Xanthoparmelia rubrireagens
≡Parmelia rubrireagens Gyeln., Ann. Mycol. 36: 288 (1938).
Description : Thallus very loosely adnate on rock, 6–10 cm diam. Lobes moderately imbricate, plane, linear-elongate, subdichotomously branched, divaricate in parts, becoming suberect and exposing lower surface, 0.5–1(–1.5) mm wide, margins black. Upper surface yellow-green, blackened in older parts, glossy, emaculate, smooth, without isidia or soredia. Lower surface wrinkled, black, rhizines absent or very sparse, when present simple, ±tufted, short, robust, black. Apothecia sessile, 1–3 mm diam., disc concave, chestnut-brown to brown-black; thalline exciple entire, thick, involute, becoming thin and crenulate. Ascospores 7–8 × 5–6 μm. Pycnidia common. Conidia bifusiform, 4–5 × 0.5 μm.
Chemistry : Cortex K−; medulla K+ yellow→dark-red, C−, Pd+ orange-red; containing usnic, salazinic, consalazinic and ±norstictic (tr.) acids.
S: Otago (Central Otago). On dry, sunny rocks. Known also from alpine areas of southern and eastern Australia and Tasmania (Elix 1994s: 284; McCarthy 2003c, 2006).
Australasian
Illustrations : Elix et al. (1986b: 240, fig. 16 – as Xanthoparmelia eradicata); Hale (1990: 184, fig. 62E).
Xanthoparmelia rubrireagens is characterised by: the saxicolous habit; narrow, linear-elongate lobes, dichotomously branched and becoming suberect at apices; a black, wrinkled, lower surface; and salazinic acid in the medulla.
