674 



The Hysteriacem 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 

 species thus far recorded as found in North America. 



KEY TO THE GENERA. 



A. Sporidia hyaline. 



* Sporidia continuous. 



Perithecia subcarbonaceous, flattened or convex, 



minute. ...... Schizothyriuin. 



** Sporidia uniseptate. 



Perithecia membranaceous, minute, simple or 



branched, flattened. - - - Aylographum. 



Perithecia carbonaceous, simple or obscurely 



branched. - - - - Glonium. 



Perithecia stellate. Actidium. 



Perithecia subcarnose. ..... Angelina. 



*** Sporidia 'd-pluriseptate. 



Perithecia carbonaceous. Gloniella. 



" subcoriaceous. - - - - Dichazna. 



**** Sporidia muriform. 



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-subcarnose. - Clithris. 



Perithecia subsphaeroid. - - - - - Ostropa. 



B. Sporidia brown. 



* Sporidia uniseptate. 



Perithecia coriaceous, widely dehiscent. - - Tryblidium. 

 Perithecia elongated, coriaceous. - - - (Lembosia). 



** Sporidia 3-pluriseptate. 

 Perithecia carbonaceous. ..... Hysterium. 



" coriaceous. {Tryblidiella). 





