Usnea austrocampestris  

Description
Thallus fruticose, yellow-green, straggling on ground, with no holdfast, up to 22 cm long, anisotomically branched, main branch not clearly distinguished, thickest branches to 0.8 mm diam., papillate, annulated towards ends. In section the central axis varies from 19 to 43 % of total branch diameter.
Apothecia in central part of thallus, lateral, on larger branches only, flat, up to 7 mm diam., disc dark brown to black, thalline margin very thin, to 0.1 mm broad. Exciple on outside with low ridges and papillae, no rays present.
Chemistry. Usnic, salazinic, norstictic acids by tlc.

Distribution and Ecology.
Straggling on soil on mountain tops in West Falkland. Endemic.

Comments.
This taxon keys out as U. aurantiacoatra (Jacq.) Bory in Walker (1985), but differs from that species in at least two characters: the central axis, which in U. aurantiacoatra (on Falkland Islands) is 53–95 % of total diam., and the ecology (always with a distinct holdfast on rock in U. aurantiacoatra).