Fibrillithecis sprucei

About

Fibrillithecis sprucei is a rare species of lichen in the family Graphidaceae, known only from a single historic collection. It was discovered by re-examining a 19th-century plant collection made by the British botanist Richard Spruce along Brazil's Rio Negro river. The species is distinguished by its unusually large ascospores and contains psoromic acid, which produces a distinctive yellow reaction in chemical spot tests.

Summary from Wikipedia