Flora of New Zealand Series

≡Lichen dispersus Pers., Annln Bot. 1: 27 (1794).

Description : Flora (1985: 215).

Chemistry : 2,7-dichlorolichexanthone (major) and pannarin (minor) (Leuckert et al. 1990a).

N: S: Throughout, in urban environments on dust-impregnated trees in parks. Known also from Great Britain, Europe, Scandinavia, North America, Africa, Bolivia, Argentina, Chile and Australia (Purvis et al. 1992; Nimis 1993; Santesson 1993; Esslinger & Egan 1995; Poelt et al. 1995; Fröberg 1989, 1997; Galloway & Quilhot 1999; Brodo et al. 2001; Becker 2002; Scutari et al. 2002a; Laundon 2003; McCarthy 2003c, 2006; Nimis & Martellos 2003; Lumbsch & Elix 2004; Ryan et al. 2004b: 215–216; Santesson et al. 2004).

Cosmopolitan

Illustrations : Ozenda & Clauzade (1970: 576, fig. 467); Phillips (1987: 169); Fröberg (1989: 46, fig 12A, B; 51, fig. 17A–C); Foucard (1990: Pl. 140); Dobson (1992: 171; 2000: 192; 2005: 220); Wirth (1995b: 459); Poelt et al. (1995: 318, fig. 8A, D); Malcolm & Galloway (1997: 100, 163); Gilbert (2000: pl. 11A); Malcolm & Malcolm (2000: 108); Brodo et al. (2001: 380, pl. 420); Scutari et al. (2002a: 377, fig. 6); Flora of Australia56A (2004: xiii, pl. 10).

Lecanora dispersa is characterised by: the corticolous habit (basic substrata); a thallus either immersed or of groups of whitish grey granules; scattered, superficial apothecia with ±flesh–coloured to brownish, epruinose discs bounded by thin, entire margins; and a chemistry dominated by 2,7-dichlorolichexanthone. L. dispersa is sometimes parasitised by the lichenicolous fungus * Zwackhiomyces lecanorae (Stein.) Nik. Hoffm. & Hafellner ffmann & Hafellner 2000; Hafellner 2000). Until recently, Lecanora dispersa was a name widely applied to specimens from calcareous rock substrata (e.g. limestone, concrete, mortar old bones etc.); however, it is now apparent that the name L. dispersa is more correctly applied to lowland, corticolous collections (Poelt et al. 1995: 316–319; Fröberg 1997: 31), and that saxicolous specimens should now be referred to L. flotoviana (q.v.), a treatment followed here. The L. dispersa–L. flotoviana populations in New Zealand need close study in the light of Northern Hemisphere work on this species complex. Taxonomic difficulties in the L. dispersa group are discussed by Laundon (2003) and Ryan et al. (2004b: 216).