Summary:
Features include 1) resupinate growth on hardwood, 2) a whitish to ochraceous fruitbody that is odontioid, with spines that are conic to nearly cylindric, the tips fringed under a 30x lens, the margin indeterminate and pruinose when young, more clearly demarcated when mature, sometimes with a narrow fibrillose zone, 3) spores that are cylindric, smooth, inamyloid, and colorless, with droplet(s), 4) sterile hyphal ends in the hymenium that are mostly capitate with apical encrustation but sometimes awl-shaped or torulose, in the tips of the spines obtuse or tapering, in some specimens a few cystidioles seen, and 5) a monomitic hyphal system, the hyphae with clamp connections, when young cyanophilic, thickened in the subiculum, spherical swellings on the hyphae of the spine trama often present.

Microscopic:
SPORES 6-7.5 x 2.5-3 microns, cylindric (adaxial side somewhat concave), smooth, thin-walled, with 1 droplet or more than one; BASIDIA subclavate at first, then subcylindric with suburniform constriction, basally tapering, mostly 25-35 x 4.5-5.5 microns, in young hymenia sometimes longer, thin-walled or basally with slightly thickened walls, normally 4-spored, containing several oil droplets, with basal clamp connection; CYSTIDIA none but sterile hyphal ends occur, in the hymenium varying in number and mostly capitate with apical encrustation, but also torulose [moniliform] or subulate [awl-shaped], in the tips of the spines obtuse or tapering to almost subulate; in some specimens a few subulate cystidioles are also seen; HYPHAE monomitic, about 2-3 microns wide, distinct, with clamp connections, thickened in the subiculum, arranged in parallel fashion in the center of the spines, "irregularly intertwined in the subiculum, in the subhymenium densely and the predominant hyphal direction perpendicular to the hymenial surface"; spherical swellings on the hyphae of the spine trama often present; younger hyphae are cyanophilic, (Eriksson), SPORES 6-7.5 x 2.5-3 microns, cylindric-oblong, smooth, inamyloid, colorless; BASIDIA 4-spored, 17-20 x 4.5-5.5 microns, clavate with median constriction; CYSTIDIA abundant in hymenial layer, 3-5 microns wide, "irregularly cylindric or slightly swollen at apex", projecting up to 10 microns, smooth or lightly encrusted with coarse crystals; HYPHAE monomitic, subicular hyphae 2.5-4 microns wide, loosely interwoven, with frequent branching, moderately thick-walled, with abundant clamp connections, [illustrated lightly encrusted with crystals], (Gilbertson), SPORES 6-8 x 2.5-3.5 microns, basidia 25-40 x 4.5-5.5 microns, (Langer)

Notes:
Hyphodontia quercina has been found in BC, NS, YT, AK, AZ, and IA, (Ginns). It has been found in BC, Italy (Sardinia), Poland, Romania, Spain, Sweden, and Iran, (Langer), and Denmark and Norway, (Eriksson).

Synonyms and Alternate Names:
Aleurodiscus macrocystidiatus P.A. Lemke Can. J. Bot.