Summary:
Features include 1) resupinate growth on wood, 2) ochraceous fruitbodies, often with a grayish or even pink or orange tint, (often becoming red in 2% KOH), uneven to tuberculate or with radial ridges, the margin abrupt, concolorous or paler, varying but mostly fringed to fibrillose, and occasionally with rhizomorphs, the subiculum paler than the spore-bearing surface, 3) spores that are elliptic, smooth, inamyloid, and colorless, with droplets, 4) cystidia that are numerous, most embedded but some projecting, narrowly cylindric with acute apex, encrusted in the apical half, and thin-walled to somewhat thick-walled and 5) a monomitic hyphal system, the hyphae without clamp connections, except in the subiculum where scattered clamp connections occur, sometimes 2 at a single septum. The description is derived from that of Phanerochaete laevis (Pers.: Fr.) Erikss. & Ryvarden for which Burdsall(5) and Breitenbach(2) give Phanerochaete affinis (Burt) Parmasto as a synonym.

Microscopic:
SPORES 4.5-6(7.5) x 2.5(3.5) microns, elliptic, smooth, inamyloid, colorless, with droplets; BASIDIA 4-spored, 30-38 x 4.5 microns, narrowly clavate, without basal clamp connection; CYSTIDIA: lamprocystidia cylindric, "pointed, thick-walled, strongly incrusted but some smooth apically, thin-walled and smooth when young", 40-75 x 4-7.5 microns; HYPHAE monomitic, 3-6 microns wide, thin-walled to thick-walled, without clamp connections, but hyphae of subiculum thin-walled and scattered septa with clamp connections, (Breitenbach), SPORES 4.5-6 x 2.5 microns, narrowly elliptic, smooth, inamyloid, acyanophilic, thin-walled, with one or more oil droplets; BASIDIA 4-spored, 25-35 x 4-5 microns, narrowly clavate, without basal clamp connection; CYSTIDIA numerous, 40-65 x 5-7 microns, projecting 15-30 microns, narrowly cylindric and tapering to acute apex, at first thin-walled and unencrusted, developing thicker walls and encrustation (in apical half, but under microscope top often naked as encrustation falls off easily), very young cystidia containing many oil droplets; HYPHAE monomitic, 2-5 microns wide, thin-walled or in the subiculum walls slightly thickened, clamp connections absent in hymenium and subhymenium but in the subiculum clamp connections often found, sometimes 2 together at one septum, "subhymenial hyphae richly and irregularly branched and densely united", subicular hyphae straight, sparsely branched and mainly horizontally arranged; "in mature specimens crystals richly attached to the hyphae"; in the reddish or orange specimens a yellow substance "occurs between the hyphal elements of the subhymenium and in the hymenium", (Eriksson), SPORES 5-7 x 2.5-3 microns, narrowly elliptic to nearly cylindric, smooth, inamyloid, acyanophilic, colorless, thin-walled; BASIDIA 4-spored, 30-40(45) x 5-5.5 microns, "clavate with a slight constriction below apex", colorless, thin-walled, sterigmata 3.5-4 microns long; CYSTIDIA 60-80(100) x 6-8(10) microns, mostly embedded but some projecting up to 25 microns, heavily encrusted over distal 1/3 to 1/2 by colorless crystals, "in squash mounts crystals frequently breaking away leaving an apparently smooth cystidium, very young cystidia having only a fine granular coating", walls colorless, 1-2(2.5) microns thick in middle and becoming thin-walled at apex and slightly thick-walled at base; HYPHAE monomitic, SUBHYMENIUM not well defined, a loose textura intricata, hyphae 2.5-4 microns wide, colorless, thin-walled, simple-septate, "encrusted irregularly and lightly with small yellow granules that dissolve and turn red in KOH"; SUBICULUM a compact textura intricata, hyphae of lower subiculum 5-9 microns wide, colorless, with walls up to 0.5-1(1.5) microns thick, mostly simple-septate, "with scattered single and rare multiple clamp connections", smooth or encrusted with large colorless crystals, hyphae of upper subiculum 4-7 microns wide, densely branched, slightly thick-walled, colorless, simple-septate, or rarely nodose-septate, "with regularly scattered yellow granules that dissolve and turn red in KOH", (Burdsall)

Notes:
It has been found in BC, WA, OR, ID, MB, NB, NS, ON, PE, PQ, AK, AL, AZ, CA, CT, IL, KY, MA, MD, ME, MI, MN, MO, MT, NC, NE, NH, NJ, NY, SC, TN, TX, VT, and WI, (Ginns). It also occurs in Europe including Switzerland, in Asia, (Breitenbach), in Denmark, Finland, Norway, Sweden, (Eriksson), and in Czechoslovakia, Estonia, France, Latvia, and Armenia, (Burdsall).