518 FUNGI IMPERFECT!. 



as important parasites. Amongst these are the foUowing British 

 and Xortli American species : 



M. brassicae Herk. On cabbage, generally somewhat decayed. 



M. sarcinula Berk. On cucumber. 



M. nobile Vize. On Diant/mtt. 



M. alliorum ( 'ke. et Mass. On onion. 



M. ramulosum Sacc. On celery. 



M. catalpae Ell. et Mart. On Catulpa Bignonioides. 



M. nigricantium Atks. is a semi-parasite accompanying other diseases 

 of the cotton plant. 



Mystrosporium. 



" Allied to Macrosporium, l^ut distinguished by the more rigid 

 and darker-coloured hyphae and conidia " (Massee). 



Mystrosporium abrodens Neumann.^ This is described as 

 the cause of a disease which destroyed one-tenth of the total 

 wheat-crop in the Haute- (laronne of France. The fungus 

 attacked the nodes and leaves, forming dark patches ; the nodes 

 were weakened and frequently broke over, while the ears were 

 badly developed. 



Alternaria. 



Conidia grey, muriform-se])tate, flask-shaped, and borne on 

 short simple conidiophores. 



" Distinguished by the clavate or flask-shaped muriformly 

 septate olive conidia being united in chains and connected 

 by narrow isthmus-like portions " (Massee). 



Alternaria brassicae (Berk.) (Britain). This species causes 

 on leaves roundish black spots marked with concentric brown 

 zones. The mycelium lives in the leaf-parenchyma and gives 

 off tufts of conidiophores through the stomata. Briosi and 

 Cavara state that it causes considerable damage to Brassica 

 oleracea, Cochlearia officinalis^, and Armorrma. (Probably th(^ 

 same species as Polydcsmus cxitiosns Kuhn.) 



Other diseases have been ascribed to species of Altenxiria. 



Septosporium. 



Conidia brown, and muriform-septaie. Coniditjphores of two 

 kinds — short and fertile, or elongated and sterile. 



Septosporium heterosporum Ell. et (Jail, causes a leaf- 



1 "Un nouveau parasite de ble."' Sodet6 de Biolog. a Toulouse, 1892. 



