134 THE AGARICACEAE OF MICHIGAN 



equal or slightly tapering downward, white or tinged rosy-pink, 

 spongy-stuffed, rattier rigid, obscurely wrinkled. SPORES sub- 

 globose, 9-10 x 7-8 (incl. apiculus), with oil-drop, rough or partly 

 smooth, almost pure loJiite in mass. ODOR none or very slightly dis- 

 agreeable. TASTE mild, sometimes slightly bitterish-subacrid. 

 CYSTIDIA moderately abundant, subcylindrical, 70-75x10-12 micr. 



Gregarious or solitary. On the ground in frondose woods. Ann 

 Arbor, Detroit. July-August. Rather rare. 



This plant occurs rather rarely in southern Michigan. It differs 

 from the description given by Bresadola (see translation Mich. 

 Acad. Rep. 11, p. 68, 1900) in that the spore-mass is nearly white, not 

 straw color, and the gills are only slightly thickish. I have found 

 specimens only during a few seasons. Peck also reports it uncom- 

 mon in New York. The margin of the pileus is sometimes slightly 

 viscid and the cuticle slightly separable on the margin. It must not 

 be confused with R. mariae whose cap and stem are less rigid and 

 more deeply colored, and which has creamy-yellowish spores and lar- 

 ger cystidia. Our plant sometimes has an entirely rose-red cap, some- 

 times, especially when older, approaching the colors of R. decolorans 

 but paler and duller, subp»ruinose when dry and variegated with 

 pinkish, yellowish or pale-orange hues becoming white in spots. It 

 is often rigid for a long time. 



Section II. Margin of pileus acute or subacute, at first incurved ; 

 cuticle viscid, slightly separable only on margin, often disappearing 

 on disk or in spots. 



109. Russula pulverulenta Pk. 

 Torr. Bot. Club, Bull. 29, 1902. 

 Illustration: Plate XVI of this Report. 



PILEUS 3-5 cm. broad, rather rigid at first, then fragile, rather 

 thin, broadly convex at first, expanded and depressed to subum- 

 bilicate, at first even on the margin, at length distinctly tuberculate- 

 striate, cuticle adnate, viscid, separable on margin, in very young 

 stage sulphur-yellow, soon ochraleucous, finally dingy yellowish 

 hrown, surface dotted by small, numerous, pale yellow, somewhat 

 mealy or foccident scales or granules, margin at very first incurved- 

 subinrolled. FLESH white, at first firm and tough, finally soft. 

 GILLS narrowly adnate, close, rather narrow, broader toward front, 

 ivJdte, unchanging, often bifurcate at stem, intervenose. STEM 3-5 



