Peltigera rufescens
≡Lichen caninus [var.] rufescens Weiss, Pl. Crypt. Fl. Goett.: 79 (1770).
Description : Thallus rosette-forming to irregularly spreading, 3–12(–30) cm diam. Lobes irregular, linear to rounded, 0.5–1.2 cm wide and 0.5–2.5(–3) cm long. Margins undulate-wavy, crisped, ascendent, often lobulate or phyllidiate, commonly tomentose, or scabrid, whitened, sometimes with small, fuzzy, brown-tomentose apothecial initials. Upper surface brownish or reddish brown, paler to ±whitish at margins and apices (in alpine forms often conspicuously eroded-white or greyish), tomentose at or near margins, glabrous centrally, matt or shining, smooth to undulate or ±bullate in parts, sometimes maculate at or near margins (×10 lens), rarely with small patches of glistening pruina towards centre. Lower surface tomentose, pale-buff or whitish at margins, dark-brown to blackening centrally. Veins 0.5–1 mm wide, rather flat, brown to dark-brown or black, anastomosing; interstices pale or whitish, lenticular. Rhizines simple at margins, soon becoming entangled–confluent, in ±dense lines along veins, pale-brownish or buff at margins soon dark-brown to black towards centre, 2–5 mm long. Apothecia saddle-shaped, 3–5 mm long, on short, marginal lobes; disc matt, epruinose dark red-brown to brown-black. Ascospores colourless, elongate–fusiform, 5–7-septate, (45–)50–60(–65) × 2.5–5 μm.
Chemistry : TLC−, all reactions negative.
N: Auckland (Waitakere Ra.), South Auckland (Ruakura, Huka Falls), Wellington (Tongariro National Park). S: Nelson (Lake Rotoiti), Marlborough (Wairau Valley), Canterbury (Arthur's Pass, Craigieburn Ra., Mt Cook), Otago (Matukituki Valley, Coronet Peak, The Remarkables, Old Man Ra., Gem Lake, Lake Onslow, Deep Stream, Mt Cargill), Southland (Kaiwera, Mavora Lakes). St: (Moturau Moana, Golden Bay) [map in Galloway (2000d: 34, fig. 14)]. On soil or among mosses, on roadside verges and banks, on old sand dunes, on stumps and decorticated wood, on rocks, and in alpine turf, generally in rather open situations, s.l. to 2000 m. Commonly associating with other cyanobacterial lichens such as Coccocarpia palmicola, Peltigera didactyla and Massalongia carnosa. Widespread in both Northern and Southern hemispheres (Purvis et al. 1992; Vitikainen 1994b, 2004; McCarthy 2003c, 2006; Nimis & Martellos 2003; Santesson et al. 2004).
Cosmopolitan
Illustrations : Martin & Child (1972: 115, pl. 27); Brodo (1981: 82, fig. 38); Moberg & Holmåsen (1982: 177); Thomson (1984: 333 – as Peltigera canina f. rufescens); Wirth (1987: 348; 1995a: 24, 679, 680 D, 690); Vitt et al. (1988: 230); Goffinet & Hastings (1994: 44, fig. 82, 45, fig. 83); Goward et al. (1994b: 99, fig. 21A); Vitikainen (1994b: 78, fig. 118); Hansen (1995: 52); McCune & Geiser (1997: 218); Belnap et al. (2001a: 7, pl. 24); Brodo et al. (2001: 20, pl. 12; 520, pls 618, 619); Øvstedal & Lewis Smith (2001: pl. 60); Sérusiaux et al. (2004: 128).
Peltigera rufescens is characterised by: the terricolous/saxicolous habit; a tomentose upper surface (often only at margins), upturned lobe margins and apices, frequently with phyllidia (in lowland forms especially), blackish confluent rhizines in ±dense lines, and veins darkening abruptly from margins to centre. Exposed alpine forms are smaller and more caespitose than lowland forms, and have thicker more leathery lobes that are much more closely and complexly folded–crowded, with conspicuously grey-white margins and apices, possibly the result of erosion by wind-blown soil or stones.
