Halecania ralfsii
≡Lecidea ralfsii Salwey, Trans. Nat. Hist. Antiq. Soc. Penzance 2: 144 (1854).
≡Lecania ralfsii (Salwey) A.L.Sm., Monogr. Br. Lich. 1 (ed. 2): 342 (1918).
Description : Thallus somewhat effuse, rimose-cracked, surface smooth, waxy or oily, bluish to slate-grey; cortex with brownish (pigment caps) and greenish (N+ reddish) pigments. Prothallus absent. Apothecia 0.2–0.5 mm diam., disc mostly flat, dark-brown to black, paler when moist. Thalline exciple concolorous with thallus, soon disappearing. Proper exciple blackish, slightly raised. Epithecium brown (K−, N−), adjacent edge of proper exciple greenish brown (N+ reddish). Hymenium 50–80 μm tall. Ascospores (13–)15–17(–20) × 6–9 μm. Pycnidia numerous, upper wall green-brown, N+ reddish.
Chemistry : K+ yellowish, C−, KC−, Pd ±red; containing zeorin (major).
S: Nelson (Ataata Point). On exposed volcanic rocks, 3–5 m from the sea, above the Verrucaria maura zone. Known also from Great Britain, Norway, Sweden and France (Mayrhofer 1987; Coppins 1989b, 2002b; Purvis et al. 1992; Santesson 1993; Coppins & Fryday 1996a; Santesson et al. 2004; van den Boom & Elix 2005).
Bipolar
Illustrations : Mayrhofer (1987: 401, fig. 9); Purvis et al. (1992: 269, fig. 16); Dobson (2005: 186).
Halecania ralfsii is characterised by: the saxicolous (marine rocks) habit; the rimose-areolate, smooth, oily, bluish to slate-grey thallus with greenish (N+ reddish) pigments; ascospores, 15–17 × 6–9 μm; and zeorin as the major secondary metabolite.
