674 



The Hysteriacece form the connecting link between the Pyreno- 

 mycetes and Discomycetes, but on account of their mostly carbona- 

 ceous perithecia and the character of their sporidia, seem more closely 

 allied to the former. It was not at first intended to include the 

 Hysteriacece. in this work, and no drawings were made to illustrate 

 the genera; but as many members of this group are widely diffused 

 and often met with, it seems better to give a brief account of the 

 speci-es thus far recorded as found in North America. 



KEY TO THE GENERA. 



A. Sporidia hyaline. 



* Sporidia contimious. 



Perithecia subcarbonaceous, flattened or convex, 



minute. Schizothyrium. 



** Sporidia uniseptate. 

 Perithecia membranaceous, minute, simple or 



branched, flattened. Aylographum. 



Perithecia carbonaceous, simple or obscurely 



branched. Olonium. 



Perithecia stellate. Actidium. 



Perithecia subcarnose. Angelina. 



*** Sporidia 3-pluriseptate. 



Perithecia carbonaceous. Gloniella. 



subcoriaceous. Bichcena. 



**** Sporidia muriforni. 



Perithecia carbonaceous. (Gloniopsis). 



***** Sporidia ^filiform. 



(a) Sporidia much shorter than the ascus. 

 Perithecia membranaceous, flattened. - Hypoderma. 



(b) Sporidia nearly as long as the ascus. 

 Perithecia elongated, flattened, membranaceous. Lophodermium. 

 Perithecia elongated, conchiform, subcarbonaceous. Lophium. 

 Perithecia elongated, coriaceo-aubcarnose. Clithris. 



Perithecia subsphasroid. Ostrona 



B. Sporidia brown. 



* Sporidia uniseptate. 



Perithecia coriaceous, widely dehiscent. Tryblidium. 



Perithecia elongated, coriaceous. {Lembosia). 



** Sporidia 3-pluriseptate. 



Perithecia carbonaceous. Hysterium. 



coriaceous. (Tryblidiella). 



