Anisomeridium laevigatum
≡Ditremis laevigata P.M.McCarthy, Muelleria 8: 1 (1993).
Holotype: New Zealand. South Island, Otago, Dunedin, Bethune's Gully, 45º50's, 170º33'E, on smooth siliceous rock, 4 feet above water level, ii.1957, J. Murray 1619 – OTA. Isotype – AK 192342.
Description : Thallus saxicolous, determinate, continuous to areolate, pale grey-green to brownish grey, UV−, K−, colour not changed on wetting, matt, smooth, 0.06–0.1(–0.14) mm thick. Areolae 0.3–0.6(–1) mm wide, regular or irregular, angular to rounded, plane, without a delimiting prothallus. Perithecia compound, semi-immersed, numerous, solitary, 0.17–0.32 mm diam., apex rounded. Involucrellum dull-black, extending to excipulum base level, 30–45 μm thick. Ostiole apical in a 20–30-μm-wide depression. Centrum subglobose to globose, 0.15–0.23 mm diam. Excipulum pale to dark-brown at base darker near apex, 11–16 μm thick. Pseudoparaphyses richly branched and anastomosing, septate. Periphyses absent. Asci fissitunicate, cylindrical to clavate, 8-spored, 63–83 × 13–16 μm, I−, ocular chamber 1–2 μm wide and to 2.5 μm high, truncate or pointed. Ascospores colourless, irregularly biseriate, obovate or clavate, 1-septate, distal cell usually larger, thin-walled, slightly constricted at septum, walls smooth, without a perispore, 12–23 × 4.5–7 μm. Pycnidia numerous, semi-immersed, black above, colourless below, 0.06–0.1 mm diam. Microconidia and macroconidia not seen.
S: Otago (Otago Peninsula, Bethune's Gully Dunedin). On damp, streamside rocks.
Endemic
Illustration : McCarthy (1993a: 2, fig. 1 – as Ditremis laevigata).
Anisomeridium laevigatum is characterised by: the saxicolous habit; the pale-grey thallus; 8-spored asci; and colourless, 1-septate, ascospores, 12–23 × 4.5–7 μm. It is distinguished from A. carinthiacum which has 0.13–0.25 mm diam., perithecia with a centrum of 0.09–0.13 mm diam.; asci that are 40–53 μm long; ascospores 9–15(–17) × 3.5–6.5 μm; and narrowly ellipsoidal microconidia, 3–4.5 × 1–2 μm (McCarthy 1993a: 2).
