The boletes of Michigan, by Alexander H. Smith and Harry D. Thiers.

BOLETUS

271

Stirps SENSIBILIS
KEY
1. Pleurocystidia 26-38 x 12-18 '; vesiculose to utriform, rarely fusoidventricose.............................. B. miniato-olivaceus
1. Pleurocystidia, if present, narrow and with apex subacute to obtuse....... 2
2. Spores (11) 12-16 (17) x (3) 4-5.5M..................... 3
2. Spores sm aller................................... 4
3. Spores distinctly blue in Melzer's as revived; pileus rich vinaceous-red,
fading slowly............................. B. bicoloroides
3. Spores pale ochraceous tawny in Melzer's; pileus soon fading to yellow or
orange-yellow........................... B. miniato-pallescens
4. Pores wide and boletinoid toward the stipe.(see B. tenax also) B. subfraternus
4. Pores round and 1-2 per mm................. 5
5. Base of stipe persistently carmine-red................. B. carminipes
5. Base of stipe rusty-rose to purplish red...................... 6
6. Many wide (15-20 M) short cells in elements of pilear cuticle B. pseudosensibilis
6. Wide short cells lacking in cuticular hyphae (the latter tubular)....... 7
7. Pileus and stipe dark apple-red; tubes 5-10 mm long......... B. bicolor
7. Pileus and stipe with more orange or yellow than in above; tubes + 1.5
cm long................................... B. sensibilis
142. Boletus miniato-olivaceus Frost
Bull. Buff. Soc. Nat. Sci. 1:101. 1874
"Pileus at first vermillion color, then disappearing and becoming
olivaceous, pulvinate, smooth, rather soft and spongy, margin at first
incurved, then applanate, 2-6 inches broad. Tubes bright lemon yellow,
partly adnate, then slightly decurrent. Stem light yellow, generally not
always lurid at base, very smooth, enlarges as it enters the pileus, about
4 to 2 of an inch thick. Flesh yellow, changing to blue, the pileus less
yellow than in stem. Spores.0125-.0063 mm.
"Borders of woods. July and August."
The above is the original description by Frost. He sent a specimen
to Peck, which is now on deposit in the Peck collections at Albany. The
following data are taken from it:
Spores 11-14 (14.5-16) X 3.5-5 (5.5-7) p, smooth, apex lacking a
pore or thin spot; color in KOH ochraceous, in Melzer's ochraceous
slowly darkening slightly but not dextrinoid; shape in face view subclavate to subelliptic, in profile typically somewhat inequilateral but
varying to subclavate; wall about 0.2 / thick.
Basidia 4-spored, 25-32 X 7-10 u, narrowly clavate, hyaline in
KOH when well revived, with yellowish walls in Melzer's. Pleurocystidia