BOLETUS ERYTHROPUS (Fries) Krombholz, Consp. Fung. Esc., p.24.1821.
Boletus luridus var. erythropus Fries, Syst. Mycol. 1:391. 1821.
Illustrations: See Microfiche No. 9
Lange, J. E., and M. Lange, 600 Pilze in Farben, p. 193.
Leclair, A., and H. Essette, Les Bolets, pl. 47.
Romagnesi, H., Nouvel Atlas des Champignons, pl. 130.
Singer, R., Die Rohrlinge, Teil II, pl. XIV, figs. 5-11.

Pileus 8-15 cm broad when mature, convex when young, becoming broadly convex to plano-convex to plane to occasionally umbonate or shallowly depressed with age; surface dry, even, smooth to occasionally rugose to reticulate on the disc, obscurely tomentose to velutinous to occasionally appressed fibrillose when young, frequently glabrous with age; color when young brown ("clay color" to "cinnamon" to "testaceous"to "pecan brown"), with age red ("Prussian red") on the disc and reddish brown ("Hay's russet" to "russet") toward the margin, usually darkening and appearing water-soaked when bruised; margin incurved to broadly decurved, entire. Context 1-3 cm thick, firm, compact, yellow ("primrose yellow" to "naphthalene yellow" to "barium yellow"), bluing quickly when first exposed, then often fading to buff ("pale olive-buff"). Taste and odor often pungent, unpleasant.

Tubes 1-2 cm in length, deeply and broadly to narrowly depressed around the stipe, yellow ("pale greenish yellow" to "olive lake" to "primrose yellow"), bluing when bruised; pores small, 0.5-1 mm broad, angular, typically red ("Eugenia red" to "jasper red" to "dragons-blood red" to "brick red"), sometimes near reddish orange ("burnt sienna" to "Mars orange"), bluing when bruised.

Stipe 8-12 cm long, 1.5-3.5(6) cm thick at maturity, clavate to subclavate to occasionally equal to tapering toward the apex, solid, with white rhizomorphs attached to the base; surface dry, glabrous to more commonly punctate to obscurely velutinous or fibrillose, not reticulate; typically yellow ("Naples yellow" to "buff-yellow") at the apex, usually with yellow background for entire length but marked with red granules ("Eugenia red" to "acajou red" to "coral red"), basal portion often appearing reddish brown ("Verona brown" to "brick red" to "Hessian brown"). Context yellow ("pale greenish yellow" to "Naples yellow") except reddish to reddish vinaceous in the base, bluing when exposed.

Spore print ochraceous brown. Spores 13-16 X 4.8-5.5 Ám ochraceous in KOH, dark ochraceous in Melzer's, moderately thick-walled, smooth, subcylindric to subfusoid.

Basidia 18-24 X 7-10 Ám, hyaline, four-spored, contents granular in KOH. Hymenial cystidia 39-45 X 9-11 Ám, scattered to numerous, sometimes embedded, subclavate with tapering apices to basidioid, often heavily incrusted and staining bright ochraceous in KOH, occasionally hyaline and apparently not incrusted.

Tube trama obscurely divergent to parallel, hyaline except for irregularly distributed areas colored bright ochraceous in KOH. Pileus trama interwoven, with numerous conspicuous, thick-walled laticifers distributed throughout. Pileus cuticle a tangled trichodermium composed of moderately thick-walled and typically incrusted free hyphal tips. Stipe cuticle composed of undifferentiated hyphal tips interspersed with numerous large, inflated, pyriform to subglobose cells staining dark ochraceous in KOH. Clamp connections absent.

Chemical reactions KOH-context yellow to pale orange, cuticle red but quickly darkening; NH4OH-context yellow; HCl-context pink; HNO3-context pink, cuticle red; sulfoformalin-context yellow; guaiac-context pale blue, cuticle pale blue.

Habit, habitat, and distribution Solitary in soil in mixed forests in the coastal regions of central and northern California. A mycorrhizal host has not definitely been established; however, oaks have always been in the vicinity where basidiocarps were found. It is not a common fungus and is apparently highly restricted in its distribution in the state.

Material studied Mendocino County: Cole 11-14-70; Thiers 9519, 10569, 10597, 10625, 14100, 21425, 24161, 24258. Sonoma County: Thiers 9410. Trinity County: Thiers 14268.

Observations The dark-brown pileus, bright-red pores and punctate rather than reticulate stipe surface distinguish this species. It is most likely to be confused with B. amygdalinus in California, which, however, is much paler colored, has a more pallid stipe, and has significantly broader spores. The nonreticulated stipe readily distinguishes it from B. eastwoodiae and B. satanas.

Singer has questioned the presence of this species in North America and has referred collections so named to B. subvelutipes. That species, however, is characterized by the presence of a dark red tomentum at the base of the stipe, which is absent in the California specimens.

It is rated as edible by some, but the presence of the red pores should serve as a warning to be very careful when first trying it.

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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