Description: Thallus thin, continuous to rimose, white to whitish gray, or creamy white; surface dull, not pruinose; Apothecia erumpent, lirellate; lirellae thin, elongate and moderately to strongly branched; labia thin, mostly entire, but in parts inconspicuously striate (especially visible in section), shiny black, not covered by the thallus, but laterally with a thallus hem; disc concealed, a thin slit; exciple laterally carbonized, open below; hymenium hyaline, clear (not inspers), I–; ascospores hyaline, I+ bluish violet, 8 per ascus, ellipsoid to broadly fusiform, 20–30(-40) x 6–9 µm, transversely septate, 6-8(-10) celled. Chemistry: No substances found; all spot tests negative.

  Notes: Staiger (2002) distinguishes G. tenella and G. duplicata mostly on spore size and septation, but there is significant overlap and the two species can better be distinguished by their lirellae morphology. In G. tenella lirella striations are inconspicuous and the lirellae are basally always hemmed in by a thin, but distinct thallus layer. In contrast, G. duplicata has prominent, distinctly striate lirellae. Graphis duplicata has not yet been observed in Galapagos. A range of Graphis species with whitish thalli and thin lirellae are very similar. For a discussion on how to best distinguish these species see the notes for G. elongata.