Galapagos Species Database

Thallus saxicolous; placodioid leprose, i.e., developing upon a common, shared hypothallus, prothallus fine, inconspicuous, main thallus distinctly delimited, but lacking a conspicuously ‘crisped’ lip; surface deep yellow to brownish yellow, pale beige only along the margin and where the surface gets eroded; hypothallus inconspicuous, exposed only as a fine prothallus along the thallus margin or where granules on the surface have eroded; rhizohyphae absent or at least indistinct; granules pseudocorticate, very compact, coarse [(35–)40–70(–100) µm in diam., rather uniform in size], mature granules without conspicuous extruding hyphae, immature or damaged granules in eroded thallus parts rarely with few protruding hyphae. Photobiont green, coccoid. Spot tests and chemistry: P+ reddish orange, K+ yellow orange, C−, KC−; UV(dark); pannaric acid 6-methyl ester and accessories. Distribution and ecology. Cosmopolitan; in Galapagos on vertical to overhanging, but ±exposed rock surfaces, though typically facing south or east and thus ±shaded, not receiving direct sunlight. Notes. The species is easily recognized by its deep brownish beige to yellowish color and the distinctly delimited thalli of densely packed, compact granules with a distinctly pseudocorticate surface. The thalli of L. vouauxii often display a distinctive coloration pattern, with pale yellowish beige margins, deeper yellowish brown towards the center, and again pale yellowish beige or even whitish in the very center, where older parts have eroded. Lepraria vouauxii not only looks quite different from most other Galapagos species of Lepraria, it is also chemically distinct. Due to the presence of pannaric acid 6-methyl ester it appears related to Lepraria tenella, which, however, has larger, pale yellowish to greenish white or ivory granules that soon branch into distinct pseudopodetia.