Polystichum andersonii M. Hopkins

Anderson's sword fern

Etymology After Walter Birney Anderson (c1856-1944), collector and Government Inspector of Indian orchards. Collected August 2, 1912 on Vancouver Island, British Columbia.
Description Rhizome: erect, forms a trunk, trunk clothed in roots.
Frond: 100 cm high by 20 cm wide, evergreen, monomorphic, blade/stipe ratio: 3:1 to 7:1.
Stipe: green, grooved, scales dense, light brown, diminishing in size upwards, vascular bundles: 4 or more, in an arc.
Blade: 1-pinnate-pinnatifid, lanceolate, base narrowed, bulblet near the tip, glossy, hair-like scales, sparse above, dense below, broader scales on rachis and costa.
Pinnae: 18 to 28 pair, first pinnule pair larger, ear-like on lower pinnae, only the upper one larger higher up; pinnules adnate to the costa; margins serrulate-spiny; veins free, forked.
Sori: abortive, indusium: .
Culture Habitat: moist forests. Distribution: Yukon, southeastern Alaska to Oregon, western Montana. Hardy to -25°C, USDA Zone 5, cool climate required.
Distinctive Characteristics buds at the tips of fronds
Polystichum braunii (Spenner) Fée subsp. andersonii (M. Hopkins) Calder & Roy L. Taylor
Polystichum braunii var. andersonii (M. Hopkins) Hultén
Polystichum jenningsi Hopkins
Polystichum andersonii
Polystichum andersonii. Buds may be found on the underside of fertile fronds.  Illustration by Edgar Paulton, from How to Know the Ferns and Fern Allies, John T. Mickel, © 1979 Wm. C. Brown Co.
Parents P. munitum and P. kwakiutlii, the former different in being 1-pinnate, the latter in being fully 2-pinnate and bearing vegetative buds. One is unlikely to confuse P. andersonii with P. kwakiutlii, because it has not been collected since 1940. (from issue 7 of Botanical Electronic News, Adolf Ceska, prop.)
Polystichum andersonii
Polystichum andersonii. a) frond, b) fertile pinna.  Illustration by V. Fulford from Ferns and Fern Allies of Canada, William J. Cody and Donald M. Britton, 1989, © Agriculture Canada, used with permission.
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