HOW TO KNOW THE FRESH-WATER ALGAE 

 37b Colony composed otherwise 38 



38a Colony composed of cells invested by a common mucilage (see 

 Oocysfis, Fig. 85b, with cells inclosed by old, expanded mother cell 

 wall, not by mucilage) 39 



38b Colony composed of an aggregate of cells not inclosed by mu- 

 cilage, but may be inclosed by old mother cell wall or fragments 

 of it 73 



39a Colony attached or adherent 40 



39b Colony free-floating or entangled among other algae, but not grow- 

 ing attached (frequently algae usually attached become separated 

 from their substrate. Look for attaching stalk, disc or other evi- 

 dence of the plant having been once attached) 49 



40a Colonies in the form of compact packets among the epidermal 

 cells of aquatic plants. Fig. 34 CHLOROSARCINA 



Fig. 34. Chlorosarcina consociata (Klebs).G. 

 ....^=^ M. Smith. 



>^§>^^y •Tv^C^- ^ is P ac ^ et_n ^ e arrangement of cells is re- 



*C?jfrQS$$\j#&pQ} min dful of the genus Sarcina among the bac- 



i(7)A^^^^^^^' teria - There are 3 species, usually free-living 



;^jvA! ; but one that is most frequently seen occurs 



V^J/^/Ta in the tissues of such aquatic plants as Lemna. 



^(jL^y Old, colorless specimens of Lemna often show 



this and other endophytic algae {Chlorochy- 



Figure 34 trium Lemnae, Fig. 94). 



40b Colonies not endophytic in the tissues of aquatic plants 41 



41a Colonial mucilage sac-like, balloon-shaped or intestiniform, often 

 macroscopic 42 



41b Colonial mucilage of other shapes, or if sac-like, microscopic .. 43 



37 



