Flora of New Zealand Series

≡Collema cyanescens Rabenh., Dtschl. Flora 2: 50 (1845).

=Leptogium rigens Nyl., Annls Sci. nat. Bot. sér. 4, 15: 368 (1861)

Leptogium rigens. Lectotype: New Zealand, d'Urville ex Herb. Buchinger – H-NYL 41335 [fide Galloway (1985a: 252)].

Description : Flora (1985: 252).

K: (Raoul I.). N: Northland (Three Kings Is) to Wellington. S: Marlborough to Southland (Milford Sound). St: (Moturau Moana). Ch: C: (map in Galloway 1999: 332, fig. 8). On bark and twigs and among mosses, rarely on damp, mossy rocks or on damp soil, in shaded, humid lowland or coastal forest habitats, and on coastal rocks in northern parts of the country, s.l. to 400 m. It seems to be rare in southern New Zealand. It is epiphyic on the following phorophytes: Acer pseudoplatanus, Aristotelia serrata, Beilschmiedia taraire, B. tawa, Cordyline australis, Corynocarpus laevigatus, Dracophyllum arboreum, Dysoxylum spectabile, Knightia excelsa, Kunzea ericoides, Leptospermum scoparium, Melicytus ramiflorus, Nestegis apetala, Nothofagus, Metrosideros excelsa, Myrsine australis, Pittosporum umbellatum, Plagianthus divaricatus, Podocarpus totara, Salix fragilis and Weinmannia sylvicola. Known also from Great Britain, Europe, Scandinavia, Asia, North and South America, Socotra and Australia (Purvis et al. 1992; Verdon 1992a; Santesson 1993; Goward et al. 1994b; Bjelland 2001; Aptroot 2002e; Wolseley et al. 2002; McCarthy 2003c, 2006; Nimis & Martellos 2003; Jørgensen & Nash 2004; Mies & Schultz 2004; Santesson et al. 2004).

Cosmopolitan

Illustrations : Sierk (1964: 314, fig. 50); Brodo (1981: 75, fig. 36); Swinscow & Krog (1988: 136, fig. 69); Goward et al. (1994b: 67, fig. 11B); Dobson (2000: 217; 2005: 249); Brodo et al. (2001: 404, pl. 455).

Leptogium cyanescens is characterised by: the corticolous (rarely saxicolous) habit; broad, rounded, unwrinkled lobes with a naked lower surface, and having laminal and marginal isidia. The isidia are terete, simple to coralloid and may occasionally be somewhat lobulate in parts, but never extensively phyllidiate. The nature of the isidia distinguish it from L. denticulatum, which has consistently flattened phyllidia.