Flora of New Zealand Series

Parmelia horrescens Taylor, Fl. hibern. 2: 144 (1836).

Thallus orbicular to spreading, 2-6 cm diam., lobes narrow, 1-3 mm wide, linear to irregular, somewhat dissected, often crowded and imbricate, margins crenate, becoming lobulate-isidiate, ciliate, cilia simple, black, 0.3 mm long. Upper surface shining, minutely maculate (×10 lens), pale grey to brownish, isidiate. Isidia cylindrical or slightly flattened, dense, becoming lobular-coralloid, with short, black, apical cilia. Lower surface black with a narrow, brown, naked, marginal zone. Rhizines simple, black, rarely squarrose. Apothecia not seen in New Zealand material. Chemistry: Cortex K+ yellow; medulla K-, C-, KC+ pink, Pd-. Atranorin, gyrophoric acid (tr.) and two unidentified compounds.

N: North Auckland to South Auckland (Mangaotaki Valley). Rather rarely collected in New Zealand, mainly from northern coastal or lowland habitats on trees and shrubs.

Cosmopolitan