The fruit bodies (mushrooms) produced by the fungus are characterized by a chocolate to reddish-brown cap covered with a sticky layer of slime, and a short whitish stipe that has neither a partial veil nor prominent, colored glandular dots.

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.

[15] The stipe is white to pale yellow, dry, solid, not bruising, and pruinose (having a very fine whitish powder on the surface).

It is either of equal width throughout, or may taper downwards; its surface bears minute puncture holes at maturity, and is it slightly fibrous at the base.

The cheilocystidia (cystidia found on the edge of a gill) are 30–60 by 7–10 μm, club-shaped to almost cylindrical, thin-walled, with brown incrusting material at the base, and arranged like a bundle of fibers.

Caulocystidia (found on the stipe) are 60–90 by 7–9 μm, mostly cylindrical with rounded ends, and arranged in bundles with brown pigment particles at the base.

[9] Field guides typically recommended to remove the slimy cap cuticle, and, in older specimens, the tube layer before consumption.

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

[25] Suillus brevipes is a mycorrhizal fungus, and it develops a close symbiotic association with the roots of various tree species, especially pine.

Under controlled laboratory conditions, the fungus has been shown to form ectomycorrhizae with ponderosa, lodgepole,[26] loblolly, eastern white,[27][28] patula,[29] pond,[30] radiata,[31] and red pines.

[28] In vitro mycorrhizal associations formed with non-pine species include Pacific madrone, bearberry,[32] western larch, Sitka spruce, and coast Douglas-fir.

[34] During the regrowth of pine trees after disturbance like clearcutting or wildfire, there appears an orderly sequence of mycorrhizal fungi as one species is replaced by another.

A study on the ecological succession of ectomycorrhizal fungi in Canadian jack pine forests following wildfire concluded that S. brevipes is a multi-stage fungus.

[36] It has been suggested that the thick-walled, wiry rhizomorphs produced by the fungus may serve as an adaptation that helps it to survive and remain viable for a period of time following disturbance.

[40] This species has been found in Puerto Rico growing under planted Pinus caribaea, where it is thought to have been introduced inadvertently from North Carolina by the USDA Forest Service in 1955.