Summary:
Features include 1) blackish brown to yellowish or reddish brown shelf-like caps, (sometimes the pore surface entirely flat on wood), 2) a marginal zone in the first year that is tomentose and light brown, in succeeding years becoming blackish, distinct, and wider, 3) small cinnamon pores, 4) black layers in the context, and 5) microscopic characters including setae and distinctive carrot-shaped spores.

Microscopic:
spores 7-10 x 2-2.5 microns, cylindric, straight, tapering toward the apex, ("carrot-shaped"), smooth, inamyloid, colorless; basidia 4-spored, 10-12 x 5-6.5 microns, broadly clavate, simple-septate at base; setae abundant, 25-37 x 6.5-8.5 microns, subulate [awl-shaped] to ventricose, straight, dark brown in KOH, thick-walled; hyphae 2.5-6 microns wide, brown to pale yellow or almost colorless in KOH, thick-walled or thin-walled, with frequent branching, simple-septate; "black layers about 20-80 microns thick, composed of very closely interwoven and agglutinated hyphae"; hyphae of trama similar to those of lower context, (Gilbertson), spores 5.5-6.5 x 1.8-2.5 microns, cylindric with laterally spurred apiculus, smooth, inamyloid, colorless; setae 25-30 x 6-7 microns, with bent base, thick-walled, exserted beyond hymenium, (Breitenbach)

Notes:
Phellopilus nigrolimitatus has been found in BC, WA, OR, ID, AB, AK, AZ, CA, CO, MT, NM, UT, and WY, (Gilbertson). It also occurs in Europe (Breitenbach).

Synonyms and Alternate Names:
Peniophora longicystidiata Litsch. [as longicystidia]