''Dirina angolana'' is a species of corticolous (bark-dwelling),

crustose lichen Crustose lichens are lichens that form a crust which strongly adheres to the Substrate (biology), substrate (soil, rock, tree bark, etc.), making separation from the substrate impossible without destruction. The basic structure of crustose lichen ...

in the family Roccellaceae. Found in

Angola , national_anthem = " Angola Avante"() , image_map = , map_caption = , capital = Luanda , religion = , religion_year = 2020 , religion_ref = , coordina ...

, it was formally described as a new species in 2013 by lichenologists Anders Tehler and Damien Ertz. The

type specimen In biology, a type is a particular wiktionary:en:specimen, 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 a ...

was collected by the first author north of Palmeirinhas ( Luanda Province). It is only known to occur in Angola, where it grows preferentially on

baobab ''Adansonia'' is a genus made up of eight species of medium-to-large deciduous trees known as baobabs ( or ). They are placed in the Malvaceae family, subfamily Bombacoideae. They are native to Madagascar, mainland Africa, and Australia.Tropic ...

tree trunks, usually near the sea. The species epithet refers to the country of its type locality. The lichen has a creamy-white

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 wer ...

with a somewhat roughened surface texture with a thickness of 0.1–0.7 mm. Its apothecia are

sessile Sessility, or sessile, may refer to: * Sessility (motility), organisms which are not able to move about * Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant * Sessility (medicine), tumors and polyps that ...

and have a circular outline, measuring up to 1.5 mm in diameter. The apothecial is , and is surrounded by a .

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 or s ...

s are 23–30 by 4–5

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 ...

. The expected results of chemical spot tests are: thallus surface C+ (red), medulla C–, and apothecial disc C+ (faint red). It contains the lichen products erythrin,

lecanoric acid Lecanoric acid is a chemical produced by several species of lichen.ubChem - Lecanoric acid"> Lecanoric acid is classified as a polyphenol and a didepside and it functions as an antioxidant. The acid is named after the lichen ''Lecanora''. The acid ...

, and some unidentified substances.

References

angolana Lichen species Lichens described in 2013 Lichens of South Tropical Africa {{Arthoniomycetes-stub