Menegazzia caliginosa P.James & D.J.Galloway
* Account prepared by P.W. James (BM).
Holotype: New Zealand. Canterbury, Craigieburn Forest Park. Track from Information Centre to Lyndon Saddle, 1000-1100 m, on bark of Nothofagus solandri var. cliffortioides, P.W. James, BM!
Thallus ± closely attached, mostly forming irregular patches or incomplete rosettes, to 10 cm diam., often smaller and partly moribund, texture rather brittle, corticolous or muscicolous. Lobes variable, medium, 2-3 mm wide, marginal lobes ± spreading but often ± angular, wide-angled, inner lobes contorted and ± imbricate-unorientated centrally, without interthalline spaces, not, or only sparingly blackened at edges, apices concolorous or ± tinged red-brown. Upper surface pale grey-green, shining, ridged-rugose or smooth, ± convex becoming plane, occasionally ± irregularly white-maculate, especially at lobe apices, weakly concave towards lobe ends. Upper side of internal cavity densely yellow or ochre-yellow, tomentose towards lobe ends, becoming blackened centrally. Perforations rather sparse, scattered, median on main lobes, ± gaping or with a depressed rim (pertransita -type), plane or slightly elevated, often low-conical. Soralia numerous, laminal, rarely subterminal, scattered or ± confluent, convex, finely granular, < 1 mm diam. Apothecia rare (only seen in type), adnate, 3-4 mm diam., markedly concave, disc red-brown, epruinose, ± wrinkled, margins thick, inflexed, smooth, rarely faintly white-maculate, becoming ± entirely sorediate. Epithecium red-brown, without granules, colour in gelatinous matrix as well as in apices of paraphyses. Hymenium c. 130 µm tall. Asci ± elongate-ellipsoid, (2-)8-spored, 100-120 × 40-45 µm. Ascospores ellipsoid, 28-35 × 15-18 µm, wall 2 µm thick. Chemistry: Atranorin (cortex), stictic, constictic, norstictic (tr.) and echinocarpic acids, accessory compounds and four or more orange-yellow pigments, one UV+ orange-red, medulla K+ yellow → orange, C-, KC+ orange, Pd+ orange.
N: Wellington (Tararua Ra.). S: East of Main Divide in Canterbury, Otago, also in Fiordland (Dusky Sound). On trees and shrubs in forest, s.l. to 1000 m.
Australasian
M. caliginosa is the sorediate counterpart of M. foraminulosa. It is distinguished from other sorediate species in the genus by the pigmented upper side of the internal cavity, the presence of echinocarpic acid, the faint white maculae of the lobe ends, and when fertile, by the 8-spored asci.
