Flora of New Zealand Series

≡Parmelia atrobarbatica Elix, Austral. J. Bot. 29: 17 (1981).

≡Neofuscelia atrobarbatica (Elix) Essl., Bryologist 89: 297 (1986).

Description : Thallus foliose or becoming somewhat crustose centrally, tightly adnate, closely appressed throughout or slightly raised centrally, 5–10 cm diam. Lobes subirregular, 0.2–0.8(–1.0) mm wide, almost flat, closely contiguous throughout or here and there radiating at periphery, subimbricate. Upper surface olive to dark brown-black, somewhat paler at lobe ends, ±smooth at periphery, fissured centrally with transverse cracks and eventually forming distinct areolae, dull except for shining lobe ends, without isidia. Medulla white. Lower surface mostly dark-brown to black, moderately to densely rhizinate, the rhizines concolorous or darkening, small and fine, tufted or not, to 0.3 mm long. Apothecia common, adnate, somewhat concave at first becoming flat, 0.5–1.0 mm diam., disc dark-brown to black, thalline exciple thick, crenulate. Ascospores ellipsoidal, 5–7 × 3–5 μm. Pycnidia common. Conidia bifusiform, 5.5–7 × 1 μm.

Chemistry : Cortex K−, HNO3 + faint blue or – in parts; medulla K−, C−, KC+ pale-yellow, Pd−; containing barbatic acid (major) and 4- O -demethylbarbatic acid.

S: Canterbury (Lake Tekapo). On rocks in pasture, 700 m. Collected by M.E. Hale (Esslinger 1986b). Known also from Australia (Elix 1981a, 1994k: 70; McCarthy 2003c, 2006).

Australasian

Illustrations : Elix (1981a: 18, fig. 1 – as Parmelia atrobarbatica; 1994k: 71, fig. 40A – as Neofuscelia atrobarbatica).

Xanthoparmelia atrobarbatica is characterised by: the saxicolous habit; the small, tightly adnate thalli, the sublinear-elongate lobes with a dark-brown to black lower surface; the lack of isidia and the presence of medullary barbatic acid. It resembles X. minuta, but is distinguished chemically (X. minuta contains medullary gyrophoric acid). It is distinct from X. melanobarbatica, which also produces medullary barbatic acid, but is distinctly foliose and has lobes with a pale-tan to pale-brown lower surface.