Caloplaca ochracea
≡Lecidea ochracea Schaer., Naturwiss. Anz. 2: 11 (1818).
Description : Thallus grey-white, in places tinged yellow in patches, forming a thin, even film, rarely finely areolate, the surface non-corticate, hyphae and crystals present giving a "felted", matt texture, prothallus marginal, thin, black, sometimes forming mosaics. Apothecia common, minute, to 0.3 mm diam., scattered, discrete, rounded, urceolate-immersed at first, eventually sessile, rounded, disc concave to plane, waxy, orange-yellow or orange-brown, proper margin swollen, concolorous with disc. Hymenium 40–50 μm tall. Paraphyses clavate or submoniliform, simple, apices swollen to 5 μm diam. Asci oblong-clavate, 30–45 × 10–15 μm. Ascospores 12–15 × 5–7 μm, the two end locules connected by a wide canal that divides, becoming 4-loculate when mature.
Chemistry : Thallus and apothecia K+ purple-red; containing parietin.
S: Canterbury (Nape Nape). On sunny, maritime limestone rocks. In the Northern Hemisphere it is known from Great Britain, Europe, the Balkans, Greece, Morocco, Tunisia, Israel, Turkey, Ukraine (Galun 1970; Hafellner & Poelt 1979; Laundon 1992; Nimis 1993; Egea 1996; Galun & Mukhtar 1996; John 1996; Kondratyuk et al. 1996a, 1996b, 1998; Seaward 1996; Diederich & Sérusiaux 2000; Fletcher & Coppins 2001i; Llimona & Hladun 2001; Nimis & Martellos 2003), and in the Southern Hemisphere from Argentina (Calvelo & Liberatore 2001).
Cosmopolitan
Illustrations : Wade (1965: 3, fig. 12); Galun (1970: 86, fig. 17C; pl. XX, fig. 2); Hafellner & Poelt (1979: 5, fig. 7; 10, fig. 12; 13, fig. 29; 30, fig. 37); Kärnefelt (1989: 165, fig. 16; 173, fig. 59); Laundon (1992: 145, fig. 7F); Dobson (2000: 96; 2005: 106).
Caloplaca ochracea is characterised by: the saxicolous habit (basicolous rocks); the unusual ascospores with a dumbell-shaped internal cavity (seen in mature ascospores); the ecorticate, patchily yellow thallus; and small, waxy, orange-brown concave apothecia that are immersed in the thallus at first.
