SUILLUS MONTICOLUS Thiers, Madrono 19:154. 1967

Pileus 4-7 cm broad when mature, convex when young, becoming plane to plano-convex to broadly convex to highly irregular with age; surface viscid to subviscid, streaked to fibrillose to appressed fibrillose-scaly; color when young light brown ("clay color" to "pale olive-buff" to "olive-buff"), with age changing to brown ("buffy brown" to dark "avellaneous" to near "cinnamon-brown"), more or less evenly colored although the streaks or fibrils may be slightly darker; margin incurved, becoming decurved with age, glabrous during all stages of development with no evidence of a partial or false veil. Context 0.5-1 cm thick, white, unchanging when exposed. Taste and odor not distinctive.

Tubes 2-5 mm long, adnate to shallowly depressed, becoming decurrent to subdecurrent with age, strongly radiately arranged, when young bright yellow ("straw yellow" to "amber yellow"), darkening with age to dark yellow ("antimony yellow" to "old gold"); pores 1-2 mm broad, often compound, concolorous with the tubes, unchanging when bruised, often staining vinaceous in KOH.

Stipe 3-5 cm long, 2-4 cm thick at the apex, sometimes eccentric, distinctly ventricose to bulbous at the base and abruptly pinched below, usually bent, sometimes almost at right angles, white mycelium at base, stuffed; surface dry, glabrous when young, becoming glandulose to punctate to occasionally obscurely fibrillose with age, glandulae apparent only in the apical region, frequently reticulate at the apex, concolorous with the tubes at the apex, usually becoming brown ("olive-buff" to "cinnamon-brown") toward the base; no evidence of an annulus or partial veil. Context white, unchanging when exposed.

Spore print color unknown. Spores 8.5-11.2 X 3-4 Ám, cylindric to subellipsoid, hyaline in KOH, pale yellow in Melzer's, smooth, thin-walled.

Basidia 30-35 X 7-10 Ám, clavate to subcylindric, two- and four-spored, hyaline in KOH. Hymenial cystidia 25-45 X 4-9 Ám, cylindric to subclavate, clustered, often massed, particularly abundant on the pores, scattered to numerous on the sides of the tubes, staining dark brown in KOH and Melzer's, usually staining more darkly on the pores; no solitary cystidia seen.

Tube trama divergent from a distinct mediostratum, hyaline in KOH, appearing gelatinous to subgelatinous in KOH, hyphae 3-6 Ám wide. Pileus trama loosely interwoven, homogeneous, more or less hyaline in KOH. Pileus cuticle clearly differentiated as a trichodermium of more or less upright to somewhat tangled hyphae with free tips, walls appearing finely incrusted, subgelatinous in KOH, staining chocolate brown in KOH, ochraceous in Melzer's; hypodermium compact, closely interwoven, staining brown to ochraceous in KOH, ochraceous tawny in Melzer's. Stipe cuticle hymeniform, with scattered clusters of caulocystidia similar to the cystidia on the pores. Clamp connections not seen.

Chemical reactions unknown.

Habit, habitat, and distribution Gregarious in soil under lodgepole pine. Elevation 7,200 ft.

Material studied El Dorado County: 32764. Nevada County: Thiers 13248.

Observations The most distinctive feature of Suillus monticolus is the highly bulbous to ventricose stipe that is frequently bent and often somewhat eccentric. The glandulae, while always present, are never strongly developed. The hymeniform cuticle of the stipe also appears highly distinctive.

Edibility unknown.

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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