Flora of New Zealand Series

Thallus squamulose to small-foliose, spreading, squamules 1-3 mm diam., pale glaucous-green to greyish, upper cortex plectenchymatous, lower cortex pale whitish to yellow-brown, lacking rhizines. Medulla white. Photobiont green, Trebouxia. Apothecia lecideine, brown to brown-black, marginate. Hymenium 80 µm tall. Paraphyses thin, 1.5-2 µm, reticulate-branched, apices not thickened. Asci clavate, 8-spored, with a thick, tholus. Ascospores ellipsoid, simple, colourless, not halonate.

Trapeliopsis, a segregate of Lecidea [Schneider Biblthca lich. 13: 143-154 (1980)] comprises 5 squamulose to small-foliose species related to Psora, among which its members are often placed. One species is known from New Zealand.