Flora of New Zealand Series

Lectotype: New Zealand. Near Wellington, J. Buchanan 247 – GLAM. Isolectotypes – BM, WELT.

Description : Flora (1985: 471).

Chemistry : TLC−, all reactions negative.

N: Northland (Tahurangi Bluff), Taranaki (Mt Taranaki), Wellington (Wellington). S: Nelson (Mt Robert) St: (Port Pegasus). Ch.: A: C: Throughout, widely distributed in mainly lowland and coastal habitats, s.l. to 1500 m, on trees and shrubs, rarely on rocks in damp, shaded habitats. Known also from E Australia and Tasmania (McCarthy 2003c, 2006), and on leaves of Drimys winteri and Laurelia sempervirens in Valdivian rainforest in southern Chile (Lücking et al. 2003).

Austral

Illustrations : Malcolm & Galloway (1997: 108, 161, 175); Malcolm & Malcolm (2000: 13); Lumbsch et al. (2001: 25); Lücking et al. (2003: 29, fig. 6F).

Psoroma caliginosum is characterised by: the corticolous (occasionally foliicolous) habit; the squamulose thallus developed on a black, minutely fibrous prothallus, sometimes extending 2–4 mm beyond marginal squamules; thalline squamules closely appressed, flattened, smooth, lobate-crenate, the margins whitish pubescent and appearing "frosted"; the large, placodioid cephalodia, to 3 mm diam., laminal or marginal on squamules or developing directly on prothallus; the ±central apothecia, with thick, inrolled, crenate-striate margins, and a matt, plane, dark-brown to black disc often obliterated by concentric rings of thalline tissue or with small thalline lobules; and large ascospores, (12–)17–24 × (9–)12–14 μm.