PSEUDOSPHAERIACEAE 



169 



Botryosphaeria ribis, first described as the cause of currant- 

 cane blight, is now known to parasitize the stems of over 50 

 species of woody plants. Its pycnidial stage, Macrophoma, ap- 

 pears on recently formed lesions. Accompanying the pycnidia 

 is another stage, Dothiorella, bearing minute spores in stromatic 

 locules. These microconidia are beheved to be spermatia [Wolf 



Fig. 61. Stroma in section showing pycnidium of Dothiorella stage of 

 Botryosphaeria ribis with conidiophoral cells and conidia. 



and Wolf (1939)]. Perithecial locules are initiated at the same 

 time that spermatia are being produced. This fungus produces 

 multinucleate conidia and multinucleate ascospores [Wolf and 

 Wolf (1939)], a condition like that described years ago for 

 Aspergillus repens by de Bary. 



IPsEUDOSPHAERiACEAE. The Pseudosphaeriaceac comprise or- 

 ganisms that have until recently been regarded as Sphaeriales. 

 Interthecal tissues remain, however, after the asci have matured. 

 These tissues are compressed as the asci enlarge and have been 

 designated pseudoparaphyses. Their stromata are spatially sepa- 

 rated, that is, are not fused, and are therefore perithecium-like in 

 appearance. 



