676 THE AGARICACEAE OF MICHIGAN 



adnate or truncate-adnexed, becoming emarginate. Pileus viscid 



or dry. 



Putrescent, terrestrial, fleshy, firm and rather large mushrooms. 

 A large -vims, approaching Clitocybe and Pleurotus, being sepa- 

 rated from the former by the non-decurrent gills, from the latter 

 by the central stem. Collybia is distinguished by its cartilaginous 

 stem, and by the absence of a cortina, and more often grows on 

 wood or decayed leaves, etc. The trama of the gills is composed 

 of parallel hyphae which distinguishes them from those Hygrophori 

 which are similar in appearance. The genus corresponds to Hebe- 

 loma, Entoloma and Hypholoma of the ochre, pink and purple- 

 spored groups. Many of them are edible, and their thick flesh fur- 

 nishes considerable substance; on the other hand several species 

 are known to be poisonous and must be avoided. 



The PILEUS may be glabrous, silky or in some species scaly; 

 viscid, dry or hygrophanous. Accordingly they are placed under 

 corresponding sections of the genus. The colors are seldom bright, 

 although several are sulfur-yellow and others purplish or lavender. 

 Many of them are dull whitish to gray or tan, sometimes umber or 

 blackish. The character of the margin of the pileus is used exten- 

 sively to determine to which sub-genns they belong. It is, there- 

 fore, important to observe carefully the presence or absence of 

 silky fibrils or flocei on the margin, as their presence indicates a 

 slight cortina in the very young stage and suggests the sub-genns 

 Cortinellus. The viscidity indicates the subgenus Limacina, al- 

 though species of other sections sometimes become slightly viscid 

 or gelatinous in very wet weather. The (JILLS are used to separate 

 this genus from (Titocybe. Theoretically, they are always emwrgi- 

 nate behind, but this condition varies considerably. It is true, that 

 in the mature plant, when the pileus is fully expanded, they become 

 either sinuate or emarginate in most cases, although a single speci- 

 men may not always be normal in this respect. When young, how- 

 ever, they often do not show this character clearly, but are then 

 adnexed, rounded-adnate, or adnate in such a way that they are 

 merely a Little less broad at the attached portion than they are 

 a few millimeters away from the stem, and this short distance is 

 often marked by a straight edge rather than by a rounded edge. 

 Such a condition may he referred to as truncately -adnate, rather 

 than as adnexed. In old stages the gills may even become spuri- 

 ously decurrent, and their Tricholoma nature is then evident only 

 by a slight sinuate portion near the stem, since in Clitocybe the 



