THE POLYPORACEAE OF WISCONSIN. 125 



clear incarnate in color but incline to dull ferruginous and by this 

 character, this and the preceding species (B. conicus Rav.) connect this 

 tribe with the Versipelles. In color B. gracilis resembles some forms of 

 B. felleus, but in size, habit and color of spores it is easily distinct. The 

 tomentum of the pileus sometimes breaks into tufts or squamules. This 

 is Boletus vinaceus Frost MS." 



Two specimens were found near Stone Lake. They were at first 

 mistaken for a slender form of B. felleus. It seems that this species 

 bears the same relation to B. felleus that B. albellus bears to B. scaber. 



The pileus is 5 cm. in diameter ; the stem is 14 cm. long, 8 mm. thick, 

 The pileus is convex above and below brownish-ochraceous, slightly 

 tomentose, margin obtuse. The tubes were free, whitish, becoming pale 

 flesh-colored, their mouths medium, roundish, the spores ferruginous, 

 the stipe long and slender, with slightly anastomosing ridges and pale- 

 brownish or fibrous context, forms the most available character for 

 identifying the species. 



Boletus nigrellus Peck. 



Pileus broadly convex or nearly plane, dry, subglabrous, blackish, 

 flesh soft, white, unchangeable; tubes plane or convex, adnate, some- 

 times slightly depressed around the stem, their mouths small, subrotund, 

 whitish, becoming flesh-colored, slowly changing to brown or blackish 

 where wounded ; stem short, even, colored like or a little paler than the 

 pileus ; spores dull flesh-colored, 10 to 12.5 microns long, 5 to 6 microns 

 broad. Pileus 8 to 16 cm. broad ; stem 3.5 to 6 cm. long, 12 to 24 mm. 

 thick. 



Peck (21, 2, 8, p. 155) says: "The blackish color of the pileus dis- 

 tinguishes this species. From B. alboater Schw., the adnate, flesh-col- 

 ored tubes will separate it. The surface of the pileus sometimes becomes 

 rimose-areolate. ' ' Mcllvaine adds : ' ' Another distinguishing mark from 

 B alboater Schw., is the velvety pileus of the latter. B. nigrellus is mild 

 in taste and smell and an excellent species for the table. ' ' 



Collected at Devil's Lake August 15, 1906. Largest specimen 15 cm. 

 broad; stipe 8 cm. long, 2 cm. thick. Pileus fuliginous, very finely 

 tomentose, margin slightly incurved. Pores subadnate, sordid, later 

 pink flesh-color, changing to dark on wounding. Spores oblique-apicu- 

 late, twice as long as broad. Stem equal, slightly radicating at the base, 

 very finely wrinkled, dark fuliginous, solid, fleshy. Flesh spongy, soft, 

 sordid slowly changing to bluish then blackish. In this respect our 

 specimens differ from the description, and therefore their reference to 



