342 University of California Publications in Botany [^^ol. 6 



VIII. KEY TO GENEKA 



A. Ascocarp with distinct external openings from hymenium. 

 a. Cavity simple, empty. 



Spores generally smooth Hydnocystis. 



aa. Cavity dissected into labyrinthine canals. 



1. Canals connected, filled with hyphae, converging at apex or base. 



a:. Canals converging at apex, spores smooth FseudohaJsamia. 



XX. Canals converging at apex, spores sculptured PachyphJoeus. 



2. Canals unconnected, empty or filled with hyphae. 

 X. Canals empty. 



z. Paraphyses forming secondary cortex beyond asci, spores papil- 

 lose or verrucose Genea. 



zs. Paraphyses not forming secondary cortex beyond asci, spores 



papillose or verrucose Hydnotrya. 



XX. Canals filled with hyphae. 



z. Hymenial areas irregularly arranged between canals 



Eutuber. (Tuber). 



zz. Hymenial areas formed by enlarged ends of canals ....Piersonia. 

 AA. Ascocarp without distinct external openings from hymenium. 

 «. Asci and paraphyses arranged in palisade. 



1. Cavity simple, empty Hydnocystis. 



2. Cavity dissected into empty chambers or canals. 



X. Canals or chambers mostly connected, ascocarp tomentose, spores 



smooth Geopora. 



XX. Unconnected chambers redissected into connected canals, asco- 

 carp smooth, spores sculptured Hydnotryopsis. 



aa. Fruiting areas irregular; cavity wanting. 



Cavity wanting, ascocarp divided into irregular fruiting areas. 



X. Ascocarp comparatively even; asci 4-spored Bdastria. 



XX. Ascocarp conspicuously lobed; asci 8-spored Hydnobolites. 



IX. ACKNOWLEDGMENTS 



For his kindly and invaluable assistance tliroughont the prepara- 

 tion of this paper, I desire to express my appreciation to Professor 

 W. A. Setchell. Thanks are likewise due Professor H. M. Hall for 

 similar assistance, and Professor N. L. Gardner for the greater num- 

 ber of Californian specimens examined. I am indebted to Professor 

 Le Roy Abrams of Leland Stanford Junior University for kindly al- 

 lowing me the privilege of examining the Harkness collection ; also to 

 Professor C. H. Kauffman of the University of Michigan, and Pro- 

 fessor F. Butters of the University of Minnesota for specimens for 

 comparison received from those states. 



I wish to thank, also, those who have kindly assisted in the prepara- 

 tion of this paper for the press. 



