Thallus: relatively thin, rimose, areolate; prothallus: pinkish gray around thallus margin or lacking areoles: flat, irregular in outline, 0.35-1.1 mm in diam. surface: grayish or yellowish white, dull, esorediate Apothecia: rounded to somewhat deformed or flexuose, single or in small groups, sessile with a constricted base, 0.75-1.45 mm wide disc: reddish or grayish brown, plane or weakly convex margin: prominent, persistent, brown-black within, lighter at the outside exciple: hyaline at the outer edge, brown-black within, laterally 75-105 µm wide, basally 125-185 µm wide, composed of radiating hyphae with 1-4 µm wide, apically unthickened lumina epihymenium: lacking hymenium: hyaline, 70-90 µm tall; paraphyses: hyaline, with lumina 0.7-1 µm below and apically 1-1.5 µm in diam., moderately branched and anastomosing subhymenium: dark brown, c. 60 µm thick hypothecium: dark brown above, pale below, c. 250 µm thick asci: clavate, with a thick ILugol+ pale blue inner wall and tholus and a darker blue outer wall, 8-spored ascospores: hyaline, simple, broadly ellipsoid to fusiform, (8-)11.5-12.6(-14) x (5.5 )6.1-6.6(-8) µm Pycnidia: not seen Spot tests: thallus K, C+ orange, KC+ orange, P-, UV+ bright yellow-orange Secondary metabolites: two unidentified xanthones. Substrate and ecology: on bark of Ipomoea at 300 m World distribution: southern North America Sonoran distribution: a single collection from Sinaloa. Notes: Lecidea floridensis belongs to a poorly known group of tropical lichens. Because of the sparse material, the identity of the single Sonoran collection is still somewhat uncertain. Within the area the species cannot be confused with any other Lecidea s. lat.