Flora of New Zealand Series

≡Lichen niger Huds., Fl. angl. ed 2, 2: 524 (1778).

Description : Flora (1985: 409).

Chemistry : TLC−, all reactions negative.

N: Northland (Waipu Caves), South Auckland (N of Waikaretu). S: Nelson (Kaihoka Lakes, Mt Arthur), Westland (Punakaiki, Dolomite Point, Pancake Rocks); Marlborough (Chalk Ra., Kaikoura Peninsula), Canterbury (Nape Nape, Weka Pass, Flock Hill, Castle Hill, Lowry Peaks Ra., Motunau Beach, Mt Somers, Ashburton Gorge), Otago (Oamaru, Hampden, Northern Cemetery Dunedin, Otago Peninsula), Southland (Queen's Park Invercargill, Forest Hill, Castle Rock near Dipton, Clifden). On limestone and a range of calcareous building materials such as cement, mortar and concrete, especially on bridge parapets, and walls made of limestone, and on tombstones and memorials in cemeteries. A widespread, circumpolar species in the Northern Hemisphere (Henssen 1963c; Nimis 1993; Wirth 1995a, 1995b; Renobales 1996; Burgaz et al. 2002; Schultz 2002b; Nimis & Martellos 2003) and also known from Australia (Weber 1977; Kantvilas 1989, 1994b; Filson 1996; McCarthy 2003c, 2006).

Cosmopolitan

Illustrations : Henssen (1963c: 1711, figs 1–4; 1716, figs 30, 34; 1717, fig. 41; 1718, figs 44, 45; pl. 1, fig. 49); Dobson (1979: 228; 1992: 271; 2000: 312; 2005: 349); Moberg & Holmåsen (1982: 180); Wirth (1987: 381; 1995b: 747); Phillips (1987: 165); Foucard (1990: pl. 255); Goward et al. (1994b: 115, fig. 6A); Malcolm & Galloway (1997: 111); Malcolm & Malcolm (2000: 108); Brodo et al. (2001: 573, pl. 692); Lumbsch et al. (2001: 2); Sérusiaux et al. (2004: 144).

Placynthium nigrum is characterised by: the calcicolous habit (limestone and calcareous sandstone); the closely attached black rosette-shaped, squamulose to subcrustose thallus surrounded by a conspicuous, blue-black prothallus; ±central apothecia to 1 mm diam., with a black or brown-black disc with a thin, entire, concolorous margin; and 1–3-septate ascospores, 7–18 × 3.5–7 μm.