Summary:
Features include 1) semicircular, hoof-shaped, cushion-shaped or irregular yellow brown to dark brown caps that are usually coarse and uneven with warts and pits, 2) a cinnamon to dark brown pore surface, 3) hard, rusty brown to dark brown flesh that may have a strong scent of anise, and 4) growth on coniferous wood or timber. The description is derived from Gilbertson(1) except where indicated.

Chemical Reactions:
flesh black when touched with KOH

Odor:
with a strong scent of anise when fresh, (Gilbertson), strong of anise or vanilla tending to disappear when old, the odor also present in wood invaded by the hyphae (Lincoff)

Microscopic:
spores 7.5-10.5(11) x 3-4.5 microns, cylindric, smooth, inamyloid, colorless, thin-walled; basidia 4-spored, 18-35 x 5-8 microns, clavate; cystidia difficult to observe, usually collapsed in dried specimens, 20-30 x 3.6 microns, thin-walled, tapering and subacute; hyphal system di-trimitic: generative hyphae 2.5-4 microns wide, thin-walled, with clamp connections, skeletal hyphae dominating in fruitbody and tomentum, 3-5 microns wide, light yellowish brown, thick-walled, binding hyphae in flesh very rare and found in only a few collections, mostly close to base, 1.5-3 microns wide, solid

Notes:
Gloeophyllum odoratum has been reported from BC, WA, OR, ID, AZ, CO, MT, and NM, according to Gilbertson(1) who suggest that some records of the species could represent Gloeophyllum protractum: referring to G. odoratum, they comment "Probably rare and restricted to the coniferous forests in the Rocky Mountains. The only report of this anise-scented taxon from North America is that of Neuman (1914) from Wisconsin, and most other reports of the species on the continent are probably referring to G. protractum". J. Ginns says "Most reports of G. odoratum before 1986 may have been misidentified specimens of G. protractum" (Ginns(28) with Latin names italicized). Apparently the anise scent characteristic of G. odoratum in Europe has not generally been present where the species has been recorded in North America. Kout(3) add [with Latin names italicized] "We regard the distribution maps of G. odoratum as unreliable because G. protractum has probably been misidentified as G. odoratum in the U.S.A. We were not able to find either species when we visited the putative areas of G. odoratum and G. abietinum occurrence in the U.S.A.".

Synonyms and Alternate Names:
Anisomyces odoratus (Wulfen) Pilat
Boletus subglabripes Peck
Leccinum subglabripes (Peck) Singer
Osmoporus odoratus (Wulfen) Singer
Polyporus odoratus Wulfen
Trametes americana Overh.
Trametes odorata (Wulfen) Fr.