Cap 3.5-10.0 cm broad, convex, expanding to plano-convex, the margin entire to lobed; surface smooth, viscid to glutinous in moist weather, often with adhering debris, otherwise dry, dark-brown to dark vinaceous-brown, fading to dull cinnamon-brown or dingy ochracous-brown, sometimes obscurely streaked; flesh thick, soft, white, pale-yellowish in age; odor and taste not distinctive.
Tubes adnate, decurrent to occasionally depressed at the stipe, 0.5-1.0 cm long, dull yellow to ochre; pores pallid becoming dingy yellowish-brown, 1-2/mm at maturity; not bruising blue.
Stipe 1.5-6.0 cm tall, 1.5-3.5 cm thick, straight, solid, equal to enlarged at the base; surface smooth, dull, white, when young, lacking glands, at maturity becoming pale-yellowish, sometimes with inconspicuous glandulae and brownish stains; veil absent.
Spores 7.5-10 x 3-4.5 µm, smooth, elliptical to narrowly elliptical; spore print brown.
Scattered to gregarious under pines; fruiting from after the fall rains to mid-winter.
Edible, but lacking in texture.
Suillus brevipes is characterized by a smooth, viscid, dark-brown to vinaceous-brown cap, and a stipe that typically lacks glands. A cosmopolitan species, it is found throughout much of the U.S. In the Bay Area, however, it's niche, at least with Monterey pine, appears to be taken by two local slippery jacks: Suillus pungens and Suillus acerbus. Suillus pungens, our most common slippery jack, can be distinguished by a viscid cap that goes through a series of color changes: at first white, then grey, orange to cinnamon-brown, finally dingy-buff, a gland-dotted stipe and a harsh, fruity odor. Suillus acerbus has a sticky, typically dull apricot-brown, buff-brown (sometimes tinged greyish), appressed to slightly scaly cap and stipe with prominent, glands, not merely dotted. Though not as common as Suillus pungens under Monterey pine, it is still more likely to be encountered than Suillus brevipes. It should be noted that the species epithet for Suillus brevipes, which suggests a short stipe, is something of a misnomer as stipe length is quite variable.