Bot. J. Linn. Soc. 158(1): 165 (2008).

Type: : St Helena, Prosperous Bay Plain, north slope of Dry Gut, on basalt, altitude 280 m, 17 October 2006, A. Aptroot 66266 (holo. B; iso. ABL).

Thallus: Initially shrubby, becoming pendant with age, up to 40 cm long but usually much smaller (c. 7 cm), without distinct holdfast, relatively sparingly to richly antler-like branched, partly terete, but mostly flattened, never contorted, not canaliculate, sometimes perforate, partly relatively broad, up to 3 cm wide, but generally c. 1.0–2.5 mm wide, c. 0.3–0.7 mm thick, with at most few inconspicuous warts, greenish-grey, most parts with conspicuous whitish linear pseudocyphellae, leaving seemingly branched greenish interspaces, the overall colour therefore pale grey. Branches generally linear, not bent below the apothecia.Branch tips often minutely curved, usually not blackened. Thallus without soredia.Thallus section with conspicuous, rounded strands of cartilaginous tissue in the medulla and at the surface, which are mostly hyaline, but brownish in section when reaching the surface. Cortex indistinct. Apothecia rather common, up to 3 mm in diameter, mostly cupular but becoming sometimes convex when old, laminal, disc yellowish-grey, margin with white pseudocyphellae and in section with rounded strands of hyaline cartilaginous material like the thallus, ascospores straight to slightly curved, 10–12 x 4.0–5.5 µm. Conidia not observed.

Photobiont: In irregular groups throughout the medulla.

Chemistry: Usnic acid with or without either binonic and protocetraric acids or with divaricatic acid (by TLC).

Ecology: The species is known from all over the island, in semi-desert areas and on cliffs.

Molecular data: Genbank

Distribution: Database

Note: This species is characterized by a flattened, sparingly to richly antler-like branched thallus with linear pseudocyphellae-like lines and often numerous, small (c. 0.5 mm) laminal apothecia. The thallus is not geniculate at an apothecium insertion. Two strains have been identified, each characterized by the secondary metabolites, as follows: I, boninic and protocetraric acids; II, divaricatic acid. Occasionally, no medullary substances are present. There is no close relative identified outside St Helena, but this species may be close to two other endemic Ramalina species of St Helena, as it shares several morphological trends, and the boninic acid strain shares its chemistry with R. geniculatella.