PLEUIIOTUS. 363 



Hygrophorus livido-albus. Fries, Epicr., p. 324 ; Ckc., Illustr., 

 pi. 915; Cke., Hdbk., p. l'9;J. 



In woods. 



Somewhat resembling H. ebnrnem in habit and size, but 

 distinguished by the livid colour of the pileus and the gla- 

 brous stem. 



PLEUROTUS. Fries, (figs. 12, 13, p. 301.) 



Pileus excentric, fleshy or membranaceous, sometimes re- 

 siipinate ; gills usually decui rent, sometimes determinate 

 behind, or not running down the stem, rarely abruptly 

 adnate, margin acute ; stem expanding gradually into the 

 flesh of the pileus, excentric, truly lateral, or absent ; veil 

 pre.^ent in some species ; spore more or less elliptical,, 

 smooth. 



Pleurotus, Fries, Epicr., p. 129 ; Cke., Hdbk., p. 101. 



The principal feature of the genus is the excentric or 

 lateral stem. Most species grow on wood, twigs, moss, &c., 

 rarely on the ground. In some of the higher species, P. cor- 

 ticatus, P. ulmarius, P. spodoleucus, &c., the stem is sometimes 

 central, and the pileus regular and horizontal. On the other 

 hand, certain species of Ciitocybc and Omplialia when growing* 

 from an oblique or lateral substratum become excentric and 

 oblique. In Lactarius, Canlharcnus, Marasmius, and the whole- 

 of the other Leucosporae, there is nothing analogous with 

 Pleurotus. (Fries.) 



ANALYSIS OF THE SPECIES. 



I. EXCEXTRICI. 



Pileus entire, extended laterally, excentric but not truly 

 lateral. 



* Veil forming a ring on the stem. 



** Veil absent ; gills sinuate or obtusely adnate. 



*** Veil absent ; gills deeply decurrent ; stem distinct* 

 more or less vertical. 



