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

GASTROBOLETUS Lohwag
Beih. Bot. Centralbl. 422:273. 1926
This is a genus of boletes modified to the extent that the spores
are not discharged from the basidia and hence typical spore prints cannot be obtained. The species connect to various genera in the Boletaceae
and are to be regarded as modified members of this family and hence
derive from it. For further information on the genus see Singer and
Smith (1959).
213. Gastroboletus scabrosus Mazzer & Smith
Mich. Bot. 6:60. 1967
Illus. PI. 157.
Pileus 2.5-6.5 cm broad; convex at first becoming broadly convex
at maturity; surface dry and unpolished to subtomentose; dingy yellowbrown with ochraceous undertones, near "snutf-brown" or slightly
paler to near "clay color" at the margin. Context 10-14 mm thick, pale
buff when first cut, slowly stained dull pinkish buff mottled with pale
olive-gray in places; taste mild, odor slight.
Tubes (gleba) 1.5-2 cm deep, curved in a flaring arrangement so
that the distal portions of the tubes are oriented away from the stipe in
a position approximately horizontal to the ground; pores small, 2-3 per
mm soon collapsing and becoming flattened as the pileus expands, dull
lemon-yellow at first, becoming dingy olivaceous-yellow (near "old gold")
and developing brownish to blackish stains on bruising.
Stipe 7-10 cm long, 9-14 mm thick at the apex, equal with a
tapering base; surface faintly striate-subreticulate above, scurfy overall;
color yellow above, paler and duller below, scabrose from yellow-brown
to orange-brown dots which are larger above and finer and more numerous below; base with a yellowish mycelium. Context pallid-yellow,
staining brownish around larval tunnels or where bruised.
Spores 15-18.5 X 4-5,, subfusiform, thin-walled, pale brown in
KOH. Basidia 22-24 X 9.5-12g, 4-spored, hyaline. Pleurocystidia 35-55
X 7-1 u, fusoid-ventricose, thin-walled, hyaline. Cheilocystidia similar

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