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Polystichum braunii (Spenner) Fee

Braun's Sword-fern

Dryopteridaceae (Wood fern family)

General Description: Erect plants (20-100 cm tall) with more or less leathery, monomorphic, arching leaves. Petioles are 1/8-1/6 the length of the leaf and densely scaly. Leave blades are broadly lance-shaped, doubly pinnate, and narrowed at the base. Pinnae are oblong-lanceolate or falcate, with an acute apex, and 2-10 cm long. Pinnules are dentate-margined, with slender bristle tips, and a broadly acute apex. The indusia are ciliate.

Field Identification Tips: Look for the arching, more or less leathery, 2-pinnate leaves with dentate pinnae margins to help this species from the many other ferns found in northern Idaho.

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Similar Species: There are several other species of Polystichum in northern Idaho. The undivided pinnae of P. lonchites and P. munitum readily differentiate these two congenerics. Adventitious bulblets on the rachis are the key feature to differentiate P. andersonii, while P. scopulinum is a smaller plant, 10-30 cm tall, generally found in rock crevice or other rocky habitats. The leaf blades of Polystichum spp. are evergreen, usually dark green-colored, leathery to somewhat leathery in texture, and spinulose-toothed. These characters are usually enough to distinguish this genus from other fern groups. The shield-shaped indusium is another good, though less obvious distinguishing character for this genus.

Habitat: Moist places in forest habitats at low elevations. The known northern Idaho populations occur in old-growth western redcedar riparian or alluvial terrace habitats.

Global Distribution: Circumboreal. In North America this species extends south along the coast of Alaska to southern British Columbia, with inland populations in southeastern British Columbia and northernmost Idaho. On the east coast it extends from Newfoundland and Labrador south to New Jersey, then west to southern Quebec and Ontario and the Great Lake states.

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Idaho Distribution: The Upper Priest River area in Boundary and northern Bonner counties.

References:

Coupe, R., C. A. Ray, A. Comeau, M. V. Ketcheson, and R. M. Annas. 1982. A guide to some common plants of the Skeena Area, British Columbia. Land Management Handbook Number 4. Province of British Columbia Ministry of Forests. 215 pp.

Flora North America Editorial Committee. 1993. Flora of North America, Vol. 2. Pteridophytes and Gymnosperms. Oxford University Press, Inc., New York. 475 pp.

Wagner, D. 1979. Systematics of Polystichum in western North America north of Mexico. Pteridologia 1: 1-64.