THE AGARICACEAB OF MICHIGAN 

 723. Tricholoma ustale Fr. 



Syst. Myc. 1821. . 



Illustrations: Fries. Icones, PL 2(5. 

 Cooke, 111., PL 88. 



Michael. Fiihrer f. Pilzfreunde, Vol. Ill, No. 115. 

 Ricken, Blatterpilze, PL SS, Fig. 3 (represents form B.j. 

 Plate CXLVI of this Report. 



PILEUS 4-10 cm., broadly convex, obtuse or subumbonate, sub- 

 gibnous, reddish-lay to dark chestnut, sometimes paler, viscid, 

 naked, even, not virgate nor scaly, margin persistently incurved. 

 FLESH white, thickish, firm, rufescent. GILLS adnate-seceding 

 or emarginate, moderately broad, crowded, pure white at first then 

 rufescent or reddish-brown when bruised, edge eroded. STEM 5-8 

 cm. long, 8-15 mm. thick, subequal or irregularly compressed, often 

 rooting, stuffed, sometimes hollow, white, becoming reddish down- 

 wards, floccose-pruinose, sometimes twisted. SPORES elliptical- 

 ovate, 6-8x4-5 micr., white. CYSTIDIA and sterile cells none. 

 ODOR none; TASTE Utter. 



Solitary or subcaespitose. On very decayed wood or leaf-debris 

 in conifer or frondose woods. Ann Arbor, New Richmond. Septem- 

 ber-October. Rare. 



This is allied to the European species T. flavobrunneum and T. 

 pe,ssundatum which are said to possess a distinct farinaceous odor, 

 while in T. ustale this odor is lacking. From T. transmutans it is 

 separable by the spores and the rooting stem. Two forms — already 

 mentioned by Fries (Icones) — have been found in the State. (A) 

 Large, with the base of the stem ending in a root-like prolongation 

 which is 2-5 cm. long, and occurs in conifer woods (white pine). 

 i Hi Smaller, with a narrowed, short subrooting base, growing in 

 frondose woods. Form (A) is illustrated by Plate CXLVI, and is 

 rather well represented by Cooke's figure of T. flavobrunneum (111., 

 Plate 58), which may be the same plant. There was no yellow 

 presenl in our specimens. 



SUBGENUS II. CORTINELLUS. Pileus dry, not absorbing 

 water, nor hygrophanous ; silky, fibrillose or somewhat scaly, some- 

 times subglabrous. Margin of pileus slightly fibrillose or floccose 

 \\ itli remains of an evanescent cortina, except in species of "Rigida." 



Cortinellus has been raised to the rank of an independent genus 



