Summary:
Phanerochaete sordida is distinguished by subicular hyphae that are broad and more or less thick-walled, branched at right angles and running in all directions, forming a well intertwined but open context (rigid lattice-work appearance). Features include 1) resupinate growth on hardwood, occasionally on conifer wood, 2) a fruitbody that is waxy to membranous, soft, whitish cream to ocher, (sometimes tinted yellow to red, at least in the herbarium), and smooth or velvety, with or without cracks, 3) a margin that is narrow and mealy and/or finely fringed, without rhizomorphs, 4) subiculum that is cottony to fibrous, 5) a KOH reaction that is negative or sometimes vinaceous red, 6) spores that are narrowly elliptic, smooth, inamyloid, and colorless, 7) (2)4-spored basidia, 8) cystidia that are projecting, mostly cylindric or fusiform, the tip usually blunt, thin-walled at the apex and thick-walled in the lower part, smooth to strongly encrusted (the encrusting material either colorless crystals or yellow - red brown resinous matter), and 9) a monomitic hyphal system, the hyphae smooth or encrusted with colorless crystals, clamp connections occurring only rarely on basal hyphae, the subicular hyphae wide, branching at nearly right angles, forming a lattice-work, becoming thick-walled, sometimes encrusted with crystals.

Microscopic:
SPORES 5-7 x 2.5-3.5 microns, narrowly elliptic, smooth, inamyloid, colorless, sometimes with droplets; BASIDIA 4-spored, more rarely 2-spored, 25-30 x 4.5-5 microns, narrowly clavate; without basal clamp connection; CYSTIDIA 60-90(130) x 6-10 microns, thin-walled, somewhat thicker-walled toward base, smooth to +/- strongly encrusted; HYPHAE monomitic, subicular hyphae 2.5-6 microns wide, thick-walled, sometimes encrusted with crystals, septa without clamp connections, (Breitenbach), SPORES mostly 5-7 x 2.5-3 microns, may be longer but in most specimens shorter than 6 microns, narrowly elliptic or subcylindric, "adaxial side almost straight, abaxial side more or less convex", smooth inamyloid, acyanophilic, thin-walled; BASIDIA 4-spored, 25-30 x 4-5 microns, narrowly clavate, without basal clamp connection; CYSTIDIA varying in shape and number, mostly 60-70 x 6-10 microns (but may reach 120 microns or more), mostly cylindric or fusiform, "tapering to the apex which usually is obtuse", "walls at first thin, more or less thickening but may in some cases remain thin", encrustation varying with the age of the fruitbody and other factors, may be none but "usually there are grains or crystals on the apical or middle part", and in some specimens the cystidia are strongly encrusted, the encrusting material is either colorless crystals or yellow - red brown resinous matter, in the latter case turning red in KOH, rarely cystidia have side branches which occur mostly in the apical part; HYPHAE monomitic, without clamp connections (occurring only rarely on the basal hyphae), SUBHYMENIAL HYPHAE "thin-walled, richly branched into a dense texture, forming a thickening subhymenium"; SUBICULAR HYPHAE 5-7 microns wide, "in young specimens with quite thin walls, later with more or less thickened walls, mostly very distinct, branched at right angles in all directions into an open context", hyphae next to the wood more parallel to the substrate, (Eriksson), SPORES 5-7.5 x 2.5-3.5 microns, narrowly elliptic to elliptic, adaxially flattened, smooth, inamyloid, acyanophilic, colorless, thin-walled; BASIDIA 4-spored, 25-35 x 4.5-5.5 microns, clavate, colorless, thin-walled, sterigmata up to 3 microns long; CYSTIDIA 60-120 x 6-8 microns, projecting up to 30 microns, nearly cylindric, tapered to obtuse apex, occasionally nearly subulate [awl-shaped], smooth or encrusted with large, colorless crystals, thin-walled at apex, thick-walled in lower part; HYPHAE monomitic, SUBHYMENIUM a compact textura intricata, hyphae 3.5-5.5 microns wide, colorless, with frequent branching, thin-walled, short-celled, simple-septate, smooth or encrusted with colorless crystals; SUBICULUM a loose textura intricata, hyphae 5-9 microns wide, "branched regularly and at nearly right angles", colorless, walls up to 2 microns thick, rigid in appearance, long-celled, mostly simple-septate, rarely nodose-septate, clamp connections often entirely absent, smooth or encrusted with large colorless crystals, (Burdsall)

Notes:
Phanerochaete sordida has been found in BC, WA, OR, ID, AB, MB, NB, NS, NT, ON, PE, PQ, AK, AL, AZ, CA, CO, DC, FL, GA, IL, LA, MA, MD, MI, MS, MT, NC, NH, NJ, NM, NY, TN, VT, and WI, (Ginns). It has also been found in Europe including Switzerland (Breitenbach), all forested parts of Scandinavia including Denmark, (Eriksson), and Mexico, Brazil, Finland, France, Germany, Italy, Netherlands, Norway, Poland, Sweden, United Kingdom, South Africa, USSR, Japan, and New Zealand, (Burdsall).

Synonyms and Alternate Names:
Polyporus odorus Sommerf.