HORMOGONALES 



17 



r 



Nostocaceae: Cylindrospermum {cylindro, cylinder; spermum, 

 seed). Fig. 12. 

 A characteristic feature of this genus is the large spore which 

 develops next to the heterocyst at one or both ends of a filament. 

 The outer wall of the spore is often papillate. 



m^<:\^y^ 



B B A 



Fig. II. Fig. 12. 



Fig. II. Nostoc. A, portion of colony of N. Linckia ( x 400). B, C, germinating 



hormogones of N. punctiforme ( x 900). (After Geitler.) 



Fig. 12. Cylindrospermum. A, C. majus ( x 680). B, C. stagnate ( x 340). (After 



Geitler.) 



REFERENCES 



Chroococcus. Acton, E. (1914). An?i. Bot., Loud., 28, 433. 



Scytonema. Bharadwaja, Y. (1933). Arch. Protistenk. 81, 243. 



Chroococcus, Gloeocapsa, Microcystis. Crow, W. B. (1922). New Phytol. 

 21, 81. 



General. Crow, W. B. (1924). J. Genet. 14, 397. 



General. Crow, W. B. (1928). Arch. Protistenk. 61, 379. 



Systematic. Geitler, L. (1932). " Cyanophyceae " in Rabenhorst's 

 Kryptogamen Flora, 14, Leipzig. 



General. Poljanski, G. and Petruschewsky, G. (1929)- Arch. Pro- 

 tistenk. 67, II. 



Cytology. Spearing, J. K. (1937). Arch. Protistenk. 89, 209. 



CSA 



