Phaeographis xanthonica

Phaeographis xanthonica is a species of corticolous (bark-dwelling), crustose lichen in the family Graphidaceae. Found in Brazil, it was formally described as a new species in 2009 by Klaus Kalb and M. Matthes-Leicht. The species epithet refers to the presence of the xanthone substance lichexanthone. The type specimen was collected in Itatiaia (Serra da Mantiqueira, Rio de Janeiro) at an altitude of 1750 m. It has also been recorded from Costa Rica.

The thallus of Phaeographis xanthonica is smooth,, whitish-grey to whitish-beige, and lacks a prothallus. Its ascomata are in form, curved with tapered ends, and measure 0.5–4 mm long. The are black and bordered by a somewhat thick and split. The have a transverse septum that divides it into four cells; their dimensions fall into the range 11–21 by 5–7 μm.