Anderson's Swordfern - Polystichum andersonii
(see State Rank Reason below)
MNPS Threat Rank
State Rank Reason (see State Rank above)
Polystichum andersonii occurs where vegetation is dense, such as moist spruce-fir forests, avalanche chutes, along streams, and shrub thickets. It is documented from about 17 locations in western Montana, but known from several more locations in the Cabinet and Bitterroot Mountains. Though its habitat may be limited in Montana, populations are present and appear stable. It can grow as a sterile hybrid that develops large colonies through vegetative propagation by its bulblets.
- Details on Status Ranking and Review
ScoreE - 5,000-20,000 sq km (~2,000-8,000 sq mi)
Area of Occupancy
ScoreD - 6-25 4-km2 grid cells
Number of Populations
ScoreB - 6 - 20
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
ScoreC - Moderate. Generalist or community with some key requirements scarce
ScoreD - Low
CommentNo known threats.
Leaves arching, 20–70 cm long, commonly with 1 to several scaly, bulblets on central axis among upper pinnae. Leaf blade narrowly elliptic or lanceolate. Pinnae narrowly lanceolate, the lower deeply divided, 2–10 cm long with sharp-pointed lobes. Indusium with sparse marginal hairs (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)
In MT known only from Lincoln, Flathead and Ravalli counties; AK south to OR and MT (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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Map Help and Descriptions
(Observations spanning multiple months or years are excluded from time charts)
- Additional ReferencesLegend: View Online Publication
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- Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.