E-Flora BC: Electronic Atlas of the Flora of British Columbia

Summary:
Features include 1) resupinate growth on wood, 2) a light yellowish buff fruitbody with teeth 0.1-0.4cm long, or sometimes varying to smooth, 3) subcylindric to subfusiform spores, 4) urniform basidia that are usually 6-8 spored, and 5) a monomitic hyphal system, the hyphae with clamp connections and oily inclusions.

Sistotrema raduloides has been found in BC, WA, OR, AB, NB, NS, NT, ON, PQ, AK, AZ, CO, IA, MI, MN, MT, NC, NY, TN, and WI, (Ginns), as well as Estonia, Finland, Norway, Poland, and Sweden, (Eriksson).

Fruiting body:
resupinate, effused [spread out], closely adnate [firmly attached]; light-colored when young, pale buff when mature; when young with small papilla-like aculei, when mature odontioid-hydnoid, with normally cylindric, rarely irregular teeth 0.1-0.4cm long, that as a rule are conically acute [sharp] but sometimes obtuse [blunt], spore-bearing surface pruinose; subiculum thin, first arachnoid [cobwebby] then finely porulose, and finally membranaceous; margin thinning out without definite demarcation, sometimes finely fibrillose, (Eriksson(7) for European material, they comment that North American material is more variable in configuration from totally smooth to as hydnoid as Scandinavian material, and add, "The American specimen is often also somewhat light coloured, more yellow than the European, which is, in the dry state, paler buff.")

Microscopic:
SPORES (6)7-9 x (2.5)3-3.5 microns, subcylindric to subfusiform, "apically obtuse, often broader below the middle, thin-walled, often clinging together in groups of 4-6"; BASIDIA (4)6-8-spored, 18-23 x 5-7 microns, urniform, with basal clamp connection; CYSTIDIA none; HYPHAE monomitic, "with clamps and oily inclusions", SUBHYMENIAL HYPHAE 2-3 microns wide, thin-walled, richly branched, BASAL HYPHAE "and those of the central part of the aculei 2-6 microns wide, with somewhat thickened walls, straight and sparsely branched", (Eriksson)