Stems short-creeping, 2--5 mm diam. Leaves few, arching to pendent, stiff. Petiole 4--15 cm. Blade dark green, linear-elliptic or linear-oblanceolate, 20--40 × 2.5--6 cm, leathery; base acuminate; margins shallowly sinuate to undulate; apex abruptly caudate-acuminate. Veins obscure, primary veins obscure, slightly to strongly curved, areoles in 4--8 series between costa and margin, with usually 2 free included veinlets per areole. Sori in 1--several rows on each side of costa. 2 n = 74. Epiphytic in swamps, on various rough-barked trees; substrate subacid; 0 m; Fla.; West Indies; Central America; South America in Venezuela, Colombia, Ecuador. In the flora Campyloneurum costatum is currently known only from Collier County, Florida. It had formerly been reported from Dade County, where it now may have been extirpated.