E-Flora BC: Electronic Atlas of the Flora of British Columbia

Summary:
Features include 1) a dry to subviscid cap that is orange brown and nearly bald, 2) white flesh that changes to pinkish then blackish, 3) white pores that become pale olive-brown and when bruised stain dark brown, 4) a white stem with conspicuous scabers that turn from whitish to dark brown or black, 5) growth under pine and aspen, and 6) microscopic characters including the absence of orange-brown pigment globules in the cap cuticle hyphae. Leccinum discolor is one of the species previously identified as L. aurantiacum (Theirs(13)).

It is found from eastern Canada west to ID, MT, WY, CO, and CA, (Bessette). It has been reported from BC (M. Beug, pers. comm.).

Cap:
7-15cm, hemispheric to convex, becoming broadly convex to nearly flat; "dull orange-brown to orange-cinnamon or orange-yellow", becoming dull cinnamon when old; dry to subviscid, nearly bald; margin with flaps of sterile tissue, (Bessette), 10-15cm, convex becoming broadly convex to flat-convex to depressed on disc to occasionally irregular in outline; brown to orange-red to sometimes pale buff; "dry to subviscid, dull, often shallowly pitted or reticulate", bald "but often appearing tomentose or fibrillose", sometimes cracked-areolate [cracked like dried mud] near margin; margin with typical sterile flaps, (Thiers(1))

Flesh:
"white when exposed, staining pinkish to brownish orange, then fuscous", (Bessette), 1-3cm thick, white when first exposed, changing to flesh color to pink then blackish, (Thiers(1))

Pores:
1-2 per mm, angular; "white at first, becoming greenish yellow to pale olive-brown", "staining dark brown when bruised"; tube layer 1-2cm thick, becoming depressed near stem when mature, (Bessette), 0.5-1mm, angular, colored as tubes; tube layer 1-2cm thick, depressed, white when young, becoming pale olive-brown when mature, staining dark brown when bruised, (Thiers(1))

Stem:
6-12cm x 1-3cm, nearly equal or widening downward, solid; with conspicuous scabers that are whitish when young and dark brown to black when old over whitish ground color; dry; basal mycelium white; partial veil and annulus absent, (Bessette), 6-12cm x 1-3cm at top, equal to club-shaped, solid; white to whitish ground color, conspicuously ornamented, squamules white to pallid when young, becoming dark brown to black when old; dry; white mycelium at base, (Thiers(1))

Odor:
mild (Thiers(1))

Taste:
mild (Thiers(1))

Microscopic:
spores 15-20 x 4.5-6.5 microns, fusoid [spindle-shaped] to subcylindric [nearly cylindric], smooth, some producing a dextrinoid reaction, ochraceous; cap cuticle hyphae lacking orange-brown pigment globules when revived in Melzer''s reagent, (Bessette), spores 15.5-20 x 4.5-6.5 microns, fusoid to subcylindric, smooth, ochraceous in KOH and Melzer''s reagent, some showing a dextrinoid reaction, thin-walled; basidia 4-spored, 30-37 x 9-12 microns, clavate to pear-shaped, colorless and with granular contents in KOH; hymenial cystidia 30-46 x 8-15 microns, "fusoid to clavate with elongated, tapering apices", colorless to sometimes appearing filled with dark brown amorphous material in KOH, thin-walled; cap cuticle a tangled trichodermium of free hyphal tips, buff in KOH, ochraceous tawny in Melzer''s reagent, "hyphae 8-10 microns 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 microns, "clavate to mucronate to subfusoid", mostly dark brown in KOH but some colorless cells present, "an occasional large cell interspersed", walls smooth, thin; clamp connections absent, (Thiers(1))

Spore Deposit:
brown (Bessette, Thiers)