MYCOSPHAERELLACEAE 



211 



into the trichogyne. Septations in the ascogonial chain are then 

 dissolved, whereupon the antheridial nuclei migrate to the asco- 

 gonium and become associated in pafi's with the ascogonial nu- 

 clei. After this stage ascogenous hyphae are developed as out- 

 growths from the ascogonium. Meanwhile the uninucleate perid- 



FiG. 83. Ventiiria inaeqiialis. A. Edge of conidial stroma in vertical section. 

 The conidial stage is commonly known as Fiisicladiiim dendriticiim. B. 

 Section of perithecium innate in tissues of decaying leaves. C. Ascospores. 

 D. The fertilized ascogonium (diagrammatic), showing the multinucleate 

 condition after migration of nuclei from the antheridium. The septa of 

 the ascogonium have been dissolved. (After Killian.) 



ial cells have multiplied to form the wall of the developing 

 perithecium and the nurse tissue for the developing asci and 

 paraphvses. 



Physalospora. Several species of Physalospora are involved in 

 the production of important crop-plant diseases. These include 

 P. cydoniae on pomaceous fruits [Hesler (1916)] and P. jiisca 

 and P. rbodina on citrus [Stevens (1926)]. Physalospora cy- 

 doniae, the cause of apple black rot, leaf spot, and canker, was 

 shown by Hesler to possess a wide host range, including other 



