Polystichum setigerum (C. Presl) C. Presl

Alaska sword fern

Etymology From saeta, a bristle or stiff hair, + gero, to wear or carry.
Description Rhizome: erect.
Frond: 100 cm high by 15 cm wide, evergreen, monomorphic, blade/stipe ratio: 5:1.
Stipe: grooved, scales dense, light brown, gradually diminishing in size upwards, vascular bundles: 4 or more, in an arc.
Blade: 2-pinnate only about the middle, lanceolate, base narrowed, lower pinnae bending downward, glossy, microscales thread-like, sparse below, confined to costa above.
Pinnae: 25 to 30 pair, alternate, lanceolate, 4--8 cm; pinnules basal ones enlarged, all eared ; margins serrulate-spiny; veins free, forked.
Sori: round, between midrib and margin, indusium: peltate, central, sporangia: brown.
Dimensionality: lowest pinna often turned downwards.
Culture Habitat: forest floor in lowland coastal forests . Distribution: southeastern Alaska, British Columbia, disjunct on Attu Island, Aleutians (or this is P. microchlamys). Hardy to -20°C, USDA Zone 6, cool climate required.
Nephrodium setigerum C. Presl
Polystichum braunii (Spenner) Fée subsp. alaskense (Maxon) Calder & R. L. Taylor
Polystichum braunii var. alaskense (Maxon) Hultén
Polystichum alaskense (Maxon) Calder & Taylor
Polystichum setigerum
Polystichum setigerum. a) frond 100+ cm; b) portion of fertile pinna, both surfaces scaly.  Illustration by V. Fulford from Ferns and Fern Allies of Canada, William J. Cody and Donald M. Britton, 1989, © Agriculture Canada, used with permission.
Parents P. munitum and P. braunii. The former is 1-pinnate, the latter 2-pinnate throughout.
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