Lecanora subumbrina
Description : Thallus crustose, uniform, closely attached to substratum, thin, smooth, continuous to areolate, verrucose, yellowish white to grey-white, without pruina, or soredia, slightly glossy. Prothallus lacking or grey-white. Apothecia immersed at first, becoming sessile, 0.2–0.7(–1) mm diam., disc brown to orange-brown, intensely orange-brown when moist, epruinose. Thalline exciple concolorous with thallus, thin to thickish, smooth, entire to verruculose. Amphithecium with large crystals, not dissolving in K (pulicaris -type). Epithecium red-brown, pigment dissolving in K, with crystals (chlarotera -type), 15 μm thick. Hymenium colourless ,60–85 μm tall. Asci 50–70 × 14–20 μm. Ascospores narrowly ellipsoidal, 14.5–20.5 × 4.5–6.5 μm.
Chemistry : Thallus and thalline margin K+ yellow, C+ orange, KC+ orange, PD+ yellow-orange; containing chloroatranorin, arthothelin and zeorin (major), atranorin, ±2,4-dichlorolichexanthone, ± 2,5-dichloronorlichexanthone and ± thiophanic acid (minor).
N: Northland (Mangonui). First collected in New Zealand, J.K. Bartlett (AK). On coastal vegetation especially mangroves (Avicennia marina). Known also from Queensland in coastal sites on mangroves, Western Australia and New South Wales (Lumbsch 1994: 144–145; McCarthy 2003c, 2006; Lumbsch & Elix 2004).
Australasian
Illustration : Lumbsch (1994: 143, fig. 71A–C).
Lecanora subumbrina is characterised by: the corticolous habit; yellow-white to grey-white, verrucose thallus; immersed to sessile apothecia with brown to orange-brown, epruinose discs; narrowly ellipsoidal ascospores, 14.5–20.5 × 4.5–6.5 μm; and a chemistry of arthothelin, atranorin and xanthones (C+ orange, KC+ orange).
