u8 



MORPHOLOGY. 



Fig. 126. Fig. 127. 



Gracillaria, portion of frond, Gracillaria, section of cystocarp 



showing position of cysto- showing spores, 

 carps. 



273. The principal groups of the algae are the following : 



Chlorophycea. 

 Green algae. 



Protococcoideae (the protococcus (Pleurococ- 



cus vulgaris); the red-snow plant (Sphaerella 



nivalis), etc. 

 Conjugateae (spirogyra, zygnema, mougeotia, 



desmids, etc.). 

 Siphoneae (vaucheria). 

 Confervoideae (cedogonium, chaetophora, cole- 



ochaete). 



Cyanophycece (nostoc, oscillatoria, etc.). The blue-green algae. 

 Phceophycece, (fucus, etc.). The brown algae. 



