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Montana Field Guides

Western Swordfern - Polystichum munitum


Global Rank: G5
State Rank: S3S4
* (see State Rank Reason below)

Agency Status
USFWS:
USFS:
BLM:
MNPS Threat Rank:
C-value: 9

External Links






State Rank Reason (see State Rank above)
Polystichum munitum occurs in west-northwest Montana in moist forests where many observations have found it to be common and tolerant of many disturbances. Montana populations are on the eastern edge of its range.
  • Details on Status Ranking and Review
    Western Swordfern (Polystichum munitum) Conservation Status Review
    Review Date = 11/14/2016
    View State Conservation Rank Criteria
    Range Extent

    ScoreE - 2,500 - 10,000 individuals

    Area of Occupancy

    ScoreD - 6-25 4-km2 grid cells

    Number of Populations

    ScoreC - 21 - 80

    Number of Occurrences or Percent Area with Good Viability / Ecological Integrity

    ScoreB - Very few (1-3) occurrences with excellent or good viability or ecological integrity

    Environmental Specificity

    ScoreC - Moderate. Generalist or community with some key requirements scarce

    Long-term Trend

    ScoreU - Unknown

    Trends

    ScoreU - Unknown

    Threats

    ScoreD - Low

    CommentThreat categories include: Housing & urban areas, Logging & wood harvesting.

    Intrinsic Vulnerability

    ScoreC - Not intrinsically vulnerable

 
General Description
Plants: Coarse evergreen perennials from scaly, short-creeping, almost vertical rhizomes (Lesica 2012).

Leaves: Clustered, monomorphic (all basically the same size and shape), arching, 30–120 cm long (Lesica 2012), 5-25 cm wide (Douglas et al. 2000); leaf blades once-pinnate, narrowly lanceolate; petiole about ¼ of the leaf length, scaly; pinnae alternate, about 35-70 pairs (McGregor et al. 1986), not overlapping, narrowly lanceolate to linear with a shallow lobe projecting from one side of the asymmetric base, 2–8 cm long with minutely toothed, erect-spiny margins (Lesica 2012); rachis and costa (vein of pinna) with 2 forms of scales (Hitchcock et al. 1969), some scales being >1 mm in width and others almost hairlike (Douglas et al. 2000).

(Lesica’s contribution adapted from Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX.)

Phenology
June-September (McGregor et al. 1986).

Species Range
Present
 


Range Comments
Northern 2/3 of CA, extending northward into s 2/3 of w BC, crossing s BC and extending into n 2/3 of ID and w MT (FNA 1993). In Montana, from Lincoln and Flathead south to Ravalli Counties (Lesica 2012).

(Lesica’s contribution adapted from Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX.)


Summary of Observations Submitted for Montana
Number of Observations: 26

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Habitat
Terrestrial, growing in soil, seldom on rocks (FNA 1993); shady banks with rich, damp soil (McGregor et al. 1986), moist forest, often with Thuja plicata; valleys to montane (Lesica 2012).

(Lesica’s contribution from Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX.)

Ecology
The pinnae are planar when the plants grow in shade. They are contorted in plants receiving more sun (FNA 1993).

Reproductive Characteristics
Sori and Indusia: Sori (clusters of sporangia) round (Douglas et al. 2000), growing on both sides of midvein in 1 or 2 rows on bottom side of fertile pinna. Indusium has fringed margins and is attached at the center of the sorus, umbrella-like (Lesica 2012).

(Lesica’s contribution adapted from Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX.)

Management
The plants, mostly wild-collected, are popular for landscaping, and the fronds are used extensively in floral arrangements (FNA 1993).

References
  • Literature Cited AboveLegend:   View Online Publication
    • Douglas, G.W., D. Meidinger, and J. Pojar, editors. 2000. The Illustrated Flora of British Columbia. Volume 5. Dicotyledons (Salicaceae through Zygophyllaceae) and Pteridophytes. British Columbia Ministry of Environment, Lands and Parks and British Columbia Ministry of Forests, Victoria.
    • Flora of North America Editorial Committee, eds. 1993. Flora of North America North of Mexico. Volume 2. Pteridophytes and Gymnosperms. Oxford University Press, Inc., NY. xvi + 475 pp.
    • Hitchcock, C. L., A. Cronquist, M. Ownbey, and J. W. Thompson. 1969. Vascular Plants of the Pacific Northwest. Part I: Vascular Cryptogams, Gymnosperms and Monocotyledons. Seattle, WA: University of Washington Press. 914 pp.
    • Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
    • McGregor, R.L., coordinator, and T.M. Barkley, R.E. Brooks, and E.K. Schofield, eds.: Great Plains Flora Association. 1986. Flora of the Great Plains. Lawrence, KS: Univ. Press Kansas. 1392 pp.
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Citation for data on this website:
Western Swordfern — Polystichum munitum.  Montana Field Guide.  .  Retrieved on , from