710 THE AGARICACEAE OF MICHIGAN 



749. Tricholoma tumidum Fr. 



Syst. Mycol., 1821. 



Illustrations : Cooke, 111., PL 93. 



Michael, Fiihrer f. Pilzfreimde, Vol. Ill, No. 111. 

 Plate CLII of this Report. 



PILEUS 6-10 cm. broad, firm, convex-expanded, then plane or 

 broadly depressed, moist, regular at length wavy, glabrous, some- 

 times watery-spotted, clouded with gray to brownish-gray especially 

 on disk, whitish on margin, even, margin thin and at first tomentu- 

 lose. FLESH white, slightly and slowly cinerascent, thin on mar- 

 gin, rather brittle. GILLS adnexed, then deeply sinuate, broad, sub- 

 distant, ventricose, at first shining white then slightly cinerascent, 

 brittle, scarcely intervenose, edge entire. STEM 5-7 cm. long, 1.5- 

 2 cm. thick, stout, solid, compact spongy within, subequal or sub- 

 bulbous, sometimes abruptly subradicating, glabrous, slightly 

 scurfy at apex, white then slightly cinerascent. SPORES minute, 

 subfusiform-elliptic, smooth, 5-6 x 3 micr., white. CYSTIDIA and 

 sterile cells none. ODOR and TASTE mild. 



Scattered or singly. On the ground among fallen leaves, etc., in 

 frondose woods. October. Ann Arbor. Infrequent. 



A rather noble plant when fresh, rather firm at first, becoming 

 brittle. It was placed by Fries in section Rigida, but is placed here 

 because of its similarity to T. cinerascens. The pileus has a slight- 

 ly raised circular ridge a short distance from the margin as indi- 

 cated in Cooke's figure. In some individuals the pileus was marked 

 by watery spots toward the margin (like those on the stem of 

 Lactarius scrobiculatus) and sometimes it was slightly oehraceous- 

 stained. The thin margin at length becomes subplicate-crenate. 

 The stems are not ventricose nor is the cap as dark, but other- 

 wise it seems to have all the marks of the species figured by Cooke 

 and Michael. It differs from T. cinerascens which it approaches 

 closely in color, by its more rigid habit and by its subdistant gills 

 which do not separate easily from the trama of the pileus. 



