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Montana Field Guide

Montana Field Guides

Short-pointed Flatsedge - Cyperus acuminatus

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Species of Concern
Native Species

Global Rank: G5
State Rank: S1
(see State Rank Reason below)
State Threat Score: No Known Threats
C-value: 4


Agency Status
USFWS:
USFS:
BLM:


 

External Links

State Rank Reason (see State Rank above)
Rare in Montana, where it is currently known from only 2 collections in the western portion of the state.
 
General Description
Caespitose annual. Stems ascending to erect, 2–5 cm. Leaves basal, 0.5–1 mm wide, U-shaped in cross-section. Inflorescence of hemispheric spikes of sessile spikelets. Spikelets flattened, 3–7 mm long. Scales acuminate, yellowish, 1–2.5 mm long, 3-veined with short ascending tips. Flowers: stamen 1; style 3-branched. Achene narrowly obovate, 3-sided, brown, ca. 1 mm long (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Phenology
Fruit mature in August-September.

Diagnostic Characteristics
Cyperus acuminatus may be distinguished from other annual members of the genus by its globose heads, solitary stamen, and short-pointed (rather than long) flower bracts, which have only 3 veins.

Species Range
Montana Range Range Descriptions

Native
 


Range Comments
Throughout the U.S., Mexico. Known from Cascade and Sanders counties (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 3

(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 soil of pond margins, lakes, and sloughs in the valleys and on the plains.
Predicted Suitable Habitat Model

This species has a Predicted Suitable Habitat Model available.

To learn how these Models were created see mtnhp.org/models

Ecological Systems Associated with this Species

Threats or Limiting Factors
STATE THREAT SCORE REASON
Threat impact not assigned because threats are not known (MTNHP Threat Assessment 2021).

References
  • 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.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.
  • Web Search Engines for Articles on "Short-pointed Flatsedge"
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Citation for data on this website:
Short-pointed Flatsedge — Cyperus acuminatus.  Montana Field Guide.  .  Retrieved on , from