Lecanora subcarnea
Lecanora subcarnea is a species of crustose lichen in the family Lecanoraceae, first described in 1792 as Lichen subcarneus by Swedish botanist Samuel Liljeblad and later transferred to the genus Lecanora by Erik Acharius in 1810. The lichen forms a continuous white to pale yellowish-grey thallus with small, distinctive pinkish to pale grey-brown apothecia covered in white powdery crystals, and produces chemical compounds including atranorin and protocetraric acid that yield characteristic reactions in spot tests. It grows primarily in sheltered cracks of silica-rich rocks with high base content, occurring locally in parts of the United Kingdom including northern England, Wales, Scotland, and the Channel Islands, though some historical records from southwest England, Pembrokeshire, and Ireland have been determined to be misidentifications.
Taxonomy
The lichen was first scientifically described in 1792 as Lichen subcarneus by the Swedish botanist Samuel Liljeblad. In the original description, Liljeblad characterized it as whitish with unequally sized, nearly meat-coloured nodules. He noted its habitat as being on mountains near Norrköping, Sweden, and described it as having a smooth edge. According to the protologue, the lichen gives a yellowish-brown colour when used for dyeing. It was transferred to Lecanora by Erik Acharius in 1810.Description
Lecanora subcarnea forms a continuous crustose thallus that is finely cracked to form small, often slightly raised with margins. The thallus varies from white or pale grey to pale yellow or yellowish grey, and its surface ranges from coarsely granular to warted. A distinct white, fibrous often borders the thallus.The apothecia are typically clustered and measure 0.4–1 mm in diameter. They begin immersed in the thallus and become or slightly raised, developing a that remains entire and is the same colour as—or gradually paler than—the thallus, though it may become excluded with age. The itself is pinkish to pale grey‑brown, convex to almost spherical, and usually covered by a dense coating of white to bluish crystals. The is brown and, while the hymenium is 35–55 μm tall. Paraphyses are 1.5–2 μm wide, unbranched or sparsely branched near their tips, with apical cells up to 3.5 μm across.
are broadly ellipsoid, typically measuring 10–14 by 6–8 μm. Standard spot tests on the thallus are C–, K+, Pd+. There is no fluorescence under ultraviolet light. These chemical reactions are characteristic of secondary metabolites such as atranorin, chloroatranorin and protocetraric acid.