Summary:
Features include 1) resupinate growth on wood, 2) fruitbodies that are whitish to pale yellowish ochraceous, and tuberculate (grandinioid), often with branched rhizomorphs, 3) spores that are small, elliptic, smooth, and inamyloid, 4) cystidia of two types: a) cylindric, encrusted when projecting with double-pyramidic crystals, yellow when enclosed, and b) smaller sulfo-positive gloeocystidia containing small oil droplets, 5) a monomitic hyphal system, the hyphae with clamp connections.

Microscopic:
SPORES 4-4.5 x 3-3.5 microns, elliptic, smooth, inamyloid, acyanophilic, thin-walled; BASIDIA 4-spored, 15-20 x 3.5-5 microns, clavate or subcylindric, basally tapering, sometimes with a short stem-like part, with basal clamp connection; CYSTIDIA of two types: 1) "encrusted cystidia in varying numbers, in some specimens numerous and easily visible, in others few", size variable, in well developed specimens 60-100 x 10-15 microns, in others not exceeding 50 x 6 microns, encrustation especially in projecting cystidia "coarse, consisting of double-pyramidic crystals, in enclosed cystidia more or less dissolved and the whole cystidium changing to yellow", [illustrated as more or less cylindric], 2) small gloeocystidia, relatively few, 30-40 x 3-5 microns, fusiform, thin-walled, containing small oil droplets, turning dark blue in sulfovanillin, in rare cases with an apical rounded appendage; HYPHAE monomitic, hyphae 2-3 microns wide, densely branched and irregularly interwoven, thin-walled, with clamp connections, "in some specimens a layer of parallel hyphae next to the substrate, in old fruitbodies sometimes strata of parallel hyphae in the subicular trama", in mature fruitbodies subicular hyphae colored more or less yellow, (Eriksson)

Notes:
Metulodontia nivea has been found in BC, ON, PQ, Northwest Territories, MD, ME, MN, MT, NY, and TN, (Ginns), as well as Finland, Norway, Sweden, central Europe, and the USSR, (Eriksson), and Austria, France, and Germany, (Bourdot).