Summary: Features include 1) resupinate growth on the bark and on the underside of branches of Douglas-fir and Western Hemlock, 2) corticioid whitish fruitbodies, at first in separate patches 0.5-1.5cm across, readily confluent, with tightly attached margins that become more distinct as they mature, 3) nearly round, amyloid spores that are densely echinulate in Melzer''s reagent, 4) a catahymenium consisting of a) initially embedded basidial elements, b) scattered paraphysoids, c) deep-seated to emergent pseudocystidia (flexuous-cylindric to subclavate, often bearing an apical bulb, darkening in sulphobenzaldehyde), and d) numerous acanthophyses (thin-walled, aculeate-pronged parts borne laterally or apically or both), and 5) a monomitic context with clamp connections.
Microscopic: SPORES (10)11.5-14(16) x (9)9.5-12(13) microns, nearly round, slightly flattened adaxially, densely echinulate in Melzer''s reagent, amyloid, firm-walled, apiculate; catahymenium consisting of initially embedded basidial elements, scattered paraphysoids, deep-seated to emergent pseudocystidia, and numerous acanthophyses; BASIDIA 4-spored, obscured, 60-90 x 10-13 microns, flexuous-cylindric to subclavate, sterigmata 7-9 microns long and 1.5-2.5 microns wide at base; PARAPHYSOIDS rare, 3-4.5 microns wide, simple to slightly branched; PSEUDOCYSTIDIA (macrocystidia) 50-85 x 4-7 microns, flexuous-cylindric to subclavate, often bearing an apical bulb, pseudocystidial contents yellowish to golden brown in KOH, darkening in sulphobenzaldehyde; acanthophyses 25-35 x 7-12 microns, subclavate to clavate, thin-walled, "aculeate-pronged parts borne laterally or apically or both", semisolid, pronged parts "separable, and then in the mount appearing as free-floating fragments", 7-15(18) x 5-10 microns, individual prongs 4-10 x 1-1.5 microns, appearing to advantage in Melzer''s reagent; CONTEXT monomitic, composed of hyphae that are 1.5-3 microns wide, subregular, thin-walled, and clamped, BASAL HYPHAE 3.5-5(6) microns wide, with partially thickened walls, (Lemke)
Notes: Aleurodiscus spiniger has been recorded from BC, OR, ID, and AZ, (Ginns). Collections were examined from BC, OR, ID, and China, (Lemke).
Habitat and Range
SIMILAR SPECIES
Acanthophysium weirii is close but has larger spores (Lemke).
Habitat
on bark, and on underside of branches, recorded from Larix occidentalis (Western Larch), Pseudotsuga menziesii (Douglas-fir), Tsuga heterophylla (Western Hemlock), (Ginns), on the bark and on the underside of branches of various conifers, in the Pacific Northwest primarily on Pseudotsuga and Tsuga, (Lemke)