E-Flora BC: Electronic Atlas of the Flora of British Columbia

Summary:
Features include 1) resupinate growth on decayed wood, 2) a thin, whitish to lurid yellow fruitbody, soft and fibrous in consistency, porose-reticulate or somewhat furfuraceous under 50x lens, bristly from projecting cystidia, the margin thinning out, and the periphery often pruinose, 3) spores that are allantoid, smooth, inamyloid, and colorless, 4) cystidia that are numerous, long-cylindric, constricted in places and sometimes with secondary septa without clamp connections, thick-walled except in the distal part, the projecting part with resinous encrustation that dissolves in mounting media, and 5) a monomitic hyphal system, the hyphae with clamp connections. The online Species Fungorum, accessed October 7, 2020, listed the current name as Kneiffia subalutacea, but MycoBank, accessed the same day, listed the current name as Hyphodontia alutacea.

Hyphodontia subalutacea has been found in BC, WA, ID, NS, ON, PQ, AL, AZ, CO, GA, IL, LA, MD, MI, MN, NC, NM, NJ, NY, UT, and WI, (Ginns). The distribution includes BC, Argentina, Finland, France, Italy, Norway, Spain, Sweden, Turkey, United Kingdom, Kenya, Taiwan, (Langer), and Denmark, (Eriksson), and Switzerland (Breitenbach).

Fruiting body:
resupinate, effused [spread out], adnate [firmly attached], thin (about 0.01cm), creamish white or lurid yellow when young and alive, "darkening to ochraceous or tan when old and dried"; "porose-reticulate or somewhat furfuraceous under the lens, pilose by the projecting cystidia"; "margin mostly indeterminately thinning out, in the periphery often pruinose", (Eriksson), resupinate, attached tightly, forming thin, membranous-crustose patches several centimeters across, consistency soft, fibrous; white when young, later and also when dry cream to ocherish; "reticulate-porous, dull and farinose to slightly tuberculate"; margin diffuse, (Breitenbach), spore deposit white (Buczacki)

Microscopic:
SPORES 6-8 x 1.5-2 microns, allantoid, smooth, thin-walled; spores and basidia may be smaller in old fruitbodies than in young ones; BASIDIA at first subclavate, then subcylindric with suburniform constriction, thin-walled except for the basal part that is somewhat thickened, 12-20 x 3-4 microns, normally 4-spored, with basal clamp connection; CYSTIDIA numerous, usually 80-150 microns but may reach 200 microns or more, width 5-7 microns, long-cylindric or somewhat widening in the apical direction, more or less constricted in places and sometimes with secondary septa without clamp connections, thick-walled except in the distal part, "projecting part normally with a resinous encrustation, which, however, normally dissolves in the mounting media"; HYPHAE monomitic; subicular hyphae 2-3 microns wide, distinct, richly branched and irregularly interwoven, cyanophilic, with thin or slightly thickened walls, with clamp connections; "subhymenial hyphae thinner and more densely united with predominantly vertical hyphal direction", (Eriksson), SPORES 6.5-8 x 1.5-2 microns, narrowly cylindric, allantoid, smooth, inamyloid, colorless; BASIDIA 4-spored, 14-18 x 3-4 microns, narrowly clavate, with basal clamp connection; LEPTOCYSTIDIA up to 130 x 6-7 microns, (according to the literature up to 200 microns long), projecting a long way, long-cylindric, thick-walled, thin-walled toward apex, some with secondary septa; HYPHAE monomitic, 2-3 microns wide, strongly branched, septa with clamp connections, (Breitenbach)