Myxophyceae 13 



soid or oblong, obtusely rounded on both ends, single or in pairs; cells 

 4-6 mic. in diameter; cell contents blue-green. 



Var. mellea (Kuetz.) Hansgirg. loc. cit. 135. 1892. De Toni. loc. cit. 31. 



WoUe. Fresh-Water Algae. II. Bull. Torr. Bot. Club. 6: I37- i877- 

 (Gloeocapsa mellea Kuetz.). 



Cell contents yellowish-red or yellowish-brown. 



Colorado. (Wolle). 



Genus -GLOEOCAPSA Kuetzing. Phyc. Gen. 174. 1843. 



Plants spherical (or immediately after division oblong), either single 

 or a number associated in families; each cell enclosed in a vesicle-like, 

 strongly thickened, usually distinctly lamellose sheath; sheaths often very 

 thick, colorless or colored, usually lamellose; lamellae often peeling off; 

 cell contents blue-green, bluish, steel-blue, reddish, yellowish, etc.; repro- 

 duction by division of .the cells alternately in three directions. 



When a cell divides into two daughter-cells, each one secretes a sheath 

 about itself, the two still being enclosed by the sheath of the mother-cell. 

 As division goes on, the sheath of the original cell remains enveloping the 

 entire family, and in fact all the sheaths remain in existence. Therefore, 

 there will always be one less than twice as many sheaths as there are 

 cells in the family (in a family of four cells there will be seven sheaths; in 

 a family of sixteen cells there will be thirty-one sheaths). Later genera- 

 tions of cells are smaller than the first ones. 

 I Sheaths colorless 

 I Sheaths lamellose 

 (i) Sheaths wide 

 A Plant mass steel blue, green, olive or dull yellow; plants 7-8 mic. 

 in diameter; sheaths very wide, indistinctly lamellose; cells 3-5 

 mic. in diameter G. granosa 



B Plant mass dull green or olive; plants 3-4.5 mic. in diameter; 

 sheaths very thick, with numerous concentric lamellae 



G. polydermatica 

 C Plant mass green; plants 7-15 mic. in diameter; sheaths very thick, 

 more or less distinctly lamellose; cells 2.2-3.4 mic. in diameter 



G. fenestralis 



D Plant mass somewhat olivaceous; plants 6-17 mic. in diameter; 

 sheaths thick; cells 3.7-6 mic. in diameter G. arenaria 



(2) Sheaths narrow 

 A Plant mass pale yellow becoming greenish; growing in hot water; 

 plants 19-39 rnic- "n diameter; cells 3-6 mic. in diameter 



G. montana 



B Plant mass mucilaginous, dull green or gray becoming blackish, 

 or red becoming brownish; plants 7-11 mic. in diameter; cells 

 3-4.S mic. in diameter G. quaternata 



C Plant mass a calcareous crust, light gray or green; plants 6-9 mic. 

 in diameter G. calcarea 



