Shining Flatsedge - Cyperus bipartitus
State Rank Reason (see State Rank above)
Rare in Montana, where it is currently known from only the Bitterroot Valley.
Caespitose annual. Stems ascending to erect, 2–8 cm. Leaves mainly basal, 0.5–2 mm wide, U-shaped in cross-section. Inflorescence of hemispheric spikes of subsessile spikelets. Spikelets compressed, 3–15 mm long. Scales purplish, 2–2.5 mm long with rounded, minutely apiculate tips and obscure veins. Flowers: stamens 2 or 3; style 2-branched. Achene obovate, black, ca. 1 mm long, 2-sided, apiculate (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX
Fruit mature in August-September.
Cyperus acuminatus, C. aristatus, and C. erythrorhizos all have scales with pointed or short, awn-tipped scales, unlike the blunt scale of C. rivularis.
Throughout temperate North America to S. America. Known from Ravalli County (Lesica et al. 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)
Wet, often gravelly shores of rivers, lakes and ponds in the valley zone.
Ecological Systems Associated with this Species
Threats or Limiting Factors
STATE THREAT SCORE REASON
Threat impact not assigned because threats are not known.
- Literature Cited AboveLegend: View Online Publication
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.