TYPE. UNITED KINGDOM. Great Britain, on branches, 1784, Dickson s.n. (LINN-SM, lectotype designated by Jørgensen & James 1983).
Description. Lichenized fungus.
Thallus foliose, forming extensive patches, to 10 cm diam. Lobes up to 1 cm wide, 100-150 µm thick, numerous, wavy, overlapping; margins ± ascending, rounded, entire, intricately folded, particularly towards center. Upper surface dark gray, matt, ± distinctly finely striate, not wrinkled. Vegetative diaspores absent. Photobiont Nostoc cyanobacteria; cells in chains. Ascomata lecanorine apothecia, frequent, sessile, up to 3 mm diam.; disk concave to flat, red-brown; margin thin, pale, ± wrinkled; exciple parenchymatous. Ascospores hyaline, muriform, fusiform-acicular, 20-35 x 12-17 μm.
Substrate and Habitat. On sheltered trunks of deciduous trees and mossy rocks, especially near streams.
Distribution. Cosmopolitan; in North Carolina found in the Coastal Plain ecoregion.
Dickson, J. (1785) Fasciculus plantarum cryptogamicarum Britanniae. 1: 1-26 (original description as Lichen cochleatus).
Giavarini, V.J. (2016). Leptogium cochleatum (Dicks.) P.M. Jørg. & P. James. In LichenIreland. http://www.habitas.org.uk/lichenireland/species.asp?item=18773 Accessed on 2022-11-28.
Gilbert, O.L. & P.M. Jørgensen. (2009) Leptogium (Ach.) Gray (1821). Pp. 541-551 in Smith, C.W., A. Aptroot, B.J. Coppins, A. Fletcher, O.L. Gilbert, P.W. James & P.A. Wolseley (eds.). The Lichens of Great Britain and Ireland. The British Lichen Society, London.
Jørgensen, P.M. & P.W. James. (1983) Studies on some Leptogium species of Western Europe. The Lichenologist15(2): 109-125.