Flora of New Zealand Series

≡Lecidea eupetraea Nyl., Flora 53: 36 (1870).

=Rhizocarpon lunulatum Zahlbr., Denkschr. Akad. Wiss. Wien math.-naturwiss. Kl. 104: 321 (1941).

Rhizocarpon lunulatum. Holotype. New Zealand. Otago, head of Verter Burn [Maungatua] near Dunedin, J.S. Thomson T358 [ZA 127] – W. Isotypes – CHR 347984, OTA 029384.

Description : Flora (1985: 505–506 – as Rhizocarpon lunulatum).

Chemistry : Thallus K+ yellow→red, C−, KC+ red, Pd+ orange; containing norstictic acid.

S: Westland (Haast River), Canterbury (Godley Valley), Otago (Damper Bay Lake Wanaka, Waikouaiti Reservoir, Waipori, Abbott's Hill, Maungatua). On sunny rocks in grassland. Known also from Europe, Scandinavia, Svalbard, Greenland, the Ukraine, North America, and Bolivia (Lynge 1932, 1936; Thomson 1968a, 1979; Feuerer 1978, 1991; Nimis 1993; Santesson 1993; Esslinger & Egan 1995; Kondratyuk et al. 1996a; Elvebakk & Hertel 1997; Scholz 2000; Hafellner & Türk 2001; Llimona & Hladun 2001; Nimis & Martellos 2003; Feuerer & Timdal 2004; Santesson et al. 2004).

Bipolar

Illustrations : Feuerer (1978: 86); Foucard (1990: 242, pl. 276).

Rhizocarpon eupetraeum is characterised by: a grey to grey-brown, areolate thallus containing norstictic acid (K+ yellow→red); scattered, black apothecia, 0.5–1.4 mm diam., with a thin, concolorous proper margin, or immaginate; a red-brown to brown-black epithecium (K+ red); 8-spored asci; and dark, smoky grey, muriform ascospores, 19–34(–42) × 10–(12–16)–18 μm. Rhizocarpon eupetraeum differs from R. grande only in chemistry, with R. grande containing gyrophoric acid (C+ red, K−, Pd–) and not norstictic acid. If the two names are indeed shown to be synonymous, then R. eupetraeum has precedence, being described in 1870, whereas R. grande was raised to specific rank in 1871.