PRINCIPAL GROUPS OF PLANTS. 



Single cell i nit alter 



daughter cells re- 

 A mass of celts after numer- tamed in a gelatinous 

 ous divisions, all surrounded mass. Diameter 

 by a mucilaginous envelope. about 4 microns. 



GLOEOCAPSA. 



A single colony. 

 Diameter of colonies varying Single cell showing 



from 40 to 290 microns. spiral chromatophore. 



Length. 14 to 18 mi- 

 UROGLENA cron ' 



Heterocyst which divides the 

 filament into smaller filaments. 



Thick-walled resting cells. 



OSCILLATORIA \Dccay,n 8 



FIG. 6. Forms of Cyanophyceae or Blue-Green Algae. Adapted from Engler and 

 Prantl and somewhat modified by Lobeck. 



