Pumice Boulders: Wellington, Desert Road, Mt. Tongariro, 1,100 m.

Hymenophore annual, membranous, loosely attached, effused forming irregular areas 4-10 x 2-5 cm, with a few scattered orbicular outlying islands; hymenial surface umber with broad fawn margins, at first somewhat porose, becoming even or slightly tomentose, not creviced; margin thinning out, to 5 mm broad, fawn, adherent. Context ferruginous, to 200 µm thick, basal layer containing numerous cordons 10-25 µm diameter of 5-10 hyphae closely compacted, intermediate layer of loosely intertwined mainly ascending hyphae; generative hyphae 3-5-4 µm, diameter, walls 0.2 µm thick, pallid yellow-brown, with clamp connections. Hymenial layer to 40 µm deep, a loose palisade of basidia, paraphyses, and paraphysate hyphae. Basidia clavate, 16-28 x 4-6 µm, bearing 4 spores; sterigmata slender, arcuate, to 5 µm long. Paraphyses subclavate, 12-18 x 4-5 µm. Paraphysate hyphae projecting to 60 µm, clavate, 52-96 x 6-8 µm, apices inflated to 12 µm, with one or two transverse septa each with a clamp connection. Spores oval or irregularly subglobose, angled, apiculate, 7-9 x 6-7 µm, walls strongly sinuate, finely irregularly verruculose, yellow-brown, 0.2 µm thick, spines to 0.5 µm long.

DISTRIBUTION: North America, France, New Zealand.

HABITAT: Lower surfaces of pumice boulders lying upon the ground.

Cordons are abundant in the base, and composed of few or many thin-walled hyphae firmly compacted. Paraphysate hyphae ('cystidia' of Burt; 'cystidioles' of Bourdot & Galzin) project for as much as 60 µm, and possess one or two transverse septa each with a clamp connection. Walls are hyaline, 0.25 µm thick, and even or bear a few mucilage granules.

TYPE LOCALITY: Wisconsin, U.S.A.