Xanthoparmelia oleosa
≡Parmelia oleosa Elix & P.M.Armstr., Austral. J.Bot. 31: 478 (1983).
Description : Thallus tightly adnate on rock, yellow-green, darkening with age and becoming greyish black, often becoming subcrustose centrally, 3–6 cm diam. Lobes sublinear-elongate to subirregular, scarcely imbricate, older lobes extensively fractured forming areolae, lobes 0.8–1.5(–2) mm wide, areolae 1 mm diam. Upper surface opaque or glossy towards apices, emaculate, often tangentially cracked, commonly black-margined towards centre, without isidia or soredia. Lower surface tan to dark-brown, somewhat darker to smoke-grey at apices, moderately rhizinate. Rhizines brown, simple. Apothecia adnate to subpedicellate, 1–2(–4) mm diam., margins thin, entire; disc concave, dark-brown; thalline exciple smooth. Ascospores 7–8 × 3.5–4.5 μm.
Chemistry : Cortex K−; medulla K−, C−, KC−, Pd−; containing usnic, protoconstipatic, constipatic, dehydroconstipatic and pertusaric acids.
S: Otago (Central Otago). On dry, sunny rocks. Known also from Australia, the USA (Arizona) and Mexico (Elix 1994s: 274; McCarthy 2003c, 2006; Nash & Elix 2004; Nash et al. 2004a).
Palaeotropical
Illustrations : Elix & Armstrong (1983: 478, fig. 9 – as Parmelia oleosa); Elix (1994s: 277, fig. 102A).
Xanthoparmelia oleosa is characterised by: the saxicolous habit; tightly adnate, small-foliose to subcrustose thalli; sublinear-elongate to subirregular lobes; a tan to dark-brown lower surface; and fatty acids in the medulla.
