MYCOLOGY 



black mould to spread rapidly and it sometimes chokes out other moulds 

 growing in competition with it on the same nutritive medium. In 1818, 

 on account of this method of growth, it was named by Ehrenberg 

 Mucor stolonifer. Related to this fungus is one named Rhizopus ory- 

 zecB which grows in Ragi. The fungus Phycomyces nitens is found in 

 empty oil casks, on oil cakes and in concentrated fodder. It puts forth 

 stifif sporangiophores 7 to 30 cm. long and 50 to 150/i in diameter which 

 bear at the summit black globular sporangia 0.25 to i.o mm. in diame- 

 ter, filled with yellow-brown, thick- walled endospores, 16 to 30/i 

 long and 8 to 15/x broad. Its zygospores are 300/x broad and their 



Fig. 31. — Black Mould, Rhizopus nigricans. A, Mature plant showing rhizoidal 

 hyphse {myc)\ stoloniferous hypha {st); sporangiophores (sph); sporangia (sp). B, 

 Younger cluster of sporangiophores and sporangia. (After Gager.) 



borders are covered with many forked projecting hyphae known as 

 suspensoria. Recently H. Burgeff^ has studied the variability, sex- 

 uality and heredity of Phycomyces nitens and has brought his cultural 

 investigations into line with the recent developments of cytology and 

 genetics. His paper should be read by all students, who may be 

 interested in the extension of the methods of genetics into an 

 investigation of the lower plants. 



The genus Absidia includes five species. In these fungi the suspen*- 

 sors are borne at the base of the two gamete cells which fuse to form the 

 zygospore, which when mature is covered by a basket-like covering of 



1 BuRGEFF, H.: Untersuchungen liber Variabilitat,. Sexualitat und Erblichkeit 

 h&i Phycomyces nitens Kuntze. Flora, Band 108: 353-448; review by G. V. Ubisch 

 (Dahlem) in Botanisches Centralblatt, Band 128, Nr. 23: 630-632, 1915. 



