On twigs. Wellington (Travers, 376).

COMPOSITAE. Brachyglottis repanda: Auckland, Cascade Kauri Park, Waitakere Ranges, 250 m. MYRSINACEAE. Myrsine salicina: Wellington, Lake Papaitonga, 20 m. ROSACEAE. Rubus australis: Wellington, Ruahine Ranges, 950 m; Lake Papaitonga, 20 m. SAXIFRAGACEAE. Carpodetus serratus: Auckland, Cascade Kauri Park, Waitakere Ranges, 250 m. VIOLACEAE. Melicytus ramiflorus: Wellington, Lake Papaitonga, 20 m. UNKNOWN HOSTS. South Australia, Belair, Blackfellows Creek.

Hymenophore annual, membranous-cretaceous, adherent, effused forming small scattered irregular colonies 2-15 x 2-7 mm, linear to lobed; hymenial surface at first white, becoming dingy grey, at length deeply areolately creviced; margin abrupt, white, often coarsely lobed, adherent. Context white, to 95 µm thick, basal layer of mainly parallel hyphae, intermediate layer wanting; generative hyphae 2-3 µm diameter, walls 0.2 µm thick, without clamp connections. Dendrophyses forming the bulk of the hymenial layer, of erect stems freely branched at apices, 2.5-3 µm diameter, encrusted with fine crystals which may be confined to branches. Gloeocystidia absent. Hymenial layer to 75 µm deep, an irregular palisade of basidia, paraphyses, and dendrophyses. Basidia subclavate, 50-75 x 10-12 µm, bearing 4 spores; sterigmata arcuate, to 8 µm long. Paraphyses commonly clavate, some cylindrical, 18-40 x 6-8 µm. Spores elliptical or obovate, a few suballantoid, apiculate, 10-14 x 6-9 µm, walls smooth, hyaline, 0.2 µm thick, nonamyloid; often adhering in fours.

DISTRIBUTION: Europe, Great Britain, North America, South Africa, Australia, New Zealand.

HABITAT: Scattered on bark of living trunks and branches.

Dendrophyses are freely branched near apices and arranged at different levels in the hymenium; most are encrusted with fine crystals, either completely or with apices of a few branches and pedicels naked. Some of the context hyphae also are encrusted. Spores are mostly elliptical or obovate, apiculate, some obliquely so, thin-walled, smooth and nonamyloid. Walls soon collapse, and frequently spores adhere in fours. Corticium ampullosporum resembles A. acerinum in macrofeatures, thin context and elliptical smooth spores often adhering in fours; it differs in the absence of dendrophyses, smaller basidia, larger spores, and presence of clamp connections.

TYPE LOCALITY: Europe.