Key to the Orders 



1. Cells club-shaped unicells (in our specimens) showing basal- 

 distal differentiation; solitary, or forming rather definite layers 

 on rocks and shells, or epiphytic; reproduction 

 by non-motile endospores chamaesiphonales 



1. Cells other shapes; not reproducing by endospores 2 



2. Cells coccoid; solitary or united in colonies of definite or 



indefinite shape; reproduction by fission chroococcales 



2. Plants filamentous; reproduction by fission, by hormogonial 



fragmentation, or by gonidia hormogonales 



ORDER CHROOCOCCALES 



This group includes plants which are unicellular or which form 

 simple colonies of cells. The colonies may be definite or indefinite 

 in shape, but there is no differentiation of cells, or interdependence. 

 A copious gelatinous investment is present in most forms. See Daily 

 (1942) and Drouet and Daily (1939) for critical studies of this group. 



FAMILY CHROOCOCCACEAE 



Unicellular or colonial, free-floating or attached to submerged or 

 aerial substrates. There are no pseudofilamentous arrangements or 

 expanses produced as in the Entophysalidaceae, another family in 

 this order, which is not represented in our region. 



Key to the Genera 



1. Plants unicellular or forming small aggregates 



of 2-8 (rarely up to 32) cells 2 



1. Plants composed of many cells embedded in copious mucilage, 



with or without apparent cell sheaths 8 



2. Cells spherical, forming small clusters 



of 2^-16-32 individuals^ Chroococcus (in part) 



2. Cells longer than their diameter 3 



3. Cells occurring as blue-green chromoplast-like 



bodies in colorless host cells 4 



3. Cells not occurring as chromoplast-like bodies 



in colorless host cells 5 



4. Host cell adherent, bearing long bristle-like setae; usually 2-4 



host cells inclosed in a common mucilage Gloeochaete 



4. Host cell free-floating, not bearing setae, 



not inclosed in colonial mucilage Glaucocystis 



5. Cells with a gelatinous sheath; several individuals 



inclosed by a common mucilage Chroococcus (in part) 



5. Cells solitary or clustered in small groups, 



without a mucilaginous investment 6 



"Cf. the symbiotic genera Glaucocystis and Gloeochaete, in which the host cells may be 

 grouped in small families. 



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