''Leucodecton canescens'' is a species of 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

Sri Lanka Sri Lanka (, ; si, ශ්‍රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...

, it was formally described as a new species in 2014 by lichenologists Gothamie Weerakoon,

Robert Lücking Robert Lücking (born 1964) is a German lichenologist. He is a leading expert on foliicolous lichens–lichens that live on leaves. Life and career Born in Ulm in 1964, Lücking earned both his master's (1990) and PhD degree (1994) at the Univer ...

and

Helge Thorsten Lumbsch Helge Thorsten Lumbsch (born 1964) is a German-born lichenologist living in the United States. His research interests include the phylogeny, taxonomy, and phylogeography of lichen-forming fungi; lichen diversity; lichen chemistry and chemota ...

. The

type specimen In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...

was collected from the Maussakanda Tea Estate (

Matale Matale ( Sinhala: මාතලේ, ta, மாத்தளை, translit=Māttaḷai) is the administrative capital city of the Matale District. It is the most urbanised and populated centre in the district. Matale is also the second largest mun ...

, Central Province) at an altitude of . The lichen, which has been recorded from several locations in the Central Province, grows in semi-exposed, disturbed areas at high elevations. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''canescens'' refers to the grey-coloured cover of the

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 ...

. ''Leucodecton canescens'' has a smooth, grey thallus that is 70–100

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 ...

thick with a thin (5–10 μm)

cortex Cortex or cortical may refer to: Biology * Cortex (anatomy), the outermost layer of an organ ** Cerebral cortex, the outer layer of the vertebrate cerebrum, part of which is the ''forebrain'' *** Motor cortex, the regions of the cerebral cortex i ...

. The

ascomata 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 ...

are rounded, immersed in the substrate, and measure 0.2–0.3 mm in diameter. The

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 are muriform, with dimensions of 25–30 by 10–12 μm. Secondary chemicals present in the lichen include

stictic acid Stictic acid is an aromatic organic compound, a product of secondary metabolism in some species of lichens. Stictic acid is the subject of preliminary biomedical research. Stictic acid has cytotoxic and apoptotic effects ''in vitro''. Computation ...

constictic acid Constictic acid is a chemical compound of the depsidone class. It was first isolated in 1968 from lichen of the genus ''Usnea''. It has since been found in many other lichen genera including ''Menegazzia'', '' Crespoa'', and ''Xanthoparmelia ...

, acetylconstictic acid, and hypostictic acid. '' Leucodecton fissurinum'' is somewhat similar in

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

, but it has a yellowish thallus and narrower ascomata pores that conceal the disc.

References

Graphidaceae Lichen species Lichens of Sri Lanka Lichens described in 2014 Taxa named by Helge Thorsten Lumbsch Taxa named by Robert Lücking Taxa named by Gothamie Weerakoon {{Ostropales-stub