Suillus brevipes

Description
Mushroom Identification
Look-Alikes
History
Synonyms

Description

Suillus brevipes is characterized by a smooth, viscid, dark-brown to the vinaceous-brown cap and a stipe that typically lacks glands. A cosmopolitan species, it is found throughout much of the U.S. It grows in a mycorrhizal association with various species of two- and three-needled pines, especially lodgepole, and ponderosa pine. In the succession of mycorrhizal fungi associated with the regrowth of jack pine after clearcutting or wildfires, S. brevipes is a multi-stage fungus, found during all stages of tree development. The mushrooms are edible and are high in the essential fatty acid linoleic acid.

Like many species of the genus Suillus, S. brevipes is edible, and the mushroom is considered a choice by some. The odor is mild, and the taste mild or slightly acidic. Field guides are typically recommended to remove the slimy cap cuticle, and, in older specimens, the tube layer before consumption. The mushrooms are common in the diet of grizzly bears in Yellowstone National Park.

Common names: Short-Stemmed Bolete, Short-Stemmed Slippery Jack, Stubby-Stalk, Short-Stalked Suillus.

Mushroom Identification

Ecology

Mycorrhizal with true pines; growing alone, scattered, or gregariously; late summer and fall; widely distributed in North America.
Cap

5-10 cm; convex becoming broadly convex and remaining so for a long time - or eventually becoming more or less flat; slimy; smooth; dark to dark reddish-brown, fading to cinnamon or yellowish-brown; the margin at first incurved and pale, but naked (without veil remnants).
Pore Surface

Pale yellow, becoming dingy olive; 1-2 circular pores per mm; tubes to about 1 cm deep.
Stem

2-5 cm long; 1-3 cm thick; swollen and squat when young; often short, even at maturity; white at first, becoming pale yellow; glandular dots absent when young, and poorly developed or absent when mature; without a ring.
Flesh

White at first, becoming yellow in age; soft; not staining when sliced.
Odor and Taste

Not distinctive.
Chemical Reactions

Ammonia purplish on cap surface; pinkish to negative on flesh. KOH dark gray to black on cap surface; lilac to gray on flesh. Iron salts olive on flesh.
Spore Print

Brown to dull cinnamon.
Microscopic Features

Spores 7-10 x 3 µ; smooth; subfusoid. Pleuro- and cheilocystidia cylindric to clavate; up to about 50 x 10 µ; hyaline to brownish.

Look-Alikes

Suillus granulatus

Has a longer stipe and distinctly raised granules on the stipe.
Suillus pallidiceps

Distinguished its pale yellow cap color
Suillus pungens

Has a characteristic pungent odor, compared to the mild smell of S. brevipes, and like S. granulatus, have glandular dots on the stipe.

Molecular phylogenetic analyses of ribosomal DNA sequences show that the most closely related species to S. brevipes include S. luteus, S. pseudobrevipes, and S. weaverae.

History

The species was first described scientifically as Boletus viscosus by American mycologist Charles Frost in 1874. In 1885, Charles Horton Peck, who had found specimens in pine woods of Albany County, New York, explained that the species name was a taxonomic homonym (Boletus viscosus was already in use for another species named by Ventenat in 1863), and so renamed it to Boletus brevipes. Its current name was assigned by German Otto Kuntze in 1898. William Alphonso Murrill renamed it as Rostkovites brevipes in 1948; the genus Rostkovites is now considered to be synonymous with Suillus.

Agaricales specialist Rolf Singer included Suillus brevipes in the subsection Suillus of genus Suillus, an infrageneric (a taxonomic level below genus) grouping of species characterized by a cinnamon-brown spore print, and pores less than 1 mm wide.

The specific epithet is derived from the Latin brevipes, meaning "short-footed".