Verrucaria glaucina
=Verrucaria otagensis Zahlbr., Denkschr. Akad. Wiss. Wien math.-naturwiss. Kl. 104: 250 (1941).
Verrucaria otagensis. Holotype: New Zealand. Otago, "Matsanoka" [sic.] [= Matanaka], on coastal limestone [= calcareous sandstone]. J.S. Thomson T2333 [A65] – W. Isotypes – CHR 373523, 373524, 373525; OTA 029029.
Description : Thallus superficial, pale- to dark-grey, grey-brown, olive-brown or dark-brown, deeply areolate, 0.2–1(–1.5) mm thick, delimited by a brown-black prothallus that is also visible beneath the areolae and forming a black rim to these. Areolae 0.1–0.4 mm wide. Perithecia compound, numerous, totally immersed, apex flat. Involucrellum black, globose, 0.1–0.25 mm diam., apical, dimidiate or extending to and merging with prothallus. Exciple colourless to black. Ascospores 10–18(–23) × 5–8 μm.
S: Canterbury (Milford), Otago (Matanaka), Southland (Forest Hill). On limestone and calcareous sandstone. Known also from Britain, Scandinavia, Europe, Russia, USA, Taiwan and Australia (Hawksworth et al. 1992; McCarthy 2001j: 183; 2003c; Aptroot 2003a).
Cosmopolitan
Illustrations : Dobson (1992: 356; 2000: 406).
Verrucaria glaucina is characterised by: the basicolous (limestone and calcareous sandstone) habit; the superficial, grey-brown, olive-brown to dark-brown, deeply areolate thallus delimited by a black prothallus; solitary, immersed perithecia; the colourless to black exciple; and ascospores 10–18(–23) × 5–8 μm.
