44 THE AGARICACEAE OF MICHIGAN 



or slightly scaly. The color is various. The FLESH varies from 

 quite tough in some species to somewhat fleshy in others ; the latter 

 may become more tough with age so that several species are easily 

 confused with Pleurotus in the young stage. It is advisable to 

 compare specimens with both genera where the texture is in doubt. 

 The GILLS have an entire edge which distinguishes them from those 

 of the genus Lentinus which have lacerate, serrate, thin edges. They 

 become tough with age and are thickish. Intermediate forms occur, 

 especially among typical species, so that some authors combine 

 Panus with Lentinus. In our plants, however, the character of the 

 edge of the gills is the best means of separation. The STEM is 

 short, as a rule, sometimes continuous with the pileus, so that the 

 pileus is not marginate behind. It is usually hairy or scaly. The 

 SPORES vary in shape and size; they are smooth and white. CYS- 

 TIDIA are present in P. rudis and P. angustatus. 



Several of the species are very common, growing on stumps, de- 

 cayed branches, etc., in the cities, or on any sort of dead timber in 

 the woods and fields. The harmless species are rather tough for the 

 table, but can be used, according to Mcllvaine, to flavor soups and 

 gravies. 



The genus is divided into three sections, of which the following 

 include the species described below : 



I. Conchati. 



II. Stiptici. 



Key to the Species 



(A) Pileus sessile or prolonged laterally into a stem-like base, 

 (a) Pileus with a gelatinous layer, whitish or yellowish, spathulate 

 to fan-shaped. 16. P. angustatus Berk. (Syn. Pleurotus stratosus 

 Atk.) 

 (aa) Pileus without a gelatinous layer. 



(b) Gills when young covered by a fugaceous veil; pileus about 1 

 cm., cupulate, rufous. On alder bushes. P. operculatus B. & 

 C. 

 (bb) Without a cortina. 



(c) Pileus hygrophanous, small, pinkish-gray; gills dark fer- 

 ruginous; on willows. 17. P. salicinus Pk. 

 (cc) Pileus not hygrophanous, small, heaped in clusters, pale 

 brownish; taste very disagreeable, astringent. 15. P. stip- 

 ticus Fr. 

 (AA) Pileus with an eccentric stem; i. e. pileus marginate behind, 

 (a) Pileus white or creamy-white when fresh, becoming yellowish 

 when drying, 

 (b) Pileus often very large, densely strigose-hairy; whole plant be- 

 comes dull yellow when dried. 12a. P. strigosus B. & C. 

 (bb) Pileus up to 6 cm. broad, surface with long, delicate hairs, 

 margin reticulated. P. laevis B. & C. 

 (aa) Pileus reddish-brown to alutaceous-tan, medium size, margin at 

 first inrolled. 

 (b) Pileus rough with tufted hairs, tawny-alutaceous, etc., gills 



