Flora of New Zealand Series

Description : Thallus superficial, areolate to subsquamulose, pale-brown to olive-green. Areolae 0.4–1.5 mm diam., flat to convex, smooth to verruculose; sterile thalli may have soralia or isidia on the margins of the areolae. Perithecia compound, ½-¾ immersed, apex flat to convex. Involucrellum black, dimidiate, 0.3–0.6 mm diam. Centrum globose, 0.2–0.4 mm diam. Exciple dark-brown to black. Ascospores 25–37 × 10–20 μm.

N: Taranaki (New Plymouth). S: Otago (Cornish Head Waikouaiti). On concrete walls of fertiliser factory (Taranaki), and on dry, calcareous sandstone, associating with Caloplaca, Lecanora flotoviana, and Physcia undulata. Known also from Great Britain, Scandinavia, central and southern Europe, Algeria, Morocco, Tunisia, the Ukraine, and Turkey (Hawksworth et al. 1992; Santesson 1993; Egea 1996; John 1996; Kondratyuk et al. 1996a; Seaward 1996).

Cosmopolitan

Illustrations : Zschacke (1934: 292, fig. 137); Dobson (2000: 407; 2005: 456).

Verrucaria macrostoma is characterised by: the basicolous (limestone) habit; the areolate to subsquamulose, pale-brown to olive-green thallus; ½–¾ immersed perithecia; dark-brown to black exciple; and ascospores 25–37 × 10–20 μm.