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Species Information
Summary: Also included in Crusts category. Features include 1) growth on the lower surface of small dead branches on live conifers, 2) disc-shaped or cup-shaped fruitbodies at first 0.1-0.4cm across, sometimes becoming confluent, surface pale orange-pink to pink, with distinct margin ringed with tiny white hairs, the abhymenial surface white, gray, or pale brown and finely hairy or matted, 3) spores large and nearly round to broadly elliptic, with amyloid spines, 4) hymenium of a) basidial elements, b) hyphidia, and c) crystals up to 10 microns wide (which also occur in the context), and 5) context monomitic with some septa clamped. Aleurodiscus grantii is more common in the Pacific Northwest than the very similar Aleurodiscus amorphus.
Aleurodiscus grantii is found from the Pacific Coast to the eastern foothills of the Rocky Mountains. Collections were examined from BC, WA, OR, ID, AB, YT, CA, and MT, (Ginns(16)).
Upper surface: disc-shaped or pezizaeform [shaped like Peziza cup fungus], 0.1-0.4cm across, "scattered to gregarious, sometimes confluent", 0.05-0.1cm thick, surface flat to slightly convex; typically pale orange pink to pink, sometimes faded when old or after storage; finely granulose; margin determinate [distinct], ringed with white, shiny fascicles of hyphal hairs up to 0.02cm long, (Ginns(16))
Underside: "white, grey or pale brown, finely hirsute or matted", (Ginns(16))
Stem: "attached by a short, central base"
Microscopic: spores 22-32(39) x 18-24(28) microns, broadly elliptic to nearly round, with amyloid spines up to 4 microns long, wall colorless, acyanophilic, up to 1 micron thick, apiculus broad (up to 3 microns), blunt; basidia 4-spored, +/- 230 x 25-28 microns, clavate, tapering to a 4 microns wide base, with clamp connection, sterigmata up to 21 microns long; hyphidia colorless, thin-walled to rather thin-walled, infrequently thick-walled, straight to wavy, unbranched or with up to 4 short branches, cylindric or with the apex irregularly swollen or strangulated, swellings sometimes moniliform, 4-6 microns wide; pseudocystidia lacking; crystals: hymenium, subhymenium, and adjacent context "with few to numerous, square to angular crystals up to 10 microns wide"; hyphae monomitic, generative hyphae in the context colorless, branched, "thin- to sometimes rather thin-walled, the wall often with a 1.5 microns thick gelatinized exterior as viewed in 2% KOH", about 10% of the septa with clamp connections; abhymenial surface "sometimes with hyphae parallel, compact", rather thin-walled to thick-walled, brownish yellow, up to 7 microns wide, hyphal "hairs" on the abhymenial surface and the margin 3-5(6) microns wide, straight, rarely branched (branching dichotomously), thin-walled to rather thin-walled, simple-septate, (Ginns(16))
Habitat / Range
typically on lower surface of small (1-6cm diameter), dead branches in the lower crown of live conifers, sometimes on trunks of dead saplings or on fallen stems; most often collected on Abies (fir), especially A. grandis (Grand Fir) and A. lasiocarpa (Subalpine Fir), and less often on other conifers, (Ginns(16))
Similar Species
Aleurodiscus amorphus also has discoid or pezizoid fruitbodies with large, spiny, amyloid spores, but 1) lacks clamp connections (in A. grantii found at about 10% of the septa on the context hyphae, and at the base of nearly all mature basidia), 2) has slightly smaller spores (unusual to find spores over 28 microns, whereas A. grantii typically has some spores over 30 microns long), and 3) has broad, apically moniliform pseudocystidia (in A. grantii some hyphidia in some specimens have the apical part strangulated to form irregular to moniliform swellings, and these strangulated hyphidia resemble the pseudocystidia of A. amorphus, but they never produce swellings that are as uniformly globose [spherical] or as broad (up to 11 microns) as those of A. amorphus), (Ginns(16)).
