Climbing vine fern

Polypodium heterophyllum Linnaeus, Sp. Pl. 2: 1083. 1753

Stems appressed to substrate, 0.5--1.2 mm diam.; scales reddish to dark brown, linear-triangular. Leaves irregularly spaced. Petiole to ca. 2 cm. Blade 4--15 × ca. 1 cm, margins entire to undulate and ± shallowly crenulate, glabrous. Veins forming 1 series of linear polygonal costal areoles without free included veinlets, medial row of larger rectangular to polygonal areoles (usually with 1--2, simple or forked, free included veinlets), and a series of short, casually anastomosing marginal veinlets. Sori terminal on included veinlets; indument of few paraphyses longer than sporangia.

Epiphytic on relatively smooth-barked trees, or growing on logs and rock, in tropical hammocks; substrate circumneutral to acidic; 0 m; Fla.; West Indies.