCVII, figs. 11, 12, specimens from borders of ponds and pools. OSCILLARIA GRATELOUPII, Bory. Stratum aeruginous, long radiating; trichomes nearly straight, subfragile, unequal in diameter ; thicker filaments, 18-20 IJL. Articulations \-\ as long as wide ; dissepiments ornate, with usually two series of granules. Ends of fila- ments straight, broadly rounded. Only habitat hitherto observed, vicinity of New York City, submarine waters. Plate CCVII, figs. 13-15, various sizes as they were found intermingled. OSCILLARIA BONNEMAISONII, Crouau. Stratum more or less extended, dark aeruginous or oliva- ceous ; filaments long radiating, dark aeruginous, flexuously curved, interwoven ; articulations one-fourth to one-fifth as long as wide, dissepiments distinctly granular, ends atten- uated, curved, apex rounded. Diameter of filaments, 23-28 yu. Wet soil, recently inundated, Pennsylvania. Plate CCVII, figs. 16, 17, two ends of motile filaments. OSCILLARIA. 317 OSCILLARIA LITTORALIS, Carm. Stratum thin membranaceous, aeruginous, shortly radiat- ing ; filaments rigid, endowed with active motion, vividly oscillating ; articulations 4-5 to a diameter ; dissepiments granular ; ends straight., broadly rounded ; light aernginons. Diameter of trichomes, 12-15 jj. Salt water marsh pools, New Jersey, Florida, and prob- ably along the whole Atlantic Coast. Plate CO VII, figs. 18, 19, two parts of trichomes, from New Jersey. OSCILLARIA PRINCEPS, Vanch. Stratum aernginons or dark blackish green, long rayed ; trichomes straight or slightly curved, somewhat thinner towards the ends, apices broadly rounded ; articulations one-fourth to one-fifth as long as broad; cell contents steel- blue. Diameter of filaments, 30-45 //. Syn. OstiUaria taenivides, Bory ; 0. aeruginea. Mart. Pools and ponds. Plate CCVII, figs. 20-22, specimens of usual appearance. OSCILLARIA IMPERATOR, Wood. Occurring in an olive-black, mucous stratum, mostly swimming ; with long rays ; trichomes straight or straight- ish, light green or deep olive, tranquil, or oscillating slowly ; moving with a gliding motion. Ends somewhat attenuate, broadly -sub -truncate at the apices, slightly curved; articulations 6-12 times shorter than the diameter, slightly contracted at the joints; cytioplasm homogeneous, olive green ; sometimes granular. Diameter of trichomes, normal form, 50-56 // ; smaller forms, 38-45 //. The principal distinction between this species and the preceding (princeps) is in the articulation which is very variable; the former averages 4-5 ; the present 9 to diameter. The diameter is more also. Frequent in ponds and pools from Maine to Florida. Plate CO VIII, figs. 3, 4, the typical form ; figs. 1, 2, a smaller variety ; articulation, 6-10 times shorter than broad. 318 FRESH-WATER ALGJ3 OF THE UNITED STATES. Genus 104, BEGGIATOA, Trevis. Filaments simple, slender, like Oscillaria, vibrating (?) cell contents colorless. The plants of this genus are of doubtful value. The fila- ments are usually clustered and attached, color dull white, or glossy silver or chalk white. They are found in sulphurous waters ; abounding in localities like Clifton Springs, New York ; Sulphur Springs, Niagara; Glen Cove Springs, Florida; arte- sian wells, Florida, and probably more or less in all sulphur springs. The same plants in fresh -water springs would be classed as Leptothrix. The white appearance is abnormal, produced by the chemical action of the sulphur water. Normally the fila- ments are without distinct transverse divisions ; in younger stage, light aeruginous, or light yellowish brown ; after a longer subjection to the action of the sulphur in the water the color disappears, and the filaments become silver white. The cytio- plasm loses its vitality, becomes opaque, white to the unaided eye, but black under the microscope, because it does not trans- mit rays of light ; in this condition it contracts lengthwise, breaks into short sections, equal or subequal to twice as long as wide, producing a semblance of articulation. The chemical effect of sulphur springs is to destroy colors, acting as a bleaching agent ; it does not affect all colors equally. Chlorophyl green plants are not usually changed by it, neither decided aeruginous colored plants, as Oscillaria. Eabenhorst describes ten or twelve European species of BEG- GIATOA, of which we identify only two forms ; these we retain as representatives of the genus, although we recognize in them mere forms of Leptothrix. BEGGIATOA NIVEUM, Bab. Usually forming extended caespitose floccose, silver white, glistening strata; filaments slender, indistinctly articu- late when in vegetative condition ; later the cytioplasm solidifies and contracts, separating into parts 1-2 times as long as broad, presenting the appearance of an articulate filament. Diameter of filaments, 1-1.5 yu. Frequent in sulphur springs, Niagara. Syn. Leptonema, nivea, Bab. Plate CCVIII, figs. 8, 1). From cliffs, Niagara, dripping sulphurous water. LEPTOTHRIX. 319 BEGGIATOA LEPTOMITIFORMIS, (Menegh. ) Trevis. Habitat, strata, and filaments, in character with the pre- ceding, but trichonies stouter and usually in larger masses. Diameter of filaments, 1.8-2.5 /-/. Syn. Oscillaria Icptomitiformis, Menegh. Larger sulphur springs, New York and Florida. Plate CCYIII, figs. 6, 7, clusters of filaments, and separate ones under higher magnification. Genus 105, LEPTOTHEIX, Kg. Filaments simple, very slender, articulation none or indistinct, without oscillating movement. LEPTOTHEIX TENAX, Wolle. Stratum sometimes expanded, attached to submerged stones, forming loosely interwoven masses, six or more inches in diameter, at other times in small caespitose, pul- vinate clusters on wet rocks. Filaments slender but strong, tough, from one-half to six inches long ; often forming firm membranes. Color of trichomes primarily light aeruginous, but soon changing to a dull yellow or light brown. Articu- lation rarely observed, as long as wide. Sheath close. Diameter of filaments, 3.5-4 yu. Sluggish or stagnant waters, wet slate, and other rocks, from Vermont to Florida. Plate CCIII, figs. 1, 2, from Pennsylvania specimens, six to eight inches long. Described in Bull. Tor. Botanical Club, 1878, as Hypheothrix tenax. LEPTOTHRIX OALCICOLA, Kg. Stratum dull aeruginous ; filaments strongly curved and closely interwoven, rather fragile ; aerial, sometimes form- ing a glossy stratum, more frequently a dull, dark aerugi- nous coating on old walls. Diameter of filaments, 2.25-3.25 //. Syu. Hypheothrix calcicola, Kg. ; Oscillaria calcicola, Ag. ; Leplo- thrix muralis, Kg. Plate CCVIII, fig. 21, stratum slightly enlarged. LEPTOTHRIX AERTJGINEA, ( Kg. ) Kirch. Stratum thin, membranaceous, bright aeruginous ; fila- 21 320 FRESH-WATER ALG^E OF THE UNITED STATES. ments irregularly intertwined ; articulation rather indistinct, somewhat longer than wide. Diameter of filaments, 1.8-2. 25 yw. Syn. Hypheothrix aeruginea, Kg. Ponds, .springs, about basins of thermal water. LEPTOTHRIX HERBACEA, Kg. Stratum somewhat herbaceous green, not so decidedly aerugmous, and not membranaceous as the last. Filaments slightly flexuously curved, upright growth, caespitose, sub- pulvinate ; often faded at the base, while bright green above. Sheath close. The preceding differing only in the strata, the one being thin smooth, membranaceous, and the other more of a loose irregular upright growth. Diameter of filaments, like the last, 1.8-2.25 /*. Very abundant on the wood-work around the artesian well, Charleston, South Carolina. In smaller quantity on wet wood, aqueducts, etc. This species, so much in size and other features like the last named (L. aerug.inea), may be a mere form of it. Plate CCVIII, fig. 13, a caespitose cluster under low power, and part of a filament under high magnification. LEPTOTHRIX HINNULEA, Wolle. Stratum light fawn colored, flocculeiit caespitose, waving, 6 mm thick. Filaments flexible and contractile, indistinctly vaginate, not articulate, 10-15 mm long; light yellow- brown, or colorless. Diameter, 1.25-1.75 /*. In trenches hot waste-water from steam mills. Syn. Beggiatoa hinnulea, Wolle. Bull., Tor. Bot. Club, November, 1877. Plate CCVIII, fig. 5, a flocculent cluster. LEPTOTHRIX CAESPITOSA, Kg. Caespitose, erect, aggregate ; filaments flexuously curved, apices attenuated, dilute aeruginous, later brownish yellow, waving, homogeneous or more rarely indistinctly articulate. Diameter, 2-2.75 /£ ; length, 125-200 yu. Attached to submerged wood or stones. Frequent in ponds and ditches. Plate CCVIII, figs. 11, 12, clusters under low power and parts of trichomes under higher power. LEPTOTHRIX. 321 LEPTOTHRIX TINCTORIA, Kg. Fasciculate-caespitose, about 6 mm (I inch) long-, deep amethyst, or purple-green ; trichomes rigid, equal, distinctly articulate, pale steel blue ; articulations as long as broad ; sheath close, colorless. Diameter of filaments, 1.75-2.25. Attached to submerged plants. Syu. Hyplieoihrix tinctoria, ( Ag. ) Rab. ; Calothrix tinctoria, (Persoon) Ag. Plate CCVIII, fig. 16, a usual appearance. LEPTOTHRIX RIGIDULA, Ag. Stratum composed, usually, of segregate or subapproxi- rnate clusters; light, dilute aeruginous. Filaments fiexu- ously curved, articulate or homogeneous. Diameter of trichomes, 1.25-1.75 yw; length, 100-130 ^. Syn. Leptomitus divergens, Kg. ; Hygrocrocis rigidula. Kg. In stagnant, or sluggish waters, parasitic on aquatic plants. Plate CCVIII, fig. 15. LEPTOTHRIX LAMINOSA, Kg. Stratum often broadly expanded, membranaceous lamel- lose, on the surface aeruginous or olivaceous, below faded yellowish or colorless. Trichomes flexuously curved, inter- woven, and sometimes spirally coiled, homogeneous or arti- culate ; articles subequal. Diameter, 1.75-2/v. Syn. Oscillaria laminosa, Ag. ; Hypheothrix laminosa, Rab. ; Oscil- laria labyrinthiformis, Ag. Stagnant waters, ponds and ditches. Plate CCVIII, fig. 17, a specimen with filaments gently curved ; fig. 18, filaments coiled. LEPTOTHRIX BULLOSA, Wolle. Thallus subspherical, gregarious, dilute straw color or yellowish white. Filaments simple, in part densely inter- woven into very tough globular, or oval, hollow bodies, 4-8 mm in diameter. Trichomes pale aeruginous, often faded and contracted. Diameter 1.5-2. /* ; sheath about twice as wide. In shallow, sluggish waters, Susquehanna River, Harris- burg, Penna. 322 FRESH-WATER AI.G.E OF THE UNITED STATES. Syn. Hpyheoihrix bullosa, Wolle, Bulletin, Tor. Bot. Club, 1877. Have been hesitating whether to place this singular plant here or with Microcoleus. Filaments rarely appear divided, and contain two trichomes (internal), but as a whole the plant has most in character with the present genus. Plate CCVIII, fig. 19, spherical bodies surrounded by loose wool-like threads, natural size, also three fragments of filaments largely magnified. LEPTOTHRIX OCHRACEA, Kg. Forming cloud-like, floating, fragile masses of an ochery color. Trichomes very slender, in short, fragmentary parts, scattered. Not articulate. Diameter of trichomes, about 2 yw. Syn. Lyngbya ochracea, Thur. ; Conferva ochracea, Dillw. ; Oscil- latoria ochracea, G-rev. Not infrequent in small pools, produced in rust colored cloud-like masses. The filaments are very slender and usually scattered in broken fragments. A very insignifi- cant form, and of doubtful value. Dillwyn represents the filaments branched ; so are most of our specimens. Sheaths and articulations indistinct. The whole seems more in character with a filamentous lichen, than an algae. Prevails in small pools from Massachusetts to Florida. The position given this plant by Thuret, Kirchner and others, does not appear justifiable, unless the European form is quite distinct. Dried specimens do not appear unlike ours. Plate CCII, figs. 32, 33, filaments sometimes decidedly branched ; Plate CCVIII, fig. 14, filaments simple. Genus ASTEKOTHRIX, Kg. Filaments indistinctly or sometimes distinctly articulate, more or less rigid ; cruciformly branched, nude, ends acute cuspidate or obtuse, somewhat genuflexuous. Propagation unknown. ASTEROTHRIX CREGINII, Wolle. Filaments short, light bluish green ; branches at right angles, cross-like; articulation usually distinct, somewhat moniliform. Diameter of filaments, 2-4 yu. Found thickly scattered through a deposit of fine siliceous sand in Norton County, Kansas. Reported by Prof. F. .W Cregin. ASTEROTHRIX. 323 A peculiar form, seems fitly placed with this genus, although unlike any of the three species named by Raben- horst. For the establishment of a good species corrobora- tive specimens are desirable. Plate CCIX, figs. 22-25, filaments in their normal appear- ance under a magnification of 500 diameters. ASTEROTHRIX PERTYANA, Naeg. A form much larger than the preceding and otherwise distinct, is described by Naegeli, found with Confervae in Switzerland. The figure is transcribed to close a vacant part of Plate CCIX, figs. 20, 21. Genus 106, SPIRULINA, Link. Trichomes articulated, spirally twisted, more or less motile, OsciUaria-\ike, usually surrounded by a somewhat liquid, color- less mucilage. SPIRULINA JENNERI, Kg. Trichomes solitary or in interwoven masses, distinctly articulated, spirals lax, a turn occurring in every 20-24 /< ; cells about as long as wide ; color light or darker aeruginous. Diameter of trichomes, 7-8 yw. Syn. Spirillum Jenneri, Hass. ; Arthrospira Jenneri, Hedw. In stagnant waters, usually only solitary filaments. Plate CCX, fig. 2, two short parts of trichomes. SPIRULINA TENUISSIMA, Kg. Trichomes very thin ; flexuous, densely or more loosely spiral, endowed with active motion, joints indistinct, form- ing a lubricous stratum, light aeruginous, on the bottom of warm sulphur springs. Diameter of spirals, 4-5 yw, making 5-7 turns in space of 25 A/. If not strictly identical in every particular with the Euro- pean forms described under this name, our plant is very near to it, and entirely unlike all others. Frequent in sulphur springs, Clifton, New York, and Glen Cove Springs, Florida. Plate CCX, fig. 3. SPIRULINA DUPLEX, Wolle. Trichome a slender, flat, strap-like, continuous band. When untwisted forms a complete ring. Normally it is 324 FRESH -WATER ALG^E OF THE UNITED STATE*. flattened and twisted, with 1-4 or more turns. Breadth ol band (trichome) 2/^; length, when twisted, 75-200 yw. Frequent in pool near Minneapolis, Minnesota. Plate CCX, figs. 4, 5. Genus 107, SPIKILLUM, Ehrb. Trichomes short filiform, imperfectly articulated, spirally twisted, curved snail-shell-like or sub-cylindrical. SPIRILLUM UNDULA, ( Muell. ) Ehrb. Trichomes short, rather stout ; twisted, making 1-1 2 turns, hyaline, distinctly articulate. Stagnant pools. Plate CCX, fig. 1. Family XIX.—CHROOCOCCACEJE. Unicellular forms of plant -life, which divide into daughter cells and separate, forming families involved in a mucous, or gelatinous, amorphous thallns. Cells divide and redivide through many generations. All the forms of this family are probably mere conditions of development of higher forms. Many of them are thus clearly connected with filamentous plants, as shown on the preceding pages, but others have not been so satisfactorily traced to their origin or to their, destiny ; we therefore retain the older classifi- cation as a means for reference to the various forms. Some of these unicellular forms run through many, even to hundreds of generations, before reproducing the original plant; and often before the whole cycle is complete, conditions of tem- perature, moisture or other essential prove adverse to develop- ment, they pass away without reproducing. Artificial cultiva- tion is attended with so many difficulties, little has been gained by many earnest efforts. The life- history of the plants needs to be studied in their own haunts. Genus 108, GLOEOTHECE, Naeg. Cells cylindrical, oblong, rounded at the ends; cells divide transversely into two nearly spherical daughter cells. The cells occur singly or two or more included in a vesiculiform, colorless tegument. After repeated division, one family with tegument may occur within another enlarged tegument also with family. SYNECHOCOCCUS. 325 GLOEOTHECE CONFLUENS, Naeg. Stratum gelatinous, usually pale reddish yellow, or green- ish j cells mostly single; sometimes two in a tegument, 11-2 times as long as wide before division ; later often nearly spherical ; cytioplasm greenish, tegument wide, colorless. Diameter of cells, 1. 6-2.25 yw; with tegument, 9-10 /A On wet rocks. Plate CCX, fig. 6. This and other forms of the genus are conditions in the development of Sirosiphon and ftteytonetna. Compare Plates CLXXXIV, CXC and CXCI. Genm 109, APHANOTHECE, BTaeg. i Cells longer than broad, near the last (Gloeofhece), but having the teguments usually confluent, forming a rather firm gelatinous body in which the cells are imbedded. APHANOTHECE PRASINA. A. Br. Thallus gelatinous more or less globose, tuberculose, size of a cherry, usually floating, dark bluish green; cells 1-1-2 times as long as wide, aeruginous or light bluish green. Cells 4-6 j.i wide by 8-11 yu long. Syn. Coccochloris stagnina, ( West, and Wall. ) Bab. ; Apkctno- thece Mooreana, Lagerh. ; Palmetto, Mooreana, Harv. See page 193. Plate CCX, figs. 9, 10, a thai 1 us, and single cells. APHANOTHECE PALLIDA, Eab. Thallus gelatinous, soft, 1-6 mm thick, forming small masses; light green with a tint of blue, cells elliptic, 11-3 times as long as wide, pale aeruginous. Diameter of cells, 3.5-8.0 //. Syn. Palmella pallida, Kg. On wet, or marshy ground, Pennsylvania. Plate CCX, figs. 7, 8, a thallus and individual cells. Genus 110, SYXECHOCOCCITS, Naeg. Cells elongated or cylindrical, membrane thin, singly, or in series of two or more. 326 FRESH-WATER ALG.E OF THE UNITED STATES. SYNECHOCOCCUS AERUGINOSUS, Naeg. Cells 13-2 times as long as broad, solitary or two joined end to end ; cytioptesm aeruginous. Diameter of cells, 7-16 /^. On wet rocks. Plate CCX, fig. 11, a number of cells variable in size. Genus 111, MERISMOPEDIA, Meyen. Cells globose, or at the time of division oblong, 4, 8, 16, 32, 64, or 128 associated in tabular families of a single stratum, forming a quadrate, plane, free swimming thallus. MERISMOPEDIA GLAIKIA, Naeg. Thallus more or less limited, light aeruginous or some- times glaucous green. Cells globose, or more or less oval or oblong as they approach division. Thallus composed of 4-64 cells, rarely more. Diameter of cells, 3-5 /j. Syn. Gonium glaucum, Ehrb. ; Mer. nova, Wood. Not infrequent in ponds or sluggish waters. Plate CCX, figs. 12-15, various sizes of cells, not different species, but conditions of the same plant. MERISMOPEDIA CONVOLUTA, Breb. Thallus membranous, visible to the unaided eye, more or less folded or convolute ; families often composed of 256 geminate cells, arranged in subfamilies, sometimes two of these families conjoined with a composite family ; cells spherical or oblong. Cytioplasm homogeneous, bluish green. Diameter of cells, 4-4.5 ^. Shallow pools, forming a distinct layer upon the muddy bottom, or separating and then floating on the surface. Plate CCX, fig. 14. may represent a small family of 64 cells. A thallus often contains hundreds of these. European works describe numerous species separated by no more distinctive features than sizes of cells, and of fami- lies, or color of cytioplasm, as molacea, aeruginea, and ochracea, all of which appear to represent mere conditions of the same plant. GOMPHOSPHAERIA. 327 Genus 112, COELOSPHAEBIUM, Naeg. Thallus spherical, vesicular, hollow ; containing many small cells which are associated in families or scattered at the periphery, immersed in a mucous stratum. Multiplication takes place by means of the peripheral cells, which enlarge and escape through the external membrane and develop daughter cells; also by the constriction and division of maternal cells. COELOSPHAERIUM KUETZINGIANTJM, Families spherical, cells globose or subglobose, geminate, or quaternate or scattered, loosely disposed ; cell contents aeruginous, delicately granulose. Diameter of cells, 2-5 ^- ; families 60 JA more or less in diameter. In ponds and pools ; stagnant waters. Plate CCX, fig. 16. Genus 113, CLATHKOCYSTIS, Henfr. Thallus, a microscopic gelatinous body, primarily solid, then saccate and later clathrate ; fragments of the broken thalli occurring in irregularly lobed forms, composed of a colorless matrix in which are imbedded large numbers of very small cells. Multiplication takes place by the division of the cells within the thallus as it increases in size. CLATHROCYSTIS AERUOINOSA, Henfr. Cells aeruginous. Families singly, or a number united forming a thallus which soon becomes largely perforated, breaks and then dissolves. Often floating in large strata as a glaucous green scum on fresh water pools. Diameter of cells, 2.5-3.5 /*; families, 30-130 //. Syn. Microhaloa aeruginosa, Kg. ; Microcystis Ichthyoblabe, Kg. ; M. ichthyolabe, Breb. ; Polycystis aeruginom, Kg. Plate CCX, figs. 17, 18, two perforated thalli ; fig. 19, when dissolved the cells float in mass. Genus 114, GOMPHOSPHAEE1 A, Kg. Cells wedge-shaped, peripheral 2-4-8 associated in radiating families, nestling in jelly, covered with a tegument and forming a globose, free swimming thallus. Cells divide alternately in three directions, 328 FRESH-WATER ALGvE OF THE UNITED STATES. GOMPHOSPHAERIA APONIA, Kg. Thallns microscopical, at first light, or darker aeruginous, but soon fades or changes to a yellow, or orange color, (var. aurantiaca, Bleisch). Diameter of cells about 4 yw ; length, 10 ^ ; diameter of family, 50-75 yw. Frequent in small pools. Plate OCX, fig. 20, two developed forms ; figs. 21, 22, young conditions. Genus 115, MICKOCYSTIS, Kg. Cells very small, numerous, densely aggregated into globose bodies, surrounded by a thin membrane, forming families, usually single, but rarely several surrounded by a universal tegument ; cell division in three directions alternately. A condition of frequent occurrence in the process of develop- ment of higher forms, specially of Scytonema and Sirosipkon. MICROCYSTIS PROTOGENITA, (Bias. ) Eab. An old name which may be applied to various forms which would come under this genus. The families are ordi- narily subspherical, measuring from 15-75 yu in diameter. Cells, which crowd the teguments more or less, are 4-6.5 /* in diameter ; in color primarily aeruginous, but changeable to light yellow, to orange, and sometimes to purple. Occurring on moist timbers, outside of old water tanks, moist ground, and trunks of trees. All of them are evi- dently mere conditions of development of higher plant-life. Confer with figures of Scytonema and ftirosiphon, Plates CLXXXVII; CLXXXVI; CXCI. . * Plate OCX, fig. 23. Genus 116, ANACYSTIS, Menegh. • Cells spherical, innumerable in mucous strata ; primarily the cells are enclosed in smaller families, by very delicate teguments which quickly dissolve, and are only rarely visible. The forms of the present genus differ from those of the last ( Microcystis ) in not having the families so distinctly separated, and enclosed in so firm teguments. The former are solitary or gregarious, the latter are united, massed together. The former is easily traceable in its life-history ; the latter is very uncertain. ANACYSTI8. 329 ANACYSTIS PULVEREUS (Wood) Wolle. Cells very small, whitish-blue-green, irregularly subglo- bose, oval or angular, associated in families. Thalli com- posed of very numerous and densely crowded families, irregular, sometimes confluent, mostly surrounded by a false hyaline tegument ; aggregated into a bright glaucous, or whitish-blue-green pulverulent stratum. Diameter of cells, 2-3 yw. Syn. Anacystis glauca, Wolle ; Pleurococcus pulvereus. Wood. Forms an extended stratum over the bottom of limestone springs. The stratum is in places nearly an inch in thick- ness, and when lifted by the hand is found to be loose and crumbly. Found by Dr. Wood in Centre County. Found in abundance also in Northampton and Lehigh Counties, Pennsylvania, where limestone springs abound. Plate CCX, fig. 25, imperfectly represents a small part of a stratum. ANACYSTIS MARGINATA, Kg. Families usually globular, sometimes flattened, often many united, and flowing together, surrounded by a thin colorless tegument. Cellules crowded, spherical, but sometimes by mutual pressure, somewhat angular, light aeruginous. The margins of the families colorless. Diameter of cellules, 3-4 ^ ; families, 80-300 yw. Found in ponds of stagnant waters. Syn. Mycrocystis marginata, Kirch. ANACYSTIS BRUNNEA, ( Naeg. ) Wolle. Thallus gelatinous-membranaceous, light brown. Cells, single or twin, crowded, tegument false, or diffused ; cytio- plasm pale yellowish-brown, or greenish-brown ; finely gran- ular. Cells very small, 1 /* diameter ; families 4-10 ^ ; often much more in diameter up to 50-60 yu. The whole forming brownish olive floating masses in stagnant waters. Syn. Palmella brunnea, A. Br. ; Aphanocapsa brunnea, Naeg. This form is not quite identical with Naegeli's descrip- tion ; it is very near. I adopt the name to avoid a new term for a very vague condition. Later observations show this form to be an old condition of dathrocystte. 330 FRESH-WATER ALG^E OF THE UNITED STATES. Genus 117, POLYCYSTIS, Kg. Cellules globose, united into spherical families which cluster together, grape-like. POLYCYSTIS ICHTHYOBLABE, Kg. Thallus membranous, aeruginous, or with a reddish tinge ; cells globose, crowded, with light aeruginous contents. Families usually about 50 yu ; sometimes as large as 1 10 /* diameter. Diameter of cells, 2-3 /*. Not frequent ; occasionally in small pools. Plate OCX, fig. 24, a small cluster of family-cells. Genus 118, GLOEOCAPSA, Naeg. Cells usually spherical, or before division somewhat oblong, with wide vesiculiform tegument, this cell undergoing division into two daughter cells. Each has a distinct tegument, the whole being surrounded by the tegument of the mother cell. This process is often repeated, the original tegument remaining and surrounding the family thus formed. Cell membrane often very thick, mostly lamellated ; strata not infrequently separating ; colorless or colored ; cell contents aeruginous, bluish green, steel blue, reddish, yellowish, fuscous, etc. Division in three direc- tions. Eabenhorst, in his Flora Algarum, describes more than sixty forms as species and varieties. These unicellular forms are very changeable in color and in details of construction, number and size of cysts. The same cells may be at one time aeruginous, then change to a light yellow or orange color ; or crimson or scarlet. Sometimes they form a crustaceous stratum, and then they occur in soft gelatinous masses, so abundant, they may be stripped from dripping, partially shaded rocks, by handfuls. Occurring in so many different conditions, and varying so much under different circumstances, it may be readily conceived how the many stages of development, found at different times and by different persons, gave rise to the record of the many forms as species. It is now clearly evident that all of these so-called unicellular plants constitute nothing more nor less than conditions in the plant-life of higher forms. This fact has already been shown under the head of Sirosiphon ; also illustrated on Plates CXC ; CXCI; CXCIV 5 CXCV. They are the spores, or macrogonidia GLOEOCAPSA. 33 1 of forms of Sirosiphon; they have their origin in the filaments, and again develop the same forms. Similar cells may occur also in the development of plants of other genera, as tiw/tonema ; (compare Plate CLXXXIV, fig. 41 ), but they appeal- specially confined to Sirosiphon. In the process of development there are several modes, the one more direct than the other. The former is shown on Plate CXCV, figs. 5-9, also on Plate CXCIV, figs. 4-10 ; the other in- volving the same principle yet more indirect. The microgonidia, scattered by the decay of the membranes of the cells of the fila- ments, begin to develop and soon present an appearance as Plate CXCI, figs. 15, 16. These small, almost colorless cells, grow and produce larger cells, with a single central nucleus (fig. 17), which next divides and they appear with two nuclei or cells ; these develop into the full-grown cells, (figs. 19, 20). Plate OCX, figs. 26-31, illustrate more fully the advancing stages of growth of Gloeocapm magma, (Breb.) Kg., from micro to macrospores. We take these as good representative forms, to serve to illustrate a few of the species (!) which have been re- corded by various authors ; many differing only in color, which in itself can not be taken as a characteristic feature. It is too inconstant. A few of the forms of this genus may be quoted for illustration, as follows : GLOEOCAPSA MAGMA, ( Breb. ) Kg. Forms a grumous thallus, purplish brown ; teguments coppery brown, or brownish red ; central cell aeruginous. Plate CCX, figs. 26-31. GLOEOCAPSA POLYDERMATICA, Kg. Thallus gelatinous dirty green or olive, becoming brownish. Tegument hyaline, lamellose. Cell (central) aeruginous. Plate COX, figs. 29-31, represent the features, not color. GLOEOCAPSA CORACINA, Kg. Thallus crustaceous, nearly black ; tegument very pale violet, distinctly lamellose ; cell aeruginous. GLOEOCAPSA AERUGINOSA, ( Carni. ) Kg. Thallus crustaceous, glaucous green ; teguments thick colorless, rather indistinctly lamellose ; cells aeruginous. Plate CCX, figs. 27, 28, differing in color from the others. 332 FRESH-WATER ALG^ OF THE UNITED STATES. GLOEOCAPSA RALFSIANA, (Harv. ) Kg. Thallus gelatinous, dark purple brown ; tegument intense purple brown ; cells light aeruginous. Plate OCX, figs. 29-31, merely a change of color. GLOEOCAPSA SHUTTLEWORTHIANA, Kg. Thallus gelatinous, dark rufous brown, tegument thick, orange red to pale orange, rarely colorless ; cells pale aeru- ginous. GLOEOCAPSA SANG-UINA, ( Ag. ) Kg. Thallus effused, gelatinous, blood red, becoming blackish brown. Tegument intense blood red, in the middle pale red, extremes colorless ; cell aeruginous. Plate OCX, figs. 29, 30, another change in color. GLOEOCAPSA RUPESTRIS, Kg. Thallus dark brown, crustaceous, rather hard. Tegument thick, lamellose, yellow, golden brown, or becoming pale and colorless ; cells aeruginous. Figs. 27, 28. GLOEOCAPSA ARENARIA, Kab. Thallus mucous, somewhat olive colored. Tegument thick, spherical, colorless, somewhat lamellose ; lamella diffluent. Cells aeruginous. Plate OCX, figs. 22, 28, well represent the form of this condition. GLOEOCAPSA ATRATA, Kg. Thallus crustaceous, mucous, black. Tegument thick, hyaline ; 2-3 times broader than the central, aeruginous cell. Plate OCX, figs. 27, 28, differing in thallus from others- older conditions. GLOEOCAPSA SPARSA, Wood. Scattered in a mucous stratum composed of various algae. Inner tegument yellowish brown, rarely colorless or lamel- late ; external tegument achromatic, scarcely visible. Plate OCX, figs. 29-31, only another condition of 6r. magma. Beside these forms 1 find notes scattered on the pages of my Sketch-books, covering observations for more than ten years, of at least ten to twenty more forms identified with APHANOCAPSA. 333 forms in Rabenhorst's long list. They have no value avS plants, hence do not name them. The above are briefly quoted to show how easily species may be multiplied by a too close notice of non-essential phases. As we have a number of species of tiirosip/ion, from vari- ous habitats as moist rocks, trunks of trees, earth and water, it is but reasonable to suppose that the macrogonidia may vary as well. The large quantities observed belong to >V. pulvinatus. Macrospores of other species of 8irosiplion were too few to enable us to determine any distinctive fea- tures. A general and variable character appears common to all of them. Genus 119, APHANOCAPSA, Naeg. Cells spherical, with a thick, soft colorless tegument, confluent in a homogeneous mucous stratum ; cells divide as in Gloeocapsa. APHANOCAPSA GREVILLEI, (Hass. ) Rab. Thallus gelatinous, globose, densely aggregated, more or less confluent, dirty green, from olive to brownish with age and when dry ; cells spherical or elliptic, somewhat crowded, singly or in pairs ; tegument quickly diffluent ; cytioplasm light aeruginous. Diameter of cells, 3.5-5 yw. Syn. Coccochloris Grevillei, Hass.; Palmella botryoides, Grev. ; Palmella Grevilleij Berk. ; Botrydma Grevillei, Menegh. ; Byssus botryoides, Huds. ; Pleococcus Grevillei, Trevis. Submerged stones, in shallow pond water. Plate CCX, figs. 38, 39, a small thallus, natural size, and a cell greatly magnified. APHANOCAPSA VIRESCENS, Rab. Thallus gelatinous, more or less expanded, dirty green or olive, becoming brownish ; cells rather pale aeruginous, scat- tered singly or some in pairs. Tegument rather indistinct. Diameter of cells, 5. 5 /*. Syn. Sorosporlum virescens, Hass. ; Aphanocapsa parietina, Naeg. On wet stones or rocks. Plate CCX, fig. 33, part of a thallus, natural size; figs. 34-37, cells greatly magnified, which are referred with some hesitancy to this species. They were found separated from the thallus, floating in pond of somewhat stagnant water. They are not unlike the teguments and cells which make up the thallus, but larger. 334 FRESH-WATER ALG.E OF THE UNITED STATES. Genus 120, CHEOOCOCCUS, Naeg. Cells spherical or more or less angular from mutual pressure ; solitary, or united in small families, without being enclosed in a distinct tegument. Cell contents aeruginous or pale bluish green, also yellow and orange. Propagation by division, alternately in three directions. The cells represented under this genus are more simple than those of Gloeocapsa, and not so numerous. Eabenhorst describes 25 ; Kirchner 9, and Cooke in his British Algce, has only two. They are not of rare occurrence, usually in- termingled with other forms to one or the other of which they are evidently related. Dr. Itzigsohn, in his superb work on the Life-history of Hapalosiphon (1853), shows that Chroococcus cells are closely related to this plant, and then remarks : "I have observed these dimorphose Chroococcus cells associated with species of Tolypothrix, and believe that all the forms described as Chroococcus, are nothing more or less than spores of Nostocece.'' Dr. Hansgirg of the University of Prague, also, in a recent paper (1885 ) of fifty pages on the Polymorphisms der Algen, shows that almost all, if not every one, of the forms of the family of Chroococcacea ?, Eab., including Chroococcus, Naeg. ; Gloeocapsa, (Kg. ) Naeg. ; Aphanocapsa, Naeg. ; Synechococcus, Naeg. ; Gloeo- thece, Naeg., etc., are closely related to more highly developed forms ; that is to say most, if not all of the so-called unicellular aeruginous algae, Cyanophycece. have their origin in filamentous plants breaking up into single cells like those which develop them. Dr. Hansgirg' s paper (German) commends itself as a very valuable contribution to all interested in the study of the mor- phology and life-history of Fresh-water Algae. As an illustration of the forms known as Chroococcus, several species are quoted. CHROOCOCCUS TURGIDUS, Naeg. Cells spherical, oblong ellipsoid, or more or less angular from compression ; single, twin, ternate, or quaternate (rarely eight ) associated in families ; tegument thick, often somewhat lamellate ; colorless. Cell membrane thin. Cell contents primarily bright aeruginous ; later becoming brownish. Diameter of cells, 13-25 yw. Syn. Protococcus turgidus, Kg. ; Haematococcus binalis, Hass. ; Chroococcus multicolor atus, Wood. CHROOCOCT'US. 335 On moist rocks, and other wet places. Plate COX, figs. 40, 41. CHROOCOCCUS RUFE&CENS, (Breb.) Naeg. Stratum mucous, brown- yellow ; cells spherical, or oblong, 2-4 consociated into families. Tegument colorless; eytio plasni finely granular, reddish, or yellowish brown. Diameter of cells, 12-16 /*. Moist rocks. Syn. Pleurococcus rufescens, Breb. ; Protococcus rufescens, Kg. Plate OCX, fig. 43. CHROOCOOCUS COHCERENS, Naeg. Cells oblong ; twin, or in fours with a distinct hyaline tegument. Cell membrane thin. Oytioplasm blue-green. Diameter of cells, 3-6 j*. Syn. Protococcus coliorrens, Kg.; Pleurococcus coha'rens, Breb.; C. refractus. Wood. On damp walls, rocks, etc. Plate OCX, fig. 42, different forms and sizes of cells. CHROOCOCCUS THERMOPHILUS, Wood. These cells were found in connection with Hydrurus occi- dentaliSj Harv. (Nostoc calidarium, Wood) and are probably the macrogonidia of Hydrurus. Benton Springs, Owen's Valley, California. 22 ADDENDA. A FEW specimens received while the preceding pages were passing through the press, call for the following few notes. Class RHODOPHYCE^E. Genus GELIDIUM, Lam. • Purple or red sea-Veeds with a cartilaginous or horny, opaque frond, without joints. Fronds flattened, irregularly branched. GELIDIUM CORNEUM, Lam. Fronds flattened, rigid, several times pinnate ; a very variable plant about an inch in height, (Pacific Coast plants 3-4 inches high). Spores imbedded in irregular clusters near the ends of the branches. Twelve or more varieties of marine forms of this specie's have been described, but none affecting inland waters. F. A. Anderson collected specimens in a rapid mountain stream, Montana. They were attached to river stones. The speci- mens received were small in size and limited in number; more have been requested for confirmation of our identifi- cation, but cannot reach us in time for notice on these pages. Seems but reasonable that where Enteromorpha abounds, Gelidium may flourish also. Class CHLOROPHYCE^L. DOCIDIUM EHRENBERGII, Rail's. V. Des. TJ. S., p. 159. Diameter 10-12 times longer than broad, having usually two, or rarely three slight inflations at the base of the semi- cells ; ends truncate, bordered by three to five minute tuber- cles which give the end view a crenate appearance. Empty 338 FRESH-WATER ALG.E OF THE UNITED STATES. cells show they are punctate ; rarely distinctly granulate. Semi-cells very slightly tapering from the base to the apex. Diameter of cells, 20-22 yw, about twelve times longer than broad. Measures taken from cells distinctly granulate, collected by A. C. Stokes in Cypress Swamps, Florida. CLOSTERIUM NASUTUM, Nord. Y. Des. U. S., p. 41. Specimens of this species from Cypress Swamps, Florida, appear perfectly straight and somewhat thicker and longer than the forms heretofore noted. Apical vacuole distinct. Chlorophyl arranged in five or six fillets ; centrally sep arated. Diameter, 83 // ; length, 7 times more than the breadth. Collected by A. C. Stokes. MICROSTERIAS FiMBRiATA, Ealfs. V. Des. U. S., p. 109. Fruiting specimens, not heretofore observed, were received from Rochester, New Hampshire, collected by W. N. Hastings. The plants are uniformly smaller than the measure given (Des. IT. S., p. 110), measuring only 125 yw, but corresponding with the smaller measures of Ralfs, Rabenhorst and Kirchner. Thev have much in common, »/ in form, with M. papillifera as figured by Cooke ; but this species is bordered with papillae, not sharp teeth, and the granules at the margins of the lobes are papillae, not distinct spines, as in M. fimbriata. Zygospores are orbicular, spinulose ; spines rather slender, elongate, scattered, mostly furcate at the ends, and some- times notched below the middle ; furcate ends, with tips recurved. Diameter of cells, about 125 /* ; length slightly more ; zygospores average 75 yw, without spines ; 125 //. with spines. ENTEROMORPHA INTESTINALIS, var. PROLIFERA, Ag. To page 107 may be added this variety. Have fine speci- mens, collected by F. W. Anderson in a rapid stream, 4000 to 5000 feet elevation, Montana. Primarily it is attached to river stones ; later floating in masses. Prevails also in salt marshes, Nebraska. — C. E. Bessey. CHAETOPHORA ENDIVIAEFOLIA. See page 117. This form is reported from Montana, very common every- where. ADDENDA. 339 TETRASPORA OYLINDRICA, Ag. See p. 190. Sometimes attains extraordinary dimensions. F. \\r. Anderson reports it from Montana as forming- in a mountain torrent (Belt River), long jelly-like fronds, very slippery and easily ruptured ; length varies from one to ten feet ; diameter from a slender thread to an inch or more wide; bright green. In connection with this plant-form, Mr. Anderson relates the following: There is a species of garter snake peculiar to the moun- tains, that just gorges itself upon this plant; grasping with its extended jaws an end of a long tube it draws it in little by little until perfectly full, then most amusingly it will shake it as a little terrier will shake a rat. These snakes are seldom over two feet long ; to see them tussling with a long slippery alga many times longer than themselves, in the swift current, is quite ludicrous. CLADOPHORA CALLICOMA, Kg. Filaments much, and often fasciculately branched, ordi- narily 8-16 cm long, bright yellowish green; cells cylin- drical, six to sixteen times longer than thick ; membrane rather thin ; cytioplasm somewhat loose, irregularly spir- ally arranged. Spore-bearing cells usually only one-half a-S long as the sterile cells. Diameter of stems, 50-70 /* ; branchlets, 22-25 ^. From rapid waters mountain stream, 40(10 to 5000 feet elevation, Montana. Collected by F. W. Anderson, who reports it forming, and growing in long ropes 3-10 feet long, undulating in the flowing water and beautifully waving its lateral branches. GLOSSARY, Acautescent. Stemless, or apparently so. Acaulis. Stemless. Achromatic. Colorless. Acicular. Needle-shaped. Aculeate. Prickly ; beset with ticulei. Acuminate. Tapering to a point. Aeru-ginons. Of the color of virdigris; blue green. A gamo-hypnospores . N e u t ral 1 y for i n e d resting spores. Agamospore. Spore formed neutrally without fecundation. Agamosporous. Bearing spores without fecundation. Agamous. Destitute of sexes. Agglomerate. ) Heaped or crowded into a Aggregate. J dense cluster, but not co- hering. Alternate. Two organs so placed as not to be opposite to each other. Amoeboid. Resembling an amoeba. Amorphous. Without definite form. Amylaceous. Resembling starch. Anastomose. The opening of one vessel into another, applied to threads or tubes which become confluent, and form an irregular net-work. Androgonidia. Peculiar zoogonidia pro- duced by female plants from which male plants are developed. Androsporangium. Sporangium enclos- ing spores of male plants, or andro- spores. Androspore. A special kind of zoos pores produced in cells, which originate the dwarf males in Oedogonium. Annulate. Marked with rings. Antheridia. Certain reproductive organs supposed to be analogous to anthers or fecundative. Antrorse. Directed upward or forward. Apical. Relating to the apex or tip. Apiculate. Ending with a short point. Appressed. Lying flat against or to- gether for the whole length. Arcuate. Bent like a bow. Areola. An angular space with an ele- vated margin. Articulate. Composed of joints. Asperous. Rough to the touch. Axile. Relating or belonging to the axis. Axillary. In or relating to an axil. Azygospore. Spore produced without copulation. Barbate. Bearded ; beset with long and weak hairs. Base. The extremity by which an organ is attached to its support. Bi or Bis. As a prefix to Latin words, two, twice or doubly. Bicornate. Two horned. Bidentate. Having two teeth. Bifid. Two cleft. Bifurcate. Two forked. Bilobed or bilobate. Of two lobes, or cleft into two segments. Binate. In pairs. Botryoid. In clusters, like a bunch of grapes. Bullate. Blistered or puckered. Caespitose. Growing in tufts, witli many stems from one root. Caeruleus. Sky blue or pure blue. Canalicaulate. Channeled or with longi- tudinal grooves. Capillary. Thread-like, resembling hair. Capitate. Head-shaped, or collected in a head. Carpogon. See Oogonia. Carpospore. Spoi'es produced (by conju- gation) in a sporocarpium. Cartilaginous. Hard and tough like car- tilage. Cauloid. Resembling, or analogous to, a stem. Caulescent. Having an obvious stem. Cellulose. The material, chemically con- sidered, of which the wall of the cell consists. Chlorophyt. The green coloring matter of leaves, and of green algae. Chlorophylose. Resembling chlorophyl- green. Ciliate. Furnished, or fringed with hairs. Ciliutn, cilia. Hairs or bristles placed marginally. Cinereous. Ash-gray. Circinate. Curled round, coiled or spir- ally rolled-up. 342 GLOSSARY. Circumscissilc. Cut round transversely. Clados. Greek for branch, whence Chladophora, branch-bearer. Clathrate. Latticed, or perforated like a window. Clavate. Club-shaped. Coenobium. A community of a definite number of individuals united in one body. Cotno. Literally a head of hair. A tuft of hairs of any kind. Concentrically. In rings, with a common center. Cordate. Heart-shaped. Confluent. Blending- into one; passing by degrees the one into the other. Connate. United congenital ly. Continuous. The reverse of articulated or interrupted. Contorted. Twisted; or bent or twisted on itself. Corniculate. Furnished with a little horn. Coriaceous. Of a leathery consistency. Corrugate. Wrinkled or in folds. Cortex. Rind or bark. Corticate. Coated with a bark or with an accessory bark-like covering. Crenate. Notched or scalloped. Cruciate. Cross-shaped. Crustaceous. Hard and brittle, or form- ing a crust. Cuneate. Shaped like a wedge. Cuspidate. Tapering gradually to a sharp stiff point. Cyathiform. Cup-shaped ; in the form of a goblet or wine-glass. Cylindrical. Elongated and with cir- cular cross-section; in the form of a cylinder. Cytioderm. Cell membrane. Cytioplasm. Cell contents. Decompound. Several times compounded or divided. Decussate. In pairs alternately crossing. Deflexed. Bent or turned abruptly down- ward. Dehiscence. Splitting into regular parts. Denticulate. Minutely toothed ; having denticulations or diminutive teeth. Derma. Greek for skin or surface of a plant or organ. Diaphanous. Nearly transparent. Dichotomous. Forked equally. Diffluent. Readily dissolving. Dioecious. When the male organs are borne on one plant and the female on another. Disciform. Depressed and circular, like a disc or quoit. Dissepiment. A partition or division. Dorsal. Relating to the dorsum or back. , Echinate. Beset with bristles. Ellipsoidal. Nearly elliptical. Emarginate. With a notch cut out of the margin. Encysted. Enclosed in a cyst or bladder. Endochrome. Coloring matter of cells. Endophytal. Growing within plants. Endosmose. The inward current between fluids of different densities when sep- arated by a membrane. Endospore. The inner coating of a spore. Epigynou*. Seated upon the female plant, Epiphytal. Growing upon plants; para- sitical. Epizoic. Growing upon animals. Eccentric. Out of the center; one-sided. Exserted. Protruding beyond or out of. Extrorse. Directed outward. Exosporium. The outer membrane or the coat of a spore. Falcate. Scythe-shaped or sickje-shaped. Fascicle. A little bundle. Fasciculate. In little bundles from a common point. Fastigiate. Said of branches when par- allel, clustered, and erect. Fevrugineom or ferruginous. Colored to imitate iron-rust. Fibrillose. Furnished or abounding with fibers or fibrils. Fibrous. Composed, or of the nature of fibers. Filiform. Thread-shaped, long, slender and terete. Flagellifonn. Like a whip-lash. Flavescent. Yellowish or pale yellow. Floccose. Bearing or clothed with locks of soft hairs or wool. Fulvous. Tawny; orange yellow and gray mixed. Furcate. Forked, or divergently branch- ed. Geminate. Twin; in pairs; two side by side. Geniculbi1<>. Movable. Moni/it'orin. Necklace-shaped, contracted at regular intervals. Monwioux. With male and female or- gans on the same plant. Mucilaginous. Slimy ; of the consistency or appearance of mucilage. Mucro. A short and abrupt small tip. Mncronate. Tipped with a mucro. MulticeUular. Composed of many cells. Multifid. Cleft into many lobes or seg- ments. Multipartite. Divided into many parts. r. Dwarf. Nanandrous. Having short, or dwarf male plants. Nodose. Knotty or knobby. Nodulose. Knotted or with swollen joints. Nucleus. The central germ around which a cell is formed. Small spherical bodies contained within spores or other cells. Obcordate. Inversely heart-shaped. Obovate. Ovate with the broader end toward the apex. Ochraceous. Ocher color; light yellow with a tint of brown. Oogonia. An ovarian sac or cell bearing oospores. Oospore. Spores produced in an ovarian sac. Operculuin. A lid ; a top which separates by a transverse line of separation. Ormogon. See Hormogon. Ovate. Of the shape of the longitudinal section of a hen's egg. Papillose; papillate. Bearing or resem- bling papillae, minute nipple-shaped projections. Parasitic. Growing on or in and living upon another plant, or animal. Parenchyma. Compressed on hexagonal cellular tissue. Parenchytnatous. Resembling the cellu- lar tissue termed parenchyma. Parietal. Growing by or to the wall. Parthenogenesis. Production of fertile seed without sexual impregnation. Parthenogonidia. Gonidia produced without fecundation. Patent. Spreading. Pectinate. Pinnatind, with narrow close segments, like the teeth of a comb. 344 GLOSSARY. Pedicellate. Having a foot or stein. Pericarpium. Covering or tegument of fruit. Periderm ; peridermic. The enclosing membrane. Peripheral. The outer portion of a circle. Piliferous. Bearing hairs, hairy. Plicate. Folded or plaited. Plumofte. Like the plume of a leather. Polymorphism ; polymorphic. Havi ng many forms. Primordial. Original, existing from the beginning. Prothallus. The false thallus first formed on germination of a spore. Pseudo-branches. False branches, or re- sembling branches. Pseudo-ramose. Having false branches. Pidveretts; pulverulent. Powdered, as if dusted with powdery matter or minute grains. Pulvinate. Cushion-shaped. Punctate. Dotted, either with depres- sions like punctures, or translucent internal glands. Purpurasceus. Purplish . Pyriform. Pear-shaped. Quadri-radiate. With four radii, or rays. Quaternate. Arranged in fours. Radical. Belonging to or proceeding from the root. Rad leans. Rooting. Radicel. A minute root or a rootlet. RamuluH. A small or secondary branch. Ramulose. Bearing many brauchlets. Recurved. Curved backward or down- ward. Reflexed. Abruptly bent or turned downward or backward. Remform. Kidney-shaped. Replicate. Folded back. Resting-spore. A spore which becomes quiescent, or rests for a time, more or less long before germination. Rhizoid; rhizome. Resembling, or ana- logous to a root. Rostrate. Terminating with a beak. Rugose. Covered or thrown into wrinkles. Saccate. Sac-shaped; baggy. Sraff triform. Barred or crossed like the rounds of a ladder. Srrobiculate. Marked "with little pits or depressions. .Scutate. Buckler-shaped. Sernnd. When parts or .organs are all directed to one side. Segment. One of the divisions into which a plane frond, such as a desmid, may be cleft. Segmentation. Dividing into segments. Segregate. To separate from others, or set apart. Semi. Prefix signifying half. Septum. A partition or division. Septate. Separated by a partition or septum. Serrate. Beset with antrorse teeth. Sessile. Sitting close, without a stalk. Seta. A bristle or bristle-shaped body. Setiform. In the form of a bristle. Sheath. A tubular or enrolled part of an organ, the envelope of filament, etc. Sigmoid. Shaped like the letter S. Sinus (pi. sinuses). A depression or notch. Spermatozoa : sjit-nnatozoids. Thread-like bodies possessed of motion, supposed to have fecundative power. Stiermogonia. Cells which give rise to the spermatozoids. Sjtinose. Furnished with spines, or of a spiny character. Sporangium. A spore case, having spores produced within it. Spore. The analogue of seed in crypto- gams. S/inriferoux. Bearing spores within it. Sporoderm. The coating or covering of a spore. Stellate. Star-shaped, arranged like the rays of a star. Sterile. Barren; destitute of fruit or fruit-bearing cells. Stipe. A stalk, the support of a cell or organ. Stratum. A layer or extended bed. Striae. Fine parallel lines, streaks or grooves. Supporting-cell. The cell below an oogo- nium as in Oedogonium. Swarming spores. See Zoogonidia. Sub. As a prefix means "almost" or " nearly." Subulate. Shaped like an awl. Suture. A junction or seam of union. Tairtiu. Same as fulvous; dark brownish yellow. Tegument. A covering or membrane. Terete. Cylindrical, having a circular transverse section. Tetrad-pores. Certain spores produced in fours. Thallus. A stratum, in place of stem and foliage. Tortuous. Bent or twisted in different directions. Torulose. Almost synonymous with moniliform. Trichogonia. The female reproductive organs in Balrachospermum. Trichogyne. A hair-like receptive organ of reproduction. GLOSSARY. .345 Trie/wine. The thread or filament of fila- mentous algse. 'lYichotomouK. Dividing in threes. Truncate. As if cut off' at the end. TubercMlate. Covered with wart-like pro- jections or excrescences. I'nice/fnlnr. Literally composed of one cell. Vacuole. A small clear space, drop-like, seen in the interior of the protoplasm of a cell. Vagina. A sheath; sheathing. Variety. A sort of modification sub- ordinate to species. Voitricose. Swelling unequally, or in- flated on one side. Vermicular. Worm-shaped. Verrueotst'. Covered with wart-like ele- vations. 1 "crsieolor. Changing color, or of more than one tint or color. Verticil-late. Arranged in whorls. Vesicle. A small bladder or air-cavity. Vibratilc. That moves to and fro, or vi- brates. Whorl. Arranged in a circle round an axis. Whorled. Disposed in whorls. Zoogonidia. Gonidia endowed with active motion. Zoosporangmm. Sporangium enclosing zoospores. Zoospores. Locomotive spores. Zygospore. A spore resulting from con- jugation. INDEX. EXCLUSIVE OF SYNONYMS. FRESH-WATER. — Classi- fication of, . . . 47-50 ANAB^ENA, Bory, . . . 285 sub -genera of, . . 286 " Cupressaphila, Wolle, 288 Flos-aquse, Kg., . . 286 Var. circinalis, Kg., 287 '* aestuarii, Wolle, 287 gigantea, Wood, . . 287 osc'illarioides, Bory, . 288 " stagnalis, Kg., . . 288 variabilis, Kg., . . 288 ANACYSTIS, Menegh., . . 328 " Brnnnea, (Naeg.) Wolle, 329 " Marginata, Kg., . . 329 pnlvereus,(Wood)Wolle, 329 APHANIZOMENON, Morren, . 291 flos-aqu^e, Allman, . 291 APHANOCAPSA, Naeg., . . 333 Grevillei, (Hass.) Rab., 333 APHANOCHAETE, A. Br.,. . 119 " globosa, (Nord.) Wolle, 119 repens, A. Br., . . 119 " verniiculoides, Wolle, . 119 APHANOTHECE, Naeg., . . 325 pallida, Rab., . . . 325 prasina, A. Br., . . 325 APIOCYSTIS, Naeg., . . . 201 Brauniana, Naeg., . 202 ARTHRODESMUS. — See Desmids U. S., p. 95, . . . 35 incrassatus, Lagh., . 35 Var. Cyclacadus, Lagh., 35 notochondrus, Lagh., . 35 pachycerus, Lagh., . 36 triangularis, Lagh., . 36 ASTEROTHRIX, Kg., . . 322 " Creginii, Wolle, . . 322 " Per ty ana, Naeg.. . 323 AUTHORITIES QUOTED, . . vii BAMBUSINA, See Desmids, U. S., p. 24, 21 " gracilescens, Nord., . 21 BANGIA, Lyngb., . . . .54 Atro-purpurea,(Dillw. ) Ag., .... 55 BATRACHOSPERMACEJE, . . 55 BATRACHOSPERMUM, Roth, . 55 " moniliforme, Roth, . 56 Var. atrum, Harv., 57 " confusum, Hass., 57 " Kuehnianum,Rab. 57 " pulcherinum,Bory,57 " setigerum, Rab., 57 " vagum, Ag., . . . 57 Var. keratophytum, Bory, . . . .58 BEGGIATOA, Trevis, . . 318 leptomitiformis, (Menegh.) Trevis, :519 " niveum, Rab., . . 318 BOTRYCOCCUS, Kg., . . . 195 Braunii. Kg., . . . 195 BOTRYDIACE^E, . . . 154 BOTRYDIUM, Wallr., . . . 155 granulatum, Linn., . 155 BOTRYDINA, Breb., . . . 194 " vulgaris, Breb., . . 195 BUI.BOCHAETE, Ag., . . .95 " species of, ... 96 Brebissonii, Kg., . . 99 " crenulata, Pringsh., . 97 " elachistandra, Wittr., . 97 " gigantea, Pringsh., . 99 insignis, Pringsh., . .101 " intermedia, D. By., . 97 " minor, A. Br., . . 101 " mirabilis, Wittr., . 100 nana, Wittr., . . .100 poly and ra, Cleve., . 9S py gmaea, ( Pringsh . ) Wittr., ... 100 rectangularis, Wittr., . 102 repanda, Wittr., . . 102 rhadinospora, Wittr., . 103 " setigera, (Roth) Ag., . 98 " subsimplex, Wittr., . 101 348 INDEX. COLOCYLIXDRUS, (DesmidsU. S., p. 54), 27 44 DeBaryi, Arch.. . . 27 44 cordanum, Breb., . . 27 CALOTHRIX, (A,g.) Thur., . 236 Brebissonii, Kg., . . 238 crustaceum, (Ag.) Wolle, 239 Dillwynii, Hass., . . 237 gracilis, Rab., . . 237 gypsophila, Kg., . . 237 Hosfordii, Wolle, . 239 lacucola, Wolle, . . 239 Meneghiniana, Kirch., 238 Orsiniana, Thur., . . 236 radiosa, (Kg.) Kirch., 238 CHAETOMORPHA, Kg., . . 143 CHAETOPHORA, Schrank. . 115 elegans, Ag., . . .116 endiviaefolio, Ag., 117-338 Var. clavata, Ag., . 117 " cornuta, Rab., 117 44 crassa, Ag., . 117 44 crystallophora, Kg., . 117 4' incrustans, Rab., 117 44 linearis, Rab., . 117 44 ramosissima,Rab. 117 longipila, Kg., . .118 monilifera, Kg., . 118 pisiformis, ( Roth ) Ag. . 1 16 tuberculosa, (Roth) Ag., 116 CHAM.ESIPHON, A. Br. et Grun., 295 confervicola, A.Br., . 295 incrustans, Grun., . 295 CHAXTRANSIA, Fr., ... 58 Hermanni, (Roth) Kg.. 60 macraspora, Wood, . 59 pygmaea, Kg., . . .61 violacea, Kg., . . 59 Var. Beardslei, Wolle, 60 44 expansa, Wood, 59 virgatula, (Harv.)Thur., 61 CHARACIUM, A. Br., . .176 acutum, A. Br., . . 177 ambiguum, Herm., . 177 heteromorphum, Reinsch, . . 178 Naegelii, A. Br., . . 178 Pringsheimii, A. Br., 177 sessile, Herm., . . 177 CHLAMYDOCOCCUS, A. Br.. . 164 nivalis, A. Br., . . 166 pluvialis, A. Br., . 164 CHLAMYDOMONAS, Ehrb., . . 167 hyalina, Cohn, . . 168 CHLAMYDOMONAS, pluviale, Wolle, . 167 pulviusculus, Ehrb., . 168 44 tingens, A. Br., . . 167 CHL.OROPHYCEJE, . xiv, xv, 63 CHROOCOCCACE^E, .... 324 CHROOCOCOUS, Naeg., . . 334 cohoerens, Naeg., . . 335 rufescens, (Breb.) Naeg., 335 thermophilus, Wood, . 335 44 turgidus, Naeg., . . 334 CHROOLEPUS, Ag., . . . 121 aureus, (Linn.) Kg., . 121 Var. corticulum, Wolle, 122 lolithus, (Linn.) Ag.. 122 lichenicolus, Ag., . . 122 moniliforme, Kg., . 123 odoratus, (Lyngb.) Ag.. 122 umbrinum. Kg., . 123 Var. quercinum, Rab.. 123 CHYTRIDIE.E, .... 202 CHYTRIDIUM, A. Br 202 acuminatum, A. Br., . 2()2 globosum, A. Br., . . 203 minus, Lacost etSuring, 203 CLADOPHORA, .... 123 Classification of, . .124 aegagropila, (Linn.)Kg., 129 brachystelecha, Rab., 129 callicoma, Kg., . . 339 canalicularis, Kg.. . 126 crispata, Kg., . . . 126 Var. brachy dados, Kg., 126 44 vitrea, . . . 126 >l navescens, Ag., . . 128 Flotowiana, Kg.. . .126 fluitaiis, Kg., . . 128 fracta, Kg 124 Var. gossypina, Kg., 125 4i horrida, Kg., . 125 " normalis, Rab.. 125 " rigidula, Kg., . 125 44 viadrina, Kg., . 125 glomerata, Kg., . . 127 Var. clavata, Wolle, 128 " genuina, Kirch. . 127 " mucosa, Kg., . 127 " pumila, Bail., . 128 " rivularis, Rab., 127 44 sirnplicior, Rab.. 127 44 sul)simplex. Rab., 127 oligoclona, Kg., . . 126 CL.ADOPHORIXJE, . . . 108 CL.ATHROCYSTIS, Henfr., . . 327 aeruginosa, Henfr., . 327 INDEX. 349 41 t. u CLOSTERIUM, (See Desmids, U.S., •p. 37), . 23 " acerosum, (Desmids, U.S., p. 41), 24 Brebissonii, Delp7, . 24 Dianae, .... 25 Delpontii, Klebs., . . 25 didymotocum, ( Desm ids, U. S., p. 39), . . 25 ensis, Delp., . . 23 juncidum(Desmids, U. S., p. 38), ... 23 " lanceolatum, (Des. U.S., p. 39), ... 24 lineatum, var. costatum, Wolle, . . . 25 " Lunula,(Des. U. S., p. 40), 24 Var. striatum, . . 24 " nasutum, (Des. U. S., p. 41), . . . 338 " prelongum,(Breb.) Delp., 24 " pronum, (Breb.) Delp., 25 " striolatnm, (Des. U. S., p. 42), 24 " subcostatum, Nord., . 24 " turgidum, (Des. U. S., p. 41), . . . .24 COEL.ASTRUM, Naeg., . . 170 cambricum, Arch., . 170 " microporum, Naeg., . 170 Var. speciosum, Wolle, 170 COELOSPHAERIUM, Naeg., . 327 Kuetzingianum, Naeg., 327 COLEOCHAETACVE, ... 63 COLEOOH^ETE, Breb., . . .63 irregularis, Pringsh., . 65 orbicuiaris, Pringsh., . 64 pulvinata, A. Br., . 64 scutata, Breb., . . 64 " soluta, Pringsh., . . 64 COMPSOPOGON, Mont., . . 62 " coeruleus, Mont., . . 62 CONFERVA, Lk., . .140 " abbreviata, Rab., . . 143 affinis, Kg., . . 141 " amoena, Kg., . .140 bomby cina, Ag., . 142 floccosa, Ag., . . 140 Fontinalis, Berk., . 141 fugacissima, Roth, . 141 Var. salina, Wolle, 141 Funkii, Kg., . . .142 " glacialioides, Wolle, . 143 punctalis, Dillw., . .142 rhypophila, Kg., . 143 " " " " " a a CONFERVA, tenerrima, Kg., . 143 " « utricnlosa, Kg., . . 140 vulgaris, Rab., . . 142 CONFER VACEJE, . . . 106 CONFERVOIDE.E, . . . 63 CONJUGATE .... 204 COSMARIUM, (See Desmids IT. S., p. 57), . 27 Americanum, Lagh., . 29 bi return, Breb., (See Dos- mids U. S., p. 86), . 34 Var. Floridense, Wolle, 34 Braunii, Reinsch, . 29 circulare, Reinsch, . . 2S conspersum, (See Des- mids V. S., p. 75), . 31 Var. retusum, Wolle, 31 excavatum, (See Des- mids U. S., p. 77), 3D Var. trigonum, Lagh., 30 " Eloisianum, Wolle, (See Desmids U. S. , p. 85 ) , :',3 " inflatum, Wolle, . 27 " lagoense, Nord., . . 34 lobatulum, Wolle, . 28 " loeve,(See Desmids U.S., p. 62), . . . 30 " microsphiiictum, Nord., 32 Var. parvula, Wille, 32 " octogonum, Delp., . 33 Var. constrictum,Lagh., 33 ocnliferum, Lagh., . 30 Nordstedtii, Delp., . 30 Pardalis, Cohn, . . 31 perforatum, Lund., . 2s " polymorphism, Nord., 31 " pseodotaxichondrnm, Nord ..... 32 " quinarium, Lund., . 32 " rhombusoides, Wolle, 28 Sendtnerianum, Reinsch., 29 sphalerostichum, Nord., 31 subcruciforine, Lagh., . 33 taxichondrum, Lund., :>2 Var. bideiitulum, Lagh., . . . 32 Wolleanum, Lagh., . 29 Var. granuliferum, Wolle, ... 29 CRATEROSPERMUM, A. Br.. . 235 " latevirens, A. Br.. . 235 CRENOTHRIX, Cohn, . . . 293 '•" polyspora, Cohn, . 294 CYANOPHYCEJE, .... 235 CVLTNDROCAPSA, Reinsch.. . I<)4 350 INDEX. CYLINDROCAPSA, amoena, Wolle, 105 EUASTRUM, pectinatum, Breb., . 36 purum, Wolle, . .' 37 ventricosnm, Lund., . 38 Wollei. Lagh., . . 37 Var. quadrigiberum, Lagh., ... 37 EUDORINA, Ehrb 159 " stagnalis, Wolle, . 160 EUGL.ENA, Ehrb., . . . 161 " viridis, . . 161 geniinella, Wolle, CYLINDROSPERMUM, Kg., . coniatum, Wood, flexuosum, Rab., . limnicola, Kg., macrospermum. Kg., 104 292 293 292 292 292 186 tl it II It It DICTYOSPHAERIUM, Naeg., Ehrenbergianum, Naeg., . . .186 " Hitchcockii, Wolle, . 186 reniforme, Bulnh, . . 186 DIMORPHOCOCCTJS, A. Br., . 199 " cordatus, Wolle, . . 199 DOCIDIUM, (See Desmids LT. S., p. 47), . . . . .25 Archerii, Delp., . . 25 " Baculum, . . .26 Var. Floridense, Wolle, 26 Ehrenbergii, (See Des- mids U. S., p. 159), 337 Georgicurn, Lagh., . 26 iiodulosum, D. By., . 26 rectum, Delp., . . 26 verticillatum, (See Des mids LT. S., p. 53), . 27 " Woodii, Delp., . . 26 DRAPARNALDIA, Ag., . . . 108 glonierata, Ag., . . 108 Var. acuta, Ag., . . 108 " genuina, Kirch., 109 " gracillima, Ag., . 109 " maxima, Wood, 109 " remota, Rab., . 108 plumosa, Ag., . . 109 " Ravenelii, Wolle, . .110 spinosa, Kg., . . 109 ENTEROMORPHA, Link, . . 107 compressa,(Linn.)Grev., 107 mtestmalis,(Limi.) Link, 107 Var. prolifera, . . 838 EREMOBIA, .... 175 EREMOSPHAERA, D. By.. . . 200 viridis, D. By., . . 200 EUASTRUM, (See Desmids U. S., p. 97), .... 36 cuneatum, .Tenner, . 37 crassum, (See Desmids V. S., p. 97), . . 38 Var. scrobicnlatum, Lund., . . . 38 integrum, Wolle, . 36 magnificum, Wolle, . 37 a n tt tt tt s. — Description of, . 51 GELIDIUM, Lam., . . . 337 " corneum, Lam., . . 337 GLOEOCAPSA, Naeg., . . 330 " aeruginosa, (Carm.) Kg., 331 arenaria, Rab., . 332 atrata, Kg., . . . 332 coracina, Kg., . . 331 magma, (Breb.) Kg., . 331 polydermatica, Kg., . 331 Ralfsiana, (Harv.) Kg., 332 rupestris, Kg., . . 332 Shuttleworthiana, Kg., 332 sanguina, (Ag. ) Kg., . 332 sparsa, Wood, . . 332 GLOEOCYSTIS, Naeg., . . 195 ampla, Kg., . . . 196 rufescens, A. Br., . 196 rupestris, Rab., . . 196 " vesiculosa, Naeg., . 196 GL.OEOTHECE, Naeg., . . . 324 " confluens, Naeg., . 325 GLOEOTRICHIA, Ag., . . . 245 " natans, Thur., . . 246 Var. augulosa, Kirch., 246 " Brauniana, . 246 " gigantea, . . 246 " typica, . . 246 " pisum, Thur., . . 247 GOMPHOSPHAERIA, Kg., . 327 " aponina, Kg., . . . 328 GONATONEMA, Wittr., . . 233 " ventricosum, Wittr., . 233 GONATOZYGON, (See Desmids U. S., p. 22), . . . .21 " sex-spiniferuni, Turner, 21 GONGROSIRA, Kg., . . . 120 " Sclerococcus, Kg., . 120 GONIUM, Muell., . . . 163 pectorale, Muell., . 163 HAPALOSIPHON, Naeg., . . 275 " Brebissonii, Kg., . 276 INDEX. 351 HAPALOSIPHON, Braunii, Kg., . " byssoideus, (Hass.) Kirch., . . . " fuscescens. Kg-., . " tennissiiiuis, Grim., torulosus, (Rab.) Kirch. HIKDEBRANDTIA, Xardo., . . " rivulares, Ag., . . rosea, Kg., . . HlL,DEBRANDTIACE.K, . . HYALOTHECA, (See Desmids U 4i dissiliens, . . Var. hians, . . HYDRODICTYON, Roth, . utriculatum, Roth, . HYDRURUS, Ag., . . " foetidus, (Vill.) Kirch., " Var. calidariuin, Wolle, " Ducluzelii, Ag., . " " irregnlaris,Kg., " occidental is, Harv., . " penicillatiis, Ag., " 275 27H 277 277 , 27(5 (H fil <>2 21 -^-i 21 21 1»>9 1<>9 187 187 188 188 188 188 188 INTRODUCTION, . . . xiii ISACTIS, Thur., . . . .244 caespitosa, (Kg.) Wolle, 245 Forma — tenuior viridis, Rab., . . 245 nuviatilis, (Rab.) Kirch., 244 LEMANEA, 51 catenata, Kg., . . 52 uuviatilis, Ag., . . 52 torulosa, (Roth) Ag., 51 LEMANEACE^E, .... 51 LEPTOTHRIX, Kg., . . . 319 aeruginea, (Kg.) Kirch., 319 bullosa, Wolle, . . 321 caespitosa, Kg., . . 320 calcicola, Kg., . . 319 herbacea, Kg., . . 320 hinnulea, Wolle, . 320 laminosa, Kg., . . 321 ochracea. Kg., . . 322 rigidula, Ag., . . 321 tenax, Wolle, . . 319 " tinctoria, Kg., . . 321 LYNGBYA, Ag. et Thur., . 295 aestuarii, Liebm., . . 296 Forma. — minus, Wolle, 29»i arenarium, (Kg.) Rab., 299 cataracta, (Rab.) Wolle, 302 23 .4 t4 LYNGBYA, cincinnata, Kg., . 29ii interrupta, Wolle, . 302 inundata, Kg., . . 303 Juliana, Meuegh., . 301 majuscula, Harv., . 2!>7 membranacea, (Kg. i Thur., . . . 300 " muralis. Ag 303 Naveanum, Urun., . 25>,s obscura, Kg.. . . 29s ochracea, (Kg.) Thur. 303 pallida, (Xaeg.) Kg., . 29s papyrina, (Kg.) Kirch., 302 phormidium, Kg., . 299 Var. rivularis, Wolle, 29! • Retzii, (Ag.) Kg., . . 302 rupestre, (Ag. ) Kg., . 3oo " subtorulosa, (Breb. i Wolle, . . . 300 " tinctoria, Kg., . . 301 vermicularis,(Kg.) Rab., 297 vulgaris, (Kg.) Kirch., 300 Wollei, Farlow, . . 297 MASTIGONEMA, (Fisher) Kirch., 241 ;erugineum,(Kg. ) Kirch., 241 elongatum, Wood. . 243 fertile, Wood, . . 244 " ribrosa, Wood, . . 244 halos. Wood, . . .242 " sejunctum, Wood, . 24: '> MERISMOPEDIA, Meyen. . . 32(> " convoluta, Breb.. . 32(> " glauca, Xaeg., . . 32H MESOCARPIN-K, . . . 229 MESOOARPUS, Hass 23o crassa, Wolle, . . 230 macrospora. Wolle, . 23o uummuloides, Hass., 231 parvulus, (Hass.) I). By., 230 " radical is. Kg., . . 2:11 recur v us, Hass., . . 231 robustus, 1). By., . 231 scalaris, (Hass.) D. By., 23o MICHASTERIAS, (See Desmids r. s., p. ios), . . . 3s alata, ^V()lle, . . 40 Americana, (See Des- mids T. S.. p. 112), 39 Var. spinosa, Turner, 39 apiculata, Menegh., . 39 " Crux Melitensis, (See Desmids r. S.), . 4n denticulata, (See Des- mids T'. S., p. 109), 39 352 TNDfiX. MICRASTERIAS, fimbriata, (See Desmids U.S., p. 109), Rails, . . .383 " f'urcata, (See Desmids U. S., p. Ill), . 40 Var. simplex, Wolle, 40 mamillata, Turner, . 39 Rabenhorstii, Kirch., . 40 ringens, (See Desinids U. S., p. 112), Bail., 41 Var. serulata, Wolle, 41 " speciosa, Wolle, . . 38 " verrucosa, Roy, . 41 MICROCYSTIS, Kg., . . . 328 " protogenita,(Bias.) Rab., 328 MICROCOLEUS, Desm. et Thur., 304 u amorpha, (Thwaites) Wolle, . . . 304 " anguiibrmis, Harv., . 306 " gracilis, Hass., . . 306 " hyalinus, (Kg.) Kirch., 307 " heterotrichum, (Ag.)- -307 Forma — Americana, Wolle, 307 " pulvinatus, Wolle, . 305 " terrestris, Desm., . 305 " Ravenelii, Wolle, . . 307 MICROSPORA, Thur., . . 140 MICROTHAMNION, Naeg., . . 118 " Kuetzingianum, Naeg. 118 MISCHOCOCCUS, Naeg., . . 200 " confervicola, Naeg., 200 MOUGEOTIA, D. By., . . 227 " delicatula, Wolle, . 228 divarecata, Wolle, . 228 " glyptosperma, D. By., 229 " Minnesotensis, Wolle, . 228 " sphaerocarpa, Wolle, 227 " verrucosus, Wolle, . 229 NEPHROCYTIUM, Naeg., . 196 " Agardhianum, Naeg., . 197 " Naegelii, A. Br., . 197 NODULARIA, Mertens, . . 291 " paludosa, Wolle, . 291 NOSTOC, Vauch., . . . 278 " French, synopsis of, . 281 " Alpinum, Kg., . . 285 calcicola, Ag., . 283 " cseruleum, Lyngb., . 284 " comminutum, Kg., . 282 commune, Vauch., . 283 " ellipsosporum, Rab., 282 " flagelliforme, Burk. et Curt., ... 285 " gregarium, Thur., . . 284 NOSTOC, humifusum, ('arm., . macrosporum, Menegh., minutissimum, Kg., . muscorum, Ag., . . pruniforme, Ag., . " ru pest re, Kg., . . sphaericum, Vauch., sphaeroides, Kg., . . " spongiseforme, Ag., . " tenuissimum, Ag., . " verrucosum, Vauch., Zetterstedtiana, N. N., . NOSTOCACE.E. --Described and classified, .... OLPIDIUM, A. Br., . . . " ampullaceum, A. Br., " entophytum, A. Br., . intestinum, A. Br., . OPHIOCYTIUM, Naeg., . . " capitatum, Wolle, . " circinatum, Wolle, . " cochleare, A. Br., . " cuspidatum,(Bail.)Rab., " parvulum,(Perty) A.Br., OSCI:L:LARIEJE, .... OSCILLARIA, Bosc., . . " aerugineo-coerulea, Kg., " amphibia, Ag., . . " anguina, Bory., . . " antliaria, Jurg., . . " Boimemaisonii, Crouan, " brevis, Kg., . . " chalybea, Mertens, . chlorina, Kg., . . Gortiana, (Pollini) Kg., . cruenta, Grun., . . detersa, Stiz., . . . elegans, Ag., . . Froelichii, Kg., . . Var. caerulea, Kg., " dubia, Rab., . . " fusca, Kirch., . neglecta, Wood, . ornata, Rab., . " violascens, Rab., . " viridis, Zeller, gracillima, Kg., . . Grateloupii, Bory., . imperator, Wood, . . leptotricha, Kg., . limosa, Ag., . . . litteralis, Carm., . major, Vauch., . . U I. " " 282 284 284 282 284 283 283 284 282 282 284 285 23(> 277 203 203 204 203 175 175 176 175 176 176 293 308 311 310 314 310 316 312 314 311 313 312 310 310 315 316 315 316 316 316 316 315 311 316 317 311 313 317 316 INDEX. OSCILLARIA, natans, Kg., 44 nigra, Vauch., 44 percursa, Kg., princeps, Vauch., . subfusea, Vauch., "• subtilissima, Kg., . 14 tenerrima, Kg., . tenuis, Ag., 44 violacea, Wallr., OEDOGONIAOE^E, OEDOGONIUM, Lk.,. OEDOGONIUM, — U. S. species of, 314 815 315 317 313 809 309 313 311 65 66 68 44 44 " 44 tt n acrosporum, D. By., Var. boreale, Wolle, 44 Floridense, Wolle, Areschongii, Wittr., . autimmale, Wittr., Borisianum,( Led.) Wittr, Boscii, (Le Cl.) Witt,, . Braunii, (Kg.) Pringsh., capillare, (Linn.) Kg., . capilliforme, Kg., carbonicum, Wittr., cardiacum, ( Hass. ) Wittr. , cataractum, Wolle, ciliatum, (Hass.) Pringsh, concatenatum , ( Hass. ) Wittr., crassiusculum, Wittr., crass um, (Hass.) Wittr., crispum, (Hass.) Wittr., Var. rostellatum, Pringsh., crytoporum, Wittr., . Var. vulgare, Wittr., . cyathigerum, Wittr., decipiens, Wittr., . delicatulum, Kg., Donnellii, Wolle, . echinatum, Wood, echinospermum, A. Br., tiavescens, (Hass.) Wittr. Fonticola, A. Br., . fragile, Wittr., Franklinianum, Wittr., giganteum, Kg., gracillimum, Wittr. et Lund., grande, Kg., hexagon um, Kg., . Huiitii, Wood, . Hystrix, Wittr., irregulare, Wittr. 83 84 83 76 73 ,81 91 79 87 88 90 90 77 ,84 81 80 74 72 72 70 70 77 75 93 85 86 80 , 78 93 71 89 94 74 95 94 85 87 79 OEDOUONIUM, Landsboroughii, (Hass.) Wittr., . !»1 Londiense, Wittr., . 94 longatuni, Kg., . . 95 Lundense, Wittr., . 79 " niacrandrium, Wittr., so moniliforme, Wittr., . 93 44 multispora, Wood. . 7s " obsoletum, Wittr., . 71 obtruiicatum, Wittr., 84 pachyandrium, Wittr., 89 " paludosum,( Hass. ) Wittr., 74 " platygynum, Wittr., . 75 plusiosporum, Wittr., 72 polymorphum, Wittr. et Lurid., . . . 7.'. princeps, (Hass.) Wittr., 93 44 Pringsheimii, Cram., . 90 pyriforme, Wittr., . 95 44 punctato-striatum,D.By., 91 rivulare, (Le Cl.) A. Br., 92 Var., major, Wolle, 92 rufescens, Wittr., . . S9 44 sexangulare, ( -leve, . S2 stagnale, Kg., . . 88 s.tellatum, Wittr., . 85 imdulatuni,(Breb.) A.Br., 76 urbicum, Wittr., vernale, (Hass.) Wittr., 72 Wolleanum, Wittr., . 82 44 zig-zag, (Cleve) Wolle, 71 PALMELL.A, Lyngb., . 41 botryoides, Kg., hyalina, Breb., . miniata, Liebm., 44 Mooreana, Harv., mncosa, Kg., nvaeformis, Kg., PALMODACTYLOX, Naeg., . simplex, Xaeg., . . varium, Naeg., . . PAXDORINA, Khrl.)., . . 44 morum, Bory., . . PKDIASTRUM, Meyen, (See Dcs- midsU. S., p. 152), PKXIUM, (Sec Desmids T. S., j). 33), . . cruciferinu, (I). By.) Wittr ..... spirostriolatum, Barker, tumidum, F. Gray. PETAL.ONEMA, Berk., . . alarum, Berk., . . 192 194 19:'. 193 193 193 193 185 189 189 189 16o 161 Hi9 22 2.". 22 23 207 207 354 INDEX. PITHOPHORA, Wittr., . . 130 " aequalis, Wittr., . 131 Var. Floriderise,Wolle, 131 Kewensis, Wittr., . 13t Oedogonia,( Mont.) Wittr., 130 Var. Vaucherioides, (Wolle) Wittr., . 130 PlTHOPHORIN.33 . . . 129 PLAGHOSPBBMUM, Cleve, . . 233 " tenue, Cleve, . . 233 Var. minor, Wolle, . 233 PLEUROCARPUS, A. Br., . 231 Columbianus, Wolle, . 232 " compressus, Lyngb., 232 " mirabilis, A. Br., . . 232 PT.ECTONEMA, Thur., . . 266 " mirabile, Thur., . . 266 POLYCYSTIS, Kg., . . . 330 " Icthyoblabe, Kg., . . 330 POLYEDRIUM, Naeg., . . 183 enorme, (Ralfs) Rab., . 184 " gigas, Wittr., . . 1S4 longispinum, (Perty) Rab., ... 185 " minimum, A. Br., . . 185 muticum, A. Br., . 185 trigonum, Naeg., . . 184 Var. bifurcatum,Wille,184 " minus, Reinsch, . 184 " pentagonum, Rab., 184 " punctatum, Kirch. ,184 " tetragonum, Rab., 184 " typicum, Kirch., 184 PORPHYRACE,E, . . . .54 PORPHYRIDIUM, Naeg., . . 194 u cruentum, Naeg., . . 194 PRASIOLA, Kg., . . . 106 " crispa, Kg., . . .106 " Mexicana, Liebm., . 107 PROTOCOCCACE.E, . . . 169 PROTOCOCCOIDE.E, . . . 156 PROTOCOCCUS, Ag., . . xiv, 178 " viridis, Ag., . xiv, 181 Var. aiigulosa, Menegh., . 181 " dissectus, Naeg., 181 " miniatus, (Kg.) Naeg., . . 181 " botryoides, Rab., 182 " gigas, Kg., . 183 " humicola, Naeg., 182 " infusionem, Rab., 182 " vestitus, Reinsch., 183 " wimmeri, Rab., . 183 PSEUDO-COENOBIA, . . 174 RAPHIDIUM, Kg., . . . 1P7 Braunii, Naeg., . IPs " convolutum, (Corda) Rab IPS polymorphum, Fres., . 197 Var. aciculare, A. Br., 197 " contortum, Wolle, IPS " falcatum, (Corda) Rab., . . IPs " sigmoideum, Rab., 19S RHIZOCLONIUM, Kg., . . 144 Casparyi, Harv., . 145 fluitans, Kg., . . . 145 fontinali, Kg., . . 144 hieroglyphicum, Kg., 144 Var. Americana, Wolle, 144 Hosfordii, Wolle, . . 145 major, Wolle, . . 146 " salinum, (Schleich) Kg., 145 " stagnate, Wolle, . 145 RHODOPHYCE^E. — Orders of, . 47 RHODOPHYCEJE, .... 51 RIVULARIA, .... 24S dura, Kg., . . . 249 echinulata, Smith, . 249 RIVULARIE^:, .... 23(i SCENEDESMUS, Meyen, . . 172 acutus, Meyen, . 173 " antennatus, Breb., . 172 Var. rectus, Wolle, 172 candatus, Corda, . . 172 Var. abundans, Kirch., 172 " horridus, Kirch., 172 " setosus, Kirch., 172 " typicus, Kirch., . 172 " dimorphus, Kg., . 173 obtusus, Meyen, . . 173 polymorphus, Wood, 173 " rotundatus, Wood, . 174 SCHIZOCHLAMYS, A. Br., . 192 SCHIZOGONIUM, Kg., . . . 139 mu rale, Kg., . . 139 SCHIZOSPOREJE, .... 235 SCIADIUM, A. Br., ... 174 " arbuscula, A. Br., . . 174 " gracilipes, A. Br., . 175 SCYTONEMA, Ag., . . . 250 " Austinii, Wood, . 260 " calotrichoides, Kg., . 251 Castellii, Mass., . . 255 cataracta, Wood, . . 252 " chrysoclorum, Kg., . 253 " cincinnatum, Thur., . 254 " cinereum, Menegh., 258 " cortex, Wood, . . 256 INDEX. 355 I SCYTONEMA, Forma, corrugata, Wolle, . 256 brunea, Wolle, . 258 Ravenelii, Wood, 257 " saxicola, Grun., 257 dubium, Wood, . 260 " gracile, .... 253 heppii, (Naeg.) Wolle, 260 " iiitertextum, (Kg.) Rab., 258 mirabilis, Wolle, . 255 " myochrous, Ag., . . 252 Naegelii, Kg.,* . 252, 260 " iiatans, Breb., . . 251 notarisii, Menegh., . 254 simplice, Wood, . . 259 tliernale, Kg., Kg., . 259 " tolypotrichoides, Kg., . 250 turfosum, Kg., . . 253 SCYTONEME^E, . . . 250 SIPHONED, . . 146 SlROGONIUM, Kg., kk sticticum, Kg., . . 222 SIROSIPHON, Kg., . 267 " argillaceous, Wood, . 273 kk Brandegeei, Wolle, . 274 " compactus, Kg., 271 kk coralloides, Kg., . . 270 Crameri, Bruegg, . 274 ki crustaceus, (Ag.) Rab., 274 lignicola, Wood, . 273 ocellatus, Kg., . 272 " pulvinatus, Breb., 268, 269 Forma alpinus, ( Kg. ) Wolle, 269 scytonematoides, (Wood) Wolle, . 271 SlROSIPHONE^E, 2(57 SORASTRUM, Kg., . 171 " spinulosum, Kg., 171 SPHAEROPLEA, Ag., . . !<>"> " amiuliiia, Ag., . 104 SPHAEROPLEACEJE, . 103 SPHAEROZOSMA, (See Desmids U.S., p. 2SK " monililbrme, Lund., pulchellum,( Arch.) Rab., 22 pulchrum, Bail., . Var. constrictum, Wolle, 22 SPHAEROZYGA, (Ag.) Ralfs, Hassallii, Rab., . polysperma, Kg., . saccata, Wolle, . 290 Smithii,(Thwaites)Wolle,290 SPIRULINA, Link., duplex, Wolle, . SPIRULINA, Jenneri, Kg., . . 323 " tenuissima, Kg., . 323 SPIRILLUM, Ehrb., . . 324 SPIROGYRA, Link., 205 SPIROUYRA— Classification of, . 206 adnata, Kg., . . 220 bellis, (Hass.) Cleve, . 217 calospora, Cleve, . 2o<» com munis, (Hass.) Kg., 213 condensata,(Vauch.) Kir., 215 crassa, Kg., . . .219 dubia, Kg., 220 Var. longi-articulata, Kg., . 220 elongata, (Berk.) Kg., 221 flavescens,(Hass.) Cleve, 211 fluviatilis, Hilse, 216 fusco-atra, Rab., . 215 " gracilis, (Hass.) Kg., 211 Grcvilleana,(Hass.) Kg., 209 Var. deducta, Kg., 209 Hassallii, (Jenn.) Petit, 210 Hantzschii, Rab., 211 inflata, (Vauch.) Rab., . 207 " iiisignis, (Hass.) Kg., 210 Var. Braunii, Rab., . 210 " elongata, Sur., 210 jugalis, (Dill.) Kg., . 219 " Jurgensii, Kg., . longata, (Vauch.) Kg., . 214 Lutetiana, Petit, 214 majuscula, Kg., . 221 maxima, (Hass.) Wittr., 218 Var. inaequalis, Wolle, 218 mirabile, Hass., . 211 neglecta, (Hass.) Kg., .216 nitida, (Dill.) Link., . 217 orthospira, (Naeg.) Kg., 218 parvispora. Wood, 221 punctata, Cleve, . 21."> quadrata, (Hass.) Petit, 208 quinina, (Ag.) Kg., . 213 rivularis, Rab., . 220 sctilormis, (Roth) Kg., . 21!* " spreeiana, Rab., . 208 subsequa, Kir., subsalsa. Kg., 212 tenuissima, (Hass. i Kg., 207 varians, (Hass.) Kg., . 212 \Yeberi, Kg., . . 208 Var. elongata, Rab.. 209 kk genuina, Kirch., . 209 k< Hilseana, Rab., 209 " intermedia, Kg., . 209 . i u 356 INDEX. SPYROUYRA, var. tennis, Rab., 209 STAURASTRUM, (See Desmids TJ. S., p. lift), ... 41 arctiscon, (See Desmids U. S., p. 148), . 45 bacillare, Breb., . . 41 Brasiliense, (See Des- mids U. S., p. 146), . 40 ^Tar. triquetrnm,Wolle, 46 brevispina, . . .42 Var. inerme, Wille. 42 ealixoides, Wolle, . 46 cornutum. Wolle, . 43 cosniarioides, Reinsch, . 42 erasum, Breb., . . 43 Var.espinulosa, Lund., 43 lutecium, Lagh., . 43 Maaniense, Arch.. . 42 Minneapoliense, Wolle. 45 Minnesotense. Wolle, . 43 mutieum, ... 41 Var. ellipticum, . 41 orbieulare, (See Des- mids U. S., p. lift), . 41 paradoxum, (See Des- mids U. S., p. 129), . 45 Var. Oseeolense, Wolle, 45 pseudocrenatum, Lund., 42 Tohopekaligense, Wolle, 45 vesiculatum, Wolle, . 42 Wolleanum, Butler. . 44 Var. Kissimmense, Wolle, . 44 xiphidiophorum, Wolle, 44 Var. simplex, Wolle, 44 STAUROGENIA, Kg., . . . 171 eruciatum, Wolle, . 171 STAUROSPERMUM, Kg., . . 234 capucirmm, Kg., . 234 Quadratum, Kg., . . 234 viride, Kg., . . 234 STKPHANOSPHAERA, Cohn, . 163 44 pluvialis, Cohn. . . 163 STIOEOCLONIUM, Kg., . . . 110 amcennm, Kg., . . 113 t'aseiculare, Kg., . .114 t'astigiatum, Kg., . 114 tiagelliforme, Kg., . 112 Var. erassiusculum, Kg., . 122 longipilus, Kg., . . 115 Nan um, (Dillw.) Kg.. . 112 nudiusculum, Kg., . 113 protensum, (Dillw.) Kg. 112 radians, Kg., . . 115 STIGEOOLONIUN, subsecundum, Kg 112 tenue, Kg., . . . 110 Var.bulbiferum,Wolle,110 " genuinum, Kirch., 110 44 irregulare, Rab., 110 44 lubrieum, Rab., 110 44 unilbrme, Rab., . 110 Thermale, A. Br., . Ill SYMPHYOSIPHON, . . . 260 " ambiguum, Naeg., . 262 Austin!!. Wood, . . 261 Bornetianum, Wolle, 261 Castelli, (Hass.) Rab., .262 44 ernstaceus, Kg., . . 263 " hirtulus, Kg., . . 261 Hoffinaniii, (Ag.) Kg., 262 SYMPL.OCA, Kg 303 Friesiana, (Ag.) Kg., 304 t'uscescens, Kg., . . 304 lucii'uga, Harv., . . 303 SYXKCHOCCTS, Naeg., . . 325 aeruginosus, Naeg., . 326 TETMEMORTJS (See Desmids, U.S., p. 90), .... 34 giganteus, . . . 34 TETRASPORA, Ag., . . . 190 bullosa (Roth) Ag., .190 " cylindrica, Ag., 190, 339 explanata, (Kg.) Kirch, 191 gelatinosa,(Vauch.)Desv. 191 lubrica, (Rotln Ag., . 191 Var. lacunosa, Chand., 191 THOREA, Bory 58 44 ramosissima, Bory, . 58 TOLYPOTHRIX, Kg., . . . 263 " aegagropila, (Kg.) Kirch, 263 distort a, Kg., . . . 263 Forma magma, Wolle, 263 flaccid a, Kg., . . .265 musicola, Kg., . . 264 pnlchra, Kg., . . . 264 Ravenellii, Wolle, . 265 ruspestris, Wolle. . . 265 tennis, Kg., . . . 265 trunoicola, (Rab.) Wolle, 266 TUOMEYA, Harvey. . . . 53 rluviatilis, Harvey. . 53 grande. Wolle, .' . 53 ULOTRICHIN.F. 132 ULOTHRIX, Kg 133 jequalis, Kg., . . . 135 compacta, Kg., . . 136 44 rlaoida, Kg., . . . 137 INDEX. ULOTHRIX, Lenormandi, Kg., 138 muralis, (Ag.) Kg., . 137 14 nitens, Menegh., . 137 oscillaria, Kg., . . 137 parietina (Vauch.) Kg., 138 rivularis, Kg., . . 136 Var. cataracta, Wolle, 136 speciosa, Carm., . . 135 44 subtilis, Kg., . . 135 Var. stagnorum, Rab. , 136 44 subtilisima, Rab., 135 tenerrima, Kg., 136 44 thermarum,Wart., 136 44 typica, Kirch., . 135 44 variabilis, Kg., 136 44 tennis, Kg., . . . 134 varia, Kg., . . . 138 44 Younganum, Dillw., . 135 zonata,(W. &M.)Aresch. 133 ULVACE.E, 106 UROCOCCUS, Hass. . . . 201 44 Hookerianus, Hass., . 201 44 insignis, Hass., . . 201 VAUCHERIA, D. C., . . . 147 44 List of European species, 147 44 aversa, Hass., . . < 149 14 dichotoma, Lyngb., . 149 44 Dillwynii, Ag., . . 150 44 gemmata, (Vauch.) D.C., 151 Var. racemo, Walz, . 152 44 hamata, (Vauch.) Lyng., 152 44 intermedia, Wolle, . 154 Var. Minor, Wolle, 154 44 Pilus, Martens, . . 153 4 sessilis, (Vauch.) D.C., 151 Var. caespitosa, (Vauch.) Ag., 151 44 ornithocephala, Hass., . . 151 VAUCHKKIA, var. sphaerocarpa, Kg., . . . 151 Var. sporangifera, Kg., 15] 44 trigemina, Kg., . 151 44 sericea, Lyngb., . . 150 terrestris, Lyngb., . . 153 44 tuberosa, A.Br., . . 154 44 velutina, Ag., . . 153 VOLVOCACE^E 156 VOLVOX, Ehrb., .... 157 44 aureus, Ehrb., . . 158 44 globator, Linn., . . 158 44 minor, Stein, . . 159 44 sphaerosira, Ehrb., . 159 stellatus, Ehrb., . . 158 ZYGNEME.«, 204 ZYGNEMIN^:, .... 205 ZYGNEMA, Kg., .... 222 44 anomalum, (Hass.) Kg., 224 Var. crassum, Wolle, 224 44 cruciatum, Ag., 224 insigne, Kg., . . . 223 44 leiospermum, D.By., . 222 44 purpureum, Wolle, . 224 stellium, Ag., . . 223 Var. genuirium, Kirch, 223 44 stagnate, Kg., . 223 44 subtile, Rab., . . .223 tenue, Rab., . . 223 Vaucheria, Ag., . . 223 ZYGOGONIUM, Kg., . . . 225 44 aequale, (Kg.) Wolle, . 226 44 Agardhii, Rab., . . 226 44 decussatum,( Vauch. )Kg. 226 parvulum, Kg., . . 227 44 pectinatum, Kg., . . 225 Ralfsii, Kg., . . . 227 ZYGOSPORE^E, .... 204 INDEX OF SYNONYMS. ACHNANTHES. diniorpha, Turp 178 ACHANTHOCOCCUS. vestitus, Lagh., .... 188 ANAB^ENA. circinalis, Phillips, . . . .289 circinalis, Rab., .... 287 tios-aquae, Hass., .... 289 gelatinosa, Wood, . . 287, 288 Hassallii, Nord. et Wittr., . . 289 impalpebralis, Hass., . . . 292 licheniformis, Hass 288 Smithii, Thwaites, ... 291) spiralis, Thompson, . . . 287 ANACYSTIS. glauca, Wolle, 829 ANKISTRODESMUS. contortus, Thur., . . . 198 falcatus, Ralfs, . . . .198 APHANOCAPSA. brunnea, Naeg 829 parietina, Naeg., .... 333 APHANOTHECE. Mooreaiia, Lagh., .... 32o A RTHRODESMUS. acutus, Ehrb., 178 pectmatus Ehrb., . . . 173 AKTHROSIPHON. alatus, Rab., 207 Grevillei, Kg., 2«7 ARTHROSPIRA. Jenneri, Hedw.. .... 823 BATBACHOSPKRMTJM. conglomeratum, Vaucli.. . . 108 detersum, Eng. Bot., o7 fasciculatum, Vauch., . . .117 ludibunda moniliformia, Bury., 5f> plumosum, Vauch., . . . 109 turfosa, Bory., .... -77 BFJGGIATOA. hinnulea, Wolle. . . . 820 BOTRYDINA. Grevillei, Menegh., . . 338 BOTRYDItTM. argillaceum, Grev., . . loo BROCHIDIUM. parvulum, Perty, . 176 BUIvBOCHAETE. Canbyii, Wood, . . . . - 98 dumosa, Wood, .... 102 BUL.BOOHAKTK. Pringsheimiana, Arch, pygmaea, Pringsh., speciosa, Wittr., . varians, Wittr., BYSSUS. aurea, Eng. Bot., . . botryoides, Huds.. flos-aquae, Linn., lolithus, Linn., CAGNIARDIA. uvaeformis, Trevis, . CALOTHRIX. atrovireus, Harv., Brebissonii, Kg., . distorta, Ag., lucifuga, Carm., inirabilis, Ag., . CERAMIUM. aureuin, Hook., . CHAETOPHORA. drapariialdioides, Kg., elegans, Lyiigb., . tastigiata, Ralfs., punctiformis, Kg., tuberculosa, Kg., CHANTRAKSIA. Lenoniiaudi, Suhr., . luxurians, J. Ag., . piliferum, Kg., . ( 'HLOROCOCCUM. vulgare, (irev., CHOASPES. serpentina, CHROOCOCCr.s. multicoloratus, Wood, relractus. Wood, . CHROOLEPUS. irregulare, Kg., CHRY8OSTIGMA. cincinnatum, Kirch., . CHTHONOBLASTl'S. anguiibrmis, Kg., lacustris, Rab., repens, Hass., salinus, Kg., tinctoria, Ag., Vaucheri, Kg.. CLADOPHORA. glomerata, Hass., 101 102 101 102 121 888 291 122 193 2KH 2«3 80] 2fi»i 121 115 UK in 249 65 til til ill 181 ±-'L' 334 335 123 254 8UI i 3(>(i 806 8UH 321 30H 360 INDEX. CiLOSTERTUM. cuspidatum, Bailey, • 176 falcatum, Meiiegh., . . 198 Griffith!!, Berk., . . . .197 OOCCOCHLORIS. Grevillei, Hass., .... 333 hyalina, Menegh., . . . 193 Mooreana, Hass., .... 193 stagnina, Rab., .... 325 terminalis, Breb., .... 193 COCCOPHYSIUM. nivale, Link., .".... 166 ( 'OENOCOLEUS. cirrhosus, Berk., .... 236 CONFERVA. aegagropila, Linn., . . . .129 atra, Dillw., .... 57 atro-purpurea, Dillw 55 aurea, Dillw., .... 121 bipunctata, Dillw., . . . .224 bombycina-inaequalis, Kg., . 142 capillaris, Linn., .... 88 decimina, Mull, .... 216 decorticans, Dillw., . . . 301 dichotoma, Linn., . . . 149 dichotoma setis porcinis, Dillw., 149 distorta, Mueller, .... 263 eehinata, Eng. Bot., . . . 249 echinulata, Gray, ... 249 floccosa ochracea, Kg., . . .143 fugacissima, Dillw., . . 140 gelatinosa, Dillw., . . . .56 gelatinosa-Damee-conm, Ray Syn.,117 genuflexa, Dillw., ... 232 globosa, Phil. Trans. Roy. Soc., . 129 jugalis, Dillw., .... 219 limosa, Roth, 314 longata, Vauch., .... 214 lubrica, Dillw., Ill mirabilis, Dillw., .... 266 muralis, Dillw., .... 137 mutabilis, Dillw., ... 108 myochrous, Dillw., .... 253 nana, Dillw., ... 61, 112 nitida, Dillw., 217 ocellata, Dillw., .... 271 ochracea, Dillw., . . . 322 ochracea, Kg., .... 143 odorata, Lyngb., .... 122 oscillatoroides, Ag., . . . 137 protensa, Dillw., . . . .112 riparia, Ag., ... 146 setiformis, Roth, .... 220 sorida, Dillw., .... 142 stictica, Eng. Bot., . . . .222 subtilis. Kg., ... .141 undulata, Breb., .... 77 velutina, Bory., .... 137 ventricosa, Kg., .... 141 Youngana, Dillw., . . 135 CONJTJGATA. adnata, Vauch., . . . 220 condensata, Vauch., . . . 213, 21o CONJUGATA. cruciata, Vauch., . . . 224 decussata, Vauch., . . - 226 inflata, Vauch., . . 208 pectinata, Vauch., . . .226 princeps, Vauch., . . 217 COSMARIUM. pseudogranatum, Wolle, . . 29 CYL.INDROSPERMUM. elongatum, Kg., . . . 28H .sphaerospermum, Rab., . . 292 CYNATONEMA. confervaceum, Kg., . . . .77 DASYACTIS. mollis, Wood, . .... 249 DASYGLOIA. amorpha, Thwaites, . . . 305 DIPLOCOLON. Heppii, Naeg., . . 260 DlSELMIS. viridis, Dujard, .... 16K DOLYCHOSPERMUM. poly sperm um, Wood, . . . 289 Smithii, Thwaites, . . . 290 Thompson!, Ann. Nat. Hist., . 289 DRAPARNALDIA. condensata, Hass., . . . .112 hypnosa, Bory, .... 109 nana, Hass., Ill pulchella, Kg., 109 tenuis, Hass., Ill DRILOSIPHON. muscicola, Kg., . . 259 DYCTYOSPHAERUM. pulchellum, Wood, . . 186 ECHINELLA. articulata, Eng. Fla., . . .24!) ECTOSPERMA. geminata, Vauch., .... 152 hamata, Vauch., . . . 152 ovoidea, Hass., ... .152 sessilis, Vauch., ... 151 terrestris, Vauch., .... 153 EMBRYOSPHAERA. Meneghinii, Trevis, . . .182 ENTEROMORPHA. spermatoidea, Kg., . 107 ERYTHROCLATHOUS. rivularis, Liebm., . . 62 GlRARDIA. fusco-purpurea, Gray, . . 55 GLOEOCAPSA. ampla, Kg., ... . 196 GONETJM. glaucum, Ehrb.. - 326 HAEMATOCOCCUS. binalis, Hass., ... .334 HASSALLIA. compacta, Hass., . . 271 byssoidea, Hass., . . . 272 INDEX. 361 H ASS A I.I A. ocellata, Hass., . HlLUEBANDTIA. tluviatilis, Breb., rosea, Kg., HORMIDIITM. parietinum, Kg., . HORMOTRICH U M . speciosum, Crouan, Youngianum, Kg., HlTMIDA. cyanea, Gray, decorticans, Gray, HYBRIANTJM. acutum, Rab., heteromorphum, Rab., HYBROCOLETJM. heterotrichum, Kg., H Y DROG ASTRUM. graiiulatum, Rab., HYGROCROSIS. rigidula, Kg., HYPEOTHRIX. pallida, Kg., HYPHEOTHRIX. aeruginea, Kg., . calcicola, Kg., luminosa, Rab., tinctoria, Rab., INACTIS. homoeotricha, Kireli., . ISACTIS. plana, Thur., . LAMANEA. setacea, Bory., LEDA. capucino, Bory., LEPRARIA. infusionum, Schrauk, LEPTONEMA. nivea, Rab., LEPTONITTJS. divergens, Kg., LEPTOTHRIX.- muralis, Kg., LICHENOIDES. fungiforme, Ray Syn., LIMNACTIS. dura, Kg., L.IMNOCHLIDE. flos-aquse, Kg., LYNGBYA. aeruginosa, Ag., cincinnatum, Kg., curvata, Rab., floccosa, Hass., . majuseula, ochraoea, Thur., ^lASTIGONEMA. caespitosum, Kg., plana, Rab., 272 6-2 62 L38 1*") 135 257 3U1 177 178 L5.5 298 320 319 321 321 308 24o o" 234 182 318 321 319 155 249 291 29li 2o4 296 140 296 . 322 245 245 MASTIGOTHRIX. flbrosa, Wood, .... 241 MERKTTIA. miuiata, Trevis, .... Hi.; MKRISMOPEDIA. nova, Wood, 32(i MESOCARPUS. angustMtus, Mass., . . , 2:!(i intricatus, Hass 230 MlORASTERIAS. falcata, (Jorda, 19s MlCROCOLETS. chthoiioplast.es, Thur., . . . 30(i mar in us, Harv., . . . . 3()ii repens, Hass., 306 variecolor, Kirch., . . . 305 MICROCYSTIS. Ichthyoblabe, Kg.. . . . 327 ichthyolabe, Breb., .... 327 marginata, Kirch., . . 329 MICRO HALO A. aeruginosa, Kg., .... 327 MICROSPORA. bombycina, Thuret, . . .142 floccosa, Hass., 140 vulgaris, Rab., . 142 MONOTREMA. bullosum, Thur., . . . 191 MOUGEOTIA. craterosperma, Itz., . . . 235 genuflexa, Ag., .... splendeus, Kg., . . 2;-50 MYRIODACTYLON. endiviaefolium, Gray, . 117 MYXONEMA. drapernaldioides, Rab., . 115 ISOSTOC. arctum, Kg., . ciniflonum, Born, et Thur., . . 283 coccy melon, Kg., . . 284 1'oliaceum, Ag., . irregulare, Wartm., ... 285 litterale, Kg., nivale, Kg., . • 2S5 Peloponnesiacum, Kg., . . 2S.~> prismaticum, Ces., rugosum, Kg., . salsum, Kg., . siihaoricum, Mencgh., OLIVIA. violacea, Gra.x . . • 122 OPHIOCYTITJM. arbuscula, (Naeg.) Rab., l") gracilipes, A. Br.. OPHIOTHRIX. apiculata, Naeg.. 175 OSCILLAKIA. Adansoiiii, Vauch., aeruginea; Mart., autumnalis, Carm., 303 autumnalis, Eng. Fla., . . 301 autumnalis, Kg 310 362 INDEX. O.SCIJ^LARIA. ealcicola, Kg., 819 contexta, Carm., .... 313 cyanea, Hass., 259 decorticans, Grev., . . . 301 distorta, Ag., 263 labyrinthiformis, Ag., . . . 321 laevigata, Vaueh., .... 302 leptomitiformis, Menegh., . 319 lumiuosa, Ag., 321 muralis, Ag., 137 papyrina, Bory., .... 302 parietina, Vauch., .... 310 Retzii, Ag., 302 rupestrls, Ag., 300 taenivides, Bory., . . . 317 tennis, Kirch., .... 314 viridis, Kg., . 313 ( )SOIL,LATOBIA. alata, Grev., 267 luoifuga, Hass., . . . 304 ochracea, Grev., .... 322 parietina, Vaueh., . . . 138 tennis, Hass., 313 OEDOGONITJM. apophysatuin, A. Br 81, 82 inaquaelis, Wood, . . . .90 gemelliparum, Hantseh., . . 92 mirabile, Wood, . . . .81 piliferum, Auers, .... 84 pulchellum, A. Br., . . . . 72 • pulchellum, Rab., . . . 90 regulare, Vaup., . . . -88 rostellatum, Priugsh., . . 72 setigerum, Vaup 81 tumidum, Pringsh., ... 74 « PALMELLA. aequalis, Naeg., .... ,193 botryoides, Grev 333 brurmea, A. Br., .... 329 cruenta, Ag., 194 Grevillei, Beck, . . . 333 Mooreana, Harv., .... 325 uivalis, Hook.. .... 1(56 pallida, Ag., 325 termiualis, Ag., .... 191 PETRONEMA. fructiculosum, Tlnvaitrs. PHYI.I.ACTIDIU.M. a ust rale, Ces., pulchellum, Kg., setigerum, Kg PHORMIDIFM. ralaractum, Rab., Julianmn, Rab., inuudatum, Kg., . lacusti'e, Naeg., Lyngbyacea, Kg., membranaceum, Kg., pallidum, Naeg., . papyraceum, Rab., . papyrinum, Kg., . 240 65 H4 302 301 303 300 299 300 298 302 302 PHORMIDIU.M. Retzii, Kg., rupestre, Kg., subtorulo.sa, Breb., vulgare, Kg., . PLEUROCOCCUS. cohoerens, Breb., . Grevillei, Trevis, pulvereus, Wood, rufesceus, Breb., seriatus, Wood, superbus, Cienk., vulgaris, Menegh., POLYCYSTIS. aeruginosa, Kg., PRASIOL.A. Flotowii, Kg., orbicularis, Kg.. Rothii, Kg., PROLIFER. Borisiana, Le Cl., rivulare, Le CL, PROTOCOCCUS. coluerens, Kg., . communis, Kg., Meneghinii, Kg., uivalis, Ag., rufescens, Ag., . turgidus, Kg., umbrinus, Kg., . RlVULARIA. angulosa, Roth, Boryana, Kg., Brauniaua, Kg., cartilaginea, Wood, durissina, Kg., . elegaus, Eng. Bot.. gigantea, Trent., Lens, Kg., radians, Kirch., pisum, Ag., tuberculosa, Eng. Bot., villosa, Rab., . RHIZOCLONIUM. t'ontaiiuni, Kg., lucustre, Kg., obtusanguluin, Kg., riparium, Harv.. rivulare, Kg., RHIZOPHYDIU3I. globosum, A. Br., . RHYNCHONEMA. amiii, Kg., diductuin, Kg.. Gallicum, Rivet. . Hassallii, Kg.. . minimum, Kg., quadratum, Kg., reversum, Kg., vesicatum, Kg., Woodsii, Kg., 3011 300 301 333 327 335 123 19(5 18] 327 II Mi 10(5 10(5 81 92 335 181 182 16(5 335 334 123 24H 24(5 24(5 247 247 11(5 246 247 249 247 11« 247 144 145 14(5 14H 144 203 211 209 210 210 207 208 213 208 212 FNDEX. 363 SCBNEDBSMUS. bilunatus et germinatus, t'usitbrmis, Menegh., peetinatus, Meyen, quadricauda, Breb., quadricaudatus, Rail's, SfHIZOSIPHON. c-ateractee, Naeg., erusiformis, Naeg., . \ grarilis, Rab., gypsophilus, Kg., Meneghinianus, Kg., . SCHIZOTHRJX. hyalina, Kg variecolor, Rab., SOYTONEMA. Brandegei, Wolle, . calotri'choides, Wood, cirrhosmn. Berk.,, coinpactum, Eng. Fla., crustaceum, (Ag.) < V.oke, crustaceum, Ag., inimersum, Wood, Julianum, Wittr. et Xor Xaegelii, (Kg ) Wood, oscellatum, Harv., . pulveruleutum, Ag., . Ravenelii, Wood, . truncicola, Rab., velut ilium, Wallr, SIMPLOCA. phormidiuni, Thur., SlROGONIUM. breviarticulatum, Kg., Braunii, Kg., . retroversum, Wood, SIROSIPHON. pellucidulus, Wood, rhizodes, Breb., truncicola, Rab., velut inus, Kg., SOLENIA. intestinalis, Jurg., SOROSPORIUM. vii*escens, Hass., . SPHAEROCARPUS. intricatus, Hass., nunimuloides, Hass., parvulus, Hass., recurvus, Hass., SPHAEROZYGA. Carmichaelis, Harv., fl os-aquae, Rab., . Flotowiana, Kg., oscillarioides, Kg., Thwaitesii, Harv., variabilis, Kg., SPIRILLUM. Jenneri, Hass., SPIRODISENS. cochlearis, Eich., . SPIROGYRA. arcta, Kg., SPIROGYRA. Kg., . 173 dcccmiiia, Kg., . . 173 diluta, Wood, 173 Hoiigata, Wood, . 172 gastroides, Kg., 172 Heeriana, (Naeg.) Kg., Hornschuehii, Kerst., 236,240 inaoqualis, Kg., . 240 mirabilis, Kg., 237 Naegelii, Kg., . 237 nodosa, Kg., . 28S orbicularis, (Kg.i Petit, orthospira, Naeg., 306 protecta, Wood, . 306 pulchella. Wood, . setiforme, var., Wolle, 252 setitbrmis, Petit, . . 251 ventricosa, Kg... 231) STAUROCARPrS. . 271 afflnis, Hass., 240 capucinus, Kg., • 274 glutinosus, Hass., 252 gracilis, Hass., d., . . 259 quadra tus, Hass.. 266 virescens, Hass., . . 272 STAl'RASTRrM. 259 enorme, Rail's, . 256 falcatum, Ehrb.. 266 STAUROSPERMUM. . 274 fraiiconicum, Reinsch.. STIGONEMA. . 299 compactum, Kirch., ocellatum, Thur., . . 222 SYMPHYOSIPHON. intertextum, Kg., . 210 TETRASPORA. • 272 minima, Dew., 274 TETRASPORELLA. . 276 lubrica, Gaill., 274 TOL.YPOTHRIX. aegagropila, Kg., . 107 fuscescens. Breb., pumilla, Kg., 333 TREMELLA. cruenta, Eng. Bot.. 230 uatans, Hedwig, . 231 uivalis, A. Br., 230 palustris, Dilhv., . 231 pruniformis, Wittr., . TREMULA. • 289 cornuum,Dillw. . 291 gelatinosa-Daina, Dill.. • 289 marina tubulosa, Dill.. 288 nostoc, Linn., . 288 TRENTEPOHLIA. 288 aurea, Ag., lolithus, Wallr.. . . 323 pulchella, Ag., . virgatula, Fail., 175 TRICHORMUS. incurvus, Allman, 212 oscillarioides, Rail's. L>1!> . 217 . 209 . 2(ts 21!» . 2d!t . 20! i .211 .207 212 .218 .221 . 210 . 20S ,219 21!» 208,212 2:!4 . 284 . 284 284 284 . 842 1N4 198 . 284 . 271 . 272 . 25K 191 1»1 2tM 277 194 246 !««« 284 117 107 107 2S8 121 122 61 289 289 364 INDEX. rectus, Ralfs, spiralis, Ralfs, Thwaitesii, Ralfs, TYNDARIDEA. auomala, Hass., conspicua, Hass., cruciata, Hass.. decussata, Hass., insignis, Hass., lutescens, Hass., Ralfsii, Kg., ULOTHRIX. flacca, Thur., isogona, Thur, UI/VA. bullosa, Roth, crispa, Hass., cylindrica, W; incrassata, En intestinalis, Jurg., granulata, Huds., lactuca Huds., lubrica, Roth, pisiformis, Huds.. pruniformis, terrestris, Gray, UREDO. nivalis, Bauer, . VAGINARIA. chthonopla vulgaris, Gray, VAUCHERIA. caespitosa, Ag., circinata, Kg., Dillwynii, Rab., globifera, D. By., hamulata, Kg., Hookeri, Kg., ovata, Gray, ovoidea, Hass., pachy derma, polymorphia polysperma, radicata, Hook., salina, Kg., Tovarensis, Ungeri, Thur., YESICULIFERA. bombycina, Condolloi, Hass., 289 289 289 224 226 224 226 223 224 eiliata, Hass., concatenata, Hass.. . crispa, Hass., . flavescens, Hass., hexagona, Hass., . Landsboroughi, Hass. paludosa, Hass., . vernalis, Hass., . 84 84 72 78 94 92 74 72 . ' . . . .227 ZONOTRICHIA. • fluviatilis, Rab., . 245 ZYGNEMA. 135 abbreviatuni, Hass., . 212 . 135 adnatum, Ag., . 220 aestivum, Hass., . 214 191 afflne, Hass., . . 211 . 106 bella, Hass., . 217 allenberg, . . 190 commune Hass., . . 213 g. Bot., . . 117 condensata, Ag., . 215 arg., .... 107 curvatum, Ag., . 222 ds., . . 155 deeiminum, Hass., . • . 21(i 106 decussata, Dillw., . 226 . 191 Dillwynii, Kg., . . . 224 ids.. . . 116 flavescens, Hass., . 211 ^inn., . . . 284 gracile, Hass., . 212 y, • . . . . 106 Grevilleaua, Hass., . 209 . 210 , 166 inflatum, Hass., . 208 insigne, Hass., . . 210 s, Grev 306 intermedia, Hass.. . 209 . 306 interruption, Hass., . 220 litoreum, Kg., . 146 lon°"atum Ag. , . . 214 151 153 maximum, Hass., . 218 b., . . . . 152 mirabile, Hass., . . 211 y., . . . .149 neglectum, Hass., . 216 152 nitidum, Ag., . 217 151 ordinarium, Berk., 227 152 orbicularis, Hass., . 218 152 quadratum, Hass., . 208 if* * i • • ' • ' — Wil7 151 quininum, Ag., . . 213 V Y <(!/'. • • • • Wood, . . . 153 To cc l.^O reversuni, Hass., . rivulare, Hass., . 113 . 221 itii^^., . > • k!55 rostratum, Hass., . 217 • j • • • • -i*jT_r 149 tenue, Rab., . . 223 a>rst. , .... 151 tenuissima, Hass., . 207 151 varians, Hass., . . 212 ZYGOftONITTM. snner, . . . 142 pleurospermum, Kg., . 232 ss., 72 saxonioum, Rab., 226 \