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IOWA ACADEMY OF SCIENCE 
Order IX. 
Protococcoideae. 
KEY TO FAMILIES. 
Unicellular or multicellular, sometimes pseudoparenchymatous. Some or 
all of the cells furnished with hairs or bristles, either simple or sheathed and 
often mucous. Multiplication by division of cells in two directions. Re- 
production by two or four ciliated gametes I. Chaetopeltidae 
Unicellular or consisting of a definite coenobium of cells, which are either 
united by protoplasmic processes or enclosed within the swollen mucous 
mother cell wall. All the cells are ciliated and motile in their vegetative 
stage II. Volvocaceae 
Unicellular, cells solitary, differentiated into base and apex, epiphytic on 
other algae; chloroplast parietal with one pyrenoid. No vegetative divi- 
sion. Reproduction solely by zoogonidia formed by successive divisions of 
the contents of a mother cell III. Characieae 
Unicellular and globular, or of short ramified few celled filaments, never 
attenuated into hairs; often, pseudoparenchymatous. Chloroplasts one or 
several, parietal, with or without pyrenoids. Multiplication by division in 
two or three directions, and more rarely by zoogonidia. Cell wall very 
firm IV. Pleurococcaceae 
Family I. 
Chaetopeltideae. 
1. Chaetosphaeridium. 
157. C. globosum (Nordst) Klebahn. 
Eagle Grove. Pond. Buchanan. 
Family II. 
Volvocaceae. 
KEY TO SUBFAMILIES. 
Unicellular, not united into coenobia I. Chlamydomonadeae 
Cells united into coenobia II. Volvoceae 
Subfamily I. 
Chlamydomonadeae. 
1. Chlamydomonas. 
158. C. DeBaryana Gorosch. 
Ames. In a puddle after rain. Buchanan. 
Subfamily II. 
Volvoceae. 
KEY TO THE GENERA. 
Coenobium flat, 16 cells 
1. Gonium 
