Flora of New Zealand Series

Description : Thallus pale-grey or grey-green, indistinct, often evanescent, endolithic, continuous, finely cracked to areolate, delicately pitted. Perithecia 0.25–0.5(–0.6) mm diam., black, prominent to mainly immersed with a distinct ostiole. Involucrellum 0.25–0.4(–0.5) mm diam., black, dimidiate or occasionally extending to exciple-base level. Exciple colourless to pale-brown. Ascospores 16–27 × 8–14 μm.

S: Canterbury (Castle Hill, Flock Hill, Cave Stream). On porous limestone. Known also from Great Britain, Europe, Asia, North America, Brazil, Hong Kong, Taiwan, Africa, India, South Georgia and SE Australia where it commonly occurs on mortar and soft limestones (McCarthy & Johnson 1995: 507; Øvstedal & Lewis Smith 2001: 359–360; McCarthy 2001j: 189, 2003c; Aptroot 2002e, 2003a; Santesson et al. 2004).

Cosmopolitan

Illustrations : Zschacke (1934: 163, fig. 67); Dobson (1992: 357; 2000: 407; 2005: 456).

Verrucaria muralis is characterised by: the basicolous (limestone) habit; its inconspicuous thallus, relatively large perithecia and moderately large ascospores.