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

Summary:
{See also Red-pored Boletus Table.} This name probably represents two species in the Pacific Northwest, neither of which are described yet (N. Siegel, pers. comm.). Features include dark brown cap, bright red to orange pores, and granular rather than reticulate [netted] stem that is not bulbous. The current name of the species in Europe in the Index Fungorum and MycoBank, each accessed February 9, 2019, is given as Sutorius luridiformis (Rostk.) G. Wu & Zhu L. Yang, but the need to use that genus name is disputed.

Neoboletus ''luridiformis'' is found in northeastern North America west to CA, north to AK, (Bessette), OR (vouchered at University of Washington), and WA (Buck McAdoo, pers. comm. from H. Thiers). It has been reported from BC (C. Roberts, pers. comm.), and from NS (Grund).

Cap:
5-12cm, convex becoming broadly convex when old; "dark brown to nearly blackish brown when young, becoming reddish brown to olive-brown" when mature; dry, somewhat tomentose to nearly smooth, (Bessette), 8-15cm, convex becoming broadly convex to flat to occasionally umbonate or shallowly depressed when old, margin incurved to downcurved; brown when young, when old red on disc and reddish brown toward margin; dry, smooth to occasionally wrinkled to reticulate on disc, obscurely tomentose to velvety to occasionally appressed-fibrillose when young, frequently bald when old, "usually darkening and appearing water-soaked when bruised", (Thiers), 5-15(20)cm, may be pitted when old, (Arora)

Flesh:
greenish yellow to yellow, quickly staining blue when cut, in stem yellow except reddish at base, rapidly turning blue when exposed, (Bessette), 1-3cm thick, firm, compact; yellow, turning blue when bruised, in stem yellow except reddish to reddish vinaceous at base, turning blue when exposed, (Thiers)

Pores:
1-3 per mm, round to irregular; "orange-red to dull orange, sometimes yellow when very young, staining blue when bruised"; tubes 0.8-1.4cm long, (Bessette), 1-2 per mm, angular; typically red, sometimes near reddish orange, turning blue when bruised; tubes 1-2cm long, depressed around stem, yellow, turning blue when bruised, (Thiers), "red to brick-red to orange-red, orange, rusty-orange, or burnt sienna (but sometimes yellowish in old age), blueing quickly when bruised", (Arora)

Stem:
6-10cm x 1.3-5cm, nearly equal or widening or narrowing downward, solid; "with reddish to orange-cinnamon pruina on a yellow ground color, often reddish at the base, blueing when bruised"; dry, not reticulate, lacking reddish hairs at base, (Bessette), 8-12cm x 1.5-3.5(6)cm, club-shaped to somewhat club-shaped to occasionally equal, solid; typically yellow at top, usually with yellow background for entire length but marked with red granules, basal part often appearing reddish brown; dry, bald to more commonly punctate to obscurely velvety or fibrillose, not reticulate, white rhizomorphs attached to base, (Thiers), 4-15cm x (1.5)2-4(5)cm, often curved, (Arora)

Chemical Reactions:
cap surface red with KOH but quickly darkening, flesh yellow to pale orange with KOH, (Thiers), cap surface dark amber with application of KOH and dark olive-green with FeSO4, flesh slowly olivaceous with application of FeSO4, blued surface bleached yellow then white with KOH, (Bessette)

Odor:
not distinctive (Bessette), often pungent, unpleasant, (Thiers)

Taste:
not distinctive (Bessette), often pungent, unpleasant, (Thiers)

Microscopic:
spores 13-16 x 4.8-5.5 microns, subcylindric to subfusoid [somewhat cylindric to somewhat spindle-shaped], smooth, dark ochraceous in Melzer''s, ochraceous in KOH, moderately thick-walled; basidia 4-spored, 18-24 x 7-10 microns, colorless, contents granular in KOH; hymenial cystidia scattered to numerous, sometimes embedded, 39-45 x 9-11 microns, "subclavate with tapering apices to basidioid, often heavily incrusted and staining bright ochraceous in KOH", occasionally colorless and apparently not incrusted; clamp connections absent, (Thiers), spores 12-16 x 4.5-6 microns, subfusoid, smooth, ochraceous, (Bessette)

Spore Deposit:
olive brown (Bessette), ochraceous brown (Thiers)