Saprophytic Fungi of Eastern Iowa. 193 



45. Agaricus papilionaceus, Fr. 



Pileus yellowish, somewhat fleshy, hemispheric, smooth, the 

 cuticle sometimes breaking into scales; lamellae very broad, 

 adnate, at length jet black; stipe slender, firm, hollow, prui- 

 nose and slightly striate above. 



Height 3 '-5'. Pileus Yi' -'ki' - Spores elliptic, .008 X 

 .015 mm. 



Common. Occurs in similar places and with the preceding 

 species. Resembles A. semiglobahis, but has no annulus. 

 The very wide lamella distinguish the plant from No. 43. 



Siibgemis Psathyrella. 



Pileus membranaceous, striate, the margin not surpassing 

 the lamellee. 



46. Agaricus atomatus, Fr. 



Pileus whitish, sub-membranaceous, campanulate, obtuse, 

 striatulate, hygrophanous, rugulose when dry, covered with 

 minute, shining particles; lamellae adnate, broad, quite distant, 

 becoming black; stipe slender, flexuous, white. 



Height 2 '-3'. Pileus Y^' -V^' . Spores elliptic, .008 X 

 .012 mm. 



A very delicate species, distantly resembling Coprinus plica- 

 tilisy for which it is often mistaken. Our species are pure white, 

 except the disk, which is ochraceous or reddish. Common on 

 grassy lawns, the stipe rooting and mycelio-attached to the 

 decaying leaves and to the ground. 



GENUS COPRINUS, Fr, 



Hymenophore distinct from the stipe. Lamellae membra- 

 naceous, at first cohering, easily split, at length dissolving into 

 an ink}' fluid: trama none. Spores black. 



The species of this genus are easily known by their deli- 

 quescent lamellse. Some of them are exceedingly transient, 

 springing up in a night and melting with the advancing sun. 

 Most species grow about manure heaps, as the name of the 

 genus would apprise us, or on manured land, but some flourish 



