52 THE AGARICACEAE OF MICHIGAN 



23 et al. (Illustrating the abnormal form, Lent odium squa- 

 mulosum.) 



PILEUS 2-5 cm. broad, fleshy-leathery, at first orbicular, con- 

 vex then plane and umbilicate, white but covered, especially at the 

 center, with blackish-brown, hairy scales, margin at length wavy 

 and often split. FLESH white, thin. GILLS decurrent, some- 

 what narrow, close, white, edge eroded-serrate. STEM 1-3 cm. long 

 slender, tapering downward, solid, minutely scaly, whitish, white 

 within, often darker at base. At first with a delicate veil, which 

 may form an evanescent annulus. SPORES elliptical-oblong, 6-7 x 

 3-3% micr., smooth, white in mass, often copious. 



Gregarious. On dead wood, which is usually hard. Ann Arbor, 

 New Richmond. September. Infrequent. 



The umbilicate, thin, pileus, different scales, and much shorter 

 spores, distinguish it from L. l&pideus. It is at first soft, but be- 

 comes coriaceous in dry weather. Ricken gives the spore-length 

 almost twice that of the American plants. 



A monstrous form occurs, which is often more common than the 

 normal form or may be the only one found. This was placed by 

 Morgan in a new genus, Lentodium squawwlosum. Prof. Lyman 

 raised this form in the laboratory from spores and considered it 

 definitely distinct from L. tigriims, as indeed his results strongly 

 indicate. (See reference above to Lyman's paper.) Peck, however 

 (N. Y. State Mus. Bull. 131), points out that the monstrosity and 

 L. tigriims itself appear on the same log and considers this to show 

 that they are one and the same. Lyman never obtained the normal 

 form from his cultures of spores from basidia of Lentodium. 



The collection which I made at New Richmond was observed for 

 several weeks, and all stages were seen on the same pieces of wood 

 lying on the ground, both the perfect form with regular gills, and 

 the deformed form. The latter has the gills obliterated by an over- 

 growth of mycelium, so that the under side of the pileus presents an 

 even surface, much as in one form of Nyctalis asterophora. In the 

 light of Lyman's researches, this form must be considered as a 

 regular variation of this mushroom, whose tramal hyphae may 

 produce basidia aud spores without the development of true gills. 

 The monstrosity often becomes quite hard and woody in dry weather 

 and is unique among our fungi. 



