Roccellina Darb.
Type : Roccellina condensata Darb. [=Roccellina cerebriformis (Mont.) Tehler]
Description : Thallus subfruticose, placodioid, effigurate or crustose, at first crustose later becoming areolate, squamulose or bullate and at length finally subfruticose, without rhizines, saxicolous. Prothallus brown or dark-brown, of loose hyphae, but when contiguous it is black and crust-like; placodioid and subfruticose species generally are without a prothallus. Surface white or grey-white to dark-brown or yellowish; pruinose or subglabrous, rarely glabrous. Soralia when present punctiform or usually maculiform, rarely rimiform or capitate. Cortex thick, well-developed, of mixed and intertwined hyphae, rarely anticlinally arranged, in a hyaline or yellow-brown gelatinous matrix, rarely opaque and granular. Photobiont Trentepohlia. Medulla of brittle or loose hyphae, in most species with an upper white and a lower brown part, or white with the hypothecium extending down to the substratum, or both, rarely completely white. Ascomata apothecia or stromatoid, lecanorine or rarely biatorine, generally absent in sorediate taxa, solitary or aggregated, sessile to subpedicellate and with a constricted base, sometimes immersed, ± evenly dispersed centrally; disc grey-white to ±black, margins entire, undulate; proper exciple thin to thick and conspicuous. Hypothecium carbonaceous or dark-brown, extending down to substratum or fusing with lower brown medulla. Hymenium hyaline. Hamathecium of paraphysoids, simple to sparingly branched, 1–2 μm diam. Epithecium brownish, 25–60 μm thick. Asci hyaline, clavate, bitunicate, 8-spored, 70–100 × 13–18 μm. Ascospores smooth, 3-septate, colourless, brownish when mature, fusiform or obtusely fusiform, curved or straight, often with one end tapering. Conidiomata pycnidia, numerous to sparse or absent, evenly dispersed over surface of thallus, immersed or slightly elevated, appearing as brown or black dots. Conidia of two types: microconidia hyaline, thread-like and sickle-shaped, 9–17 × 1 μm; macroconidia (in only 1 species) rod-shaped, slightly curved, 11–19 × 2–3 μm. With a chemistry of erythrin, lecanoric acid, roccellic acid, schizopeltic acid, atranorin and four unidentified compounds.
Roccellina is a genus of 24 species included in the family Roccellaceae (Eriksson et al. 2004; Pennycook & Galloway 2004; Eriksson 2005), with the main areas of speciation being in the Southern Hemisphere with only 4 taxa spreading into the Northern Hemisphere (California, Mexico, Socotra and Japan). Chile has 12 endemic taxa, and one is endemic to Peru and the Galapagos Is; three species are common to Peru and Chile. Ascencion, the Cape, the Falklands Is and Australasia (northern New Zealand and Tasmania) have one species each. The genus is best developed in coastal habitats on cliffs and boulders close to the sea. The genus was monographed by Tehler (1983: 23) who notes: "The most striking features of Roccellina are the concentration of species to the South American west coast, the Circum-Pacific distribution, and the occurrence in Africa". One species is recorded from New Zealand (Tehler et al. 1991).
