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

Summary:
Features include 1) resupinate growth on the underside of rotten hardwood, 2) dense spines that are waxy, whitish to yellowish or yellow-ochraceous when young, darkening to brown or blackish, the tip fringed under a lens, the fruitbody margin pruinose or indeterminately thinning out, 3) the young yellow parts of the fruitbody turning red with drops of KOH, 4) subcylindric spores that are smooth and inamyloid, 5) cystidia present as needle-like cystidioles projecting beyond the hymenium, 6) cystidia-like, encrusted hyphal ends at the tips of the spines, 7) a monomitic hyphal system, the hyphae with clamp connections.

Mycoacia fuscoatra has been found in WA, ID, MB, NS, ON, AZ, CO, GA, IA, MI, MN, NC, NY, OH, WI, (Ginns(5) - some of which might be regarded as Mycoacia nothofagi by Nakasone(11)). It has been found in BC, MB, NS, ON, YT, AK, AL, GA, ID, IL, IA, LA, MD, ME, MT, NM, NY, OH, OR, WI, Czech Republic, Estonia, Finland, France, Germany, Lithuania, Russia, Slovak Republic, Sweden, and Japan, (Nakasone(11)). It occurs in Europe (including Switzerland) and Asia, (Breitenbach). It has been recorded from all parts of Scandinavia, from Denmark to N. Lappland, (Eriksson).

Fruiting body:
resupinate, effused [spread out], adnate [firmly attached], when young ceraceous [waxy], when mature firmer; when young cream, citrine or ochraceous-yellow, when mature "darkening to brown or black-brown and when old almost black"; aculei [spines] dense, conic to subcylindric, apically tapering, the tip fimbriate to penicillate [brush-like] under lens, the bases often joined in pairs or in small groups; margin when young fimbriate [fringed] under lens, "pruinose or indeterminately thinning out"; subiculum "thin, fertile only in the marginal part"; "young yellow parts of the fruitbody turning red by drops of KOH" , (Eriksson), resupinate, tightly attached, forming patches several centimeters to decimeters across, consisting of thin (about 0.01-0.03cm), wax-like subiculum, from which arise cylindric to somewhat subulate [awl-shaped] spines that are pointed in the distal part and 0.1-0.3cm x 0.02-0.04cm, the spines sometimes fused at base, "whitish yellowish when young, brown to blackish when old", wax-like and soft, brittle when dry; according to the literature, young fruitbodies turn dark red with KOH, (Breitenbach), spore deposit white (Buczacki)

Microscopic:
SPORES 5-6 x 2-2.5 microns, subcylindric "with almost parallel sides or with slightly concave adaxial side", smooth, inamyloid, acyanophilic, thin-walled; BASIDIA narrowly clavate, mostly 15-22 x 4-5 microns, 4-spored, with basal clamp connection "from which new basidia develop"; CYSTIDIA present as thin-walled, needle-like cystidioles in the hymenium, 30-40 x 4-5 microns, "projecting beyond the basidia", "and cystidia-like, encrusted hyphae in the apical part of the aculei"; HYPHAE monomitic, hyphae 2-3 microns wide, thin-walled, with clamp connections, "densely parallel in the aculeal trama, projecting in the aculeal apex, such projecting hyphae as a rule strongly encrusted and may look like differentiated cystidia"; "beside the crystalline encrustation also many non-crystalline grains in the texture which dissolve and in young fruitbodies turn red in KOH, in Cotton-blue floating together to yellow, oil-like drops or bodies with a foamy interior structure, often joined to irregular bodies, floating in the medium or sticking to hyphae or hymenial elements", (Eriksson), SPORES 4.5-5.5 x 2-2.5 microns, cylindric-elliptic, smooth, inamyloid, colorless, with droplets; BASIDIA 4-spored, 20-25 x 4-5 microns, narrowly clavate, with basal clamp connection; LEPTOCYSTIDIA up to 45 x 4 microns, fusiform; HYPHAE monomitic, the hyphae 2-4 microns wide, thin-walled to thick-walled, with clamp connections; HYPHAL ENDS at the tips of the spines strongly encrusted, up to 10 microns across, (Breitenbach)