''Rhabdodiscus isidiatus'' 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 Glo ...

in the family

Graphidaceae The Graphidaceae are a family of lichen-forming fungi in the order Graphidales. The family contains nearly a hundred genera and more than 2000 species. Although the family has a cosmopolitan distribution, most Graphidaceae species occur in tropic ...

. Found in

Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...

, it was

formally described A species description is a formal scientific description of a newly encountered species, typically articulated through a scientific publication. Its purpose is to provide a clear description of a new species of organism and explain how it differ ...

as a new species in 2014 by lichenologists

Gothamie Weerakoon Gothamie Weerakoon () is a Sri Lankan-based botanist, lichenologist and environmentalist. Early life and education Weerakoon's passion for the environment was initiated during her childhood, which she spent largely outdoors, inspired by her co ...

Robert Lücking Robert Lücking (born 1964) is a German lichenologist, known for his extensive research on foliicolous lichens (lichens that live on leaves) and his significant contributions to the taxonomy, ecology, and biodiversity of fungi and lichens. He e ...

, and

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

. The

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

was collected from the Elkaduwa Plantation in

Matale Matale ( Sinhala: මාතලේ, , , ) is a major city in Central Province, Sri Lanka. It is the administrative capital and largest urbanised city of Matale District. Matale is also the second largest urbanised and populated city in Central P ...

( Central Province) at an altitude of . The lichen is only known to occur at the type locality, which is a patch of mid-elevation, disturbed

montane Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures lapse rate, fall as elevation increases, causing the ecosystem to stratify. This stratification is ...

forest. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''isidiatus'' refers to the presence of

isidia An isidium (plural: isidia) is a tiny, wart- or finger-like outgrowth on the thallus surface of certain lichen species. It is one of two principal types of vegetative reproduction, vegetative reproductive structures in lichens, the other being ...

on the

thallus Thallus (: 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. A thallus usually names the entir ...

. ''Rhabdodiscus isidiatus'' has a cream-colored to white, smooth to uneven thallus up to in diameter. The

ascomata An ascocarp, or ascoma (: ascomata), is the fruiting body (sporocarp (fungi), sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded ascus, asci, each of which typically contains four to ...

are rounded and prominent, measuring 0.7–1.0 mm in diameter with a 0.3–0.5 mm wide pore and a light brown rim. Its

ascospore In fungi, an ascospore is the sexual spore formed inside an ascus—the sac-like cell that defines the division Ascomycota, the largest and most diverse Division (botany), division of fungi. After two parental cell nucleus, nuclei fuse, the ascu ...

s are

hyaline A hyaline substance is one with a glassy appearance. The word is derived from , and . Histopathology Hyaline cartilage is named after its glassy appearance on fresh gross pathology. On light microscopy of H&E stained slides, the extracellula ...

ellipsoid An ellipsoid is a surface that can be obtained from a sphere by deforming it by means of directional Scaling (geometry), scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a Surface (mathemat ...

in shape, contain three thick

septa SEPTA, the Southeastern Pennsylvania Transportation Authority, is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly four million people througho ...

, and measure 12–15 by 5–6

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

. Secondary chemicals present in the lichen include

psoromic acid Psoromic acid is a β-orcinol depsidone with the molecular formula C18H14O8. Psoromic acid inhibits herpes simplex viruses type 1 and type 2. Furthermore, it inhibits the RabGGTase. Psoromic acid occurs in antarctic lichens A lichen ( , ) ...

, subpsoromic acid, and 2'-''O''-demethylpsoromic acid.

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