130 JOHN H. SCHAFFNER Vol. XXII, No. 5 



peculiar in many respects they are nevertheless plainly related 

 to the other filamentous green algae and the same is true of the 

 Siphoneae and related forms which according to the writer's 

 views do not warrant segregation into a distinct phylum as was 

 done by Bessey. On the other hand, the Charales are so aberrant 

 that their origin is very obscure and they have, therefore, been 

 placed in a distinct phylum. 



SYNOPSIS OF THE ALGAL PHYLA 



I. Cells typically with poorly differentiated nuclei and chromatophores, repro- 

 ducing by fission, motile and nonmotile, never with a pure chlorophyll-green 

 color, but containing phycocyanin; unicellular or filamentous, apparently 

 without sexuality. The most primitive of the algae and along with the 

 bacteria the most primitive of all organisms. Marine or mostly freshwater, 

 some species growing in very hot springs. Phylum, Schizophyt.\. 



IT. Cells with well differentiated nuclei and usually with definite chromato- 

 phores; green or variously tinted by coloring matters. 



A. Unicellular or filamentous plants containing chlorophyll, either of a 

 brownish or yellowish color and with silicified, two-valved walls, or 

 green with complex chromatophores or fantastic cells, the walls not 

 silicified; sexual or apparently nonsexual by degeneration; conjugating 

 cells not ciliated, isogamous. Phylum, Zygophyt.\. 



L With silicified, valved cell walls, usually with fantastic forms and 

 markings, and usually of a yellowish or brownish color. Marine 

 and fresh water plants. Subphylum, Diatomeae. 



2. Cell walls not silicified; plants filamentous or unicellular, green, 

 the unicellular often with fantastic forms and markings. Fresh 

 water plants. Subphylum, Conjugatae. 



B. Plants not with silicified two-valved walls; usually with zoospores when 

 green, or with heterogamous sexuality, sometimes nonsexual, the iso- 

 gamous green forms usually not with fantastic chromatophores nor with 

 a constriction in the middle of the cell. 



L Antheridium when present not consisting of a globular structure 

 containing sperm-bearing filaments; sometimes with an alternation 

 of generations. 



a. Plants mostly green, nearly all producing nonsexual zoospores, 

 the sexual forms isogamous or heterogamous. Characteristic 

 water plants, but also numerous marine species. 



Phylum, GONIDIOPHYTA. 



b. Plants with the chlorophyll usually hidden by a brown, red, or 

 purple pigment always with a multicellular body and with 

 sexuality or apparently from sexual ancestors. 



(a) Mostly marine, often large, brown algae with phycophaein; 

 isogamous or heterogamous or sexuality unknown, with 

 ciliated sperms, both gametes discharged from the game- 

 tangium. Phylum, Phaeophyta. 



(b) Mostly marine red or purple algae with phycoerythrin; 

 heterogamous, with stationary eggs and non-ciliated sperms. 



Phylum, Rhodophyta. 



2. Filamentous, green algae with globular antheridia containing sperm- 

 bearing filaments, the sperms being biciliated; nonsexual spores 

 absent. In fresh or brackish water. Phylum, Charophyta. 



