Porina aptrootii
Description : Thallus on rocks, dark-green to green-black, matt, smooth, 30–80(–100) μm thick, continuous to cracked, K−, with a discontinuous, black basal layer, 15–30 μm thick, but without a prothallus. Perithecia superficial, subglobose, numerous, usually solitary, (0.45–)0.55(–0.65) mm diam.; apex usually rounded, otherwise concave, flattened or somewhat papillate; ostiole inconspicuous or in a depression 40–80 μm wide. Involucrellum dull greenish black, 60–90 μm thick, extending to exciple base level, K+ reddish. Exciple hyaline or pale to dark olive-brown, 30–40 μm thick, with the outer 10–15 μm often being darker than the inner layers. Centrum globose, 0.3–0.48 mm diam. Paraphyses unbranched, 1–1.5 μm thick. Periphyses absent. Hymenium interspersed with minute granules. Asci elongate-cylindrical with truncate apices, 125–145 × 9–13 μm. Ascospores (5–)7(–9)-septate, fusiform to elongate-fusiform or elongate-cylindrical, usually straight, with rounded or subacute apices, irregularly biseriate in ascus, occasionally with a 1–2.5-μm thick, gelatinous sheath, (30–) 40(–50) × (3.5–)5(–6.5) μm. Pycnidia numerous, semi-immersed to superficial, black above, pale- to dark-brown below, 0.1–0.2 mm diam. Conidia elongate-bacillar to elongate-fusiform, straight, (3–) 4–6(–7) × 0.8 μm.
S: Southland (Doubtful Sound, Deep Cove). On wet boulders in a stream. Known also from Tasmania (McCarthy 1993b, 2001f, 2003c, 2003d).
Australasian
Illustration : McCarthy (1993b: 30, fig. 3).
Porina aptrootii is characterised by: the aquatic, saxicolous habit; the dark thallus; the rather large and prominent perithecia; the elongate, multiseptate ascospores; and the unusually elongated conidia.
