Caloplaca thomsonii Zahlbr.
Lectotype: New Zealand. Southland, Clifden, on limestone rocks. J.S. Thomson A11 (T 2264), CHR 374039!
Thallus crustose, scurfy-granular, 0.1 mm thick, grey-brown to black, ± areolate, areolae 0.05 mm diam., separated by shallow to deep cracks, uneven-verrucose, K-, in irregular patches 1-5(-8) cm diam., saxicolous. Apothecia sessile, scattered to crowded, rounded or contorted through mutual pressure, 0.1-0.5(-0.8) mm diam., disc shallowly concave at first then plane, becoming distinctly convex and immarginate with age, dull reddish-orange to bright cinnabar-red, matt, margins thin, entire, concolorous with disc or paler, persistent or occluded with age. Ascospores biseriate, ellipsoid, apices rounded, straight, 2-locular, 15.3-17 × 5.1-7.0 µm, septum c. ⅓ length of spore.
S: Canterbury to Southland. On limestone rocks.
Endemic
