Flora of New Zealand Series

Description : Thallus epilithic, crustose, usually buff-brown, or grey-brown or grey-green, matt, smooth, rimose, 0.05–0.15(–0.3) mm thick, with a brown to brown-black basal layer, 0.02–0.06(–0.15) mm thick, that is often discontinuous; margin diffuse. Cortex brown, poorly defined, 5–10 μm thick. Photobiont layer diffuse, 0.05–0.1 mm thick, cells broadly ellipsoidal to globose, 5–11 × 5–9 μm. Perithecia compound, semi-immersed to almost entirely immersed, numerous, solitary. Ostiole inconspicuous or slightly depressed. Involucrellum ranging from a thickening about the uppermost third of the perithecium, to dimidiate, to ±subentire, contiguous with the exciple, 0.25–0.5 mm diam., 0.06–0.08(–0.12) mm thick, externally occasionally smooth or with 12–20 faint to pronounced carbonised ridges radiating from the ostiole. Perithecial apex somewhat flattened, often grey-brown around ostiole. Centrum globose, 0.2–0.35 mm diam. Exciple brown to brown-black, 20–35 μm thick. Periphyses 30–40 × 1.5–2 μm. Asci clavate, 65–67 × 18–25 μm; hymenial gel and ascoplasm I+ deep wine-red. Ascospores 14.5–23.5 × 7–11 μm, contents finely granular.

A: On boulders in lower hygrohaline belt. First collected by G. Einar Du Rietz in 1927. Also known from Macquarie I. from where it was first described (McCarthy 1991d, 2003c). A maritime species of hard siliceous rocks, often associating with Verrucaria durietzii, V. maura, species of Mastodia and Pertusaria.

?Austral

Illustration : McCarthy (1991d: 345, fig. 1).

Verrucaria bubalina is characterised by: the coastal rock habit; a smooth, buff-brown thallus and semi-immersed to immersed perithecia with a thick, blackish, 0.25–0.5 mm diam. involucrellum that, uniquely, has ridges radiating from the ostiole. The ascospores are 14.5–23.5 × 7–11 μm. It is distinguished from other buff-brown Verrucariae in the supralittoral by its thallus, its moderately large perithecia with a dark exciple, and by the size of its ascospores. In contrast, V. durietzii (q.v.) has a lobate thallus margin, a persistently thicker hypothallus, smaller perithecia and smaller ascospores; while V. tessellatula (q.v.) has black-walled rimae and very much smaller perithecia and ascospores (McCarthy 1991d: 345).