Rhizocarpon viridiatrum (Wulfen) Körb.
Lichen viridiater Wulfen, Pl. Rar. Carinth.: 186 (1788).
Thallus small 0.5-2(-8) cm diam., areolate, prothallus indistinct. Areolae 0.3-1.2 mm diam., roundish to angular, strongly convex to plane, greyish-green or pure green, surface smooth, matt. Apothecia 0.4-1 mm diam., round to irregularly angular, strongly convex, or elevated and subconvex, immarginate when old. Hymenium 85-140 µm tall, colourless, upper parts dark reddish. Hypothecium dark brown, 200-300 µm thick. Asci clavate, 80-110 × 30 µm, 8-spored. Ascospores muriform, with few septa, 12-27 × 7-17 µm. Chemistry: Rhizocarpic acid, rarely stictic or gyrophoric acids.
S: Canterbury (Mt Sebastopol, Lake Pukaki). On subalpine to alpine rocks, probably widespread in Southern Alps.
Cosmopolitan
