Flora of New Zealand Series

≡Lobaria dubia Hoffm., Dtschl. Fl.: 156 (1796).

Description : Thallus loosely to closely attached centrally, apices ±free and ascending, spreading in small rosettes (0.5–)1–3(–6) cm diam. Lobes narrow, 0.4–0.8(–1.2) mm wide, rather short, 1–3 mm long, crowded–congested centrally, discrete at periphery, apices bifurcate to irreguarly and minutely divided (×10 lens); margins slightly thickened and in places ±inrolled. Upper surface pale mineral grey to grey-white, darkening to somewhat blackened at apices, matt, minutely lumpy to papillate to here and there coarsely areolate–scabrid (×10 lens). Soralia marginal often on small secondary lobes, distinctively labriform, soredia greenish (in shaded specimens), grey-white to somewhat blackened, coarse, granular. Lower surface corticate, whitish to pale buff-pink, darkening slightly towards centre; rhizines scattered, whitish to brownish or somewhat blackened, simple, 0.5–1(–1.2) mm long. Apothecia and pycnidia not seen in New Zealand material.

Chemistry : Cortex K+ yellow; medulla K−; containing atranorin.

S: Canterbury (Port Hills, Temuka), Otago (Pisa Ra., Nevis Valley, Poolburn, Old Man Ra., Gem Lake, Umbrella Mts, Mt Benger, Roxburgh, Teviot Valley, Upper Pomahaka River, Black Gully, Blue Mts, Lawrence Cemetery, Dunedin, Merton), Southland (Lumsden, Waikaia Cemetery; Mataura, Wyndham, Invercargill, S. Mavora Lake). Being a rather small, delicate species it is probably frequently overlooked and no doubt is more widely distributed in New Zealand than present records show. On sloping, sunny schist ledges and underhangs; sunny tops of bird-perch rocks; on concrete paving, grave headstones and coping; on decorticated wood (old window frames, stockyard fences, garden furniture) and on living bark (old apple trees, Olearia odorata), s.l. to 1708 m. A widespread, cosmopolitan species common in the Northern Hemisphere (Thomson 1963; Moberg 1977; Moberg & Hansen 1986; Purvis et al. 1992; Nimis 1993; Santesson 1993; Esslinger & Egan 1995; Hansen 1995; Egea 1996; Kondratyuk et al. 1996a; Elvebakk & Hertel 1997; Scholz 2000; Brodo et al. 2001; Hafellner & Türk 2001; Llimona & Hladun 2001; Coppins 2002b; Moberg 2002b, 2002g; Kurokawa 2003; Nimis & Martellos 2003; Santesson et al. 2004), East Africa (Moberg 1986b; Swinscow & Krog 1988), southern South America (Moberg 1990; Galloway & Quilhot 1999; Calvelo & Liberatore 2001; Elvebakk & Moberg 2002) and Antarctica (Øvstedal & Lewis Smith 2001; Søchting et al. 2004).

Cosmopolitan

Illustrations : Kashiwadani (1975: pl. 3,4); Moberg (1977: 76, fig. 34); Moberg & Holmåsen (1982: 201); Thomson (1984: 355); Wirth (1987: 369; 1995b: 733); Dobson (1992: 264; 2000: 304; 2005: 340); Goward et al. (1994b: 110, fig. 8A); Hansen (1995: 54); St. Clair (1999: 148); Brodo et al. (2001: 554, pl. 665); Nordic Lichen Flora Vol. 2 (2002: 98).

Physcia dubia is characterised by: the corticolous/lignicolous/saxicolous habit; the narrow lobes rarely exceeding 1 mm diam.; the marginal, labriform soralia most commonly produced at lobe tips; the mineral-grey matt, epruinose upper surface, noticeably darker (to brownish or blackish) at apices; K− medulla (zeorin absent); and the prosoplectenchymatous lower cortex. It is distinct from P. tribacia, which has a shiny upper surface and a paraplectenchymatous lower cortex