Platyloma brachyptera T. Moore, Gard. Chron., 141. 1873

Stems compact, ascending, stout, 5--10 mm diam.; scales bicolored, linear-subulate, 0.1--0.3 mm wide, centers dark brown to black, thick, margins brown, thin, dentate. Leaves monomorphic, clustered on stem, 8--40 cm; croziers sparsely villous. Petiole dark brown, lustrous, flattened or slightly grooved adaxially, without prominent articulation lines. Blade linear-oblong, 2-pinnate proximally, 1--4 cm wide; rachis brown throughout, straight, shallowly grooved adaxially, usually glabrous. Pinnae strongly ascending, not decurrent on rachis, usually with 5--11 ultimate segments; costae straight, 5--20 mm, usually shorter than ultimate segments. Ultimate segments linear, 5--20 mm, leathery, glabrous; margins on fertile segments strongly revolute, covering more than 1/2 abaxial surface, borders greenish, crenate; apex mucronate. Veins of ultimate segments obscure. Sporangia short-stalked, containing 64 spores, intermixed with abundant farina-producing glands.

Sporulating summer--fall. Cliffs and rocky slopes, usually on igneous substrates, occasionally on serpentine; 900--2700 m; Calif., Oreg., Wash.

The distinctive Pellaea brachyptera reportedly hybridizes with P . mucronata (A. F. Tryon 1957; D. B. Lellinger 1985); the hybrids are morphologically intermediate plants with malformed spores.