Bryologist 108: 404 (2005).
Protolog: "Thallus ut in Parmelia (Parmotrema) rigida sed sporae 9-15 x 5-9 µm, et conidia 11-20 µm. Atranorinum et acidum alectoronicum vel atranorinum, acidum alectoronicum et acidicum norsticticum continens. U.S.A. Florida. Franklin County: 6 miles E of Apalachicola, on branches of scrub oaks, back from the beach, June 1963, Mason E. Hale, Lichenes Americani Esciccati No. 91 (as Parmelia rigida Lynge), DUKE (holotype), OMA and other herbaria (isotypes)". Chemical strain 1 (K-, lacking norstictic acid)".
Type locality: USA, Florida, Franklin County, 6 miles E of Apalachicola, on branches of scrub oaks, back from the beach, June 1963, M. E. Hale, Hale: Lichenes Americani Esciccati: 91 (as Parmelia rigida Lynge) (DUKE - holotype; OMA and other herbaria - isotypes).
Type locality coordinates: 29°43'31"N, 84°59'33"W; 29.725278°, -84.9925°.
Barcode: Data lacking.
Thallus: foliose, lobes often suberect, broad, with marginal cilia, underside brown to black with a broad white marginal zone. Apothecia perforate. Ascospores 8 per ascus, hyaline, 9-15 / 5-9 µm. Pycnidia common toward the periphery of the thallus lobes, pycnospores 11/20 µm (Egan et al. 2005: 404).
Photobiont: Green alga, probably Trebouxia.
Chemistry:
Ecology: On wood and corticolous on various substrates including pines, junipers, cypress in coastal areas.
Distribution type: In coastal areas from southeastern Texas to Louisiana, Alabama, Mississippi and throughout Florida, northward along the Atlantic coast to Delaware. Bahamas.
Race I: Cortex K+ yellow, medulla K-, UV+, contain atranorin (major), alectoronic acid (major) (Egan et al. 2005: 404).
Race II: Cortex K+ yellow, medulla K+ orange-red, UV+, atranorin (major), alectoronic acid (major), norstictic acid (major) (Egan et al. 2005: 404)