Leioderma erythrocarpum
≡Pannaria erythrocarpa, Delise ex Nyl., Annls Sci. nat. Bot. sér.4, 11: 256 (1859). [For additional synonymy see Galloway & Jørgensen (1987: 379)].
Description : Thallus orbicular to irregularly spreading, 1–5(–8) cm diam., rather loosely attached. Lobes to 6 mm wide, laciniate, discrete to ±imbricate. Margins slightly thickened, shallowly undulate to sinuous, ±ascending, crenate, incised with squamulose to digitate phyllidia. Upper surface finely and ±uniformly arachnoid–hairy, often irregularly undulate or ± shallowly pitted, dark grey-blue when wet, pale buff-grey when dry, often with numerous brown-pink apothecial initials. Lower surface ecorticate, whitish to pale buff, arachnoid, with scattered tufts of white to blue-black rhizohyphae. Apothecia laminal, scattered to crowded, sessile, 1–2 mm diam., disc concave, pale red-brown to pinkish rarely dark brown or blackened; proper exciple prominent, persistent, transparent when wet, whitish when dry. Hymenium I+ persistent blue. Ascospores ellipsoidal, rather thick-walled, slightly roughened, 13–20(–23) × 6–12 μm.
Chemistry : TLC−, all reactions negative.
N: Northland (near Russell, Rakitu I., Tapu Bush N. Kaipara). S: Marlborough (Motuara I., around Cook's Cairn). On bark and on rocks in Kunzea ericoides forest, s.l. to 200 m. Known also from Madagascar, Mauritius, Réunion, the Philippines, Sarawak, Indonesia, Java, Papua New Guinea, Tahiti, the Marquesas Is, and New Caledonia (Galloway & Jørgensen 1987; Elix & McCarthy 1998).
Palaeotropical
Illustrations : Galloway & Jørgensen (1987: 380, fig. 22, 381, fig. 23).
Leioderma erythrocarpum is charaterised by: the corticolous habit; and its arachnoid–hairy upper surface (×10 lens) a character shared only with its sorediate counterpart, L. sorediatum.
