THE GENUS CLITOCYBE IN NORTH 
AMERICA 
William A. Murrill 
(With Plates 164-166) 
Before this large and difficult genus is published in North 
American Flora, it is thought advisable to present a preliminary- 
paper which will direct attention to the group and add to our 
knowledge of it through additional collections and observations. 
Species of Laccaria, formerly included in Clitocybe, have 
already been treated in North American Flora, volume 10, part 
I. Monadelphus is another small segregate of Clitocybe, which 
is characterized by a densely cespitose, wood-loving hymenophore. 
The relation of these two genera to Clitocybe and to the segre- 
gates of Tricholoma may be indicated in the following key: 
Lamellae decurrent or adnate. 
Spores not conspicuously verruculose or echinulate, usu- 
ally ellipsoid ; lamellae decurrent or adnate. 
Hymenophore usually solitary or gregarious ; subces- 
pitose to cespitose but not wood-loving in C. nittl- 
ticeps and a few other species. 
Hymenophore densely cespitose and wood-loving, at- 
tached to decayed trunks or roots. 
Spores conspicuously verruculose or echinulate, globose ; 
lamellae adnate. 
Lamellae sinuate; spores usually ellipsoid and smooth. 
Pileus smooth or inconspicuously decorated with fibrils 
or scales. 
Pileus conspicuously decorated with fibrils or scales. 
Clitocybe. 
Monadelphus. 
Laccaria. 
Melanoleuca. 
CoRTINELLUS. 
EASTERN SPECIES OF CLITOCYBE 
Some of the species here included are confined to the eastern 
United States, while others may occur throughout temperate 
North America, or even in Europe or Asia. So little is at present 
known of the Rocky Mountain region, that it will be treated 
temporarily as a part of eastern North America. The New 
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