FAGACEAE. Nothofagus cliffortioides: Wellington; Mt. Tongariro, 1,000 m, type collection, P.D.D. herbarium, No. 4971; Waihohonu River, Mt. Tongariro, 1,200 m; Kaimanawa Ranges, 600-850 m; Ohakune, 700 m; York Bay, 120 m. Nelson, Maitai Valley, 60 m; Murchison, 170 m. Nothofagus fusca: Auckland, Mamaku Forest, 600 m. Hawke's Bay, Turangakumu Saddle, 800 m. Wellington, Kaimanawa Ranges, 800 m; Days Bay, 120 m. Nelson, Lake Rotoiti, 700 m; Staircase Creek, Reefton, 700 m; Murchison, 170 m; Orwell Creek, Ahaura. Nothofagus menziesii: Wellington, Whakapapaiti Valley, Mt. Ruapehu, 800 m; Upper Mohaka River, 700 m. Nothofagus truncata: Auckland, Little Barrier Island; Orere, Hunua Ranges, 300 m; Lake Waikaremoana, 800 m.

Hymenophore annual, cretaceous, adherent, at first composed of numerous small orbicular scattered colonies 1-2 mm diameter, soon coalescing to form effused areas to 15 x 3 cm; margin thinning out, irregular, arachnoid, adherent; hymenial surface chalk-white, sometimes tinted cream or pallid pink, deeply areolately creviced, even or finely tuberculate. Context white, to 0.5 mm thick, intermediate layer of loosely arranged erect hyphae radiating from points of attachment, embedding masses of crystals; generative hyphae 3-6 µ diameter, walls 0.5 µ thick, or lumena almost capillary, with clamp connections. Acanthophyses coralloid, branched, freely spinose, varying in shape and size, arising from hyphae of the context at different levels, projecting, lumena capillary. Gloeocystidia absent. Hymenial layer vaguely defined, to 80 µ deep, a scanty palisade of basidia, paraphyses, and acanthophyses. Basidia subclavate, often distorted and genlculated, soon collapsing, 60-115 x 15-26 µ bearing 4 spores; sterigmata arcuate, subulate, to 24 µ long. Paraphyses subclavate, scanty, buried in the context, 40-110 x 8-12 µ. Spores commonly oval, many subglobose, a few globose, 18-25 x 16-22 µ, walls irregularly aculeate, 1 µ thick, amyloid, spines to 3 µ long.

TYPE LOCALITY: Mt. Tongariro, Wellington, New Zealand.
DISTRIBUTION: New Zealand.

HABITAT: Effused on bark of dead branches, twigs and standing dead saplings.

A. coralloides is common in New Zealand on four endemic species of Nothofagus. It may be identified by the chalk white (sometimes pink) deeply creviced hymenophore, oval irregularly aculeate spores, and thick-walled acanthophyses. The hymenophore, although appearing effused, is in reality composed of many small orbicular coalesced colonies. In sections each colony is apparent since the context hyphae develop from a small submerged base, and are arranged radiately from its centre. Hyphae merge with those of neighbouring colonies, at points of coalescence being less densely compacted. On the surface, margins of colonies are indicated by deep crevices.
Acanthophyses are produced in such masses that the scanty hymenium is masked, and give to sections their characteristic chalky appearance. They simulate pieces of coral, being short-branched, both stems and branches bearing spines and possessing walls so thickened that lumena are capillary. An almost endless variety of shapes may be seen in any section, so that exact descriptions are difficult to prepare. Among the acanthophyses are embedded the paraphyses and young basidia. The latter, when mature, elongate and project above the hymenial surface, produce spores, then collapse. Spores are formed in large numbers and may be found lying upon the surface and scattered through the hymenial tissues. Although appearing almost smooth in lactic acid aniline blue mounts, they are seen to be coarsely and irregularly aculeate when treated with Melzer's reagent.