BOLETI OF THE UNITED STATES 155 
Boletus nigrellus Px. 
BiackisH BoLetus 
Rep. 29, p. 44 
Pileus broadly convex or nearly plane, dry, subglabrous, 
blackish, flesh soft, white, unchangeable; tubes plane or con- 
vex, adnate, sometimes slightly depressed around the stem, 
their mouths small, subrotund, whitish, becoming flesh- 
colored, slowly changing to 6rowx or blackish where wounded, 
stem equal, short, even, colored like or a little paler than the 
pileus; spores dull flesh-colored, .o004 to .0005 in. long, .oco2 
to .00025 broad. 
Pileus 3 to 6 in. broad; stem 1.5 to 2.5 in. long, 6 to 12 
lines thick. 
Woods and copses. New York, Peck. 
The blackish color of the pileus and stem distinguishes 
this species. From Boletus alboater Schw., the adnate, flesh- 
colored tubes will separate it. The surface of the pileus 
sometimes becomes rimose-areolate. 
CARIOSI 
Stem never reticulated, stuffed with a spongy pith, at 
length commonly excavated. Tubes at first white, then 
often yellowish, their mouths minute, round. 
Fries adds to these characters, “spores white.” But in 
our species the spores are pale-yellow when shed in a mass 
on white paper. [hey are more elliptical in outline than 
the spores of most Boleti. The character of the stem is 
peculiar and easily distinguishes the tribe. The exterior is 
firm, the interior soft and spongy, becoming irregularly hol- 
low or cavernous in the typical species. 
HMleshynunc hang eal Cressey octre eyes ys Hiefey Fite neers se I 
Flesh quickly changing to blue where wounded...... B. cyanescens. 
Pens mice ly velveny-LOMmeMLOSCr 4. 254) a ota 4 +56 _ B. castaneus. 
Rene MUSA Claes Sick ye Ste bay: Wrest fatsi seed wtanees wots eve lete B. Murrayi. 
