E-Flora BC: Electronic Atlas of the Flora of British Columbia

Summary:
Features include 1) resupinate growth on bark and barkless wood of hardwoods and conifers, 2) a somewhat pellicular fruitbody that is delicate, easily separated from the substrate, white then yellowish, and smooth (cystidia visible under 50x lens), the margin not differentiated, the subiculum thin and loosely cottony, rhizomorphic strands white and fine, 3) spores that are small, nearly round to elliptic, asperulate with small, mostly rounded warts, amyloid and colorless, 4) cystidia of 2 types: a) gloeocystidia that are cylindric to fusiform or narrowly clavate, with granular contents, and either sulfo-positive (Eriksson) or sulfo-negative (Ginns(24)), and b) pseudocystidia that are thick-walled, encrusted tips of skeletal hyphae that often penetrate the hymenium, and 5) a dimitic hyphal system, with thin-walled generative hyphae that have clamp connections, and thick-walled skeletal (or pseudoskeletal) hyphae that have a pink tint in Melzer''s reagent, the skeletal hyphae predominating in the rhizomorphic strands.

Collections were examined from BC, ON, CA, MI, and NM, and it has also been reported from AZ, (Ginns). It occurs from Denmark in the south of Scandinavia to N. Lappland in the north, but also in other parts of Europe, (Eriksson).

Fruiting body:
effused [spread out], subpellicular to submembranous, easily separated from substrate; "at first white, then yellowish, in the herbarium often darkening to pale buff"; smooth (under 50x lens with projecting cystidia); margin not differentiated; subiculum loose, cottony; white rhizomorphic strands present in subiculum and periphery, (Eriksson), effused, pellicular, the largest piece studied 7cm x 3cm and very thin; pale yellow, "light ochraceous buff", "pinkish buff", "warm buff" to "cartridge buff"; smooth, a delicate brittle crust; margin white to pale yellow, thin, adnate [firmly attached], typically with uncommon, thin (up to 0.015cm wide), branched, white to pallid strands; subiculum thin, loosely cottony, white to pallid, (Ginns(24)), surface smooth, cracking sparingly; margin pale yellow, byssoid [cottony] or with rhizomorphs, (Freeman)

Microscopic:
SPORES 3.2-4.0 x (2.4)2.6-3.2 microns, broadly elliptic to nearly round, asperulate, amyloid, acyanophilic, colorless, walls slightly thickened, spore with a small, rounded, indistinct apiculus; BASIDIA 4-spored, 14-24 x 4-6 microns, suburniform, typically broadly clavate, sterigmata 4 microns long; GLOEOCYSTIDIA "arising in the subiculum, or from subhymenial hyphae", cylindric to narrowly clavate, "some with apex fusoid", 40-110 x 7-8 microns, sulfo-negative, the walls thin, colorless, encrusted with scattered yellow granules or crystals in KOH; CYSTIDIA-LIKE elements "are the thick-walled, incrusted tips of skeletal hyphae which penetrate the hymenium"; HYPHAE dimitic; generative hyphae 1.6-4.4(6.0) microns, "loosely woven, distinct", "with a single clamp connection at each septum, frequently branched and septate", the walls thin, colorless, inamyloid, and acyanophilic; skeletal hyphae "scattered in the subiculum but easily found, predominating in the strands", 2.0-3.6 microns wide, unbranched, aseptate except for a clamp connection at the base, pale yellow in KOH, pale yellow with a pink tint in Melzer''s reagent, cyanophilic, the walls up to 1.4 microns thick on the broadest skeletal hyphae, some with the terminal 30 microns heavily encrusted "and projecting through the hymenium as cystidia", (Ginns(24)), SPORES 3.5-5 x 2.5-3.5 microns, nearly round to elliptic, "with thin or somewhat thickened walls, asperulate with small, mostly rounded warts, some oval or oblong, amyloid"; BASIDIA 15-20 x 3.5-5 microns, clavate-suburniform, often constricted, with a basal clamp connection, normally 4-spored; CYSTIDIA of 2 types: 1) gloeocystidia developed from generative hyphae, 60-100 x 5-12 microns, "thin-walled, generally fusiform, often with apical schizopapillae, protoplasm with droplike, granular, or irregular oily contents with sulfoaldehyde reaction", strongly stained in cotton blue, especially in the apical part, and 2) "pseudocystidia, formed by thick-walled hyphae, developed from thin-walled hyphae in the subiculum", bending towards and often penetrating the hymenium, apical part 79-100 x 10-15 microns, encrusted by crystalline matter; HYPHAE dimitic; generative hyphae 1.5-4 microns wide, thin-walled, in the subhymenium richly branched and with clamp connections, in the subiculum straighter and with more sparse clamp connections and branches; pseudoskeletal hyphae 1.5-2.5 microns wide, straight and thick-walled, rarely with clamp connections and branches; RHIZOMORPHS composed of pseudoskeletal and generative hyphae of varying width (up to 5 microns), "often encrusted by crystals or by rounded resinous bodies", (Eriksson), gloeocystidia sulfobenzaldehyde positive (Freeman)