THE POLYPORACEAE OF WISCONSIN. 131 



ish. The flesh and tubes change instantly to a dark dull blue, almost 

 black where bruised. One of the specimens was minutely grayish- 

 tomentose toward the base of the stem, suggesting kinship to B. snivel- 

 utipes Peck, which however, has larger spores and is velvety hairy 

 toward the base. 



F. Edules. Tubes depressed, nearly free. Pores at first white-stuffed. 



Boletus edulis Bull. (Plate XXII, fig. 78) . 



Pileus convex or nearly plane, glabrous, moist, at first compact, then 

 soft, variable in color, grayish-red, brownish-red, or tawny-brown, often 

 paler on the margin, flesh white or yellowish, reddish beneath the cuti- 

 cle ; tubes convex, nearly free, long, minute, round, white, then yellow 

 and greenish ; stems short or long, straight or flexuous, subequal or bul- 

 bous, stout, more or less reticulate, especially above, whitish, pallid or 

 brownish; spores oblong-fusiform, 12.5 to 15 microns long, 4 to 5 mic- 

 rons broad. 



Var. clavipes. Stem tapering upward from an enlarged base, every- 

 where reticulated. Pileus 10 to 15 cm. broad ; stem 5 to 15 cm. long, 2 

 to 5 cm. thick at base. 



Both the species and the variety are common here. Localities: Devil's 

 Lake, Crystal Lake, The Dells and Blue Mounds. The species grows 

 luxuriantly reaching a diameter of 25 to 30 cm. Deeply cracked forms 

 resemble B. frustulosus Peck. 



Boletus exiinius Pk. (Plate XXIII, fig. 79.) 



Pileus at first compact, subglobose or hemispherical, subpruinose, 

 purplish-brown or chocolate color, sometimes with a faint tinge of li- 

 lac, then convex, soft, paler, becoming smoky red or a pale chestnut 

 color, flesh reddish- white or grayish; tubes at first concave or nearly 

 plain, stuffed, colored nearly like the pileus, at length paler, de- 

 pressed around the stem, minute, round; stem stout, generally short, 

 equal or tapering slightly upward, abruptly narrowed at the base, mi- 

 nutely furfuraceous, colored like or a little paler than pileus, purplish- 

 gray within; spores subferruginous. Pileus 7.5-25 cm. broad, 5-10 

 cm. long, 12-25 mm. thick. Woods. July to September. 



Boletus separans Peck (Plate XXII, fig. 77). 



Pileus convex, thick, glabrous, sub-shining, often pitted, lacunose or 

 corrugated, brownish-red or dull-lilac, sometimes fading to yellowish on 

 the margin, flesh white, unchangeable; tubes at first nearly plane, ad- 



