Rolland's bulrush - Trichophorum pumilum
Scirpus pumilus, Scirpus rollandii
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.
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)
Fruiting in July.
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.
Circumboreal south to CA and WY. Known from Glacier and Teton counties (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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(Observations spanning multiple months or years are excluded from time charts)
Calcareous fens in the foothills.
Ecological Systems Associated with this Species
- 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 Unpublished report to the Shoshone National Forest.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 Unpublished Report to the Nature Conservancy. 15 Pp.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.