TYPE. “cort. arb. Nov. Angl. Amer.” [English North America], Swartz s.n. (Acharius 1799) (H H-ACH 1387, holotype).

Description. Lichenized fungus.

Thallus foliose, forming rosettes. Lobes solid, appressed to +/- ascending, 1-2 mm wide, much-branched. Upper surface smooth, greenish gray, dotted with black pycnidia on lobe tips; vegetative diaspores absent. Medulla white; photobiont Trebouxia alga. Lower surface ecorticate hypothallus, black, thick, composed of spongy rhizohyphae. Ascomata lecanorine apothecia, common, cup-like, 1.3-5.0 mm diam.; disk concave, brown. Ascospores hyaline, simple, oblong or club-shaped, often curved, 3-6 x 1.2-2 μm.

Chemistry. Cortex UV-, K+ yellow, KC-/+ yellowish, C-, PD-; medulla UV+ blue-white, K-, KC-, C-, PD-; atronorin, divaricatic acid.

Substrate and Habitat. Corticolous.

Distribution. Eastern North America; in North Carolina throughout.

Literature

Acharius, E. (1799) Lichenographiae Sueciae Prodromus. Lincopiae, D.G. Björn. Pp. 1-264 (original description as Lichen colpodes).

Brodo, I.M., S. D. Sharnoff & S. Sharnoff. (2001) Lichens of North America. Yale University Press, New Haven & London. 795 pp.

Fink, B. (1935) The Lichen Flora of the United States. University of Michigan Press, Ann Arbor (description as Parmelia colpodes).

Lendemer, J.C. & N. Noell, (2018) Delmarva Lichens: An illustrated manual. Memoirs of the Torrey Botanical Society 28: 1-386.