Lepraria nothofagi

The thallus—the visible body of the lichen—forms a white to ivory, powdery crust that can reach several millimetres in thickness. At the margins it may show faint, irregular lobes, but it never develops the cup-shaped fruiting bodies (apothecia) seen in many other lichens; reproduction is entirely by soredia, minute bundles of fungal hyphae wrapped around algal cells that look like dust under a hand lens. Individual soredia are mostly 50–90 μm across, often clustering into larger consoredia up to about 0.2 mm; short, filamentous hyphae sometimes project from their surface, giving the thallus a slightly woolly appearance. Beneath the soredial layer there may be a paler, compact zone that functions as a primitive medulla, while a sparse hypothallus—strands of anchoring hyphae—attaches the lichen to the bark.^[2]

Chemical analysis shows a constant suite of secondary metabolites: atranorin (major), strepsilin and porphyrilic acid (both variable but usually conspicuous) and a trace of lecanoric acid; minor amounts of norascomatic acid, di-O-methylstrepsilin and pannaric acid have also been detected. When a drop of calcium hypochlorite (the "C" spot test) is placed on a fresh fragment the strepsilin produces a green reaction, a quick field test that supports laboratory results.^[2]

Lepraria nothofagi is known to occur only in the Andean–Patagonian forests of Neuquén Province, Argentina. All collections have been made on the trunks and larger branches of Nothofagus species—principally N. obliqua, N. dombeyi and N. pumilio—in cool, moist woodland often mixed with the conifer Austrocedrus chilensis. Sites are generally between 850 and 1000 m above sea level around lakes such as Quillén, Traful and Correntoso.^[2]