Enterographa lichexanthonica
Enterographa lichexanthonica is a species of crustose and corticolous lichen in the family Roccellaceae. Found in the Brazilian Amazon, it was formally introduced as a new species in 2017 by lichenologists Marcela Eugenia Cáceres and André Aptroot. The type specimen was collected by the authors from the Adolfo Ducke Forest Reserve, along trails near a field station; here, it was found growing on tree bark in an old-growth rainforest. The lichen has a thin, dull, pale greenish thallus surrounded by a thin black prothallus. Its ascospores are hyaline, have seven septa, and measure 21–27 by 5–6 μm; they have a 1 μm-thick gelatinous sheath surrounding them. The specific epithet lichexanthonica refers to lichexanthone, a secondary chemical that occurs in the cortex of the lichen. This compound causes the lichen to fluoresce yellow when a UV light is shone upon it. Enterographa lichexanthonica is morphologically similar to E. kalbii, but this latter species has lichexanthone only on the ascomata, not on the thallus.