Type: Brazil. Rio Grande do Sul: Boqueirão do Leão, Spielmann, A.A. 1307 & Sulzbacher, M.A. (SP – holotype!).
Description.Thallus corticolous; uppersurface white to whitish gray, dull to shiny, epruinose, densely reticulate-maculate, typically cracked; abundantly isidiate; isidia marginal and laminal, cylindrical, sparsely branched to distinctly coralloid, often clustered (caespitose) and apically breaking apart into soredia, the isidia located along the lobe margin typically longer and more elaborate, often with a brown to blackened tip, frequently ciliate (thus appearing ‘tufted’); lobes small to moderate-sized, 0.3–4(–5) mm wide, ± angular, axils rounded but not forming conspicuous loops, margins sparsely to abundantly ciliate; cilia short and slender, 0.2–0.8(–1) mm long, black, mostly simple, very rarely branched; lower surface black, gradually becoming dark brown towards the margin, lacking a distinctly erhizinate zone, the marginal rhizines not much shorter than the central ones; rhizines long, slender, black, mostly simple, rarely sparsely branched; medulla white. Apothecia and pycnidia not observed among the Galapagos specimens.
Chemistry. Cortex with atranorin [P+ yellow, K+ yellow, KC–, C–, UV–]; medulla with salazinic acid [P+ deep yellow, K+ yellow, soon turning blood-red, KC–, C–, UV–].
Ecology and distribution. Africa (Cape Province), Brazil (Marcelli et al. 2007; Spielmann 2009). New for Galapagos and previously not reported from Ecuador; a single historical specimen has been collected on Bursera by Weber on Floreana Island, followed by an additional recent collection, also on Bursera, in the transition zone, at Mina Granillo Rojo, on Santa Cruz Island.
Notes.Parmotremalacteum is one of several isidiate species with a gray, distinctly reticulate-maculate surface, and salazinic acid in its medulla. The species is unusual because of its unique isidia that typically form clusters breaking apart into irregular soredia. Specimens then look ‘peppered’ with granular soredia.