ssp. arcticum
≡Rhizocarpon tinei ssp. arcticum Runemark., Opera Bot. 2 (1): 125 (1956).
Description : Thallus 1–5 cm diam, areolae and apothecia close together or dispersed on a distinct, black prothallus. Areolae 0.4–1.0 mm diam., rounded to angular, plane to convex, whitish yellow to whitish, smooth, matt. Apothecia 0.5–1.0 mm diam., rounded to angular, 0.5–1.0 mm diam., disc plane, black, epruinose, with a thin, concolorous proper margin. Hymenium 100–150 μm tall. Ascospores with few septa, comprising 6–8 cells, 22–30 × 10– 16 μm.
S: Southland (S Mavora Lake). On rocky outcrops in grassland. Known also from Great Britain, Europe, Scandinavia, and Svalbard (Runemark 1956a, 1956b; Hertel & Ullrich 1976; Purvis et al. 1992; Nimis 1993; Santesson 1993; Elvebakk & Hertel 1997; Nimis & Martellos 2003; Santesson et al. 2004).
Bipolar
Illustrations : Runemark (1956a: fig. 30A, F; 98, fig. 36A, B; 100, fig. 38C – as Rhizocarpon tinei ssp. arcticum).
Rhizocarpon geographicum ssp. arcticum is characterised by: the whitish, convex areolae; and ascospores with rather few septa.
