No. 104.] 65 



white color, sessile pileus, and its lamellae forking or even anastomos- 

 ing near the base in large specimens. 



I find no good characters by which to distinguish Agaricus nephre- 

 tus, Ellis, from this fungus. The spores in this, as well as in P. stria- 

 tulns, P. niger and some others, have a slight depression on one side, 

 which makes them broader in one diameter than in the other, and 

 gives them a slightly curved appearance when viewed edgewise. 



Pleurotus septicus, Fr. 



Wood-rotting Agaric. Thin Pleurotus. 



Agaricus piibescens, Sow. 



Pileus small, thin, three to six lines broad, nearly plane, pubescent 



or suhpulverulent , sessile or with a short white pubescent stem or 



stem-like base, pure white; lamellae rather broad, sitbclistant, white ; 



spores subglobose, .00016 to .0002 in. broad. 



Decaying wood. Ballstoii and Adirondack mountains. August. 

 The clear white color ot J\ porrigens is seen also in this species, 

 which may be easily distinguished by its smaller size, nearly pubescent 

 pileus, subdistant lamella) and smaller sporeS. 



Pleurotus atrocaBr ulcus, Fr. 

 Dark-blue Agaric. Blue-black Pleurotus. 

 Agaricus alne^is, Schaeff. 



Pileus fleshy with an upper brownish gelatinous stratum, one to two 

 inches broad, convex or nearly plane, reniform dimidiate or obovate, 

 rutlier tough and flexible, sometimes Cffispitosely imbricated, sessile, 

 villose-tomentose, dark-blue, blackish, grayish or tawny-brown, flesh 

 soft, whitish ; lamellre rather broad, close, whitish or yellotoish; spores 

 elliptical, .00025 to .0003 in. long* .00016 to .0002 broad. 



Decaying trunks and branches of beech, alders and poplars. Kar- 

 ner. September. Buffalo. G. W. Clinton. 



I have seen no American specimens with the dark-blue or indigo 

 color shown in the published figures of the European plant, but Fries 

 himself says that the pileus is sometimes brown, so that we have no 

 doubt of the specific identity of our plant. The pileus is covei*ed 

 with a grayish or cinereous villosity, which in small specimens forms 

 a thin uniform velvety pubescence, but in large specimens it is more 

 dense and somewhat tufted. Sometimes it is much thinner on the 

 margin than toward the base of the pileus, and in such specmiens the 

 real color of the pileus is best seen on the margin. This, in large 

 specimens, is often wavy or somewhat lobed. Small, blackish forms 

 frequently resemble large forms of the next species, but are dis- 

 tinguishable by the paler color of the lamellas. The plant readily 

 revives on the application of moisture. 



Pleurotus atropellitus, n. sp. 



Black-skinned Agaric. 



Pileus very thin, three to eight Imes broad, rather tough, flaccid. 



resupmate or reflexed and lateral, convex or nearly plane, suborbicuiar 



obovate or reniform, villose-tomentose except on the margin, sessile or 



[Assem. Doc. No. 104.] 9 



