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Montana Field Guide

Montana Field Guides

Short-pointed Flatsedge - Cyperus acuminatus

Species of Concern

Global Rank: G5
State Rank: S1
* (see State Rank Reason below)

Agency Status
USFWS:
USFS:
BLM:
MNPS Threat Rank:
C-value: 4

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 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
Present
 


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

Summary of Observations Submitted for Montana
Number of Observations: 1

(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.

Ecological Systems Associated with this Species

References
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Citation for data on this website:
Short-pointed Flatsedge — Cyperus acuminatus.  Montana Field Guide.  .  Retrieved on , from