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



Phylum, Rhodophyta. Red Algae. 



I. Nonsexual reproduction by single thallus cells; trichogyne imperfectly 

 developed; no pits between the thallus cells. Class, Monospor^. 50 species. 

 One order, Bangiales. Bangiaceae, Rhodochaetaceae, Compsopogonacese. 

 II. Nonsexual reproduction by tetraspores usually developed in groups of four; 

 trichogyne well developed; cells protoplasmically connected through large 

 pits in the walls. Class, Floride^. 3000 species. 



A. Sporophores ("gonimoblasts" or branches bearing the carpospores) of 

 the sporocarp produced directly from the fertilized oogonium; mostly 

 plants with filiform fronds. Fresh water or marine. Nemalionales. 

 Lemaneaceae, Helminthocladiaceas, Chaetangiaceae, Gelidiaceae. 



B. Sporophores produced by auxiliary cells after these conjugate with the 

 fertilized oogonia or their branching processes ("ooblastema"). 



1. Sporophores produced by nearby auxiliary cells; marine plants. 



a. Sporophores produced by nearby auxiliary cells and growing 

 outward in the plant body; filiform, foliaceous or massive plants. 

 Rhodymeniales. Sphaerococcaceje, Rhodymeniaceas, Deles- 

 sariaceae, Bonnemaisoniaceae, Rhodomelaceae, Ceramiaceae. 



b. Sporophores produced by the nearby auxiliary cells and branch- 

 ing copiously in the surrounding tissues of the plant body; fronds 

 parenchymatous, flattened or leaf-like. Gigartinales. Acroty- 

 laceae, Gigartinaceas, Rhodophyllidaceae. 



2. Sporophores produced by remote auxiliary cells after these have 

 conjugated with the branched "ooblastema" filaments arising from 

 the fertilized oogonium; fronds filiform, branched, often flattened. 

 Mostly marine, but a few fresh water species. Cryptonemiales. 

 Gloiosiphoniaceae, Grateloupiaceae, Dumontiaceas, Nemastomaceae. 

 Rhizophyllidaceae, Squamariaceae, Corallinaceae. 



Phylum, Charophyta. Stoneworts. 



One class and one order, Chare^e. "160 species. Charales. 



I. Crown of the oogonium with ten cells. Nitellaceas. 

 II. Crown of the oogonium with five cells. Characeae. 



KEY TO THF ORDERS OF ALG^ 



1. Nonsexual fission algse, unicellular, colonial or filamentous, blue-green or 

 brownish, never with a pure chlorophyll-green color, usually with gela- 

 tinous walls; filaments often with heterocysts; never with cilia or flagella, 

 but sometimes motile; chromotophores usually poorly defined. 2. 



1. Mostly sexual algas, but sometimes nonsexual, with a pure chlorophyll-green 



color or often red, purple, yellow, or brown; plants not propagating by 

 fission; tmicellular, colonial, filamentous, or massive; chloroplasts usually 

 well defined; commonly with zoospores; some with silicious walls. 6. 



2. With poorly differentiated nuclei, without a definite nuclear membrane, 



and with a low type of chromatophore. (Cyanophyce/E). 3. 



2. With well developed nuclei, with a nuclear membrane, and with highly 



differentiated chromatophores. (Glaucocyste^). Glaucocystales. 



3. Not filamentous; tmicellular or colonial, free or attached. Chroococcales. 



3. Cells arranged in definite filaments. 4. 



4. Filaments without hair-like tips, sometimes narrowed at the ends. 5. 



4. Filaments with hair-like tips at one or both ends, with or without hetero- 



cysts. Rivulariales. 



5. Without heterocysts. Oscillatoriales. 



5. With heterocysts. Nostocales. 



6. Cells covered with two silicious, usually ornamental valves, mostly brown or 



yellowish in color; unicellular, or simple filaments, sometimes on gelatinous 

 stalks. (DiATOME^). 7. 

 6. Cells not covered with two silicious valves. 8. 



