Flora of New Zealand Series

≡Verrucaria guentheri Flot., Bot. Zeit. 8: 575 (1850).

=Porina saxicola (C.Knight.) Müll.Arg., Bull. Soc. Roy. Bot. Belg. 31 (2): 39 (1892).

≡Verrucaria saxicola C.Knight, Trans. N. Z. Inst. 8: 324 (1876). Trans. Linn. Soc. ser. 2, Bot. 1: 280 (1877).

≡Segestria saxicola (C.Knight) Hellb., Bih. K. Sv. Vet.-Akad. Handl. 21 (3/13): 133 (1896).

Verrucaria saxicola. Holotype: New Zealand. Sine loco [probably Wellington], 1.ix.75, Charles Knight – WELT Herb Knight Vol. 55A, P. 11.

Description : Flora (1985: 416–417 – as Porina saxicola).

N: Wellington. S: Canterbury (Lees Valley, Dog Stream Hanmer), Otago (Leith Valley Dunedin, Broad Bay Otago Peninsula), Southland (above Lake Chamberlain, Doubtful Sound). A: On shady rocks beside streams. Subalpine collections from Fiordland associate with Placopsis murrayi and Porpidia macrocarpa. Known also from Great Britain, Scandinavia, Europe, Macaronesia, Asia, North America, Papua New Guinea, South Africa, Taiwan, China, and Australia (Purvis & James 1992e; Nimis 1993; Santesson 1993; Esslinger & Egan 1995; Scholz 2000; Valcárcel & Carballal 2002; Aptroot 2003a; McCarthy 2003c, 2006). A detailed geographical coverage of this species is given in McCarthy (2003d: 49–50).

Cosmopolitan

Illustrations : Knight (1876: pl. X, fig. 22; 1877: pl. XXXVIII, fig. 2 – as Verrucaria saxicola); Keissler (1938: 332, fig. 104); McCarthy (1993b: 57, 57, fig. 12; 1999b: 338, fig. 1E): Malcolm & Malcolm (2000: 79); Valcárcel & Carballal (2002: 253, fig. 2B); Dobson (2005: 357).

Porina guentheri is characterised by: the saxicolous habit; the olive-green, grey-brown or in parts rust-red thallus; black, semi-immersed perithecia; and fusiform, (3–)5–7(–9)-septate ascospores, 20–50 × 3.5–6.5 μm.