Menegazzia inactiva
Description : Thallus appressed but ascending towards lobe ends, irregularly spreading, 4–7 cm diam. Lobes 1.5–3 mm diam., fragile, elongate, partly subdichotomously branching, often with toe-like secondary lobes at right angles to main lobes, frequently overlapping, very inflated, convex to tubular in part, very pale-grey to ivory, semi-pellucid when moist. Upper surface smooth or faintly rugose, rumpled; lobe ends concolorous. Lower surface jet-black, shining, colour not spreading laterally or onto upper surface. Cavity white, finely tomentose. Perforations frequent, round or oval, to 1 mm wide; margins often elevated, lacerate, occasionally with a collar. Soralia numerous, terminal or subterminal, on ragged, recurved, flange-like extensions of perforation margins, or as small inflated vesicles towards lobe ends, soon disintegrating to expose soredia and ragged, proliferating margins. Soredia powdery, granular, concolorous with upper surface. Apothecia and pycnidia not seen.
Chemistry : Cortex K+ yellow; medulla K−, C−, KC−, Pd−, UV−; containing atranorin and four fatty acids of the murolic acid complex.
S: Canterbury (Lewis Pass). Known also from Tasmania where it is rare (Kantvilas & James 1987: 26; James & Galloway 1992; McCarthy 2003c, 2006).
Australasian
Illustrations : James & Galloway (1992: 237, fig. 87A); Kantvilas & Jarman (1999: 83).
Menegazzia inactiva is characterised by: the corticolous habit; the extreme fragility of the lobes, the recurved, sorediate extensions of both perforations and subterminal areas of lobes; and the chemistry (fatty acids).
