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Montana Field Guide

Montana Field Guides

Hudson's Bay Bulrush - Trichophorum alpinum
Other Names:  Scirpus hudsonianus, Eriophorum alpinum

Species of Concern

Global Rank: G5
State Rank: S2
* (see State Rank Reason below)

Agency Status
USFWS:
USFS:
BLM:
MNPS Threat Rank: 2
C-value: 9

External Links






State Rank Reason (see State Rank above)
Rare in Montana, where it is only known from a few sites in the northwest corner of the state.
 
General Description
Stems 3-angled, 10–40 cm, loosely clustered on short rhizomes. Leaf blades ca. 0.5 mm wide. Spikelet 5–7 mm long, many-flowered; awn of lowest bract inconspicuous, shorter than the spikelet. Scales 4–5 mm long, glabrous, brown with a pale midstripe; tips acute. Flowers: bristles 6, white, greatly exceeding the spikelet. Achene ca. 1.5 mm long (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Phenology
Mature fruit in July-August.

Diagnostic Characteristics
The solitary spikelet and tuft of long bristles make this species resemble a slender Eriophorum; however, species of true cottongrass have at least 10 bristles per achene. It differs from the other species of Scirpus with solitary infloresences in having bristles that are longer than the scale, and a 3-sided stem.

Species Range
Present
 


Range Comments
Circumboreal south to BC, MT. Known from Flathead and Glacier counties (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Summary of Observations Submitted for Montana
Number of Observations: 17

(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
Wet, cold organic soil of fens and slopes in the montane and subalpine zones.

Ecological Systems Associated with this Species

References
  • Additional ReferencesLegend:   View Online Publication
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    • Bursik, R. J. 1992. Field investigations of sensitive plant taxa occurring on the Priest Lake Ranger District, Kanisku National Forest, Idaho Panhandle National Forests. Idaho Department of Fish and Game, Conservation Data Center, Boise. 141 pp. plus appendices.
    • Fassett, N. C. 1985. (3rd ed.) A Manual of Aquatic Plants, with Revision Appendix by E. C. Ogden. University of Wisconsin Press, Madison. 405 pp.
    • Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
    • Maguire, B. 1939. Distrubution notes concerning plants of Glacier National Park, Montana-II. Rhodora 41:504-508.
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Citation for data on this website:
Hudson's Bay Bulrush — Trichophorum alpinum.  Montana Field Guide.  .  Retrieved on , from