Summary: Features include shelf-like or flat growth, white to gray or yellowish non-zoned caps, whitish pores, growth on barked Western Red-cedar wood, and microscopic characters including cystidia of 2 types. Wu(2) proposed a name in Rigidoporus from a reorganization based on molecular evidence. MycoBank, accessed August 30, 2018, gave this as the current name but the online Species Fungorum, accessed the same day, did not. The description is derived from Gilbertson(1).
Microscopic: spores 4-5.5 x 3-4 microns, broadly elliptic to nearly round, smooth, inamyloid, colorless; basidia 4-spored, 13-18 x 5-6 microns, clavate, simple-septate at base; cystidia of two types: 1) abundant, 17-40 x 4.5-6 microns, narrowly clavate to cylindric, apically incrusted, 2) gloeocystidia imbedded, 19-30 x 5.5-9 microns, cylindric to clavate, with refractive contents, arising in subhymenial layers; hyphae of context monomitic, 2.5-6 microns wide, colorless in KOH, thin-walled, frequently branched, simple-septate, hyphae of trama similar
Notes: Oxyporus cuneatus has been found in BC, WA, OR, ID, MB, AK, CA, CO, IL, and MT, (Gilbertson).
Habitat and Range
SIMILAR SPECIES
Trametes hirsuta and Trametes pubescens are macroscopically similar, "but the thin-walled simple-septate hyphae, abundant cystidia, and broadly ellipsoid spores are not found in that group of species", (Gilbertson). Oxyporus populinus, Oxyporus corticola, Oxyporus similis, and Oxyporus latemarginatus grow on hardwoods. O. similis could be confused if growing on conifers, but pores of O. similis are 4-6 per mm, cystidia are thick-walled, and there are no gloeocystidia.
Habitat
annual, single or imbricate [shingled], mainly on Thuja plicata (Western Red-cedar), developing with bark still attached, also reported on Sequoia, Abies, Larix, Taxodium, and Tsuga, causing white rot of sapwood of Western Red-cedar