Xanthoparmelia isidiotegeta
Description : Thallus small-foliose to foliose, moderately adnate to adnate, to 3–6 cm diam. Lobes imbricate, sublinear to sublinear-elongate, subirregularly to subdichotomously branched, 0.2–1.2 mm wide. Upper surface pale yellowish green, mostly flat, glossy, emaculate, smooth, without soredia; margins often blackening near apices, sometimes appearing ciliate. Isidia moderately dense, cylindrical, simple or branched and becoming coralloid, apices syncorticate and intact, ±blackened. Lower surface black, rhizinate. Rhizines moderately dense, usually projecting beyond margins and resembling cilia, simple or rarely dichotomously branched, to 2 mm long, black. Apothecia and pycnidia unknown.
Chemistry : Thallus K−; medulla K+yellow, C−, KC−, Pd+ orange-red; containing usnic acid (major), stictic acid (major), constictic acid (minor), cryptostictic acid (minor or tr.) and norstictic acid (minor).
S: Nelson (Denniston Plateau). On exposed sandstone in boggy heath. Known also from Victoria, New South Wales, Queensland and Tasmania (Elix & Kantvilas 1999a: 91; McCarthy 2003c, 2006; Elix 2004d).
Australasian
Illustration : Elix & Kantvilas (1999a: 90, fig. 1).
Xanthoparmelia isidiotegeta is characterised by: the saxicolous habit; moderately adnate, small-foliose to foliose thalli; narrow, imbricate lobes with a black lower surface; cylindrical isidia; and stictic acid in the medulla. The common and widespread species X. mougeotina is similar but differs in being much more tightly adnate to subcrustose, and in having radiating, mostly non-overlapping lobes that form neat rosettes and which lack conspicuous, marginally protruding rhizines.
