Xanthoparmelia concomitans
Holotype: New Zealand: Otago, Alexandra, ¼ mile beyond Lookout, 11.iv.1971, W.Martin s.n. – CHR 343817 pr. p.
Description : Thallus unattached or loosely attached to soil, in neat rosettes, 0.5–2 mm diam. Lobes imbricate or not, ±discrete and divergent at apices, sublinear-elongate, subdichotomously to dichotomously branching, 0.2–1(–2) mm wide. Upper surface pale-yellow to pale yellow-green, weakly convex, matt, ±maculate (×10 lens), smooth, without isidia, sorediate. Soredia farinose, yellowish, developed in swollen, terminal, subcapitate soralia at apices and margins of lobes. Lower surface partly canaliculate, pale-yellow to yellow-brown, rhizinate. Rhizines sparse to moderately dense, simple or rather sparsely branched, black. Apothecia and pycnidia unknown.
Chemistry : Cortex K−; medulla K+ dingy brown, C−, Pd+ orange-red; containing ±succinprotocetraric, fumarprotocetraric, protocetraric (tr.) and usnic acids.
S: Marlborough (Molesworth), Canterbury (Tekapo, the Wolds Stn; N of Hakataramea Pass), Otago (Otamatapaio River, Clyde, Alexandra, Lake Roxburgh above dam). On silty, arid soils in xeric communities, often with Cladia aggregata, Siphula coriacea, Xanthoparmelia semiviridis, and X. reptans. Known also from subarid areas of Western Australia and Victoria (Elix 1994s: 225; McCarthy 2003c, 2006).
Australasian
Illustration : Elix et al. (1986b: 212, fig. 9).
Xanthoparmelia concomitans is characterised by: the terricolous habit; convex, dichotomously branched lobes with a canaliculate lower surface; the presence of soredia in terminal, eroded soralia; and fumarprotocetraric and succinprotocetraric acids in the medulla.
