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Montana Field Guide

Montana Field Guides

Rolland's bulrush - Trichophorum pumilum
Other Names:  Scirpus pumilus, Scirpus rollandii

Species of Concern

Global Rank: G5
State Rank: S3
* (see State Rank Reason below)

Agency Status
USFWS:
USFS:
BLM:
MNPS Threat Rank: 3
C-value: 10

External Links






State Rank Reason (see State Rank above)
Rare in Montana, where it is currently documented from only a few calcareous fens near the Rocky Mtn Front.
 
General Description
Caespitose. Stems terete, 5–25 cm, clustered on thin rhizomes. Leaf blades ca. 0.5 mm wide. Spikelet 3–4 mm long with 3 to 6 flowers; awn of lowest bract shorter than the spikelet. Scales 2.5–3.5 mm long, glabrous, brown with a pale midstripe; tip rounded. Flowers: bristles absent. Achene 1.5–2 mm long (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Phenology
Fruiting in July.

Diagnostic Characteristics
After mid-summer, T. pumilum looks like a tiny stick with a few little black eggs glued on top. It is most likely confused with species of Eleocharis, but in these species, the base of the style is enlarged, and the scales are persistent. Trichophorum cespitosum is a larger plant that forms distinctive tussocks. A hand lens will be necessary for positive identification.

Species Range
Present
 


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

Summary of Observations Submitted for Montana
Number of Observations: 14

(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
Calcareous fens in the foothills.

Ecological Systems Associated with this Species

References
  • Additional ReferencesLegend:   View Online Publication
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    • Fertig, W. and G. Jones. 1992. Plant communities and rare plant species of the Swamp Lake Botanical Area, Clark's Fork Ranger District, Shoshone National Forest. Unpublished report to the Shoshone National Forest. Challenge Cost Share Agreement No. CSA-2-91-14-0001. Wyoming Natural Diversity Database. 113+ pp.
    • Lesica, P. 1991. Noteworthy Collections in Montana....
    • Lesica, P. 1991. The Rare Vascular Plants of Pine Butte Swamp Preserve. Unpublished Report to the Nature Conservancy. 15 Pp.
    • Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
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Citation for data on this website:
Rolland's bulrush — Trichophorum pumilum.  Montana Field Guide.  .  Retrieved on , from