218 



THE ASCOMYCETES 



pomaceous species and about a score of forest trees and shrubs. 

 Its conidial stage is Sphaeropsis rimlonim. Physalospora fzisca 

 and P. rhodina are associated with the imperfect Genus Diplodia. 



Fig. 84. Physalospora cydomae. A. Perithecium in section. B. Ascus and 

 paraphvses. C. Ascospores. D. Pycnidium, in section, of Sphaeropsis 

 ?nalorn7?2, the conidial stage. E. Conidia. F. Stages in conidial formation. 



(Adapted from Hesler.) 



Diplodia natalensis, a cause of stem-end rot of citrus, is the conid- 

 ial stage of P. rhodina. Stevens (1926) regards P. gossypina, 

 with its associated Diplodia gossypina, as synonymous with P. 



