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|Western sword fern growing in the Columbia River Gorge|
Polystichum munitum, the western swordfern, is an evergreen fern native to western North America, where it is one of the most abundant ferns. It occurs along the Pacific coast from southeastern Alaska to southern California, and also inland east to southeastern British Columbia, northern Idaho and western Montana, with disjunctive populations in northern British Columbia, Canada; the Black Hills in South Dakota, United States; and Guadalupe Island off of Baja California, Mexico.
The dark green fronds of this fern grow 50 to 180 centimetres (1.6 to 5.9 ft) tall, in a tight clump spreading out radially from a round base. They are single-pinnate, with the pinnae alternating on the stalk. Each pinna is 1 to 15 centimetres (0.39 to 5.91 in) long, with a small upward-pointing lobe (a sword hilt, hence the name) at the base, and the edges are serrated with bristly tips. Individual fronds live for 1.5 to 2.5 years and remain attached to the rhizome after withering. The round sori occupy two rows on either side of the midrib of each pinna and are covered by a centrally-attached, umbrella-like indusium with fringed edges. They produce light yellow spores.
Habitat and cultivation
The preferred habitat of this fern is the understory of moist coniferous woodlands at low elevations. It grows best in well-drained acidic soil of rich humus and small stones. It is very resilient and survives occasional droughts, but flourishes only with consistent moisture and light sunlight, and it prefers cool weather.
In cultivation, it also responds well to regular, light fertilizations. While this fern is a favored horticultural subject in western North America, it has proved difficult or impossible to cultivate satisfactorily in the eastern part of the continent.
In spring, when other food is unavailable, Quileute, Makah, Klallam, Squamish, Sechelt, Haida, and other Native American/First Nations peoples roasted, peeled, and ate the rhizomes. The plant is also cultivated for its ornamental foliage, which florists include in vases.
- "Polystichum munitum". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 12 October 2015.
- "RHS Plantfinder - Polystichum munitum". Retrieved 11 May 2018.
- "AGM Plants - Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 81. Retrieved 11 May 2018.
- Paul Alaback, Joe Antos, Trevor Goward, Ken Lertzman, Andy MacKinnon, Jim Pojar, Rosamund Pojar, Andrew Reed, Nancy Turner, Dale Vitt (2004). Jim Pojar and Andy MacKinnon, ed. Plants of the Pacific Northwest Coast (Revised ed.). Vancouver, British Columbia: Lone Pine Publishing. p. 53. ISBN 978-1-55105-530-5.
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