1914] 
BURT—THELEPHORACEJE OF NORTH AMERICA. I 193 
system has been communicated to my correspondents in con- 
nection with specimens. Its principal features are: 
1. To restrict Thelephora to pileate species with simple basi- 
dia and colored spores. 
2. To follow Karsten and Bresadola in placing under Hypoch- 
nus only resupinate species with colored echinulate spores. 
9. To restriet Stereum to pileate species which have simple 
basidia and colorless spores and lack sets in the 
hymenium. 
4. 'To include in Hymenochate all species having setze. 
5. To include in Corticium species always resupinate, which 
have colorless spores and lack cystidia, excepting those 
species which for other reasons are placed іп Exobasidium. 
Include in Corticium hypochnoid as well as compact 
species. 
6. To include in Peniophora all species which differ from 
Corticium merely by the presence of cystidia. 
I find this system workable and very satisfactory for the 
accurate location of species in genera, except in the case of the 
species intermediate between Peniophora and Corticium. The 
proposals to subdivide Peniophora into Gleocystidium, Penio- 
phorella, Gleopeniophora, etc., would create large numbers of 
species intermediate between the new genera, without compen- 
sating advantages. 
I have studied the species of my predecessors and co-workers 
sympathetically and have endeavored to find real differences 
between their species and those previously known so that the 
validity of theirs might be confirmed. The great area of land 
covered by the present work, the differences in climate and 
substratum, and the keen search by my correspondents have 
brought to hand a very large number of specimens. I have 
earnestly striven to place them under species already known, 
but it has been necessary to describe many as new. I regret 
that there are so many of these. Should any one have reason 
to believe that in any case I have described as new a species 
already known, I shall esteem it a favor to receive an authentic 
specimen of the older species or to be informed where such a 
specimen can be consulted. 
