LECCINUM DISCOLOR Smith, Thiers and Watling, Mich. Botan. 5:152. 1966

Illustrations: See Microfiche No. 30

Pileus 10-15 cm broad, globose to convex when young, becoming broadly convex to plano-convex to depressed on the disc to occasionally highly irregular in outline; surface dry to subviscid, dull, often shallowly pitted or reticulate, glabrous but often appearing tomentose or fibrillose, sometimes rimose-areolate near the margin; color brown ("Kaiser brown" to "cinnamon-brown") to orange red ("russet" to "auburn" to "rufous") to sometimes pale buff ("pale pinkish buff" to "cinnamon-buff"); margin with typical sterile flaps of cuticular tissue. Context 1-3 cm thick, white when first exposed, changing to flesh color ("testaceous") to pink ("pinkish cinnamon") then blackish ("fuscous"). Taste and odor mild.

Tubes 1-2 cm in length, depressed, white when young, becoming pale olive brown ("pale olive-buff" to "olive-buff") at maturity, staining dark brown when bruised; pores angular, 0.5-1 mm broad, concolorous.

Stipe 6-12 cm long, 1-3 cm thick at apex, equal to clavate, white mycelium at the base, solid; surface dry, conspicuously ornamented, ground color white to whitish, squamules white to pallid when young, becoming dark brown to black with age, often somewhat crowded when young, becoming separated at maturity. Context white, undergoing color changes similar to pileus, bluing not observed.

Spore print brown. Spores 15.5-20 X 4.5-6.5 Ám, fusoid to subcylindric, inequilateral, ochraceous in KOH and Melzer's, some showing a dextrinoid reaction, walls smooth, thin.

Basidia 30-37 X 9-12 Ám, clavate to pyriform, hyaline and with granular contents in KOH, four-spored. Hymenial cystidia 30-46 X 8-15 Ám, hyaline to sometimes appearing filled with dark brown amorphous material in KOH, fusoid to clavate with elongated, tapering apices, thin-walled.

Tube trama divergent from a distinct to poorly developed central strand, hyaline to pale ochraceous in KOH, hyphae 3-4 Ám wide, often appearing gelatinous. Pileus trama interwoven, homogeneous, hyaline in KOH, hyphae 8-16 Ám wide. Pileus cuticle differentiated as a tangled trichodermium of free hyphal tips; buff colored in KOH, ochraceous tawny in Melzer's; hyphae 8-10 Ám wide, walls smooth to asperulate and sometimes appearing incrusted, considerable disarticulation of cells noted, terminal cells only slightly narrowed at apex. Caulocystidia 25-45 X 10-17 Ám, clavate to mucronate to subfusoid, mostly dark brown in KOH but some hyaline cells present, an occasional large cell interspersed, walls smooth, thin. Clamp connections absent.

Chemical reactions unknown.

Habit, habitat, and distribution Solitary to scattered in soil under aspens. Known only from Luther Pass in the Sierra Nevada.

Material studied El Dorado County: Thiers 20744, 20750, 20755, 20766, 20768, 20769, 20770, 23564, 23565, 23566, 23626, 23627.

Observations This is one of the species previously identified as L. aurantiacum. The most obvious characteristic distinguishing the two species is found in the appearance of the cuticular hyphae in Melzer's. The true L. aurantiacum has an abundance of pigment globules formed within the cells, whereas in L. discolor the contents remain homogeneous or only become finely granular. The absence of any reddish phase in the discoloration of the exposed context distinguishes L. insigne from L. discolor.

Edible.

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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