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

212

THE BOLETES OF MICHIGAN

Tubes dark wood-brown, 1.5 cm deep, depressed around the stipe;
pores minute, gray where undamaged, where injured staining dark cinnamon-brown.
Stipe 5 cm long, 1 cm thick at apex, solid, white within, very little
color change (merely pinkish tan) when sectioned; surface dark gray to
apex from closely set punctations, white beneath but ground color
hardly showing.
Spore deposit about wood-brown fresh (with a vinaceous tone);
spores 16-22 X 5-7 Mi, smooth, yellow-brown in KOH singly, rusty
brown in groups, in Melzer's dingy yellow-brown or a few dextrinoid; in
profile elongate-inequilateral, in face view subfusiform to nearly elongate-oval, with a hyaline apical spot.
Basidia 20-25 X 8-10 ju, 4-spored, clavate, hyaline in KOH. Pleurocystidia 32-46 X 8-12 iu, fusoid-ventricose, the neck often flexuous,
apex subacute, hyaline in KOH. Cheilocystidia clavate to fusoid-ventricose, 15-28 X 5-10 i, pale dingy ochraceous in KOH to hyaline. Caulocystidia clavate to subfusoid or submucronate (not typically fusoid-ventricose), 35-50 X 8-20 i, many clavate cells also present, caulohymenial
elements as well as many ground hyphae with smoky ochraceous content in KOH.
Cuticle of pileus with epicuticular hyphae 5-10 iu wide, with end-cells
inflated to 15-25 (30) J, walls smooth, hyphal cells not disarticulating,
in KOH the content dingy ochraceous to dull brown, in Melzer's the
hyphae of the subcutis with homogeneous orange-red content and the
epicuticular hyphae with dull brown content aggregating in part to form
globules and particles 5-10 u (or more) in diameter and colored smoky
brown, end-cells subellipsoid to cystidioid and almost uniformly wider
(usually much wider) than the cell from which they were differentiated.
Clamp connections absent.
Habit, habitat, and distribution.-Solitary, Vermillion, July 29,
1965, Smith 71899.
Observations.-The distinguishing features of this species are the
greatly enlarged end-cells of the epicuticular hyphae, their dull brown
pigment masses (globules) as seen in Melzer's, and the mostly clavate to
ellipsoid or submucronate caulocystidia. The spore-print color is somewhat problematic as under the microscope the spores are the same color
as in the rest of this subsection. The ornamentation of the stipe reminds
one of L. murinaceo-stipitatum, but the cuticular hyphae of the pileus
distinguish them at once.