''Buellia oidalea'' is a species of crustose lichen found along the

Pacific coast Pacific coast may be used to reference any coastline that borders the Pacific Ocean. Geography Americas Countries on the western side of the Americas have a Pacific coast as their western or southwestern border, except for Panama, where the Pac ...

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

, from

Coos County, Oregon Coos County ( ) is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the population was 64,929. The county seat is Coquille. The county was formed from the western parts of Umpqua and Jackson counties. It is named a ...

Baja California Sur Baja California Sur (; 'South Lower California'), officially the Free and Sovereign State of Baja California Sur ( es, Estado Libre y Soberano de Baja California Sur), is the least populated state and the 31st admitted state of the 32 federal ent ...

Morphology

The thallus of ''B. oidalea'' is crustose, varying from thin and rimose- areolate to thick and rugose- verrucose or even subsquamulose. The prothallus is often present, appearing black. The thallus surface is yellowish white to glaucous gray, smooth, and esorediate. The medulla is white and lacks

calcium oxalate Calcium oxalate (in archaic terminology, oxalate of lime) is a calcium salt of oxalic acid with the chemical formula . It forms hydrates , where ''n'' varies from 1 to 3. Anhydrous and all hydrated forms are colorless or white. The monohydrate ...

.Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2. The apothecia of Buellia oidalea are lecideine and commonly found, ranging from 0.2 to 2 mm in diameter, and are sessile in nature. Initially, the disc is black, devoid of pruina, and flat, but as it matures, it becomes convex. The margin starts as distinct but eventually becomes excluded and black. The proper exciple measures between 35 and 95 μm in thickness, lacking secondary metabolites, and appears uniformly dark brown throughout, with carbonized cells smaller than 6 μm. It is transient and accompanied by a brown hypothecium, which is less than 280

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 ...

thick. The epihymenium shares a continuous brown pigmentation with the outer exciple. The hymenium is hyaline, generously interspersed with oil droplets, and measures 115 to 165 μm in height. The tips of the

paraphyses Paraphyses are erect sterile filament-like support structures occurring among the reproductive apparatuses of fungi, ferns, bryophytes and some thallophytes. The singular form of the word is paraphysis. In certain fungi, they are part of the fe ...

typically measure less than 3 μm in width and are adorned with distinct apical caps. Asci are clavate, of

Bacidia ''Bacidia'' is a genus of lichen-forming fungi in the family Ramalinaceae. The genus was circumscribed by Giuseppe De Notaris in 1846. Species in the genus are crust-like lichens with stemless apothecia; they have green algae (chloroccoid) as p ...

-type, measuring 95 to 112 x 20 to 40 μm, and typically contain 8 spores. The ascospores of Buellia oidalea typically exhibit a

hyaline A hyaline substance is one with a glassy appearance. The word is derived from el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none. Histopathology Hyaline cartilage is ...

to ±olive coloration, eventually transitioning to brown, while often retaining unpigmented apices. They possess a muriform structure, comprising 13–40 cells in optical section, and are ellipsoid to oblong in shape, measuring (29.5-)33.7- 9.645.5(-57) x (12.5-)13.3- 5.517.7(-26.5)

. The

ascospores 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 ...

feature apical, lateral, and septal wall thickenings, with the apical thickenings often being permanent. Their proper wall is approximately 1.2 μm thick, and they lack a perispore, with no discernible ornamentation visible under DIC. Pycnidia are rare, immersed with only the uppermost part protruding, and the wall is mainly pigmented in the upper part. The conidia are bacilliform, 4-6 x 1 μm.

Chemistry

Spot tests show the thallus is K-, C+ orange (best seen under the microscope), P-. The medulla is K-, C-, P-. The lichen exhibits UV+ bright or pale yellow to orange fluorescence, and the medulla is

nonamyloid In mycology a tissue or feature is said to be amyloid if it has a positive amyloid reaction when subjected to a crude chemical test using iodine as an ingredient of either Melzer's reagent or Lugol's solution, producing a blue to blue-black stai ...

in iodine reaction. The secondary chemistry includes diploicin (major), isofulgidin (minor), an unknown (minor) compound, and 2,5-dichloro-3-O- methylnorlichexanthone (trace).

Ecology and distribution

Buellia oidalea thrives on the bark and wood surfaces of trunks, branches, and twigs found on both broad-leaved and coniferous trees and shrubs. Its habitat encompasses various open environments along the Pacific coast, including dune areas,

salt marshes A salt marsh or saltmarsh, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. It is dominated ...

chaparral Chaparral ( ) is a shrubland plant community and geographical feature found primarily in the U.S. state of California, in southern Oregon, and in the northern portion of the Baja California Peninsula in Mexico. It is shaped by a Mediterranean c ...

, and

coastal deserts The desert climate or arid climate (in the Köppen climate classification ''BWh'' and ''BWk''), is a dry climate sub-type in which there is a severe excess of evaporation over precipitation. The typically bald, rocky, or sandy surfaces in desert ...

. This species is predominantly found along the Pacific coast and islands of North America, spanning from Coos County, Oregon to

. Notably, within the Sonoran region, it has been documented in the coastal fog zones of southern California, Baja California, and Baja California Sur.

Distinguishing features

Buellia oidalea is distinguished by its prominent muriform

. While resembling '' Buellia oidaliella'', it sets itself apart with notably larger spores featuring thickened, frequently unpigmented apices, along with a taller

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 some ...

, and the lack of

References

oidalea Fungus species {{Improve categories, date=March 2024