''Phaeographis xanthonica'' is a species of corticolous (bark-dwelling), crustose lichen in the family

Graphidaceae The Graphidaceae are a family of lichens in the order Ostropales. Distribution and ecology The vast majority of Graphidaceae species are restricted to the tropics. Most Graphidaceae species are epiphytic (i.e. they grow only on plants). Gene ...

. Found in Brazil, it was formally described as a new species in 2009 by

Klaus Kalb Klaus Kalb (born 1942) is a German lichenologist and an authority on tropical lichens. Biography Klaus Kalb was born in Nuremberg in 1942 and grew up in southern Bavaria. From 1960 to 1965 he studied biology, chemistry, and geography at ...

and M. Matthes-Leicht. The

species epithet Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany) A botanical name ...

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 . It has also been recorded from

Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...

. 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 In biology, a septum (Latin for ''something that encloses''; plural septa) is a wall, dividing a cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Human anatomy * Interatri ...

that divides it into four cells; their dimensions fall into the range 11–21 by 5–7

μm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...

References

{{Taxonbar, from=Q108172096 Graphidaceae Lichen species Lichens described in 2009 Lichens of Brazil Lichens of Central America Taxa named by Klaus Kalb