Flora of New Zealand Series

Description : Thallus effuse, indeterminate, forming discontinuous patches, thin, black (dark reddish brown when moist), entirely and deeply rimose-areolate. Areolae plane to slightly convex, angular, 0.2–0.9 mm wide and (40–)60–80(–100) μm thick. Perithecia minute, almost entirely immersed, 0.10–0.16 mm diam. Involucrellum rudimentary. Exciple colourless or pale-brown, 10–15 μm thick. Ascospores ellipsoidal to subglobose, (7.5–)9(–11.5) × 5.5– 7.5 μm.

S: Otago (Black Head, Taieri Beach). On coastal rocks at or above high tide mark. Common in northern Europe, northern Norway, Spitzbergen, Greenland, Novaya Zemlya, NE Siberia, Bering Straits, NE North America, Kerguelen, Marion I., Palmer Peninsula Antarctica, South Shetland Is, South Orkney Is (Lamb 1948a; Redón 1985; McCarthy 1991; Hansen 1995; Øvstedal & Gremmen 2001; Øvstedal & Lewis Smith 2001: 356; Søchting et al. 2004; Elvebakk & Bjerke 2006).

Bipolar

Illustrations : Zschacke (1934: 194, fig. 85); Lamb (1948a: 14, fig. 3B); Foucard (1990: fig. 337); Hansen (1995: 118).

Verrucaria ceuthocarpa is characterised by: the coastal rock habit; effuse, black, deeply areolate thallus; minute, immersed perithecia; colourless to pale-brown exciple; ascospores (7.5–)9(–11.5) × 5.5–7.5 μm.