Type. UNITED STATES. FLORIDA, C.F. Austin s.n. (US 00067771, isotype). Description. Lichenized fungus.
Thallus thin, white, continuous; prothallus dark. Ascomata arthonioid apothecia (rounded), numerous, semi-immersed, reddish brown to black, occasionally with some white pruina. Parathecium with a purplish pigment, dissolving in K. Ascospores hyaline to brown, (3–)4–5(–7)-septate, 17.0–23.5 × 6.0–8.0 µm, with an enlarged apical cell (macrocephalic).
Chemistry. Calcium oxalate crystals abundant in the ascomata.
Substrate and habitat. Corticolous in coastal forests.
Distribution. Southeastern coastal North America (USA: Texas to Florida).
References
Fink, B. (1935) The Lichen Flora of the United States. University of Michigan Press, Ann Arbor (as Arthonia tuckermaniana).
Van den Broeck D., A. Frisch, T. Razafindrahaja, B. Van de Vijver & D. Ertz. (2018) Phylogenetic position of Synarthonia (lichenized Ascomycota, Arthoniaceae), with the description of six new species. Plant Ecology and Evolution151(3): 327-351.
Willey, H. (1890) A synopsis of the genus Arthonia. New Bedford. 62 pp (original description as Arthonia tuckermaniana).