140 THE POLYPORACEAE OF WISCONSIN. 



The tubes are adnate-decurrent, pores greenish-yellow, irregular, and 

 turn greenish-black where bruised. The stem is hard and flexuous, 

 yellow within, ferruginous to reddish without. 



The species may be recognized by its yellow, dry, pulverulence, ec- 

 centric stem, and its lignicolous habit. 



Boletus Ravenelii B. & C. (Plate XIX, fig. 67). 



Pileus convex or nearly plane, slightly viscid when young or moist, 

 covered with a sulphur-yellow pulverulent tomentum, becoming naked 

 and dull red on the disk, flesh whitish; tubes at first plane, adnate, 

 pale-yellow, becoming yellowish-brown or umber, dingy-greenish where 

 bruised, the mouths large or medium size, subrotund; stem nearly 

 equal, clothed and colored like the pileus, yellow within, with a slight 

 evanescent webby or tomentose annulus; spores ochraceous-brown, 10 

 to 12.5 microns long, 5 to 6 microns broad. 



Pileus 2.5 to 8 cm. broad; stem 3.5 to 10 cm. long, 6 to 12 mm. thick. 



Localities : Ladysmith, Devil 's Lake. Largest pileus 7 cm. in diameter ; 

 the stem 12 cm. long and 1 cm. thick. The pileus was scarcely viscid, 

 strongly pulverulent, yellow. The tubes free in some specimens, de- 

 pressed-free in others, small, roundish, compound, yellow. The stem 

 flexuous, floccose-pulverulent, yellow, tough. Flesh pale yellow or 

 whitish. The tubes change slightly to greenish-blue. When young the 

 tubes are concealed by a veil composed of " webby powdered filaments " 

 which at first cover the whole plant but which soon disappears from the 

 disk. The pilei are often spotted with bright red, which disappears at 

 maturity. 



The species may be known by the bright yellow color, due to its cov- 

 ering of bright yellow flocculent powder, and the long stem and webby 

 veil. 



L. Viscipelles. Viscid or glutinous. Pores adnate. 



Boletus piperatus Bull. 



Pileus convex or nearly plane, glabrous, slightly viscid when moist, 

 yellowish, cinnamon or subferruginous, flesh white or yellowish, taste 

 acid, peppery; tubes rather long and large, angular; often unequal, 

 plane or convex, adnate or subdecurrent, reddish-ferruginous; stem 

 slender, subequal, tawny-yellow, bright yellow at the base ; spores sub- 

 fusiform, ferruginous-brown, 8.75 to 11.25 microns long; 4 microns 

 broad. 



