6 Charles E. Bessey 



Family 8. Stigonemataceae. Cells in more than one row, het- 

 erocysts present; trichomes present. Stigonema, Haplosiphon. 

 (Pf. I, I a, 80.) 



Class 2. HOLOPLASTIDEAE. Nucleus with a membrane, 

 definitely outlined ; chromatophores differentiated. 



Order Glaucocystales. Plants unicellular or in colonies, di- 

 viding in one plane only. 



Family 9. Glaucocystaceae, With the characters of the order. 

 Glancocystis. (De Toni, V, 693.) 



Phylum 11. PROTOPHYCEAE. The Simple Algae. 



Single cells or threads of cells, rarely a plate of cells; repro- 

 ducing asexually (propagation) by fission and gonidia, and sex- 

 ually (generation) by the union of gametes, wdiich are commonly 

 free-swimming ; nucleus with a membrane ; chromatophores dif- 

 ferentiated, and containing chlorophyll. Typically freshwater 

 plants. 



Class 3. PROTOCOCCOIDEAE. Plants all unicellular, 

 sometimes aggregated into colonies. 



Order Palmellales. Cells not in true colonies. 



Family i. Pleurococcaceae. No zoospores; chlorophyll pres- 

 ent. Plcnrococcns, Ankistrodcsmus. (Pf. I, 2, 54.) 



Family 2. Protococcaceae. With zoospores; chlorophyll pres- 

 ent. Protococcns, Tctraspora, ChlorocJiytrhim. (Pf. I, 2, 43, 

 60.) 



Family 3. Synchytriaceae. With zoospores; no chlorophyll; 

 colorless parasitic hysterophytes. Olpidinm, Synchytrium. (Pf. 



I, I, 7-) 



Order Coenobiales. Cells in true colonies. 



Family 4. Hydrodictyaceae. With zoospores; chlorophyll 

 present; cells aggregated into floating colonies. Pediastrnm, 

 Scenedcsmns, Hydrodictyon. (Pf. I, 2, 70.) 



Family 5. Volvocaceae. Vegetative cells ciliated; zoospores 

 present; chlorophyll present; cells single or aggregated into mo- 

 tile colonies. Goniuin, Pandorina, I'oJvnx. (Pf. I, 2, 29.) On 



280 



