Porina ahlesiana
≡Segestrella ahlesiana Körb., Parerga. Lich.: 324 (1865).
Description : Thallus thin, superficial, continuous to richly cracked, yellowish brown, 40–100 μm thick, with or without a marginal pale or whitish prothallus. Perithecia semi-immersed, 0.4–0.65 mm diam., dominated by a brownish grey or orange-grey involucrellum, translucent when wet; ostiole not obvious, pale pinkish or red-brown. Ascospores 7(–9)-septate, clavate-fusiform, 36–66 × 6– 10 μm. Pycnidia pale greyish pink, partly emergent, inconspicuous. Conidia 6–7 × 0.5 μm.
S: Southland (South Fiord, Lake Te Anau, N side below Mt Owen and Mt Lyall; S side W of Driftwood Cove). On lakeshore boulders, 200 m. Collected by Peter Johnson (McCarthy & Johnson 1965: 499; McCarthy & Malcolm 1996a: 548). Known also from Great Britain, Scandinavia, Germany, Austria, Spain, Macaronesia, and Turkey (Purvis & James 1992e; Santesson 1993; Scholz 2000; Hafellner & Türk 2001; Llimona & Hladun 2001; Valcárcel & Carballal 2002; McCarthy 2003d).
?Bipolar
Illustration : Valcárcel & Carballal (2002: 253, fig. 2A).
Porina ahlesiana is characterised by: the saxicolous, semi-aquatic habit; yellow-brown, cracked thallus; semi-immersed perithecia with a brown-grey to orange-grey involucrellum; and 7(–9)-septate ascospores, 36–66 × 6–10 μm.
