Etymology Munitum means fortified or protected.

Description Rhizome: erect.
Frond: 150 cm high by 25 cm wide, evergreen, monomorphic, blade/stipe ratio: 5:1.
Stipe: grooved, green, scales dense, red-brown to dark brown or nearly black, gradually diminishing in size above, vascular bundles: 4 or more, in an arc.
Blade: 1-pinnate, linear-lanceolate, base slightly narrowed, glossy, microscales ovate-lanceolate to linear-lanceolate, with contorted projections, dense, below only.
Pinnae: 35 to 50 pair, narrowly lanceolate, straight to falcate, 1--15 cm; base ± cuneate, well developed ears; margins serrulate-spiny; veins free, forked.
Sori: round, in 1 row between midrib and margin, indusium: peltate, central, sporangia: yellowish, becoming brown.

Culture Habitat: forest floor, only occasionally on rock, in mesic coniferous to moist, mixed evergreen forests. Distribution: Alaska, British Columbia and Montana to California, disjunct in South Dakota, Guadalupe Island, Mexico. Hardy to -20°C, USDA Zone 6.

Synonyms
Aspidium munitum Kaulfuss
Dryopteris munita O. Ktze.
Polystichum plumula Presl
Aetopteron munitum House
Nephrodium plumula Presl