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Buellia stellulata

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Buellia stellulata
Scientific classification Edit this 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

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Thallus

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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

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The medulla is white and lacks calcium oxalate.[3]

Apothecia

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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

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The epihymenium is brown, with pigmentation continuous with the outer exciple.[3]

Hymenium

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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

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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

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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

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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

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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

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Notes and references

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Note

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  1. ^ 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

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  1. ^ disc lichen - Encyclopedia of Life (eol.org)
  2. ^ a b Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
  3. ^ a b c d e f g h i j "Consortium of Lichen Herbaria - Buellia stellulata". lichenportal.org. Retrieved 2024-03-14.
  4. ^ 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)