Linnaea 18: 526. 1844.
Stems ca. 2 mm diam. Leaves partially dimorphic (sporangia limited to proximal pair of pinnae), (15–)22–45 × 8–16 cm. Petiole straw-colored, 1/2–2/3 length of leaf, ca. 1 mm wide, glabrate. Blade deltate-lanceolate, 1-pinnate, somewhat leathery. Pinnae 4–7 pairs, mostly alternate, lanceolate, base truncate, margins minutely serrulate, proximal margins often slightly excavate, apex acuminate, hirsute with minute white hairs to glabrous on abaxial surface, glabrous adaxially. Fertile pinnae usually taller than sterile blades. Spores with ridges parallel and closely placed. 2n = 76.
Habitat: Lightly shaded limestone outcrops of the Edwards Plateau
Elevation: 400–500 m
Tex., n Mexico.