Buellia stellulata
| Buellia stellulata | |
|---|---|
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Caliciales |
| Family: | Caliciaceae |
| Genus: | Buellia |
| Species: | B. stellulata
|
| Binomial name | |
| Buellia stellulata (Taylor) Mudd
| |
Buellia stellulata, commonly known as the disc lichen[1]) is a species of crustose lichen that is widely distributed throughout the Northern Hemisphere.[2]
Morphology[edit]
Thallus[edit]
The thallus is crustose, areolate, and thin to moderately thickened, often forming a continuous layer. The prothallus is conspicuous and black, strongly developed in most specimens, growing between the areoles to form a hypothallus. The thallus surface is usually white to whitish gray, rarely dark gray, and can be dull or slightly shiny. The thallus is epruinose and phenocorticate, and lacks soredia.[3][4]
Medulla[edit]
The medulla is white and lacks calcium oxalate.[3]
Apothecia[edit]
The apothecia exhibit a lecideine structure, with a diameter ranging from (0.2-)0.3-0.4(-0.5) mm. They are typically immersed to adnate, occasionally found in a sessile form. The margin may appear black or masked by grayish remnants of necrotic thalline material, forming a thin and usually persistent boundary, occasionally excluded as they mature. The disc is characterized by a black, epruinose surface, typically flat but occasionally developing a slight convexity over time. Within the apothecia, the proper exciple appears narrow and lacks differentiation, resembling the aethalea-type. The inner excipular hyphae are narrow, hyaline, and often prosoplectenchymatous, exhibiting structural and orientational similarities to the paraphyses. The hypothecium is characterized by a deep reddish-brown color, described as leptoclinos-brown with a textura intricata. Outer excipular hyphae are arranged parallelly, moderately swollen (textura oblita), and heavily carbonized, displaying a range of brown shades and aeruginose pigments.[4][3]
Epihymenium[edit]
The epihymenium is brown, with pigmentation continuous with the outer exciple.[3]
Hymenium[edit]
The hymenium is hyaline and not inspersed with oil droplets. The paraphyses are simple to moderately branched, with apically swollen tips containing a brown pigment cap.[3]
Asci and ascospores[edit]
The asci are clavate, Bacidia-type, and 8-spored. The ascospores soon become brown, 1-septate, oblong to ellipsoid, usually not constricted, with obtuse ends, and not curved, measuring (8-)8.7-[9.9]-11.1(-13) x (4.5-)4.8-[5.5]-6.1(-7) μm. The proper septum is narrow and does not thicken during spore ontogeny (Buellia-type). The spore ornamentation is microrugulate.[3]
Chemistry[edit]
The lichen contains the secondary metabolites atranorin, 2'-O-methylperlatolic acid,[a] and confluentic acid. Spot tests are K+ yellow (sometimes weak), P- or + faintly yellow, C-, KC-, and CK-. UV fluorescence is -(dark).[3]
Substrate and ecology[edit]
Buellia stellulata, an epilithic lichen, thrives on siliceous rock surfaces (typically HCl-) and is commonly found in coastal regions. However, its habitat is not restricted solely to seashore environments.[3]
Distribution[edit]
Buellia stellulata exhibits a broad distribution across the Northern Hemisphere. Within the Sonoran region, this species is notably present in coastal areas spanning from southern California to Baja California and Baja California Sur.[3][2]
See also[edit]
Notes and references[edit]
Note[edit]
- ^ Buellia stellulata is very similar to Buellia spuria, but differs in containing 2'-O-methylperlatolic acid rather than stictic or norstictic acid, and having a I- medulla. Specimens reported from inland localities as B. stellulata actually belong to B. spuria.[3]
References[edit]
- ^ disc lichen - Encyclopedia of Life (eol.org)
- ^ a b Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
- ^ a b c d e f g h i j "Consortium of Lichen Herbaria - Buellia stellulata". lichenportal.org. Retrieved 2024-03-14.
- ^ a b Mudd, W. 1861: A manual of British lichens, description of all the species and varieties, five plates, with figures of the spores of one hundred and thirty species, illustrative of the genera. - Darlington. 1-309 pp. [Mattick Rec. # 33113] - (Recent Literature on Lichens - Mattick No.) (PDF file)