656 THE AGARICACEAE OF MICHIGAN 



seems necessary. Schroeter gives 13-15x4-5 micr. as the size of 

 the spores of A. corticata, a measurement nearly equal to the spore 

 Length of our form. The size of the spores of A. dryina is not men- 

 Honed by most authors; Massee says they are 10x1 micr. Large 

 specimens of this species when the veil has disappeared, might be 

 mistaken for Pleurotus ulmarius or Panus strigosus; but P. ul- 

 marius lias sinuate-adnexed gills and P. strigosus has a nap of 

 strigose-villose hairs on cap ami stem and is much larger. 



Pleurotus Fr. 

 i From the Greek, pleuron, a side, and oils, an ear.) 



White-spored, (except P. sapidus and P. subpalmatus) . Stem 

 fleshy, eccentric, lateral or lacking, continuous with the pileus. 

 <;ills adnate, adnexed or decurrent. Veil none. 



Putrescent, (except P. atrocaeruleus P. atropellitus, P. niger, and 

 P. st rial ul as) , lignicolous, medium to large, or often small and 

 then resupinate. Intergrading with the genera Clitocybe and Ariuil- 

 laria. They correspond to the genera Claudopus and Crepidotus 

 of the pink-spored and ochre-brown-spored groups respectively. All 

 are believed to be edible, and are considered by many people the 

 most delicious of our mushrooms when properly prepared. 



The PILEFS varies from quite large in those attached laterally 

 or with a stem, to quite small when it is resupinate. P. ulmarius 

 and P. ostrcutus and their near relatives have a thick, fleshy pileus 

 and ample gills, thus providing a large amount of food for the 

 mushroom enthusiast. The small species are rather thin, often 

 membranous; four of the species revive on moistening. Our large 

 species are nearly all white when fresh, becoming tan-colored or 

 darker when old. and are always firm and even tough in age. The 

 medium-sized species are ashy, greenish, yellowish or reddish in 

 color. The small forms are white, gray or blackish. Several are 

 hygrophanous. Several have a gelatinous or viscid upper layer, of 

 which the thick-fleshed J', serotinus is the most note-worthy. The 

 <iILLS are fastened to the stem, but their mode of attachment is 

 so differenl in the various species as to have given some authors 

 ground for making distinct genera out of the sections. In some 

 they are deeply decurrent as in Clitocybe, in others, sinuate-ad- 

 nexed as in Tricoloma, and in the resupinate and lateral species 

 they radiate from the point of attachment of the pileus as in 

 Crepidotus of the ochre-brown-spored group. In the large species 



