Summary:
Features include 1) resupinate growth on wood, 2) a spore-bearing surface that is dingy yellowish gray flushed with violaceous or pink tints, with conic or fringe-tipped spines, the margin filamentous to rhizomorphic, and often lighter to cream-colored, 3) spores that are small, elliptic, smooth, inamyloid, and colorless, 4) cystidia that are numerous in the spines especially at the tips, originating in the trama, cylindric in their distal part, projecting, thick-walled, and encrusted, and 5) a dimitic hyphal system, the generative hyphae with clamp connections.

Microscopic:
SPORES 3.2-3.5(4) x (2)2.2-2.5 microns, elliptic, smooth, thin-walled; BASIDIA 4-spored, 18-20 x 4-4.5 microns, "subclavate, slightly sinuous", with basal clamp connection; CYSTIDIA (pseudocystidia) numerous in the spines, more rare or lacking in the spore-bearing layer between the spines, strongly encrusted toward the obtuse tip, "the encrusted part normally 40-50 x 8-10 microns"; HYPHAE dimitic, generative hyphae 3.5-4 microns wide, thin-walled, with clamp connections and sparse branching, in the spine trama together with skeletal hyphae that are (2.5)3 microns wide, thick-walled, rarely branched, without clamp connections, interwoven with the generative hyphae; subhymenial layer thin, with short-celled hyphae, always with clamp connections; RHIZOMORPHS composed of generative and skeletal hyphae, (Eriksson), SPORES 4-5 x 2.5-3 microns, elliptic-oval, smooth, inamyloid, colorless, some with droplets; BASIDIA 4-spored, 15-18 x 3.5-5 microns, narrowly clavate, with basal clamp connection; CYSTIDIA (skeletocystidia) thick-walled, upper half +/- strongly encrusted, projecting part 20-40 x 2.5-9 microns, aggregated on the tips of the spines; HYPHAE dimitic, generative hyphae 2-4 microns wide, thin-walled to thick-walled, septa with clamp connections, skeletal hyphae 2-6 microns wide, thick-walled, (Breitenbach), SPORES 3.3-4 x 2.5-3 microns, broadly elliptic to oboval, adaxially little flattened, smooth, colorless, with small oblique apiculus; BASIDIA 4-spored, 15-20 x 3.5-5.5 microns, clavate, with basal clamp connection; CYSTIDIA 3-9 microns wide, "of tramal origin, numerous to abundant at tip of spine, rare to absent further back", conspicuously projecting, usually heavily encrusted, cylindric in the distal part, with obtuse tip, HYPHAE dimitic, of generative and skeletal hyphae, generative hyphae 2.5-4.5 microns wide (not inflating), branched, thin-walled to moderately thick-walled, septate, with clamp connections, skeletal hyphae 3.6-5.4 microns wide, "thick-walled to almost solid", those adjoining substrate frequently brownish, context of spines similar, with most skeletal hyphae solid, (Maas Geesteranus)

Notes:
Steccherinum fimbriatum has been found in BC, WA, OR, MB, NB, NS, ON, PE, AZ, CA, CO, GA, IA, MI, MN, MT, NC, NM, NY, OH, PA, and WI, (Ginns). It is the most common species of the genus in Scandinavia (Eriksson). It is widely distributed in the northern hemisphere (Maas Geesteranus). It occurs in Switzerland and Asia (Breitenbach).

Synonyms and Alternate Names:
Irpex fimbriatus (Pers.) Kotir. & Saaren. 2002
Odontia fimbriata Pers. 1796