ALG^E CONTINUED: CLASSIFICATION. 



Class Schizophyceae ( = Cyanophyceae). 



351. The Blue Green Algae, or Cyanophyceae form slimy looking thin 

 mats on damp wood or the ground, or floating mats or scum on the water. 

 The color is usually bluish green, but in some species it is purple, red or 

 brown. All have chlorophyll, but it is not in distinct chloroplasts and is 

 more or less completely guised by the presence of other pigments. Two 

 orders and eight families are recognized. The following include some of 

 our common forms: 



352. ORDER COCCOGONALES (COCCOGONEJE). Single -celled plants, 

 occurring singly or in colonies, in some forms 



forming short threads. One of the two fami- 

 lies is mentioned. 



353. Family Chroococcaceae. The plant? 

 multiply only through cell division. Chroococ- 

 cus, forms rounded, blue-green cells enclosed 

 in a thick gelatinous coat, in fresh water and 

 in damp places; certain species form " lichen - 

 gonidia" in some genera of lichens. Gloeo- 

 capsa is similar co Chroococcus, but the col- 

 onies are surrounded by an additional common 

 gelatinous envelope (fig. 168); on damp rocks, 

 etc. 



354. ORDER HORMOGONALES (HORMOGONEJE). Plants filamentous, 



simple celled or with false 

 or true branching, usually 

 several celled (Spirulina is 

 single celled). Multiplica- 

 tion takes place through 

 hormogones, short sections 

 of the threads becoming 

 free; also through resting 

 cells. Two of the six fami- 

 lies are mentioned. 



355. Family Oscillatori- 

 aceae. This family is rep- 

 resented by the genus Oscil- 

 latoria, and by several other 

 genera common and widely 

 distributed. Oscillatoria 

 many species, 

 are found on the 

 damp ground or wood, or floating in mats in the water. They often form on 



Fig. 1 68. 

 Gloeocapsa. 



Fig. 169. 



A, Oscillatoria princeps, a terminal cell; b, c. 

 portions from the middle of a filament. In c, a 

 dead cell is shown between the living cells; B, 

 Oscillatoria froelichii, b, with granules along the contains 

 partition walls. 



