295 



The descriptions of species have been taken to a great extent from 

 the original descriptions and comments appended thereto, as given in 

 'North American Pyrenomycetes" by Ellis and Bverhart. In nearly all 

 cases, however, the writer has made some changes, and in some instances 

 the whole description has been rewritten to suit the specimens at hand. 

 All measurements of asci and spores are original. Where the measure- 

 ments given by Ellis and Everhart differ, their figures are given in paren- 

 theses. In some cases the measurements given by Saccardo are included 

 also. 



The identification of all species covered by this paper has been verified 

 by Dr. Charles H. Peck, State Botanist of New York, who was kind 

 enough to examine all our specimens. In a few cases the species was de- 

 termined by liim. I take this opportunity to express my thanks for his 

 assistance in this work. 



I am also indebted to Prof. J. M. Van Hook, of Indiana University, 

 for material placed at my disposal, and for aid and advice in forniulatin'.i; 

 this paper. 



Key to Species. 



I. Stroma large, irregular, thrown into folds or ridges, spores 8 microns 

 long or less 1. H. Petersii. 



II. Stroma more or less effused. 



A. Stroma broadly effused. 



1. Externally colored whitish or gray. 



a. Smooth, whitish, dotted with black ostiola 



2. TI. atropinictatniii. 



2. Externally colored not whitish or gray. 



a. Perithecia 2/3-1 mm. long, spores 11-13 microns long 



3. H. a tro pur pure It in. 



b. Perithecia 1/2 mm. long, spores 9-11 microns long 



-'/.//. rubiginosum. 



B. Stroma variously effused or confluent, usually in small areas. 

 1. Externally colored not black. 



a. Surface of stroma bright purple, ostiola not white-margined, 

 spores 12-1.1 microns long 5. H. fuscopurpurcum. 



b. Surface of stroma brown or slightly purplish, ostiola white- 

 niargined, spores S-11 microns long *6. H. perforatum. 



