Summary: Features include 1) resupinate growth on wood of species of Ericaceae, 2) corticioid fruitbodies forming linear patches, the surface drying cream to ochraceous-buff, the margins distinct and tightly attached, 3) elliptic-cylindric spores that are smooth and amyloid, 4) catahymenium composed of a) scattered basidial elements, b) conspicuous embedded pseudocystidia that are clavate to ampulliform and darken in sulphobenzaldehyde, and c) numerous acanthophyses variable in shape with aculeate pronged part thick-walled, and 5) context monomitic without clamp connections.
Microscopic: SPORES 14-16 x (6.5)7-8(9) microns, elliptic-cylindric, rounded at both ends, smooth, amyloid, apiculate; catahymenium composed of scattered basidial elements, conspicuous pseudocystidia, and numerous acanthophyses; single basidium observed, 55 x 9.5 microns, with 4 sterigmata up to 9 microns long, basidioles numerous, (40)50-60(7.5) x (8)13-17 microns, subclavate to clavate; PSEUDOCYSTIDIA (macrocystidia) (40)45-60(70) x (9)15-18(23) microns, clavate to ampulliform, contents guttate and yellowish in KOH, darkening in sulphobenzaldehyde, generally embedded; ACANTHOPHYSES variable, basal part cylindric, 3.5 microns wide, to swollen-rectangular, and then measuring up to 45-50 x 14-15 microns, "walls thin to slightly thickened, naked", aculeate-pronged part borne laterally or at the apex, 20-30 x 7.5-8 microns, cylindric, thick-walled to semisolid, occasionally branched, pronged part faintly yellowish (in KOH), individual prongs 1.5-2.5(3) x 0.8 microns; CONTEXT monomitic, composed of hyphae (2.5)3-4 microns wide, subregular, thin-walled, simple-septate, BASAL HYPHAE up to 4.5 microns wide, with partially thickened walls, (Lemke)
Notes: Acanthophysium macrocystidiatum has been recorded from BC and CA (Ginns).
Habitat and Range
SIMILAR SPECIES
Acanthophysium diffissum differs by having 1) a darker color, alutaceous to fuscous-gray, 2) margins often slightly reflexed, 3) narrower spores with different details (but note that some collections of A. diffissum from Mexico have wider spores than those in type), 4) distinctly different pseudocystidia (cylindric to subclavate-moniliform with granular-guttulate contents as opposed to guttate and varying from clavate to ampulliform), 5) prongs on the acanthophyses that are more linear-acicular (as opposed to short aculeate), (Lemke).
Habitat
found on lower surface of branches of Arbutus menziesii that have recently died, recorded also from Arctostaphylos sp., (Lemke)
Synonyms
Synonyms and Alternate Names: Hymenochaete agglutinans Ellis Thelephora corrugata Fr.