Separated from other sterile sorediate species by a combination of its yellow to blue-grey soralia, its unique chemistry (atranorin and alectoronic acid) and lignicolous habit.
Type: Falkland Islands, Weddell Island, Weddell Settlement, behind Mountain View Cottage, 51.891525°S, 60.912416°W, 15 m, fence post, 24 January 2015, Fryday 10863 (MSC—holotype).
Description
Thallus not apparent, endoxylic, completely within the substrate. Soralia erumpent, initially orbicular to 0.3 mm diam., becoming elongate to 0.6 × 0.3 mm, plane to concave, following the grain of the wood, but soon confluent and convex and forming a ±continuous crust; soredia farinose, pale green below becoming blue-grey at the surface, 20–25 µm diam., aggregating to 75–100 µm across. Photobiont trebouxioid, cells (6–)10–15 µm diam.
Apothecia unknown.
Conidiomata not observed.
Chemistry. K+ yellow, KC –, C–, Pd–; atranorin and alectoronic acid by TLC.
Etymology. The name reflects the substrate on which the species occurs.
Ecology and Distribution: Known only from the Falkland Islands where it occurs on fence posts and worked timber on both main islands and Weddell Island. It is possible that this species was imported with the fence posts, which probably originated in Chile. Associated species: Blastenia circumpolaris Søchting, Frödén & Arup, Buellia punctata (Hoffm.) A. Massal., Cliostomum griffithii (Sm.) Coppins, Lecanora expallens Ach., Xylographa vitiligo (Ach.) J.R. Laundon.