Polystichum munitum is one of 40 species of ferns found in the northern Pacific coast (Pojar & MacKinnon 1994). Ferns are distinct from flowering plants that produce seeds, instead producing and dispersing primarily through spores.
Description:
P. munitum has dark green fronds (leaves) that persist all year (evergreen) and renews growth of new fronds from an underground stem (rhizome) each spring (perennial). The young fronds called fiddleheads uncurl and extend into fronds typically 20-150 cm in length and between 5-25 cm in width (Klinkenberg 2017). Each frond is divided into leaflets (pinnae) that have a characteristic sword shape. The entire plant can grow up to 180 cm in height.
Ecology:
P. munitum are commonly found in the understory of coniferous and deciduous forests along the coast of British Columbia. They thrive in low light conditions and acidic soil (Garrison et al. 1977). P. munitum avoid being eaten by many herbivores by producing unpalatable organic compounds stored in their fronds. However, some caterpillar larvae, mountain beavers, and a variety of forest rodents tolerate these compounds and will consume the fronds (Slater Museum of Natural History 2017).
Reproduction and Dispersal:
P. munitum, like all ferns, have a distinctive alternation of generations. Sexual reproduction occurs in a small gametophyte, from which the larger recognizable sporophyte plant grows. On the underside of each frond, clusters of spore-producing structures are formed. The small spores that are typically dispersed by wind or rain then develop into the small gametophyte (Soltis & Soltis 1987).
References Cited:
Garrison GA, Bjugstad AJ, Duncan DA, Lewis ME, Smith DR. 1977. Vegetation and environmental features of forest and range ecosystems. Agricultural handbook 475. Washington, DC (US): Department of Agriculture, Forest Service.
Klinkenberg B, editor. 2017. E-Flora BC: Electronic Atlas of the plants of British Columbia [eflora.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [accessed 2017 Jan 18]. http://http://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Polystichum%20munitum .
Pojar J, MacKinnon A. 1994. Plants of coastal British Columbia: including Washington, Oregon & Alaska. Vancouver: Lone Pine Publishing.
Slater Museum of Natural History, University of Puget Sound. 2017. Sword fern (Polystichum munitum). [accessed 2017 Jan 18]. http://www.pugetsound.edu/academics/academic-resources/slater-museum/exhibits/terrestrial-panel/sword-fern/.
Soltis PS, Soltis D E. 1987. Population structure and estimates of gene flow in the homosporous fern Polystichum munitum. Evolution. 41(3): 620-629.
Klinkenberg B, editor. 2017. E-Flora BC: Electronic Atlas of the plants of British Columbia [eflora.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [accessed 2017 Jan 18]. http://http://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Polystichum%20munitum .
Pojar J, MacKinnon A. 1994. Plants of coastal British Columbia: including Washington, Oregon & Alaska. Vancouver: Lone Pine Publishing.
Slater Museum of Natural History, University of Puget Sound. 2017. Sword fern (Polystichum munitum). [accessed 2017 Jan 18]. http://www.pugetsound.edu/academics/academic-resources/slater-museum/exhibits/terrestrial-panel/sword-fern/.
Soltis PS, Soltis D E. 1987. Population structure and estimates of gene flow in the homosporous fern Polystichum munitum. Evolution. 41(3): 620-629.