Summary:
Features include 1) resupinate growth on wood, 2) fruitbodies that are pale ochraceous or yellowish cinnamon to saffron (generally brightly colored), the surface waxy and smooth, 3) spores that are narrowly elliptic to subcylindric, inamyloid, and cyanophilic, 4) cystidia that are projecting, cylindric, moderately thickened at base, and often septate, and 5) a monomitic hyphal system, the hyphae dense, vertical, and agglutinated.

Microscopic:
SPORES 7-8(9) x 2.5-3.5 microns, narrowly elliptic to subcylindric, rarely narrowly obovate or adaxially slightly concave, illustrated smooth, inamyloid, cyanophilic, with thin or slightly thickened walls; BASIDIA normally 4-spored, 24-30 x 5-6 microns, narrowly clavate to subcylindric, when old somewhat thick-walled; CYSTIDIA numerous, 80-120 x 5-7 microns, projecting 40-60 microns, cylindric or apically tapering, rarely somewhat clavate, walls basally thick, tapering apically, basal clamp connection present, usually 1-3 adventitious septa, apical protoplasm denser and in phase contrast refractive; HYPHAE monomitic: hyphae 2-4 microns wide, "yellowish, the basal hyphae somewhat thickwalled, in the subhymenium mostly thinwalled, richly branched and provided with clamps", most of the fruitbody consists of dense vertically oriented agglutinated hyphae, making clamp connections difficult to observe, (Eriksson), SPORES 8-12 x 3-4 microns, cylindric to cylindric-elliptic, inamyloid, colorless; BASIDIA 25-35 x 5-6 microns; CYSTIDIA abundant, up to 160 microns long, 6-10 microns wide, cylindric, thin-walled to slightly thick-walled, not encrusted; hyphae with clamp connections, (Gilbertson), slightly thick-walled cystidioles with adventitious septa were observed, (Nakasone)

Notes:
Crustoderma dryinum has been found in BC, WA, OR, ID, ON, PQ, AK, AL, AZ, CO, MD, MO, MS, NM, VA, and WI, (Ginns), and Sweden and Finland, (Eriksson).

Synonyms and Alternate Names:
Aleurodiscus abietis H.S. Jacks. & P.A. Lemke