130 THE AGARICACEAE OF MICHIGAN 



sordid reddish or reddish-brown. STEM 3-0 cm. long, 1.5-3 cm. 

 thick, stout, spongy-stuffed, rather brittle, equal or tapering down, 

 uneven, white at first becoming reddish or reddish-brown in age or 

 from handling. SPORES subglobose, echinulate, with large oil- 

 globule, 8-10x7-8 inicr., white in mass. TASTE mild or slightly and 

 tardily acrid. ODOR becoming disagreeable in age or on drying, 

 like that of R. squalida Pk. 



Gregarious. On the ground in beech and maple woods. New 

 Richmond. August-September. Rare. 



This is a very distinct species. The whole plant becomes diffused 

 with the rusty-reddish color which is at first pale incarnate, but be- 

 comes more marked as the plant ages. The stem has the consistency 

 of that of Boletus castaneus or B. cyancscens but the interior be- 

 comes cavernous less readily than in those plants. The scanty juice 

 which causes the color change has the same relation to the flesh as 

 that which causes the reddish and then blackish color in R. nigricans. 

 The disagreeable odor of the drying plant is quite marked, and is 

 an aid to its identification. It is probably quite rare; it was found 

 only a few times in New York by Peck but has been reported by 

 Van Hook from Indiana. R. mewrnata Morgan (Oinn. Soc. Nat. 

 Hist., 1883) is probably identical. The edges of the gills are pro- 

 vided with microscopic, subcylindrical. sterile cells. In age the plant 

 becomes quite fragile. Peck's figure is not at all illustrative of the 

 .colors. 



RIGIDAE. Flesh compact, rather thick. Pileus rigid, provided 

 with an adnate cuticle which often cracks or disappears in parts df 

 the surface, especially on disk, mostly separable only at the margin. 

 Gills usually somewhat forked, and with shorter ones intermingled. 



The subgenus differs from the Compactae in that the gills do not 

 alternate regularly as long and short and by the presence of an 

 adnate pellicle; it differs from the Subridgidae and Fragiles, by the 

 more rigid substance of the pileus, the adnate pellicle, the presence 

 of short gills and usually by the forking of some of the gills 

 especially at or near the stem. Most of the species are mild or 

 very slightly acrid. 



Section I. Margin of pileus obtuse, cuticle soon dry, at length 

 pulverulent, granular or rimosely-cracked in places. Gills broader 

 anteriorly. 



