Flora of New Zealand Series

≡Lecidea confervoides var. polycarpa Hepp, Flecht. Eur.: No. 35 (1853).

Description : Thallus irregularly spreading or in compact patches, 1–3 cm diam., areolate, with a rather thin, black marginal prothallus. Areolae plane to shallowly convex, angular to rounded, 0.2–0.5 mm diam., separated by narrow cracks, surface smooth, dark-brown with a pale greyish or pinkish tinge, or somewhat weathered and appearing grey-white. Apothecia sessile, scattered to crowded, solitary or 2–4-together, 0.2–0.5(–0.8) mm diam., plane to convex, black, matt, epruinose, with a thin, black, slightly raised proper margin at first, becoming occluded with age. Epithecium densely granular, dark brownish red (K+ purple), 8–13.5 μm thick. Hymenium colourless, 75–95 μm tall. Hypothecium red-brown to dark-brown. Asci clavate, 75–95 × 25–30 μm, 8-spored. Ascospores 1-septate, colourless, halonate, 16.6–22 × 8–10 μm (without halo).

Chemistry : Thallus K+ yellow, C−, K−, Pd+ yellow; containing stictic acid.

S: Otago (Old Woman Ra., Rock & Pillar Ra.). On exposed alpine to high-alpine rocks and on pebbles (quartz) in exposed soil patches. Known also from Great Britain, Europe, Scandinavia, Svalbard, Morocco, Turkey, the Ukraine, North America, Australia, South Georgia, South Orkney Is, South Shetland Is, and Antarctica (Thomson 1968a, 1979; Feuerer 1978; Purvis et al. 1992; Nimis 1993; Santesson 1993; Esslinger & Egan 1995; Wirth 1995a; Egea 1996; John 1996; Kondratyuk et al. 1996a; Elvebakk & Hertel 1997; Diederich & Sérusiaux 2000; Scholz 2000; Hafellner & Türk 2001; Llimona & Hladun 2001; Øvstedal & Lewis Smith 2001; Coppins 2002b; McCarthy 2003c, 2006; Nimis & Martellos 2003; Feuerer & Timdal 2004; Santesson et al. 2004; Søchting et al. 2004).

Bipolar

Illustrations : Feuerer (1978: 95); Wirth (1995a: 535, pl. 55K).

Rhizocarpon polycarpum is characterised by: the saxicolous habit; the dark-brown to greyish, or weathered grey-white, areolate thallus (containing stictic acid), with or without a thin, black marginal prothallus; scattered, small, plane to convex, black apothecia; a K+ purple epithecium; I+ blue medulla; and large, colourless, halonate, 1-septate ascospores, 16.6–22 × 8–10 μm (without halo); and stictic acid in the medulla.