Apothecia whitish pruinose; paraphyses branched at apices and forming true epithecium; asci 1-spored; thallus ecorticate = Solenographa confluens 
Apothecia non-pruinose or with thin dark pruina; paraphyses not forming epithecium; asci 6-8-spored; thallus with cartilaginous cortex
Apothecia elongate; disc exposed only in mature apothecia = Graphis "apertelloides"
Apothecia rounded; disc exposed from beginning; apothecia immersed in stromata; ascospores transversally septate = Glyphis cicatricosa
Apothecia rounded; disc exposed from beginning; apothecia solitary, prominent; ascospores muriform = Glyphis scyphulifera
Apothecial labia covered by pruinose layer formed by warty periphysoids; ascospores I- or I+ weakly blueviolet, submuriform and very small (less than 20 µm in length) = Carbacanthographis marcescens
Apothecial labia not covered by layer formed by warty periphysoids; ascospores I+ blue or blueviolet, if (sub)muriform then distinctly larger (more than 30 µm in length)
Slit between apothecial labia brownish pruinose; walls of paraphyses thick and strongly gelatinose = "Pallidoglyphis" substriatula
Slit between apothecial labia not brownish pruinose; walls of paraphyses thin and weakly gelatinose = Graphis (see separate key
)
= Phaeographina "sipmanii"
Apothecia aggregate and immersed in stromata = Sarcographa labyrinthica
Apothecia solitary; hypothecium strongly carbonized and with vertical growth to become very thick in old apothecia; lateral excipulum rather thin and proper apothecial margin indistinct; ascospores 5-11-septate, less than 40 µm long
Apothecia angular-rounded with chroodiscoid margin; ascospores unknown = Leiorreuma "lobatum"
Apothecia distinctly elongate; hypostictic acid and related substances present; species typical of higher elevations = Leiorreuma hypomelaenum
Apothecia distinctly elongate; lichen substances absent; species typical of lower elevations = Leiorreuma exaltatum
Apothecia solitary; hypothecium uncarbonized and without vertical growth; lateral excipulum well-developed and proper apothecial margin distinct; ascospores 9-19-septate or muriform, more than 40 µm long
Ascospores transversally 9-19-septate = Platygramme praestans
Ascospores muriform; apothecial labia black; lateral excipulum completely carbonized to base = Platygramme "costaricensis"
Ascospores muriform; apothecial labia greyish pruinose; lateral excipulum carbonized only in upper half = Platygramme caesiopruinosa
Ascospores transversally 3-septate; apothecia greyish pruinose = Hemithecium "triseptatum"
Ascospores muriform, brown; apothecia whitish to chamois-coloured; hymenium inspers; apothecia very elongate; stictic acid and related substances present = Hemithecium chrysenteron
Ascospores muriform, hyaline; apothecia whitish to chamois-coloured; hymenium not inspers; apothecia usually shortly elongate; lichen substances absent
Asci 8-spored; ascospores 30-45 x 10-15 µm = Hemithecium balbisii
Asci 1-2-spored; ascospores 90-120 x 25-50 µm; thallus distinctly verrucose = Hemithecium oryzaeforme
Asci 1-2-spored; ascospores 45-60 x 17-25 µm; thallus smooth to uneven = Hemithecium "pallidum"
Ascospores dark brown, thin-walled and with somewhat wavy outline (as if degenerated); thallus ecorticate, farinose = "Gymnographa glaucinariaeformis"
Ascospores greyish brown, distoseptate; thallus with cartilaginous cortex, smooth to uneven = Phaeographis (see separate key )
= Anomomorpha "tuberculata"
Ascospores muriform, I+ distinctly violet = Fissurina "subcingalica"
Ascospores 3-septate, I- or I+ weakly violet
Ascospores 18-35 x 10-15 µm; stictic acid present = Fissurina triticea
Ascospores 11-23 x 5-12 µm; no lichen substances present; excipulum apically brownish or weakly carbonized; paraphyses and periphysoids often with warty tips = Fissurina comparilis
Ascospores 11-23 x 5-12 µm; no lichen substances present; excipulum pale throughout; paraphyses and periphysoids often with smooth tips = Fissurina dumastii
Ascospores very small (less than 20 µm); thallus with cartilaginous cortex
Base of excipulum brown; ascospores submuriform; testacein present = Platythecium allosporellum
Base of excipulum pale; ascospores 3-septate; testacein absent = Platythecium grammitis
Ascospores larger; thallus ecorticate, minutely farinose; apothecia whitish pruinose; disc partially concealed by labia; hypostictic acid and relatives present; paraphyses thin-walled = Glaucinaria poitaei
Ascospores larger; thallus ecorticate, uneven; apothecia non-pruinose; disc exposed; often isohypocrellin (red pigment) and other lichen substances present; paraphyses thick-walled and gelatinous
Apothecia with dark red, K+ greenish pigment (isohypocrellin); ascospores 7-15-septate, I+ weakly blue = Thalloloma buriticum
Apothecia with dark red, K+ greenish pigment (isohypocrellin); ascospores 5-9-septate, I+ dark blueviolet; apothecia elongate and radiately branched with narrow disc = Thalloloma astroideum
Apothecia with dark red, K+ greenish pigment (isohypocrellin); ascospores 5-9-septate, I+ dark blueviolet; apothecia rounded to oval and eventually lobate with wide disc = Thalloloma cinnabarinum
Apothecia without dark red pigment; ascospores 3-9-septate, 20-30 x 6-8 µm = Thalloloma hypoleptum
Apothecia without dark red pigment; ascospores muriform, 30-40 x 10-15 µm = Thalloloma anguinum
Apothecia whitish pruinose; paraphyses branched at apices and forming true epithecium; asci 1-spored; thallus ecorticate = Solenographa confluens
Apothecia non-pruinose or with thin dark pruina; paraphyses not forming epithecium; asci 6-8-spored; thallus with cartilaginous cortex
Apothecia elongate; disc exposed only in mature apothecia = Graphis "apertelloides"
Apothecia rounded; disc exposed from beginning; apothecia immersed in stromata; ascospores transversally septate = Glyphis cicatricosa
Apothecia rounded; disc exposed from beginning; apothecia solitary, prominent; ascospores muriform = Glyphis scyphulifera
Ascospores 120-220 x 18-30 µm = Graphis cinerea
Ascospores 60-150 x 12-16 µm = Graphis "subflexibilis"
Ascospores 15-21-septate, 90-120 µm long; apothecia with thalline margin = Graphis flexibilis 
Ascospores 7-17-septate, 30-70 µm long; apothecia lacking thalline margin
Ascospores 11-17-septate, 50-70 x 10-13 µm = Graphis longula
Ascospores 7-11-septate, 30-50 x 7-9 µm = Graphis rimulosa
= Graphis anfractuosa
Ascospores 3-9-septate, 20-40 x 6-9 µm = Graphis hyphosa
Ascospores 11-25-septate, 70-130 x 11-20 µm
Apothecial labia with yellow, K+ pinkish cover = Graphis "flava"
Apothecial labia blackish with pale grey thalline cover, K- = Graphis anguilliformis (= Graphis serpens)
= Graphis glaucescens (= Graphis bulacana)
Norstictic acid present (thallus sections K+ yellow then red) = Graphis elegans
Norstictic acid absent (thallus sections K– or + yellow); carbonization of lateral excipulum not reaching apothecial base = Graphis proserpens
Norstictic acid absent (thallus sections K– or + yellow); lateral excipulum completely carbonized
, with dark red, K+ green pigment (isohypocrellin) = Graphis "hypocrellina"
Norstictic acid absent (thallus sections K– or + yellow); lateral excipulum completely carbonized, lacking pigment, K–
Apothecia with thalline margin; ascospores up to 70 µm long = Graphis longula
Apothecia lacking thalline margin; ascospores 5-9-septate, 20-32 x 6-8 µm = Graphis tenella
Apothecia lacking thalline margin; ascospores 7-11-septate, 25-50 x 6-9 µm; excipulum only laterally carbonized = Graphis duplicata
Apothecia lacking thalline margin; ascospores 7-11-septate, 25-50 x 6-9 µm; excipulum also basally carbonized in part but not entire = Graphis rimulosa
Apothecia lacking thalline margin; ascospores 9-15-septate, 40-60 x 8-12 µm = Graphis striatula
Hymenium inspersed; apothecial disc visible in old apothecia = Graphis "apertelloides"
Hymenium inspersed; apothecial disc concealed
Stictid and constictic acid present = Graphis leptocarpa
No lichen substances present = Graphis lineola
Hymenium not inspersed; norstictic acid present (thallus sections K+ yellow then red); apothecial labia with whitish cover formed by hyaline hyphae = Graphis caesiella
Hymenium not inspersed; norstictic acid absent (thallus sections K– or + yellow); apothecial labia black but laterally or basally with thalline margin
Ascospores 5-9-septate, 25-35 µm long; apothecia only basally with thalline margin = Graphis furcata
Ascospores 8-17-septate, 30-60 µm long; apothecia laterally with thick thalline margin = Graphis pavoniana
Ascospores 60-90 x 20-30 µm; lateral excipulum completely carbonized = Graphis "subhiascens"
Ascospores 13-40 x 8-15 µm; excipulum only apically carbonized
Ascospores 13-26 x 8-15 µm; apothecial labia and excipulum entire = "Graphina" dimidiata
Ascospores 30-40 x 9-11 µm; apothecial labia and excipulum strongly striate = Graphis "pseudoserpens"
= Graphis "argentea"
Ascospores 50-60 x 10-12 µm = Graphis "pseudocinerea"
Ascospores 100-140 x 18-25 µm = Graphis "cinereoides"
Only terminal parts of ascospores muriform = Graphis vestitoides
Ascospores muriform throughout = Graphis acharii
Asci 4-8-spored; ascospores 20-65 x 16-20 µm; apothecia without thalline margin
Ascospores 35-65 x 10-20 µm = Graphis ruiziana
Ascospores 20-30 x 16-18 µm = "Graphina" nuda
Asci 1-4-spored; ascospores 60-140 x 18-35 µm; apothecia with distinct thalline margin
Apothecia immersed in thallus, only slightly prominent = "Graphina hiascens"
Apothecia distinctly prominent to almost sessile, completely covered by thallus tissue; laterally between excipulum and thallus no crystals = Graphis carassensis
Apothecia distinctly prominent to almost sessile, covered by thallus tissue but dark grey to blackish slit visible; laterally between excipulum and thallus large clusters ("chambers") of calcium oxalate crystals; apothecia distinctly elongate = Graphis illinata
Apothecia distinctly prominent to almost sessile, covered by thallus tissue but dark grey to blackish slit visible; laterally between excipulum and thallus large clusters ("chambers") of calcium oxalate crystals; apothecia rounded = Graphis muscicola
Apothecia embedded in whitish, stroma-like tissue (resembling Sarcographa); ascospores 3-5-septate, 14-26 x 5-7 µm = Phaeographis intricans
Apothecia lacking stroma-like tissue; ascospores 3-septate, 10-15 x 5-6 µm = Phaeographis inconspicua
Ascospores 5-septate, 28-35 x 12-15 µm; apothecia strongly branched and stellate = Phaeographis "ramificans"
Ascospores 3-septate, 10-25 x 4-7 µm; apothecia unbranched to radiately branched
Apothecia radiately branched; ascospores 10-17 x 4-6 µm = Phaeographis subtigrina
Apothecia unbranched; ascospores 18-25 x 5-7 µm = Phaeographis "pseudotigrina"
Apothecia angular-rounded, with strongly prominent, often ruptured margins; virensic acid present = Phaeographis lecanographa
Apothecia oval to distinctly elongate, with slightly prominent, entire margins; virensic acid absent = Phaeographis scalpturata