Summary:
Features include 1) flat, tightly attached growth on conifer wood, 2) fruitbodies that are tough, dark brown, smooth or slightly uneven, later densely irregularly cracked, with an abrupt margin, 3) fine dark bristles visible on the surface under 20x hand lens, 4) spores that are elliptic, smooth and inamyloid, 5) 2-4 microscopic layers: a hymenium of basidia, hyphidia, and setae 60-100 x 7-11 microns, a setal layer, and sometimes a hyphal layer and cortex layer.

Microscopic:
SPORES 5.5-6.5 x 2.5-2.8 microns, elliptic, smooth, inamyloid, colorless, some with droplets; BASIDIA 4-spored, 15-19 x 3.5-5 microns, narrowly clavate, without basal clamp connection; CYSTIDIA none; SETAE 50-80 x 6.5-8.5 microns, thick-walled, dark brown, narrowly subulate [awl-shaped], both exserted beyond the hymenium and enclosed in the trama, young setae colorless and very narrow, exserted beyond the hymenium; HYPHAE monomitic, "hyphae in the hymenium agglutinated and difficult to see, hyphae in the middle layers brownish, thin-walled, branched, 1.5-3 microns across, septa without clamps", (Breitenbach), SPORES 5-6.5(7) x 1.8-2.6(2.8) microns, cylindric, slightly curved; fruitbody lacks a tomentum layer next to the substrate and consists of 2-4 layers: 1) hymenium with basidia, hyphidia, and setae, 2) setal layer with setae and vertically oriented hyphae, 3) hyphal layer (present or absent), 4) cortex (absent or indistinct); BASIDIA 4-spored, 13-18 x (3.5)4-5 microns, clavate or subclavate, sterigmata about 4 microns long, basidioles absent or present, 2.5-3.5 microns wide, without encrustation; HYPHIDIA not numerous to numerous, 2.5-3 microns wide, colorless or yellowish, "thin-walled, without incrustation"; CYSTIDIA absent; setal layer 50-575 microns thick, SETAE numerous, (60)65-100 x (6)7-11 microns, "partly projecting up to 65 microns, subulate, with acute or very sharp tip, straight, naked, without incrustation"; "hyphal layer when present up to 30 microns thick, hyphae compact, longitudinally agglutinated"; cortex 5-25 microns thick when present, with hyphae "densely interwoven, indistinct, agglutinated, brown"; HYPHAE monomitic, setal hyphae absent [from hyphal layer], generative hyphae 2-4 microns wide, agglutinated, subindistinct [somewhat indistinct], "yellowish to brownish, thin-walled or with thickened walls"; "in context and hymenium crystalline matter absent", (Parmasto)

Notes:
Hymenochaete fuliginosa has been found in BC, WA, ID, AB, ON, AK, AZ, CA, CO, MD, MI, MT, NC, NY, PA, TN, Austria, Belarus, Czech Republic, Estonia, Finland, Germany, Norway, Poland, Russia, Slovakia, Sweden, Ukraine, China, Japan, and Turkmenistan, (Parmasto). It has also been recorded in Switzerland, but note setae are relatively short, (Breitenbach).

Synonyms and Alternate Names:
Aleurodiscus zelleri Burt
Corticium aurantiaca Bres.