SUILLUS TOMENTOSUS (Kauffman) Singer, Snell and Dick, Mycologia 51:570. 1959
Boletus tomentosus Kauffman, Papers Mich. Acad. Sci. Arts and Letters 1 :117. 1921.
Suillus hirtellus var. mutans (Peck) Snell, Lloydia 7:23. 1942.
Xerocomus lenticolor Snell and Dick, Mycologia 52:448. 1960.
Illustrations: See Microfiche No. 49
Smith, A. H., Mushroom Hunter's Field Guide, p. 86.
Smith, A. H., and H. D. Thiers, The Boletes of Michigan, pl. 13.
Smith, A. H., and H. D. Thiers, A Contribution Toward a Monograph of North American Species of Suillus, pls. 17, 18.
Snell, W. H., and E. A. Dick, The Boleti of Northeastern North America, pl. 22.

Pileus 6-12 cm broad at maturity, acutely convex to convex when young, becoming plano-convex to plane to highly irregular in outline; surface viscid, but not glutinous, conspicuously fibrillose-scaly to squarrose scaly when young, unchanging or becoming more or less appressed fibrillose-scaly to rarely subglabrous with age; when young background color yellow ("apricot yellow" to light "cadmium yellow"), changing to lighter yellow ("pinard yellow" to "empire yellow") with age, scales and fibrils often colored grayish ("olive" to "drab") to yellow ("Naples yellow"), darkening to dark yellow ("yellow ocher" to antimony yellow"), in higher elevations fibrils and scales characteristically become bright red ("jasper red" to "dragons-blood red"); margin incurved when young, becoming decurved to highly irregular and uneven with age, entire, often eroded with age. Context 1-2.5 cm thick, yellow ("massicot yellow" to "naphthalene yellow"), bluing irregularly when exposed. Taste and odor not distinctive.

Tubes 1-1.5 cm long, adnate to subdecurrent when young, becoming depressed with age, yellow ("naphthalene yellow"), bluing when exposed; pores up to 1 mm broad, angular, brown ("Verona brown" to "snuff brown") when young, changing to yellow ("olive lake" to "old gold") with age, bluing when bruised.

Stipe 6-11 cm long, 1-2.5 cm thick at the apex, equal to typically clavate, solid; surface dry to moist, usually giving a resinous feel to the fingers, noticeably glandulose, ▒ concolorous with the pileus except for the glands, which are darker; no annulus. Context yellow, bluing when exposed.

Spore print dark olive brown to brown. Spores 7-11 X 3.5-4.5 Ám, pale ochraceous in KOH and Melzer's, smooth, thin-walled, subfusoid to subellipsoid in face view, slightly ventricose in side view.

Basidia 25-31 X 6-9 Ám, clavate, four-spored, hyaline to pale yellow in KOH. Hymenial cystidia 33-45 X 6-12 Ám, scattered to numerous, more abundant on the pores, clustered, hyaline, staining dark brown in KOH, clavate to cylindric.

Tube trama gelatinous in KOH, hyaline, divergent, hyphae 5-6 Ám wide. Pileus trama interwoven, homogeneous. Pileus cuticle differentiated as a tangled ixotrichodermium with scattered fascicles of hyphae forming the scales. Stipe cuticle composed of caulocystidia similar to the cystidia of the hymenium. Clamp connections absent.

Chemical reactions HNO3-cuticle pale pink, tubes pink; FeSO4-cuticle, context, and tubes pale gray.

Habit, habitat, and distribution Scattered to gregarious in soil under beach and lodgepole pine. Usually abundant wherever these pines occur and characteristically fruits during the late fall and early winter.

Material studied El Dorado County: Thiers 20763. Humboldt County: Thiers 13979, 17747. Lassen County: Kowalski 2073. Madera County: Thiers 20841. Mariposa County: Thiers 21022. Mendocino County: Jensen 47; Largent 58; Motta 11, 34; Thiers 8164, 8300, 8781, 8788, 9247, 9249, 9300, 9308, 9468, 9634, 9744, 10639, 10699, 11072, 11858, 14603, 18115, 21516, 23060, 23079. Mono County: Thiers 20967. Nevada County: Sundberg 333; Thiers 13131, 13158. San Francisco County: Thiers 8572, 12089. San Mateo County: Thiers 7503. Shasta County: Thiers 11984. Sierra County: Sundberg 306, 352; Thiers 13863, 21137. Tuolumne County: Ammirati 604; Thiers 13271.

Observations This very distinctive Suillus is distinguished by the strongly developed, fibrillose-scaly surface of the pileus, the bluing of the context upon exposure, and the absence of a veil or annulus. Although the fibrillose scales are grayish to olivaceous when young, they frequently become red to bright red with age, at least in regions where the temperature becomes relatively low at night, such as the Sierra Nevada and other mountain ranges. Because of this color change, it is sometimes misidentified as S. americanus, but its larger size and the blue discoloration of the context make it readily distinct. Suillus tomentosus can be distinguished from other Suillus species having a fibrillose-scaly cuticle, such as S. fuscotomentosus and S. californicus, by the much paler color of the fibrils and the color changes in the context. It is distinguished from the species in which the context changes to blue, such as S. caerulescens, S. ponderosus, and S. reticulatus, by the fibrillose-scaly cuticle, the absence of a veil, and the lack of reticulations on the surface of the stipe.

Edible, but of poor quality.

Online edition addendum

Other Descriptions and Photos: The Fungi of California

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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