Galapagos Species Database

Thallus thin, continuous to rimose, lead gray to whitish gray; surface smooth, not pruinose; Apothecia prominent to sessile, lirellate; lirellae broad, elongate, moderately to sparsely branched; labia thick, broad, blackened, soon distinctly striate, almost entirely covered by a fine pale yellow, K+ reddish salmon pruina, which in older specimens ‘melts’ into an orange, K+ reddish purple residue that may in parts erode with age; disc concealed, a thin slit; exciple completely carbonized, carbonization extending below the hymenium; hymenium hyaline, clear (not inspers), I–; ascospores hyaline, I+ bluish violet, 4-8 per ascus, narrowly oblong to fusiform, 10-150 x 12-16 µm, mostly transversely septate, but terminally becoming muriform, with 15-23 transversal septa, terminal cells with 1-2 septa. Chemistry: No substances found in thallus; lirellae with a fine yellow pruina (unknown anthraquinone), K+ reddish salmon, slowly turning purple when drying.

Specimens with a fine yellow pruina covering their lirellae can be easily recognized. The pruina, when fresh, typically reacts K+ faint reddish-salmon. In older specimens it is not unusual to find the pruina dried up (‘melted’) into a fine orange film, reacting K+ reddish purple. Staiger (2002, p. 265) already observed this pigment layer and treated these specimens as a variation of G. vestitoides. The pruina, if well developed, is very distinct, but often erodes with age and these specimens can then indeed be confused with G. vestitoides. Specimens that at first glance lack the pruina must therefore be checked very carefully.