''Megalospora occidentalis'' 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

Megalosporaceae The Megalosporaceae are a family of mostly lichen-forming fungi belonging to the class Lecanoromycetes in the division Division or divider may refer to: Mathematics *Division (mathematics), the inverse of multiplication *Division algorithm, a ...

. Found in Australia, it was formally described as a new species in 1994 by lichenologist

Gintaras Kantvilas Gintaras Kantvilas (born 1956) is an Australian lichenologist, who earned his Ph.D in 1985 from the University of Tasmania with a thesis entitled ''Studies on Tasmanian rainforest lichens''. He has authored over 432 species names, and 167 gener ...

. 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 along the

Vasse Highway Vasse Highway is a Western Australian highway connecting Busselton and the South Western Highway south of Manjimup. It is long and travels through jarrah and karri hardwood forests for most of its length, with some small agricultural areas a ...

Beedelup National Park Greater Beedelup National Park is a national park in Western Australia, 277 km south of Perth. It is situated on the Vasse Highway some 10 km west of Pemberton. The park is especially lush and damp due to an abundance of water. Gazet ...

(

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

) at an altitude of ; here, in a

karri ''Eucalyptus diversicolor'', commonly known as karri, is a species of flowering plant in the family Myrtaceae and is Endemism, endemic to the Southwest Australia, south-west of Western Australia. It is a tall tree with smooth light grey to cre ...

-dominated wet

sclerophyll forest Sclerophyll is a type of vegetation that is adapted to long periods of dryness and heat. The plants feature hard leaves, short internodes (the distance between leaves along the stem) and leaf orientation which is parallel or oblique to direct ...

, it was found growing on '' Trymalium floribundum''. The lichen has a thin, pale grey to

glaucous ''Glaucous'' (, ) is used to describe the pale grey or bluish-green appearance of the surfaces of some plants, as well as in the names of birds, such as the glaucous gull (''Larus hyperboreus''), glaucous-winged gull (''Larus glaucescens''), g ...

-grey

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 ...

that usually has scattered soredia. Its

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 oblong to

ellipsoid An ellipsoid is a surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a surface that may be defined as the ...

in shape, measuring 50–90 by 20–30

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 ...

. They are muriform, meaning they are divided into many internal cells, up to about 22 by 10. The species contains the lichen products pannarin and

zeorin Zeorin is a triterpene with the molecular formula C30H52O2 which occurs in many lichens A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among hypha, filaments of multiple fungus, fungi species in a mutu ...

. The author named it ''occidentalis'' because, at the time of writing, it was the only Western Australian species known in genus ''

Megalospora ''Megalospora'' is a genus of lichen-forming fungi in the family Megalosporaceae. Taxonomy The genus was circumscribed in 1843 by Prussian botanist Franz Meyen, with '' Megalospora sulphurata'' assigned as the type, and at that time, only spec ...

''.

References

Teloschistales Lichen species Lichens described in 1994 Lichens of Australia Taxa named by Gintaras Kantvilas {{Teloschistales-stub