Summary:
Features include 1) resupinate growth on wood, 2) pellicular to hypochnoid fruitbodies that are light yellowish with a faint greenish tint, the surface even and the margin thinning out, 3) spores that are broadly cylindric to broadly elliptic, smooth, inamyloid, and colorless, and 4) a monomitic hyphal system with clamp connections. The Eriksson description is for Athelopsis hypochnoidea Julich, given by Ginns (fide Julich) as a synonym.

Microscopic:
SPORES 6-7.5 x 4-4.5 microns, broadly cylindric to broadly elliptic, smooth, inamyloid, colorless, thin-walled, acyanophilic, contents granulose or slightly guttulate, with distinct apiculus; BASIDIA 4-spored, 13-18 x 4-5 microns, stemmed-cylindric, colorless, thin-walled, with a basal clamp connection, the sterigmata about 3.5 x 1 micron, "the contents homogeneous or slightly granulose"; CYSTIDIA absent; HYPHAE monomitic; hyphae 2-3 microns wide, cylindric, colorless, rather thin-walled (about 0.3 microns thick), "with clamps at all septa, the surface smooth or slightly covered with small granules or crystals", (Julich), SPORES 6.5-8 x 4-4.5 microns, elliptic, smooth, thin-walled; BASIDIA 4-spored, about 15-20 x 5 microns, clavate, with basal stem; CYSTIDIA absent; HYPHAE monomitic, of hyphae 2.5-3.5 microns wide, very loosely arranged, thin-walled, colorless, clamped, BASAL HYPHAE are straight and sparsely branched at right angles, while SUBHYMENIAL HYPHAE are more abundantly branched, (Eriksson)

Notes:
Athelopsis subinconspicua has been found in BC, ON, and PQ, (Ginns), and Europe including Norway and Sweden (Eriksson).