''Lecidea tessellata'' is a species of saxicolous (rock-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

Lecideaceae The Lecideaceae are a family of lichens in the order Lecideales (Ascomycota, class Lecanoromycetes). Genera According to a recent (2022) estimate, the Lecideaceae comprise 29 genera and about 260 species. The following list indicates the genus n ...

. It was formally described as a species in 1819 by German botanist Heinrich Flörke. In northern North America, it is common and widely distributed, growing on non-calcareous rocks. It also occurs in Afghanistan, China, Nepal, Europe, and Russian Asia. In India, it has been recorded only from the alpine Western Himalayas at an altitude of . Its southern distribution extends to James Ross Island, where it is locally common.

Description

''Lecidea tessellata'' has a chalky white to grey, cracked and areolate

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 ...

. Its apothecia are black, subimmersed, appressed to adnate and range from 0.5 to 1.8 (–2.0) mm in diameter. The apothecial is smooth, initially rounded in young apothecia, but becomes convex and irregular in mature ones, sometimes with a thin white pruinose layer. The is brownish-green to blackish-green and the is colorless, measuring 40–60

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 ...

in height. The is pale brown and measures 30–40 μm in height, while the is blackish-green externally and colorless internally. The are clavate and measure 30–50 by 8–14 μm, and the ascospores are

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 ...

and measure 7–9 by 5–6 μm. ''Lecidea tessellata'' contains confluentic acid, a lichen product that can be detected using thin-layer chromatography. Both the thallus and medulla of the lichen have negative reactions with standard chemical spot tests (K−, C−, PD−). '' Lecidea oreophila'', found in the mountains of California's

Sierra Nevada The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primarily ...

, is similar in appearance to ''L. tessellata'', but it has a dark hypothecium and produces 2′-''O''-methylmicrophyllinic acid as the primary lichen product, with or without accessory confluentic acid.

References

{{Taxonbar, from=Q10556093 tessellata Lichen species Lichens described in 1819 Taxa named by Heinrich Gustav Flörke Lichens of China Lichens of Europe Lichens of India Lichens of Western Asia Lichens of North America

Description

See also

References