Halecania australis
Description : Thallus crustose, rimose, areolate to scurfy-squamulose; areolae 0.2–0.4 mm diam., 0.3 mm high, angular to rounded, squamules sometimes upturned at margins and often wavy, incised, sometimes overlapping, up to 0.5(–0.7) mm diam., but not lobulate at margins. Upper surface pale-brown, grey-brown to clay-brown, pale to dark olivaceous to rarely almost blackish. Prothallus sometimes visible, thin and pale- to mid-brown. Apothecia 0.2–0.5 mm diam., frequent, adnate to broadly sessile or somewhat immersed, scattered or in small groups, sometimes crowded. Disc red-brown to dark-brown when dry, paler when moist, plane to subconvex, epruinose. Thalline exciple concolorous with thallus, swollen at first, then narrowing, sometimes crenulate, not excluded. Epithecium brown, red-brown to orange, without granules, uniformly coloured, K−, N−. Hymenium 60–70 μm tall, hyaline. Hypothecium to 150 μm thick, hyaline. Asci narrowly clavate, c. 40–50 × 12– 20 μm. Ascospores ellipsoidal, clavate or ovoid, (9–)10–14(–16) × 3– 5 μm. Pycnidia occasional, inconspicuous, immersed, c. 80–100 μm diam., pale-brown around ostiole, hyaline below. Conidia simple, short, bacillar, 3–4 × 1 μm.
Chemistry : K−, C−, KC−, Pd−; containing unidentified triterpenes. Two chemodemes appear to be present (van den Boom & Elix 2005: 239).
S: Nelson (Maitai River Road). On shaded roadside rocks (van den Boom & Elix 2005: 240). Known also from Australia (Lumbsch & Feige 1994; van den Boom & Elix 2005) and from the Sonoran Desert in Arizona (van den Boom & Ryan 2004a).
?Palaeotropical
Illustrations : van den Boom & Ryan (2004a: 131, fig. 12); van den Boom & Elix (2005: 238, fig. 1).
Halecania australis is characterised by: the saxicolous habit; an areolate to subsquamulose thallus; the areolae sometimes upturned at the margins; the yellowish brown to dark olivaceous brown, but not oily, upper surface (without green pigment, K−, N−); ascospores 9–14 × 3–5 μm; and unidentified triterpenes as major secondary metabolites.
