LECCINUM MONTANUM Thiers, Mycologia 63:274. 1971

Illustrations: See Microfiche No. 35

Pileus 3-8 cm broad, convex to broadly convex when young, becoming broadly convex to plano-convex to shallowly depressed with an uplifted margin at maturity; surface dry to sometimes moist but not viscid, glabrous to occasionally somewhat tomentose or appressed fibrillose, often shallowly and irregularly pitted or roughened; color brown to gray brown ("buffy brown" to "drab" to "cinnamon-brown"), somewhat paler ("cinnamon-buff" to "pinkish cinnamon") toward the margin when older; margin entire, without sterile cuticular flaps. Context 1-2 cm thick, white, unchanging or rarely erratically and irregularly becoming pale watery gray upon exposure. Taste and odor mild.

Tubes 1-2 cm in length, depressed, white to buff ("pale pinkish buff" to "pale olive-buff") when young, becoming pinkish brown ("light pinkish cinnamon"), and eventually becoming lavender brown ("avellaneous" to "wood brown") at maturity, staining yellow brown to dark brown when bruised; pores up to 1 mm broad, angular, concolorous.

Stipe 5-10 cm in length, 1-1.5 cm thick at the apex, equal, solid; surface dry, conspicuously squamulose, ground color white to whitish, squamules white to pallid when young, becoming brown in apical portion and black toward the base with age, often small and inconspicuous with age. Context white, unchanging when exposed or rarely developing scattered watery spots, rarely bluing in the base.

Spore print brown. Spores 14-17.5(20) X 4-6 Ám, pale ochraceous in KOH, some dextrinoid in Melzer's, fusoid to subcylindric to subellipsoid, inequilateral, walls smooth, thick.

Basidia 24-35 X 8-10 Ám, four-spored, hyaline in KOH, clavate to pyriform. Hymenial cystidia 30-50(63) X (7)12-16 Ám, very obscure, hyaline, thin-walled, scattered to rare, clavate with elongated, tapering flexuous apices.

Tube trama divergent from a distinct central strand, hyaline except for pale buff color of strand, hyphae 4-7 Ám wide. Pileus trama loosely interwoven, homogeneous, hyphae 7-10 Ám wide. Pileus cuticle differentiated as a tangled trichodermium with numerous free hyphal tips, hyphae 5-8 Ám wide, occasional large, somewhat fusoid-shaped cell interspersed among smaller cells, walls smooth, some tendency for pigment globules to form when mounted in Melzer's, terminal cells with apex slightly narrowed or tapered. Caulocystidia 30-50 X 8-15 Ám, clustered, brown in KOH, clavate to pyriform to mucronate. Clamp connections absent.

Chemical reactions No distinctive reactions observed.

Habit, habitat, and distribution Scattered to gregarious in soil under aspens. Known only from the vicinity of Grass Lake at Luther Pass in the Sierra Nevada.

Material studied El Dorado County: Thiers 20757, 20828, 23562, 23563, 23638,23629.

Observations Leccinum montanum is distinguished from L. scabrum, which it superficially resembles, by the presence of cystidia along the sides of the tubes, the absence of any pinkish discoloration in the flesh when exposed, the dry to moist but not viscid pileus, and a different mycorrhizal host. The discovery of this species and L. californicum mark the first report of any species belonging to this section of the genus from this state. Leccinum californicum is easily distinguished by the pallid to white color of the basidiocarp.

Edibility undetermined.

The Boletes of California
Copyright © 1975 by Dr. Harry D. Thiers
Additional content for the online edition © 1998 by Michael Wood, Fred Stevens, & Michael Boom
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