Summary:
Features include 1) growth on the bark of recently dead branches on live conifers, primarily fir, 2) disc-shaped or cup-shaped fruitbodies at first 0.0-0.5cm across, sometimes becoming confluent, the surface salmon pink when fresh and producing spores, with a 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) a hymenium of a) basidial elements, b) hyphidia, c) pseudocystidia (not darkening in sulphobenzaldehyde) typically with 1 to several, successively smaller apical swellings, and d) crystals up to 10 microns wide (which also occur in the context), and 5) a context that is monomitic without clamp connections. A. amorphus is rare to uncommon within the range of Aleurodiscus grantii, a similar common species.

Microscopic:
SPORES about 25 x 20 microns, nearly round to broadly elliptic, "densely covered with fine, cylindrical to slightly conical and abruptly cut (not tapering) spines"; BASIDIA 4-spored, about 100 x 25 or even larger, sterigmata 15-25 microns long; PARAPHYSOID HYPHAE "present between the basidia, moniliform (like a string of pearls) and not projecting", HYPHAE "monomitic with simple septate hyphae, 2-4 microns wide, in an open texture of distinct hyphae", (Eriksson), SPORES 25-30 x 22-25 microns, nearly round to oval, with fine blunt spines, colorless, amyloid; BASIDIA 4-spored, 140-180 x 20-30 microns, without basal clamp connection; CYSTIDIA 100-200 x 15 microns, moniliform hyphal ends; HYPHAE monomitic 2-4 microns wide, septa without clamp connections, (Breitenbach), SPORES (22)24-28(32) x (18)20-23(26) microns, broadly elliptic to nearly round, with amyloid spines up to 4 microns long, wall either colorless and thin or pale yellow and thickened, acyanophilic, apiculus broad and blunt; BASIDIA 4-spored, about 200 x 22-28 microns, tapering to a narrow (4-5 microns) base, basal septum without clamp connection, sterigmata 30-40 microns long and up to 7.5 microns wide at base; HYPHIDIA scattered, (2)3-5 microns, cylindric or some irregularly swollen, "straight to wavy, some with one or two branches"; PSEUDOCYSTIDIA usually numerous, "typically with 1 to several, successively smaller, acropetal, apical swellings" up to 10-11 microns wide (moniliform), acyanophilic, inamyloid, not darkening in sulphobenzaldehyde; CRYSTALS: hymenium and context with few to numerous, small to large (up to 10 microns in diameter) crystals scattered throughout; HYPHAE monomitic, generative hyphae in context 3-5 microns wide, colorless, simple-septate, thin-walled to rather thin-walled, "the exterior surface of the walls swelling in 2% KOH, with few to numerous segments crystalline incrusted", branched, inamyloid, acyanophilic; ''external hyphae, including those forming the "hairs" around the hymenial surface and those of the abhymenial surface, hyaline, pale yellow or some on the abhymenial surface yellow-brown, thin- to rather thin-walled, septate, rarely branched'', the branches arising as an apical dichotomy, encrusted with few to numerous (up to 5 microns), roughed or angular crystals (3)4-6.5 microns in diameter, (Ginns(16))

Notes:
Aleurodiscus amorphus has been found in BC, WA, OR, ID, AB, MB, NB, NF, NS, ON, PE, PQ, SK, YT, AZ, CA, CO, CT, MA, ME, MI, MN, MO, MT, NH, NY, TN, VT, WI, WV, (Ginns(5), who notes that "From the Pacific Coast to the eastern foothills of the Rocky Mountains, the very similar, Aleurodiscus grantii [italicized] is more common"). A. amorphus also found in Mexico, Europe, Russia (Siberia), Japan, and China, (Ginns(16)). It occurs in Switzerland (Breitenbach), and Sweden (Eriksson).

Synonyms and Alternate Names:
Nodularia balsamicola Peck
Peziza amorpha Pers.
Thelephora amorpha (Pers.) Fr.
Thelephora violaceolivida Sommerf.