Flora of New Zealand Series

Holotype: New Zealand. Canterbury, Banks Peninsula, Mt Herbert Forest, 8.2 km S of Diamond Harbour, 450–530 m, along stream in mixed hardwood- Podocarpus forest, on siliceous boulder, 6.xi.1980, L. Tibell 9340, UPS.

Description : Thallus on rocks, pale greenish grey to medium grey-green, intense-green when wet, matt, 40–60(–100) μm thick, heavily impregnated with crystals and rock fragments, cracked to areolate, smooth to minutely wrinkled, ecorticate, K−. Areolae (0.2–)0.4(–0.6) mm diam., angular to rounded, irregular, strongly convex. Prothallus not apparent. Perithecia semi-immersed to almost superficial, scattered, numerous, usually solitary, (0.4–) 0.6(–0.75) mm diam.; apex rounded or strongly flattened. Ostiole inconspicuous, or in a depression 40–80 μm wide. Involucrellum superficially dark-grey to black, with a dark outer layer 20–30 μm thick, becoming paler towards exciple, with crystals and rock fragments but without photobiont cells, c. 60 μm thick near apex, to 100–150 μm thick at base, extending to exciple base level. Exciple colourless, to pale-brown near apex, 15–25 μm thick. Centrum globose, 0.3–0.42 mm diam. Paraphyses unbranched, 1 μm thick. Periphyses absent. Asci elongate-cylindrical to elongate-fusiform, apices truncate, 120–165 × 9–15 μm Ascospores 3–7-septate, fusiform to elongate-fusiform, usually straight, occasionally slightly curved, apices acute or subacute, with a gelatinous sheath 1.5 –2.5 μm thick, (25.5–)30(–37) × 4.5–7 μm. Pycnidia numerous, almost entirely immersed, dark-brown and 80–120(–14) μm above, colourless to pale-brown and 100–200 μm below. Conidia fusiform to elongate-fusiform, 3–5 × 0.7–1 μm.

S: Nelson (Brook Stream Track) on siliceous rock; Canterbury (Banks Peninsula).

Endemic

Illustrations : McCarthy (1993b: 90, fig. 25; 1999b: 338, fig. 1F); Malcolm & Malcolm (2000: 79).

Porina partita is characterised by: the saxicolous habit; its thallus of convex areolae and rather large perithecia. Most significantly, the involucrellum is superficially black, but pale internally. This suite of characters distinguishes it from other temperate taxa such as P. aptrootii and P. guentheri, both of which have a uniformly black involucrellum (McCarthy 1993b: 91).