TYPE. UNITED STATES. “Granitic rocks, common in New England, and in the Blue Ridge of Virginia; and perhaps throughout the Appalachian chain. New Jersey: Mr. C.A. Austin. Mountains of North Carolina: Rev. Dr. Curtis.” (Tuckerman 1866).

Description. Lichenized fungus.

[modified from Nimis 2022] Thallus foliose, homoiomerous (not stratified), subgelatinous when wet, 1-6 cm in diam., adnate, broadly lobed. Lobes 0.5-1.0 cm wide, 50-85 µm thick when wet, rounded and often somewhat ascending at apex, densely pustulate and coarsely ridged, dark olive-green to brown or rarely black, often pale yellowish brown in old parts. Lower surface greenish brown, pitted with a few hapters. Photobiont Nostoc cyanobacteria, in long chains. Upper and lower cortices absent. Ascomata lecanorine apothecia, crowded 0.5-1.5 mm across; disk flat to convex, brownish red to blackish; thalline margin entire, persistent. Proper exciple thin, euthyplectenchymatous; epithecium brownish; hymenium colorless, 85-110 µm high; hypothecium colorless. Asci 8-spored, clavate, the apex thick, with a I+ blue apical dome and a I+ blue annulus projecting downwardly. Ascospores 4-7-septate, hyaline, fusiform, straight or curved, 22-47 x 4-11 µm. Pycnidia immersed or semi-immersed, on both sides of the thallus, pale. Conidia bacilliform or with slightly swollen ends.

Chemistry. Spot tests negative; secondary metabolites not detected.

Substrate and Habitat. Saxicolous on steeply inclined seepage tracks of siliceous rocks at low elevations.

Distribution. Eastern North America, Europe, northwestern Africa; in North Carolina found in the western Piedmont and Blue Ridge ecoregions.

Literature

Nimis P.L. (2022). ITALIC - The Information System on Italian Lichens. Version 7.0. University of Trieste, Dept. of Biology, (https://dryades.units.it/italic), accessed on 2022-11-07.

Tuckerman, E. (1866) Lichens of California, Oregon and the Rocky Mountains, so far as yet known. 35 pp. (original description as Collema nigrescens subsp. ryssoleum).