MARINE ALG^E OF BEAUFORT, N. C. 407 



CLASSIFICATION AND DESCRIPTION OF SPECIES. 



KEY TO DIVISIONS. 



a. Thallus composed of single cells or of rather short filaments; multiplication purely vege- 

 tative, either by simple cell division or by means of hormogonia or gonidia; color 

 usually blue-green.../ , . . . . I. MYXOPHYCE^E (p. 407). 



aa. Thallus composed of single cells, or filamentous, or forming tubes or sheets or complex 

 structures of various shapes composed of closely interwoven filaments; multiplica- 

 tion asexual or sexual asexual by fragmentation or by motile zopspores or by aki- 

 netes, sexual by similar or dissimilar motile or nonmotile gametes; color usually 

 grass-green II. CHLOROPHYCE^ (p. 417). 



aaa. Thallus filamentous or forming complex structures of various shapes; multiplication 

 asexual or sexual asexual by motile biciliate zoospores or by aplanospores or by 

 certain portions of the thallus, sexual by similar or dissimilar motile or nonmotile 

 gametes, in some genera by distinct eggs and sperms; color usually brown, some- 

 times shading to yellowish or to olivaceous green III. PILEOPHYCE.3J (p. 435). 



aaaa. Thallus filamentous or forming sheets or complex structures of various shapes; multi- 

 plication asexual or sexual asexual usually by nonmotile spores usually produced 

 four in a sporangium, sexual by nonmotile male gametes (spermatia) and nonmotile 

 female gametes remaining inclosed within special organs (carpogonia), usually with 

 the association of special cells (auxiliary cells), a fruit of a special kind (cystocarp) 

 usually being formed as the result of fertilization ; color usually some shade of red, 

 purple, or pink, sometimes green or blackish IV. RHODOPHYCE^ (p. 462). 



Division I. MYXOPHYCEAE (Wallroth) Stizenberge/. 



Myxophykea Wallroth, 1833, p. 4. 

 Chlorospermeae, in part. Harvey, 1858, p. i. 

 Myxophyceae, Stizenberger, in Rabenhorst, 1860, p. 18. 

 Cryptophyceae, Thuret, in Le Jolis, 1863, p. 13. 

 Cyanophycese, Sachs, 1874, p. 248. 

 Schizophyceae, Cohn, 1879, p. 279. 

 Cryptophyceae, Farlow, 1882, p. 26. 

 Myxophyceae, Forti, in De Toni, 1907, p. i. 

 Myxophyceae, Tilden, 1910, p. i. 



BLUE-GREEN ALG^B, FISSION ALG^. 



Algae typically blue-green, possessing within their cells endochrome composed of 

 chlorophyll and a characteristic blue pigment; pigments of other colors sometimes 

 present; endochrome diffuse, rarely gathered in large, sharply defined bodies. Thallus 

 variable in form and size, unicellular or multicellular, sometimes having a peculiar 

 motion; plants usually in gelatinous masses, sometimes solitary among other algae. 

 Multiplication purely vegetative; either by simple cell division in one, two, or three 

 planes; or by means of hormogonia (multicellular fragments of the thallus, at first 

 motile, afterwards coming to rest); or by means of nonmotile gonidia formed within 

 gonidangia; or by means of resting gonidia (formed from ordinary cells). Algse living 

 for the most part in fresh or salt water, sometimes aerial, more rarely endophytic; the 

 individual cells and filaments microscopic in size; sometimes brown, violet, gold, or 

 reddish. 



About 1,500 species described, representatives occurring in all parts of the world, 

 at extreme variations of temperature. 



a This group is often treated as a class under the division Schizophyta. which then includes the Myxophyceae. or as they are 

 sometimes called, the Schizophyceae (the blue-green algae), and the Schizomycetes (the bacteria). 



