Xanthoparmelia cheelii
≡Parmelia cheelii Gyeln., Ann. Mycol. 36: 271 (1938).
Description : Thallus loosely adnate on rock, 5–10 cm diam. Lobes very densely imbricate, building up thalli into thick mats, plane, apices not ascending, sublinear-elongate, subdichotomously branched, not constricted at branch points, 0.5–1(–1.5) mm wide. Upper surface yellow-green, glossy, emaculate, smooth, without isidia or soredia, margins blackened especially at apices. Lower surface smooth, black, brown-black at apices, rhizinate. Rhizines very sparse, simple, short, robust, black. Apothecia subpedicellate, to 7 mm diam., disc deeply concave, reddish brown. Ascospores 10–11 × 6–7 μm. Pycnidia common. Conidia bifusiform, 6–7 × 0.5 μm.
Chemistry : Cortex K−; medulla K+ yellow→dark-red, C−, KC−, Pd+ orange-red; containing salazinic, consalazinic, protocetraric (tr.) and usnic acids.
S: Otago (Lindis River near Cluden, Alexandra). On rocks in arid grassland, associating with X. congesta, X. glareosa and X. tegeta. Known also from southern Australia and Tasmania (Elix 1994s; McCarthy 2003c, 2006).
Australasian
Illustrations : Elix et al. (1986b: 210, fig. 8); Hale (1990: 85, fig. 31D); Kantvilas et al. (2002: 174).
Xanthoparmelia cheelii is characterised by: the saxicolous habit; densely imbricate, narrow (0.5–1 mm wide), subdichotomously branching lobes; a black lower surface; and salazinic acid in the medulla. It differs from X. tasmanica that has wider lobes (1–5 mm wide), and subirregularly branched.
