Flora of New Zealand Series

Holotype: New Zealand. Southland, Garvie Mountains, Dome Burn, 1300 m, on inudated schist stones, 8.i.1996, P.N. Johnson 2023. CHR. Isotypes – CANB, WELT.

Description : Thallus crustose, epilithic, effuse to determinate, dark greenish brown to greenish black, matt, ±smooth, continuous, 20–40(–50) μm thick, up to 80 μm thick around perithecial bases, becoming darker but not thicker when moistened, ecorticate but with an uppermost dark-pigmented, photobiont-free layer, 5–10 μm thick. Photobiont irregularly massed, green, broadly ellipsoidal to globose, (4–)5–10 × 4–8 μm. Perithecia very numerous, semi-immersed to ±superficial, usually with a partial to ±complete thalline covering, 10–30 μm thick. Apex convex to ±rounded. Ostiole inconspicuous or in a shallow, c. 20 μm diam., depression. Involucrellum convex to hemispherical, dull-black and minutely uneven in surface view, brown-black in section, extending down to exciple-base level, arching slightly away from exciple or ±contiguous with it, 0.22–0.44(–0.5) mm diam., 30–50 μm thick near apex, 40–80 μm thick at base. Centrum depressed-ovate, 0.13–0.28 mm diam. Exciple hyaline to pale-brown at base and sides, occasionally darkening with age, brown to brown-black near apex, 15–20 μm thick. Periphyses 20–35 × 1.5–2 μm, simple to sparingly branched. Paraphyses absent. Hymenial gel I+ red-brown (Lugol's). Asci clavate to cylindrical-clavate, 60–100 × 20–32 μm. Ascospores simple, colourless, ellipsoidal, obovate or subglobose, massed or irregularly biseriate in ascus, (13–)19(–24) × (9–)12(–15) μm; wall 0.7–1 μm thick, contents finely granular and guttulate.

S: Otago (Roaring Meg Stream, Pisa Ra., Old Man Ra.), Southland (Dome Burn, Garvie Mts). On inundated schist rocks in alpine stream. Associating with Ionaspis lacustris, Staurothele fissa, Verrucaria austroschisticola, V. inconstans, V. margacea and V. rheitrophila (McCarthy & Johnson 1997: 387).

Endemic

Illustration : McCarthy & Johnson (1997: 386, fig. 1).

Verrucaria amnica is characterised by: the saxicolous habit; a very dark, thin, non-gelatinous thallus and small to moderately large and prominent perithecia that often have a thin, thalline covering. The ascospores are short to moderately long and ellipsoidal to subglobose, a combination that is very uncommon in Verrucaria (McCarthy & Johnson 1997: 386).