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

BOLETUS

353

191. Boletus pseudooivaceus Smith & Thiers, sp. nov.
Illus. Pls. 141-43.
Pileus 3-10 cm latus, convexus, siccus, adpresse fibrillosus demum
fibrillose squamulosus, olivaceus vel olivaceo-brunneus. Contextus ochraceus tactu caeruleus. Tubuli 1 cm longi, lutei tactu caerulei; pori rubidi.
Stipes 8-12 cm longus, 1-3 cm crassus, pruinosus, subreticulatus
deorsum olivaceo-luteus. Sporae 13-16 X 5-6.5 g. Specimen typicum in
Herb. Univ. Mich. conservatum est; prope Mackinaw City, July 12,
1967, legit Smith 74510.
Pileus 3-10 cm broad, broadly convex; surface dry and unpolished,
appearing somewhat fibrillose-scurfy, the margin matted-fibrillose, in age
some becoming appressed-squamulose over the disc; color when young
"light brownish olive" to "Isabella color" and yellowish to olive-yellow
when dried, when fresh soon streaked fuscous where bruised as the
aftermath of staining blue; margin even and incurved. Context dingy
ochraceous but instantly changing to blue when cut, finally changing to
olive-fusocus. Taste mild, odor none.
Tubes up to 1 cm deep, depressed around the stipe, dingy yellow
but instantly bluish when cut; pores dark maroon-red (near "Moroccored"), slowly becoming paler and darker in age to almost garnet-brown,
evenly colored from pileus margin to stipe.
Stipe 8-12 cm long, 1-3 cm thick at apex, enlarged downward,
yellow within, when cut instantly blue, in the base a deep rusty rose;
surface pruinose with reddish pruina, purina often arranged in a reticulate pattern over upper half, the flavous ground color showing beneath
the particles, lower half with paler yellow ground color and at the base
olivaceous to olive-ocher; base lacking any sign of hairs or strigosity.
Spores 13-16 X 5-6.5 u, smooth, wall -0.5,u thick, apex furnished
with a minute thin spot; shape in face view narrowly elliptic to subfusoid, in profile suboblong with a broad suprahilar depression, color
dull tawny-brown in KOI and in Melzer's, the fleeting-amyloid reaction
absent to very slight.
Basidia 4-spored, 20-26 X 9-12 j, with large oil drop when nearly
mature. Pleurocystidia rare to scattered, 28-37 X 9-17 i, ventricose
below, neck 2-4 u wide and tapered to an acute apex, content hyaline in
KOH, walls thin and smooth. Cheilocystidia mostly resembling small
basidioles but pale rusty brown from color in the wall or content as
revived in KOH. Caulocystidia clavate to subelliptic or fusoid-ventricose
but the latter rare and resembling pleurocystidia, content typically
brownish ochraceous in KOH (cells often revived poorly), 26-38 X
8-14 pu for the clavate to subelliptic cells.