Flora of New Zealand Series

Thallus squamulose, pulvinate, areolate-diffract, dispersed at margins on a black prothallus. Photobiont green. Trebouxia. Apothecia lecideine, red-brown, plane to convex and immarginate. Hymenium colourless, 60-70 µm tall. Paraphyses parallel, branched at apices, thickened and darkened. Ascospores 8 per ascus, simple, colourless, ellipsoid.

Lecidoma is a monotypic genus, characterised by the areolate-diffract, pulvinate thallus delimited by a black prothallus [Schneider Biblthca lich. 13: (1980)]. It spreads over peat or soil or decumbent vegetation in subalpine areas. In New Zealand it seems rare and local. Formerly included in Lecidea and in the illegitimate genus Lepidoma (Ach.) S.F. Gray , non Link, see Hertel [ Herzogia 5: 460 (1981)].