Terrestrial, mostly 20-30 cm tall; rhizome stout, erect; petiole bases closely spaced; rhizome and petioles bearing stiff, dark, threadlike, seemingly jointed scales. Leaves simple, dimorphic; petioles on sterile leaves 3-5 cm long; sterile blades deeply pinnatifid, oblong-lanceolate, tapered to very long filiform apex, 3.5-5 cm broad, glabrous above, with short-jointed filiform. scales on underside of veins (particularly midrib); lobes mostly to 5 mm broad, acute at apex, +/- uncinate-serrate, the veins anastomosing, the lowermost lobes reduced; sporophylls linear, denticulate, ca 15 cm long and 6 mm wide, on a petiole 9-18 cm long. Sori immersed into margin; sporangia sessile on a filiform, exserted receptacle. Croat 10813. Throughout American tropics. In Panama, known from tropical moist forest in the Canal Zone, San Blas, Veraguas, and Darién; known also from premontane wet forest in Colón (Santa Rita Ridge), from tropical wet forest in Colón and San Blas, and from premontane rain forest in Darién (Cerro Pirre).