Summary:
Phanerochaete sanguinea is easily recognized in the field by the combination of reddish or red-spotted surface, reddish rhizomorphs, and reddish-stained wood, (Breitenbach). The red color can be seen at least in the rhizomorphs or as patches on the surface, though young specimens may lack the red (old specimens are wholly red), (Eriksson). Features include 1) resupinate growth on wood of conifers, less often of hardwoods, 2) a fruitbody that is membranous, soft, smooth, and whitish to ocherish, spotted red in places or when old wholly red, 3) a margin varying but mostly fibrillose and often growing out into rhizomorphs, 4) a subiculum that is cottony, colored as the surface or more orange when the surface is pale, 5) an olive green reaction in 2% KOH of the orange areas and the rhizomorphs , 6) spores that are narrowly elliptic, smooth, inamyloid, and colorless, with droplets, 7) cystidia that are cylindric to awl-shaped or fusiform, projecting, thin-walled or slightly thick-walled, smooth or encrusted on the distal third (the encrustation dissolving in KOH), the tips smooth and blunt (cystidia not always easy to find), 8) a monomitic hyphal system, the hyphae with frequent branching (in the subiculum at right angles), without clamp connections (except scattered on subicular hyphae, these clamp connections sometimes multiple), the subicular hyphae thick-walled, colorless or sometimes with orange to orange-brown content, and 9) crystals present in the context of mature fruitbodies.

Microscopic:
SPORES 5-6 x 2.5-3 microns, narrowly elliptic, smooth, inamyloid, colorless, with droplets; BASIDIA 4-spored, 22-38 x (4)5-6 microns, narrowly clavate, without basal clamp connection; CYSTIDIA 40-60 x 5-7 microns, projecting beyond the hymenium, subulate [awl-shaped] to fusiform, encrusted on distal third, tips smooth, the encrustation dissolves in KOH in several minutes; HYPHAE monomitic, 3-7 microns wide, thin-walled to thick-walled, septa without clamp connections except scattered clamp connections on basal hyphae, (Breitenbach), SPORES narrowly elliptic to subcylindric, mostly 4.5-5.5 x 2.5-3 microns, sometimes longer (up to 7 microns), smooth, inamyloid, acyanophilic, thin-walled, containing 1-2 oil droplets; BASIDIA 4-spored, 25-35 x 4-5 microns, narrowly cylindric, without basal clamp connection; CYSTIDIA "varying in number and not always easy to find", projecting 25-35 microns, cylindric or tapering, thin-walled to somewhat thick-walled, mostly obtuse, not acute, naked or with varying degrees of encrustation; HYPHAE monomitic, without clamp connections "except for some few on the basal hyphae, singly, in pairs or in whorls"; SUBHYMENIAL HYPHAE 2-3 microns wide, "richly branched and densely intertwined", thin-walled; SUBICULAR HYPHAE 4-10 microns wide, "straight, more or less parallel", with sparse septa and branching, "most hyphae with more or less thickened walls"; lots of CRYSTALS in the context of mature fruitbodies, (Eriksson), SPORES 4.5-6 x 2.5-3 microns, elliptic, adaxially flattened, smooth, inamyloid, acyanophilic, colorless, thin-walled; BASIDIA 4-spored, 25-45 x 4-6 microns, clavate, colorless, thin-walled, sterigmata 3-4 microns long; CYSTIDIA 35-70 x 3-6 microns, projecting 10-25 microns, cylindric or slightly tapered to apex, smooth, colorless, thin-walled or slightly thick-walled; HYPHAE monomitic, SUBHYMENIUM a textura intricata, hyphae 3-5 microns wide, much branched, colorless, smooth, walls thin or slightly thickened; SUBICULUM a textura intricata, hyphae 4.5-8 microns, with frequent branching, at right angles, thick-walled, colorless, sometimes with orange to orange-brown content, simple-septate or nodose-septate [without or with clamp connections], with occasional multiple clamp connections; CORDONS a textura intricata-porrecta parallel to the axis, "hyphae like those of the subiculum", (Burdsall)

Notes:
Phanerochaete sanguinea has been found in BC, WA, OR, ID, NS, ON, PQ, AL, AZ, CA, CO, FL, GA, LA, MA, MD, ME, MI, MN, MS, MT, NC, NH, NJ, NM, NY, PA, SC, TN, VA, and WI, (Ginns). It has also been found in Europe including Switzerland, and Asia, (Breitenbach), Denmark, Finland, Norway, and Sweden, (Eriksson), and Czechoslovakia, France, United Kingdom, and Russia, (Burdsall).

Synonyms and Alternate Names:
Polyporus pulchellus Schwein.