ii8 



MORPHOLOG Y. 



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 algse are the following : 



ChlorophycecB. 

 Green algse. 



Protococcoidese (the protococcus (Pleurococ- 



cus vulgaris); the red-snow plant (Sphserella 



nivalis), etc. 

 Conjugateae (spirogyra, zygnema, Inougeotia, 



desniids, etc.). 

 Siphonese (vaucheria). 

 Confervoidese (oedogonium, chcetophora, cole- 



ochaete). 



CyanophycecB (nostoc, oscillatoria, etc.). The blue-green algse. 

 PkcBophycecB (fucus, etc.). The brown algse. 



