Summary: Features include 1) growth on twigs and stems of species of Rosaceae, 2) fruitbodies as patches that are palish with orange tinges, thin and leathery, and often pruinose, 3) spores that are oval to oval-elliptic, amyloid, and finely spiny, 4) a catahymenium composed of a) a loose network of basidial elements, b) naked dendrohyphidia (may be covered with crystals), and c) abundant yellowish pseudocystidia (macrocystidia) of a deep origin, and 5) a monomitic context without clamp connections.
Microscopic: SPORES about 20 x 13 microns, elliptic to nearly round, finely echinulate (spiny), amyloid; BASIDIA 4-spored, about 60 x 15 microns, sterigmata about 15 microns long; DENDROHYPHIDIA numerous, richly branched and covered with crystals; PSEUDOCYSTIDIA "variable in shape, narrowly paraphysoid with rounded apex, or wider and more rounded, tapering basally to a long shaft with a +/- moniliform apex, or even smooth to simply tapering", cell contents yellowish (darken in sulfovanillin), making pseudocystidia easy to separate from basidia; HYPHAE monomitic with hyphae 2.5-4 microns wide, simple-septate, thin-walled, in an open texture, (Eriksson), SPORES (14)16-20(22) x (10)12-15(16) microns, oval to oval-elliptic, "apiculate, flattened adaxially, firm-walled, finely echinulate in Melzer''s, amyloid"; catahymenium composed of a loose network of basidial elements, naked dendrohyphidia, and abundant pseudocystidia (macrocystidia) of a deep origin; BASIDIA 4-spored, (30)50-70(80) x 10-14 microns, cylindric to flexuous-subclavate, sterigmata divergent and up to 20 microns long and 4 microns wide at base; PSEUDOCYSTIDIA embedded, (30)40-60 x 12-20 microns, variable, mostly ampulliform with one to several apical constrictions, contents yellow brown in KOH, PARAPHYSOIDS 2-2.5 microns wide, hypha-like, "without clamps, simple to branched, forming a mass of naked dendrohyphidia at the level of the hymenium"; HYPHAE monomitic, of hyphae 2.5-4 microns wide, simple-septate, thin-walled, branched, (Lemke)
Notes: Aleurodiscus aurantius has been recorded from BC, ON, and CA, (Ginns). It occurs in Europe including Denmark, Norway, and Sweden, (Eriksson). Collections were examined from BC, CA, France, Germany, Norway, and Sweden, and the range includes South America, Japan, and New Zealand, (Lemke).
Habitat and Range
SIMILAR SPECIES
Among amyloid-spored Aleurodiscus species, A. aurantius is distinct in having naked, profusely branched dendrohyphidia, (Lemke). Peniophora erikssonii is somewhat similar in appearance, but very different microscopically, (Eriksson).
Habitat
on dead twigs and stems, in Europe primarily on Rosaceae, in BC a collection from Vaccinium, in California from Arctostaphylos columbiana (hairy manzanita), Rhododendron occidentalis (western azalea), Ribes sanguineum (redflower currant), Rubus ursinus (Pacific blackberry), Umbellularia californica (California laurel), Notholithocarpus densiflorus (Tanoak), (Lemke), also recorded from Tsuga (hemlock), (Ginns), usually on Rosaceae, but recorded from Taxus (yew), (Eriksson for North Europe), fall, winter, spring, (Buczacki)