Psoroma soccatum R.Br. ex Cromb.
Lectotype: Tasmania. Table Mountain (Mt Wellington). On dead trunks of trees. R. Brown 502, BM!
Thallus small, squamulose, often widely scattered, on a prominent black, thin, continuous, fibrous or byssoid prothallus, 3-5(-10) cm diam. Squamules small, ± discrete, 0.1-1.0 mm diam., round to irregular, plane to subconvex, rarely forming a continuous crust, ± consistently sorediate, especially at centre, esorediate near margins, sometimes forming a diffract-areolate, sorediate crust centrally, some squamules ascending, white tomentose below. Upper surface pale greenish or yellowish-white, smooth, waxy or matt, commonly with fine, silky, bristling crystals (×10 lens). Soredia white, or yellowish, granular, surrounded by a halo of white, silky crystals. Cephalodia common, scattered, between squamules on prothallus, never developing on squamules, simple, globose to glomerulate, smooth, purplish-brown. Apothecia not common, scattered, sessile or subpedicellate, 0.1-1.2 mm diam., round to irregular, disc dark red- brown to blackish, matt, epruinose, not gyrose-etched, sometimes ± sorediate, margins crenulate-striate, waxy, occasionally granular-sorediate, thalline exciple wrinkled-striate, ± sorediate. Ascospores 15-17 × 11 µm.
N: North Auckland to Wellington. S: Nelson to Fiordland mainly west of the Main Divide, reaching to the east coast near Dunedin (Mt Maungatua). An epiphyte of Nothofagus, Leptospermum and Griselinia, and other trees and shrubs less commonly.
Australasian
In deep shade squamules are fewer and more scattered on a better-developed black prothallus. The species will tolerate deep shade but is also common at edges of forest in moderate light.
