BSFOBT OF THE STATE BOTANIST 177 



genus under the name Lacoaria laocata. It is closely related to 

 Clitocyhe ochropurpurea B. & C, a much larger species with a 

 paler cap and brighter gills, and a short thick stem and often an 

 irregular deformed development. This also should be associated 

 with it generically under the name Laccaria ochropurpurea, if 

 that genus is sustained. 



Pleurotus Fr. 



The genus Pleurotus scarcely differs from Tricholoma and 

 Clitocyhe except in the relative position of the stem and the cap. 

 In these genera the cap is supported by a stem which is attached 

 to it centrally. In Pleurotus the stem is attached to the cap at 

 some point to one side of the center. Sometimes this point is on 

 the very margin of the cap, and in a few species the stem is 

 scarcely developed at all. Some of the species have the gills 

 rounded or notched at the inner extremity as in the genus 

 Tricholoma, and some have them decurrent on the stem as in 

 Clitocyhe. A distinctive character which is worthy of notice in 

 this genus is found in the habitat. All the species, with which 

 we have to do, grow on dead wood, while those of the two pre- 

 ceding genera, so far as here given, grow on the ground. Gen- 

 erally their flesh is more tough than in terrestrial species. 

 Sometimes they grow from dead spots or dead branches of living 

 trees, and are often out of reach, being far up from the ground. 



Stem present, distinct 1 



Stem wantiug or indistinct P. ostreatus. 



1 Spores white P. ulmarius. 



1 Spores faintly lilac-tinted p. sapidug. 



Pleurotus ulmarius Bull. 

 Elm Pleukotus. 



Plate 86. Figs. 1 to 4. 



Pileus convex or nearly flat, firm, glabrous, white or centrally 

 tinted with reddish-yellow or brownish-yellow, flesh white; 

 lamella) rather broad, rounded or notched at the inner extremity, 

 adnexed, white or creamy white ; stem firm, eccentric, generally 

 curved, white or whitish ; spores globose, white, .0002 to .00025 

 in. broad. 



The Elm pleurotus, or elm tree mushroom, is a conspicuous 

 object, growing, as it generally does, from dead places in or on 

 23 



