ANALYTICAL KEY 



TO THE SUBORDERS, FAMILIES AND GENERA OF 



THE 



NORTH AMERICAN P Y R E N O M Y C E T E S AND 



H Y S T E R I A C E A E. 



The Nat. ORDER PYRENOMYCETES embraces those 

 fungi in which the asci and sporidia are enclosed in a perithecium, 

 and is divided into 4 SUBORDERS as follows: 



Perithecia superficial, astoiuous, membranaceous, 



mostly on a subiculum. Perisporiaceae. 



Perithecia carnose, or membranaceo-carnose, 



ostiolate, bright colored (red, yellow, etc..) 



not black. Hypocreaceae. 



Perithecia black or brown, mostly ostiolate, of 

 various consistence, membranaceous, co- 

 riaceous, carbonaceous, woody or corky, but 

 not carnose; stroma when present not car- 

 nose, dark colored outside, often white 

 within. Sphaeriaceae. 



Stroma always present, of firm texture not carnose, 

 black outside. Perithecia reduced to mere 

 cells in the stroma. Dothideaceae. 



KEY TO THE FAMILIES. 



SUBORDER PERISPORIACEAE. 



Mycelium of colorless, interwoven threads. Per- 

 ithecia seated singly on the mycelium, subglobose, 



