''Graphis crebra'' is a species of

corticolous lichen A corticolous lichen is a lichen that grows on bark.Alan Silverside's Lichen Glossary (a-f), Alan Silverside/ref> This is contrasted with lignicolous lichen, which grows on wood that has had the bark stripped from it,Alan Silverside's Lichen Glossa ...

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 ...

. It has a

pantropical A pantropical ("all tropics") distribution is one which covers tropical regions of both hemispheres. Examples of species include caecilians, modern sirenians and the plant genera ''Acacia'' and '' Bacopa''. '' Neotropical'' is a zoogeographic t ...

distribution. Like other '' script lichens'', it grows on

bark Bark may refer to: * Bark (botany), an outer layer of a woody plant such as a tree or stick * Bark (sound), a vocalization of some animals (which is commonly the dog) Places * Bark, Germany * Bark, Warmian-Masurian Voivodeship, Poland Arts, en ...

and resembles calligraphy. It can be distinguished from several other similar species by the white

pruina Pruinescence , or pruinosity, is a "frosted" or dusty-looking coating on top of a surface. It may also be called a pruina (plural: ''pruinae''), from the Latin word for hoarfrost. The adjectival form is pruinose . Entomology In insects, a "blo ...

(powder) on its

apothecia An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are mo ...

l discs.

Taxonomy

The lichen was described as new to science in 1899 by Finnish lichenologist

Edvard Vainio Edvard August Vainio (born Edvard Lang; 5 August 185314 May 1929) was a Finnish lichenologist. His early works on the lichens of Lapland, his three-volume monograph on the lichen genus ''Cladonia'', and, in particular, his study of the clas ...

from a collection made in

Gourbeyre Gourbeyre is a commune in the French overseas region and department of Guadeloupe, in the Lesser Antilles. It is a suburb of the city of Basse-Terre. The commune of Gourbeyre was in the past a pivotal point in the defense of Guadeloupe's Bas ...

Guadeloupe Guadeloupe (; ; gcf, label=Antillean Creole, Gwadloup, ) is an archipelago and overseas department and region of France in the Caribbean. It consists of six inhabited islands— Basse-Terre, Grande-Terre, Marie-Galante, La Désirade, and the ...

Description

''Graphis crebra'' has a corticate

thallus Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or " twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms ...

that is dull to somewhat shiny, and pale grey. The lirellae (an

ascoma An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are mo ...

with a long, narrow disc resembling dark squiggly lines) are (bursting through the surface) with a lateral , short, unbranched to rarely one-branched, straight to slightly curved. The apothecial becomes exposed very early, with a distinct white (a crystalline or powdery surface covering). The (a layer of sterile tissue that contains the

hymenium The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others som ...

) is black. ''Graphis crebra'' produces

ascospore An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera o ...

s that are 5–9-

septate 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 * Interatr ...

, and measure 20–30 by 5–8

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 Uni ...

. The main

secondary compound Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the nor ...

in ''Graphis crebra'' is

norstictic acid Norstictic acid is a depsidone produced as a secondary metabolite Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fu ...

Similar species

Similar species include ''

Graphis cincta Graphis may refer to: * ''Graphis'' (lichen), a genus in the family Graphidaceae * ''Graphis'' (gastropod), a genus of sea snails in the family Cimidae *Graphis Inc. ''Graphis, Inc.'' is an international publisher of books and awards for the ...

'', which lacks open pruinose discs, and '' G. handelii'', which does have open discs but is not pruinose. Another lookalike species is the Australian '' G. streimanii'', which has larger spores and lirellae that are longer and more branched. The species '' G. manipurensis'' and '' G.sirohiensis'', both known only from

Manipur Manipur () ( mni, Kangleipak) is a States and territories of India, state in Northeast India, with the city of Imphal as its capital. It is bounded by the Indian states of Nagaland to the north, Mizoram to the south and Assam to the west. It ...

, India, are also similar in appearance to ''Graphis crebra''. The Indian species, however, do not have the white pruinose disc characteristic of ''G. crebra''. Another pantropical, norstictic acid-containing species, '' Graphis handelii'', can be distinguished from ''G. crebra'' by its epruinose apothecial discs.

Habitat and distribution

In addition to the

type locality Type locality may refer to: * Type locality (biology) * Type locality (geology) See also * Local (disambiguation) * Locality (disambiguation) {{disambiguation ...

in Guadeloupe, ''Graphis crebra'' is also known from

St. Helena Saint Helena () is a British overseas territory located in the South Atlantic Ocean. It is a remote volcanic tropical island west of the coast of south-western Africa, and east of Rio de Janeiro in South America. It is one of three constit ...

and the Galapagos. In 2011, it was reported from

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, a ...

in North America. In 2016, ''G. crebra'' was reported from Portugal, which was also a new occurrence for Europe, and in 2017 from

the Seychelles Seychelles (, ; ), officially the Republic of Seychelles (french: link=no, République des Seychelles; Creole: ''La Repiblik Sesel''), is an archipelagic state consisting of 115 islands in the Indian Ocean. Its capital and largest city, ...

References

{{Taxonbar, from=Q21269329 crebra Lichen species Taxa named by Edvard August Vainio Lichens described in 1899 Lichens of the Caribbean Lichens of Southwestern Europe Fungi of Florida Lichens of Seychelles Fungi without expected TNC conservation status