Galapagos Species Database

Thallus moderately thickened, continuous to rimose-areolate; surface dull, ±pruinose; Apothecia erumpent to prominent, lirellate; lirellae broad, elongate, not branched, or very sparsely branched; labia thin, entire, black, not pruinose, typically hemmed in basally by a distinct thallus rim; disc typically wide open, grayish from a thick white pruina; exciple laterally carbonized, open below; hymenium hyaline, inspers; ascospores hyaline, I+ bluish violet, 6(-8) per ascus, ellipsoid to oblong, 22-29 x 7-9 µm, transversely septate, 5-6 celled. Chemistry: Norstictic acid; K+ orange-red (forming needle shaped crystals).

Superficially very similar is G. tenellula because of its short lirellae with a distinct and broad thallus rim, however, that species has closed labia, i.e. a concealed disc, without any pruina, and it is more commonly found in the humid highlands, not the transition zone. For comparison with G. caesiella see the discussion there. Lücking et al. 2008) mention G. apertella as a possible synonym saying that the original description in Archer (2001c) does not mention disc pruina. Archer (2006), however, refers to the epithecium as pruinose.