TYPE. UNITED STATES. FLORIDA, 1878, C.F. Austin, s.n. (US 02482561, holotype).
Description. Lichenized fungus.
Thallus crustose, thin, whitish, smooth, becoming obscurely powdery. Ascomata arthonioid apothecia, minute, 0.07-0.15 mm diam., adnate, round to slightly irregular or oblong; disk flat to convex, black; hyaline within. Asci pyriform, 8-spored; ascospores hyaline, ovoid-ellipsoid, 3-septate, 13-17 x 4-5 μm.
Chemistry. Not reported.
Substrate and Habitat. Corticolous on trees; may be a cabbage palm (Sabal palmetto) specialist (Kiviat et al. 2021).
Distribution. Southeastern (coastal areas from Texas to North Carolina) and southwestern (southern California) North America; in North Carolina in the Coastal Plain.
Fink, B. (1935) The Lichen Flora of the United States. University of Michigan Press, Ann Arbor. 426 pp.
Kiviat, E., P.G. Davison, R.C. Harris, R.C. & S. Dickman. (2021) Novel hepatic and lichen assemblage on Phragmites stubble in a Florida freshwater swamp. Evansia 38(1): 9-14.
Willey, H. (1890) A synopsis of the genus Arthonia. New Bedford. 62 pp (original description).