SUILLUS BREVIPES (Peck) Kuntze, Rev. Gen. Pl. 3:535. 1898

Boletus brevipes Peck, Ann. Rept. N.Y. State Mus. 38:110. 1885.

Illustrations: See Microfiche No. 39

Smith, A. H., The Mushroom Hunter's Field Guide, p. 89, pl. 55.

Smith, A. H., and H. D. Thiers, A Contribution Toward a Monograph of North American Species of Suillus, pl. 42.

Smith, A. H., and H. D. Thiers, The Boletes of Michigan, pl. 28.

Snell, W. H., and E. A. Dick, The Boleti of Northeastern North America, pl. 21.

Pileus 5-10 cm broad when mature, globose to convex becoming broadly convex to plano-convex to plane; surface glabrous, glutinous, in wet weather the gluten often 2 mm deep; color evenly dark vinaceous-brown ("Natal brown" to "army brown") when young, gradually becoming paler to dull cinnamon ("sayal brown" to "cinnamon"), sometimes dingy yellow ocher in age; margin incurved, becoming decurved to plane, entire, in buttons faintly white tomentose, but veil absent and no distinct roll of white cottony tissue present. Context 1-2 cm thick, white when young, becoming yellow in age, soft, unchanging when bruised. Odor and taste not distinctive.

Tubes 4-10 mm long, adnate to decurrent, yellow ("honey yellow"), darker and more olivaceous in age; pores 1-2 mm, round, not elongating radially, when young pale dingy yellow.

Stipe 2-6 cm long, 1-2 cm thick, equal, solid; surface white, becoming pale yellow, unpolished to pruinose under a lens and when young lacking glandular dots, glandulae sometimes visible in age but never well developed; no annulus. Context white, becoming yellow in cortex or apex.

Spore print brown. Spores 7-10 X 3-4 µm, narrowly elliptic to oblong, obscurely inequilateral in side view, smooth, pale yellowish in Melzer's and KOH.

Basidia 18-24 X 5-6 µm, four-spored, clavate, hyaline in KOH, yellowish in Melzer's. Hymenial cystidia clustered, with amorphous brown pigment surrounding the base of the cluster, individual cystidia 35-50 X 6-9 µm, cylindric to clavate, contents hyaline or either partly or entirely brown from coagulated pigment.

Tube trama divergent, gelatinous. Pileus trama homogeneous, interwoven. Pileus cuticle differentiated as a thick ixotrichodermium composed of narrow (4-6 µm) hyphae. Caulocystidia like the hymenial cystidia, but the bundles not numerous. Clamp connections absent.

Chemical reactions According to Singer: KOH-dark gray on the cuticle, gray to dark brown on the tubes, lilac on the context; NH₄OH-purplish on the cuticle; H₂SO₄-rust ochraceous on the pores.

Habit, habitat, and distribution Solitary to scattered or gregarious in soil under two- and three-needle pines. This bolete occurs throughout the pine forests of the state, and is probably the most abundant and widely distributed Suillus within the state. It is typically associated with beach pine in the coastal forests and with lodgepole and occasionally ponderosa pine in the mountains.

Material studied Alpine County: Thiers 20805. El Dorado County: Thiers 20760, 23633. Fresno County: Thiers 13366. Humboldt County: Thiers 17728. Madera County: Thiers 20843, 23614. Marin County: Shervanick 380. Mariposa County: Thiers 20976. Mendocino County: Thiers 8298, 8777, 8862, 9302, 9334, 9353, 9474, 9814, 11073, 18390, 24236. Mono County: Thiers 20964. Nevada County: Thiers 13130, 13160, 13855, 26908. Placer County: Sundberg 336. Riverside County: Thiers 24999. Santa Cruz County: Thiers 10773, 10946. Shasta County: 21594, 21611, 21698, 21701, 23091. Sierra County: Sundberg 345; Thiers 13224, 21165. Siskiyou County: Thiers 21688. Tuolumne County: Thiers 13273.

Observations Suillus brevipes is recognized by the deep-reddish-brown pileus, which is glabrous and typically very viscid, the absence of a veil, and the usually short, pallid stipe, which has very obscure glandulae, at least when young. This is a highly variable fungus, and one should expect to find basidiocarps in which the stipe is considerably elongated and in which the color of the cap is quite variable. Particularly noticeable is the tendency of the pileus to fade and assume a noticeably streaked appearance when older or when exposed to prolonged cold or dry weather.

This fungus is probably most closely related to S. granulatus and S. glandulosipes, but these species typically have stipes in which the glandulae are strongly developed during all stages of development, and much paler or at least differently colored pilei.

Edible.