HOW TO KNOW THE FRESH-WATER ALGAE 



47a Cells inclosed by concentric layers of mucilage (individual cell 

 sheaths distinct). Fig. 41 GLOEOCYST1S 





. $ 



b v 



/ 



& 



\ 



• 



- 



°^ 



Figure 41 



Fig. 41a. Gloeocystis gigas (Kuetz.) Lag.; h.Gloeocystis ampla (Kuetz.) 

 Lag.; a Gloeocystis major Gerneck, showing dense, cup-shaped 

 chloroplast. 



There are several species of Gloeocystis and all are very common. 

 They are not very distinctive plants and therefore many small, round 

 green cells, especially when inclosed in mucilage, belonging to other 

 genera may be mistaken for them. The concentric layers of mucilage 

 about the cells provide a helpful character for identification. Gioeo- 

 cystis ampla (Kuetz.) Lag. does not have layers of mucilage, however, 

 but this free-floating species is identified by its oblong or oval cells. 



47b Cells without evident individual sheaths; mucilage not in con- 

 centric layers 48 



48a Chloroplast cup-shaped, not covering the entire wall; cells all the 

 same size within the colonial mucilage. See Fig. 36. . .PALMELLA 



This genus has shapeless lumps of attached mucilage, sometimes 

 large enough to be seen easily with the unaided eye. The oval cells 

 scattered throughout the mucilage may have individual sheaths. Like 

 Gloeocystis (which also has cup-shaped chloroplasts, Fig. 41) other 

 small, oval cells may be mistaken for Palmella and vice versa. 



41 



