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

Summary:
A distinctive character of the genus is the presence in the tissues of asterosetae, with 3-5(7) unbranched setae radiating from a central point. Other features of the species include 1) resupinate growth on rotten logs, under roots of old stumps, or in forest litter of mainly coniferous trees, 2) easily detachable, cottony, round fruitbodies, 3-20cm across and up to 0.5cm thick but much more extensive when confluent, the surface brownish orange to cinnamon brown, warted, soon composed of densely arranged teeth, and the margin thin, and radially fibrillose or cobwebby, 3) spores that are broadly elliptic, and colorless, with their walls thin or slightly thickened, 4) hymenial setae, and 5) hyphal system that is trimitic with generative hyphae, skeletal hyphae, and asterosetae. Fruitbodies of this species sometimes grow over the remains of the ones from the previous year, and seem to be layered: one such specimen had 7 layers and was more than 1.5cm thick, (Parmasto).

Asterodon ferruginosus has been found in BC, WA, ID, NB, ON, PQ, YT, AK, CT, ME, MI, MT, NH, and NY, (Ginns(5)), and also AR, DE, MA, VT, WI, and Russia, (Parmasto).

Fruiting body:
"annual, effused, easily detachable from substrate, cottony soft", up to 0.5cm thick, round, 3-20cm across (when confluent up to 500cm long); bright fulvous or ochreous-fulvous to sienna (brownish orange, caramel brown or cinnamon brown); "warted, soon composed of densely arranged teeth", teeth (0.02)0.05-0.2(0.4)cm long, 0.012-0.03(0.04)cm wide, cylindric-conic; margin 0.05-0.2cm wide, "thin, radially fibrillose or almost arachnoid", whitish then colored as rest of surface, later disappearing, "margin and rotten substrate with numerous, sometimes branched, soft, whitish, later brownish mycelial threads" up to 0.07cm wide, (Parmasto), resupinate, soft and cottony; hymenial surface cinnamon brown to reddish brown; surface hydnaceous; margin with brown rhizomorphs, (Martin), "membranous, hymenial surface whitish grey and covering densely packed spines, subiculum yellow brown, cottony and darkening in KOH", (Ginns(23), regarding the genus)

Microscopic:
SPORES 5-6.5(7) x 3.5-4.5 microns, broadly elliptic, with one side slightly flattened, walls thin or slightly thickened, [smooth from Parmasto notes on family]; BASIDIA 4-spored, 17-25(30) x 5-7(8) microns, "clavate, some slightly flexuose", sterigmata 4-5 microns long, basidioles present, without encrustation; HYPHIDIA rare, 1-2.5(3) microns wide, colorless; CYSTIDIA (cystidioles) not numerous, 20-50 x 4-6 microns, "mainly situated on top of a tooth, fusoid, with usually cylindric upper part, thin-walled"; HYMENIAL SETAE "numerous, 40-80 x 5-10 microns, single or as side branches of setal hyphae, simple or with 2-4 sidebranches at base, 25-80 x 5-10 microns, projecting to 40 microns, subulate to fusiform, with acute tip, straight, naked, without incrustation"; crystalline matter absent from hymenium; HYPHAE trimitic with 1) generative hyphae numerous, 1.5-3 microns wide, with thin, colorless or yellowish walls, septate, branched, 2) skeletal hyphae 1.5-3 microns, thick-walled, brownish, 3) asterosetae common, with 3-5(7) unbranched rays, each 30-120(150) x 5-8 microns, "in subhymenium smaller than at substrate"; hyphae in teeth more or less parallel, setal hyphae present in teeth, 60-170 x 5-7 microns, (Parmasto), SPORES 5-7.5 x 3-4 microns, oval to broadly elliptic, colorless; stellately branched setal hyphae abundant in subiculum and hymenium, (Martin), "hymenial setae with rays to 100 microns long and occasionally branched, generative hyphae narrow, simple-septate, and skeletal hyphae", (Ginns(23), regarding genus)