Summary:
Features include 1) resupinate growth on wood (Red Alder), 2) a thin, adherent fruitbody that is white, with a dry surface, the margin thinning out, 3) spores that are cylindric or subelliptic, smooth, inamyloid, and thin-walled, 4) 2 types of cystidia a) halocystidia, broadly clavate to capitate, and b) gloeocystidia, long cylindric, obtuse, and not projecting, and 5) hyphae with clamp connections, mostly thin-walled but a few with thickened walls and others intermixed with fine encrustation. Nakasone(9) maintains this species does not belong in Resinicium sensu stricto (as characterized by the presence of astrocystidia) and suggests it may have affinities to Ceraceomyces.

Microscopic:
SPORES 5-7.5 x 2.5-3.5 microns, cylindric or subelliptic, "flattened and appearing straight on one side with prominent lateral apiculus", smooth, inamyloid, thin-walled; BASIDIA 4-spored, 25-30 x 5-8 microns, slender, "slightly ventricose above the middle", sterigmata 3.5-4.5 microns long, slender, slightly arcuate; GLOEOCYSTIDIA 30-60 x 4-6 microns, long cylindric or flexuous-cylindric, arising in the subhymenium, "sometimes tapering gradually from below, obtuse at apex, not projecting"; other structures [designated halocystidia by Ginns(5)] 13-20 x 6.5-9 microns, subpyriform or abruptly spherical capitate arising in the hymenium; HYPHAE for the most part thin-walled, 1.5-3 microns wide, not gelatinized, a few present with thickened walls and other intermixed with fine encrustation, clamp connections regularly present, (Jackson)

Notes:
Resinicium praeteritum is known from the type, collected on Vancouver Island in BC.

Synonyms and Alternate Names:
Vararia borealis Pouzar
Vararia granulosa (Pers.: Fr.) Laurila sensu Aucts.