LITERATURE CITED 121 



members of all families of Mucorales, but it was unable to attack 

 members of any other class of fungi. 



The genera Choanephora and Blakeslea are of unusual interest 

 in several respects. In nature both form copious sporangiophores, 

 having the luster of a rifle barrel, on a variety of plant tissues. 

 Actually acres of freshly mowed Sida spinosa in Florida have 

 been observed covered with Blakeslea trispora [Weber and Wolf 

 (1927)]. Both are tropical to subtropical species, although 

 Choanephora aiciirbitantm extends farther northward than does 

 B. trispora. Choanephora ciiciirbitannn is abundant every sum- 

 mer on cotton, cucurbit, and cowpea flowers [Wolf (1917)] 

 throughout the southeastern United States. Blakeslea trispora 

 has been collected only once as far north as Durham, North 

 Carolina. 



In nature both genera are known to produce only their spo- 

 rangial (sporangiole) stage. In culture, however, true nodding 

 sporangia and zygospores are readily developed. The sporangio- 

 spores of both are striate and are provided with polar tufts of 

 delicate hairs. 



All species of Pilobolus are adapted to a coprophilous habit and 

 react positively to the source of light. The researches on this 

 problem, especially the physical and chemical principles involved 

 in this phototrophic reaction, are summarized in Buller's Re- 

 searches on Fungi (1934). Brief consideration is given this mat- 

 ter in Chapter 6, Volume II, of the present work. 



LITERATURE CITED 



Ayers, T. T., "Parasitism of Dispira cormeta,^^ MycoL, 27:235-261, 1935. 

 Blakeslee, a. F., "Sexual reproduction in the Mucorineae," Proc. Aui. 



Acad. Arts Sci., 40:205-319, 1904. 

 "Zygospore germinations in the iVIucorineae," Aiui. MycoL, 4: 1-28, 1906. 

 "Sexuality in mucors," Science, n.s., 51: 375-409, 1920. 

 BuLLER, A. H. R., Researches on fimgi, Vol. 6. 224 pp. Longmans, Green 



and Co., London. 1934. 

 BuRGEFF, H., "Untersuchungen iiber Variabilitat, Sexualitat, und Erblich- 



keit bei Phy corny ces nitens Kunze," flora, 107:259-^16; 70^:353-448, 



1915. 

 Callen, E. O., "The morphology, cytoIog\% and sexuality of the homo- 



thallic Rhizopns sexualis (Smith) Callen," Ann. Botany, n.s., 4: 791-818, 



1940. 



