Caloplaca crenulatella
≡Lecanora crenulatella Nyl., Flora 69: 461 (1886).
Description : Thallus crustose, corticate, endolithic or little-developed to somewhat granular around apothecia, or ±areolate, areolae 0.2–1(–1.5) mm diam., contiguous or ±dispersed, yellow, K+ purple. Apothecia to 1 mm diam., sessile, scattered to aggregated in small groups, ±rounded, flat, disc epruinose, orange. Proper exciple surrounded by a slightly warted thalline exciple, concolorous with disc or yellowish. Epithecium yellow, K+ purple, 10–15 m thick. Hymenium colourless, 80–90(–100) μm tall. Hypothecium colourless. Ascospores colourless, (13–)15–17.5–20(–23) × (5–)6–7–8(–12) μm, septum 1–3 μm thick.
S: Nelson (Takaka). On limestone outcrops (Rosinés & Hladun 1996: 148). Widespread but rare in the Northern Hemisphere from Great Britain (known only from the type locality); Austria; Germany; Belgium, Luxembourg, Spain; France; Italy; Macedonia; Sweden and Norway (Laundon 1992; Nimis 1993; Santesson 1993; Rosinés & Hladun 1996; Diederich & Sérusiaux 2000; Scholz 2000; Gilbert et al. 2001; Llimona & Hladun 2001; Nimis & Martellos 2003; Santesson et al. 2004).
?Bipolar
Illustrations : Wade (1965: 3, fig. 2); Navarro-Rosinés & Hladun (1996: 144, fig. 2); Dobson (2000: 92; 2005: 100).
Caloplaca crenulatella is characterised by: the saxicolous habit (basicolous rocks); the endolithic to poorly developed, yellow, areolate thallus; scattered, orange apothecia; and ascospores, (13–)15–17.5–20(–23) × (5–)6–7–8(–12) μm, septum 1–3 μm thick. A table showing differences between C. crenulatella, C. holocarpa and C. lactea is given in Coppins & Fletcher (2001e).
