Summary:
Features include 1) resupinate growth on wood, 2) fruitbodies with a soft-membranous texture, the color tan or yellow to pink-ochraceous, the surface with convoluted fine folds, and the white margin sometimes with rhizomorphs, 3) spores that small, oval, smooth, inamyloid, and thin-walled, 4) a monomitic hyphal system, the hyphae with clamp connections, and the subhymenial hyphae with crystalline to granular or resin-like material. Justo(6) indicates that this species belongs in Irpicaceae, and since the holotype of Ceraceomyces (C. tessulatus) is in Amylocorticiaceae, C. serpens would need a different name.

Microscopic:
SPORES 3.5-5 x 2-2.5 microns, oval to broadly oval, in side view "adaxially flattened or slightly concave, with a distinct, truncated, somewhat elongated apiculus", smooth, inamyloid, colorless, thin-walled; BASIDIA 16-33 x 3.5-5.5 microns, narrowly clavate; CYSTIDIA none; HYPHAE monomitic: CONTEXT HYPHAE 2-4.5(6.5) microns wide, sometimes swollen at a septum, thin-walled, colorless, with clamp connections, sometimes crystalline-encrusted, SUBHYMENIAL HYPHAE 2-4 microns, the subhymenial area "often heavily impregnated with fine granules or a resin-like substance", (Ginns(12)), SPORES 4-5.5 x 2-2.5 microns, narrowly elliptic; BASIDIA 4-spored, 18-28 x 4-5 microns, narrowly clavate; CYSTIDIA none; HYPHAE monomitic, SUBHYMENIAL HYPHAE 2.5-3.5 microns wide, "densely intertwined, more or less covered with crystalline material", with clamp connections, BASAL HYPHAE 3-5 microns wide, more loosely intertwined and more sparsely branched, often joined in parallel fashion to hyphal strings, with clamp connections; abundant crystalline material in interhyphal spaces, (Eriksson), SPORES 4-5.5 x 2-2.5 microns, elliptic, smooth, inamyloid, colorless, some with droplets; BASIDIA 4-spored, 20-30 x 4.5-5 microns, narrowly clavate, with basal clamp connection; CYSTIDIA none; HYPHAE monomitic: hyphae 2-4 microns, septa with clamp connections, no crystals observed (according to literature with crystal deposits), young fruitbody, (Breitenbach)

Notes:
Ceraceomyces serpens has been found in BC, WA, ID, AB, MB, NS, NT, ON, PQ, AK, AZ, CA, CO, FL, MI, MN, MT, NC, NJ, NM, NY, SC, and WI, (Ginns(5)), Brazil, widespread in Europe from France to Hungary to Finland, Siberia in Russia, and China, (Ginns(12)), and Switzerland (Breitenbach).

Synonyms and Alternate Names:
Hydnum spathulata Schrader
Radulum spathulatum (Schrad.) Bres.