Peltigera ulcerata
Description : Thallus orbicular, small, 1–5 cm diam. Lobes crowded, concave, ±cochleate, 2–5(–10) mm diam., 5–25 mm long, to 250 μm thick. Margins entire, sinuous, to ±ascending, slightly thickened below, often downrolled, ±sorediate, occasionally lobulate, tinged brownish or brown-black. Upper surface glabrous, matt or glossy, pale greyish-green to olive-brown when wet, cinnamon-brown or yellowish, suffused brownish at margins when dry, sometimes ±red-brown, sorediate. Soralia laminal and marginal, at first rounded, 1–2(–5) mm diam., forming in breaks in upper cortex, eroding and becoming confluent-ulcerose; soredia coarse, granular, blue-grey at first becoming red-brown when mature, often totally eroding and exposing patches of pale medulla. Lower surface pale-buff or whitish, ±uniformly buff-tomentose at margins. Veins flat, broad to confluent, indistinct at margins, with small, white, oval to irregular, fibrous; interstices pale pinkish brown at margins, darkening centrally. Rhizines fasciculate, penicillate, solitary or in lines to ±clustered, 1–3 mm long, pale-buff at margins, darkening to brown-black centrally. Apothecia not seen.
Chemistry : Medulla TLC−, all reactions negative: soralia C+ red; containing methyl gyrophorate, ±gyrophoric acid.
N: Auckland (Rangitoto I.), South Auckland (Karangahake Gorge, Te Kauri Park, Waihaha). S: Malborough (Seaward Valley), Canterbury (Arthur's Pass, Cass, Moa Creek, Mt Cook), Otago (Cluden Hill near Tarras, Alexandra, Teviot Valley) [map in Galloway (2000d: 38, fig. 16)]. On soil, among moss or on tree trunks near the ground, in rather open, well-lit situations, s.l. to 1500 m. A widespread pantropical and pantemperate species (Vitikainen 1992, 1996; Goffinet et al. 2003), originally described from Brazil (Müller Argoviensis 1880, 1881; Aptroot 2002e). It is not yet known from Australia (Filson 1996; McCarthy 2003c, 2006), but was recently recorded from Chile (Goffinet et al. 2003: 359).
Pantropical
Illustration : Swinscow & Krog (1988: pl. 12b).
Peltigera ulcerata is characterised by: the terricolous/muscicolous habit; the small, crowded, cochleate lobes having a glabrous, rather coriacous upper surface and with prominent, marginal and laminal, ulcerose soralia containing coarse, granular grey-blue to red-brown soredia that are C+ red (gyrophoric acid). It is distinguished from P. didactyla by its smaller, thicker lobes and glabrous upper surface and the buff-brown lower surface and the morphology of the rhizines. The relationship of the pantropical P. ulcerata to the boreal taxon P. leptoderma Nyl. (Nylander 1860: 325), is discussed by Vitikainen (1994a: 39).
