Flora of New Zealand Series

≡Leptogium diaphanum f. coralloideum Meyen & Flot., Suppl. Nova Acta Acad. Caes. Lepold.–Carolin. 19: 226 (1843). [For notes on neotypification of L. diaphanum f. coralloideum see Jørgensen (2002f: 567–568)].

Description : Thallus lobate, dark green-black or blue-black, pulpy and conspicuous when wet, olive-brownish, dark-grey or grey-blue when dry, closely to loosely attached to bark or encircling twigs, orbicular to spreading, 2–8(15) cm diam. Lobes irregular, rounded to oblong, margins rounded, often ascending, thickened, inrolled, densely isidiate. Upper surface strongly ridged–plicate, ridges sharply defined, isidiate. Isidia cylindrical to coralloid, to 1 mm tall, densely crowded. Lower surface concolorous with upper surface or slightly paler, ridged–complicate, without tomental hairs. Apothecia not seen.

N: Northland (Taratara) to Wellington. S: Nelson (Aniseed Valley), Marlborough (d'Urville I. to Kowhai Bush). In coastal forest or forest remnants, exposed coastal scrub, on rocks and rarely on soil, between latitudes 35º18's to 42º23's (map in Galloway 1999: 328, fig. 6). It is an epiphyte of the following phorophytes: Acer pseudoplatanus, Agathis australis, Berberis glaucocarpa, Cordyline australis, Corynocarpus laevigatus, Kunzea ericoides, Melicytus ramiflorus, Metrosideros excelsa, Myoporum laetum, Myrsine australis, Olearia furfuracea, Populus nigra, Pseudopanax arborea and Salix fragilis. It has a wide, tropical to warm-temperate distribution and is recorded from NW Europe, East Africa, Brazil, Australia, Arizona, and Mexico (Swinscow & Krog 1988; Verdon 1990, 1992a; Jørgensen 1994a; Aptroot 2002e; McCarthy 2003c, 2006; Jørgensen & Nash 2004).

Cosmopolitan

Illustration : Jørgensen (2002f: 567, fig. 2 – as Leptogium diaphanum f. coralloideum).

Leptogium coralloideum is characterised by: the corticolous habit; the deeply ridged upper surface and the crowded cylindrical to coralloid isidia. It differs from the rather similar L. brebissonii (not present in New Zealand) mainly in having coralloid isidia on the laminal ridges, and in apothecial characters (Verdon 1990: 431; Jørgensen 1994a: 6).