268 



MANUAL OF POISONOUS PLANTS 



Fig 90. Stem Blight (Gibbellina cerealis), one of the 

 Sphaeriaceae. a, general appearance. b, asci with 

 ascospores and paraphyses. c, stroma, mycelium, and 

 perithecium. After Cavara. 



PERISPORIALES 



Perithecia spherical, closed, or with the ostiolum obscure, coriaceous or 

 brittle carbonaceous, opening irregularly, generally without stroma, but mostly 

 seated on a well developed, superficial mycelium. This division includes the 

 order Erysibaceae. 



ERYSIBACEAE 



Superficial mycelium, branching, septate, closely adhering to the surface by 

 means of the haustoria; asci arising from the base of the perithecium, delicate, 

 thin-walled, colorless, oblong, obovate or suborbicular, stalked, usually contain- 

 ing from 2-8 ascospores; perithecium spherical with appendages, without 

 ostiolum; conidia (Oidium) simple, colorless, cylindrical, oval or ovate, borne 

 one above the other on septate, colorless hyphae. Contains many important 



