Menegazzia aucklandica

Detailed description

Thallus closely to loosely attached, forming regular or irregular, complete or partial rosettes, irregularly encircling twigs, to 12 cm diam., often coalescing to form small colonies, corticolous. Lobes numerous, ± radiating at outer edges, medium, rather uniform, 1.5-2(-3) mm wide, distinct, occasionally discrete at margins, becoming intricately interwoven, zig-zag, markedly contorted centrally and there often copiously secondarily lobulate, terminal lobes ± subdichotomously branched, margins sinuous-angular-convoluted, entire, not, or sparingly blackened, apices concolorous with thallus, hollow, swollen, internal cavity white. Upper surface uneven, mostly convex, occasionally where lobes are bunched, forming ridges, pale greenish-grey, emaculate, ± rugose-uneven, ± matt, perforate, without soredia or isidia. Perforations frequent, mostly median, margins notably elevated, appearing slightly inflated, conical, sometimes with a collar-like rim, 0.5-1.0 mm diam., rounded, oval or crescentic. Apothecia scattered, adnate, 2-10 mm diam., cupuliform at first, margins smooth, crenulate, or with scattered fissures, shining, thinner at maturity, disc 3-7(-10) mm diam., red-brown, shining, epruinose, ± plane to convex, pedicellate, pedicel ± coarsely faveolate. Epithecium red-brown, without granules, c. 10 µm thick. Hymenium colourless, c. 100 µm tall. Paraphyses not thickened at apices. Asci oval, 90-100 × 40-45 µm, 2-spored. Ascospores ellipsoid to subspherical, 48-60 × 32-40 µm [Zahlbruckner, loc. cit. gives 38-50 × 17-22 µm], wall 3-5 µm thick.

Chemistry: Medulla K+ yellow-orange, C−, KC+ orange, Pd+ orange; containing atranorin, stictic, constictic and menegazziaic acids and an accessory compound.