After John Gill Lemmon, 1832-1908, a collector in the American west.
Frond: 35 cm high by 6 cm wide, evergreen, monomorphic , blade/stipe ratio: 3:1 to 4:1.
Stipe: grooved, sparsely scaly, reddish brown, abruptly diminishing in size distally, vascular bundles: 4 or more, in an arc.
Blade: 2-pinnate, scarcely narrowed at base, linear to lanceolate, very erect, glossy, stipe scales pale tan, microscales narrowly lanceolate, ± confined to costa of both surfaces.
Pinnae: ovate, folded inward and twisted horizontally, 0.5--2 cm; base truncate to oblique; margins entire to weakly dentate; veins free, forked.
Sori: round, seemingly scattered at random on fertile pinnae, indusium: peltate, central, sporangia: dark brown to blackish.
Dimensionality: pinnae twisted horizontally.
Habitat: rocky serpentine slopes, uncommon.
Distribution: British Columbia to central California.
Hardy to -20°C, USDA Zone 6. Unlikely to be in cultivation..
Non-spiny, the only such Polystichum here.
Polystichum mohrioides (Bory) C. Presl var. lemmonii (L. Underwood) Fernald
Aetopteron lemmoni House