opegrapha

plural opegraphas

1. Any lichen species of the genus Opegrapha.

   [...] and finally a fourth description of Lichens (Opegraphas) establish themselves upon the bark of living trees, occasionally burying themselves beneath the skin, through which their shields alone peep forth in the strange form of the letters of some eastern tongue.

   1848, John Lindley, “The Lichen Tribe.”, in Ladies' Botany, fifth edition, volume 1, page 283

   1 more example

   But every part is usually covered with thin, membranaceous lichens, (Lecanoras, Lecideas, letter-like Opegraphas) in clouds of every shade of white, gray, and brown, outside, which are often large patches of gray, yellow, and sulphur-colored foliaceous lichens, (Parmelias).

   1846, A report on the trees and shrubs growing naturally in the forests of Massachusetts, page 159