HOW TO KNOW THE FRESH-WATER ALGAE 



51b Colony formed otherwise 



52 



52a Colony cubical, consisting of 4 cells at the corners of a hollow 

 cube built of gelatinous strands. Fig. 44 PECTODICTYON 



Figure 44 



Fig. 44. Pectodictyon cubicum Taft. 

 drawn from Taft.) 



(Re- 



There is only one species known for this 

 genus and it has been found but once since 

 it was originally described by Taft from 

 Ohio. It is to be expected in open water 

 plankton. 



52b Colony formed otherwise 53 



53a Cells arranged in a linear series within gelatinous tubes (often 

 branched). Fig. 45 PALMODICTYON 



© © © Q Q< 



Figure 45 



Fig. 45. Palmodictyon viride Kuetzing. 



This species and Palmodictyon varium (Naeg.) Lemm. are fairly 

 common in mixtures of algae from the shallow water of ponds and 

 swamps. The former has cells inclosed in individual sheaths, whereas 

 the latter is without cellular sheaths. Some strands of colonial muci- 

 lage may be simple, others irregularly branched and sometimes ana- 

 stomosing. 



53b Cells arranged otherwise 54 



54a Cells cylindrical or elongate-ellipsoid 55 



43 



