Flora of New Zealand Series

Parmelia petriseda Zahlbr., Denkschr. Akad. Wiss. Wien math.-naturwiss. Kl. 104: 352 (1941).

Holotype (fide Esslinger, 1977): New Zealand. Otago, Waikouaiti, Ram Rock. J.S. Thomson W 61, W.

Thallus very loosely appressed, or raised off substrate, loosely adnate, attached mostly only centrally, 1.5-3 cm diam., saxicolous. Lobes 0.2-1 mm broad, flat or subconvex, sublinear and ± discrete, to rather short and loosely imbricate. Upper surface yellowish-brown to dark brown, paler at apices, ± smooth, becoming wrinkled centrally, some areas with numerous, small, blackened pits (senescent pycnidia) without isidia. Lower surface pale tan to brown, darker at apices, smooth to wrinkled, without rhizines, attached by occasional central loboid holdfasts. Apothecia numerous, sessile, concave to 5 mm diam., margins entire to crenulate. Ascospores ellipsoid, 8-10.5 × 4.5-6 µm. Pycnidia numerous, senescing to form small black pits. Conidia 6.5-8 × 1 µm, bifusiform to rod-shaped. Chemistry: Cortex K-, HNO3+ dark blue-green; medulla K+ yellow-orange, C-, KC+ orange, Pd+ red-orange. Protocetraric and fumarprotocetraric acids.

S: Canterbury (Port Hills, Christchurch), Otago, (Rock and Pillar Ra., Fruitlands, Roxburgh, Maungatua).

Endemic

Alpine to subalpine. Closely related to N. stygiodes from which it differs mainly in the longer, more discrete (although loosely entangled) and more dissected lobes, and by the very loosely adnate thalli. Another sympatric species somewhat similar to N. petriseda is N. epheboides which is distinguished by its much smaller and thinner lobes and its dark brown or black lower surface.