SUILLUS BRUNNESCENS Smith and Thiers, Contr. Toward a Monogr. of N. Am. Sp. of Suillus, p. 91. 1964

Smith, A. H., and H. D. Thiers, A Contribution Toward a Monograph of North American Species of Suillus, pls. 38, 39.

Pileus 4-15 cm broad, convex to nearly plane, surface glutinous to viscid; color at first dull white, the gluten soon changing to chocolate color, but often showing a lilac-brown tone in the darkening process, often appearing streaked from the gluten; herbarium specimens dark brown ("Natal brown") overall. Context thick, white when young, in age yellowish in apex of stipe and along the tubes or finally yellowish throughout, not staining when cut or bruised. Taste and odor mild.

Tubes up to 15 mm deep in large caps, mostly less than 10 mm deep, pale ochraceous, adnate to decurrent, not staining when bruised; pores small (about two per millimeter), pale ochraceous and not staining when bruised.

Stipe 3-6(8) cm long, 1-2.5(3) cm thick, solid; surface white at first and unpolished, apical region becoming yellowish with small glandular dots, base where handled staining vinaceous and then brownish like the pileus; veil thin, membranous, white staining vinaceous gray, breaking away from the stipe and collapsing on cap margin, in age all traces have disappeared. Context white within at first but slowly yellowish, especially in apex.

Spore print unknown. Spores 6.6-8.8 X 2.8-3.2 Ám, oblong in face view, in profile oblong to obscurely inequilateral, smooth, thin-walled, hyaline to dingy yellow brown in KOH, pale yellow brown in Melzer's.

Basidia 18-25 X 4.4-6.6 µm, four-spored, clavate, hyaline to yellowish in KOH and often with amorphous granules, in Melzer's pale yellowish to brownish. Hymenial cystidia 40-70 X 8-12 Ám, in fascicles with the bundles surrounded by incrusting pigment more or less bister in KOH, content hyaline to dingy yellow brown, subcylindric to fusoid-ventricose, thin-walled, smooth or with some incrusting debris.

Tube trama with a central strand of parallel, hyaline to dingy-yellow-brown hyphae (in KOH and in Melzer's), with hyaline, gelatinous hyphae diverging to the hymenium, the hyphae of the central strand (4)6-10(12) Ám wide, walls thin, hyaline to yellowish in Melzer's. Pileus cuticle a gelatinous trichodermium of hyphae 4-9 Ám wide, containing numerous dark-brown granules in KOH, the walls soon almost completely gelatinized. Caulocystidia similar to hymenial cystidia, in bundles and heavily incrusted around the base of the bundle with bister material. Clamp connections absent.

Chemical reactions KOH-context vinaceous lilac on the cuticle, slowly changing to greenish in places.

Habit, habitat, and distribution Scattered to gregarious under sugar pine. Known as far south as Grants Pass, Oregon.

Observations This species has never been reported from California. It is included, however, because it has been found nearby in the vicinity of Grants Pass in Oregon where it was associated with sugar pine. This description is adapted from the Smith and Thiers monograph of North American species of Suillus. As indicated by them, this species is distinguished by the white pileus when young, which changes to brown with age and stains brown when bruised, the tendency of the veil to remain attached to the pileus margin, and the obscure glandulae on the stipe. It appears to be closely related to S. albidipes, a species occasionally found within the state.

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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