Leptogium limbatum
≡Leptogium inflexum var. limbatum (F.Wilson) F.Wilson, Proc. Roy. Soc. Victoria 5: 158 (1893).
≡Leptogium tremelloides var. limbatum (F.Wilson) Müll.Arg., Bull. Herb. Boissier 4: 87 (1896).
=Leptogium tasmanicum F.Wilson, Pap. Proc. Roy. Soc. Tasmania 1892: 144 (1893).
Description : Thallus orbicular to irregularly spreading, loosely attached to substratum, 1–5(–8) cm diam., 60–130 μm thick, pale to dark bluish or lead-grey, often ±browned to livid, red-brown, especially at apices. Lobes rounded, rarely oblong, flat or concave, 3–12(–18) mm wide, margins entire, wavy, crisped, sometimes thickened and ±involute, ±isidiate. Upper surface smooth to minutely roughened, matt or shining in parts, here and there slightly ridged, but never wrinkled, usually without isidia, or with isidia clustered in lines or small, delimited areas. Isidia marginal and laminal, often dense, squamiform, granular at first, swollen to flattened, simple to coralloid, 0.1–0.3(–0.5) mm tall, concolorous with thallus or somewhat darker, to livid, red-brown. Lower surface smooth, concolorous with upper surface or paler, especially centrally, naked near margins, with scattered patches of white, silky tomentum towards centre, not uniformly or continuously tomentose. Apothecia often absent, or rare to abundant, scattered, sessile to subpedicellate, 0.5–1.5(–2.0) mm diam., disc pale-orange, concave to plane, matt or shining, thalline exciple smooth, to lobulate or occasionally isidiate, concolorous with thallus or whitish cream, often with white, silky basal hairs. Ascospores ellipsoidal, submuriform, 23–30 × 10–15 μm, apices obtuse, one often narrower than the other.
N: Northland (Wellsford) to Wellington (Tararua Ra.). S: Nelson (Tasman Mts) to Southland (Homer). St: (Golden Bay). C: On rocks, soil and among bryophytes in coastal scrub, and in Nothofagus forests, and also extending into upland, ±open grassland, s.l. to 1500 m (map in Galloway 1999: 340, fig. 12). It will also spread among small stones on gravel paths in shaded, urban woodland or parkland sites, and it grows quickly on damp, mossy S-facing banks in gardens and also on bare patches in lawns where it can reach diameters of 1–4 cm in a rapid burst of winter growth. It is known from the following phorophytes: Aristotelia serrata, Discaria toumatou, Dacrycarpus dacrydioides, Dicksonia squarrosa, Metrosideros excelsa, Nothofagus menziesii, N. solandri var. cliffortioides and Pseudopanax colensoi. Known also from Australia (Verdon 1992a; McCarthy 2003c, 2006).
Australasian
Leptogium limbatum is characterised by: the saxicolous/terricolous/muscicolous habit; the bluish, lead-grey thallus with phyllidiate margins that often become whitish and thickened, and the ±conspicuous bundles of rhizines on the lower surface, which are occasionally in dense patches but never ±continuous as in L. malmei and L. menziesii (Verdon 1990: 437;Verdon et al. 1996). It is a very variable species with regard to thallus size, thickness, colour, development of tomentum on the lower surface (occasionally it is restricted to a few, widely spaced small and scarcely apparent tufts), and development of isidia. Some grassland forms approach L. menziesii, but are readily distinguished by the marginal isidia, and the scattered tufts of tomentum below. The description of L. limbatum given in Galloway (1985a: 253) is in fact referable to L. malmei, as discussed by Verdon et al. (1996: 26). Verdon (1992a) keeps L. tasmanicum separate from L. limbatum on account of its having larger apothecia which are furnished with basal hairs, however, these characters are not really sufficient to separate two independent taxa, as indicated in Jørgensen (1997a: 129)
