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Montana Field Guide

Montana Field Guides

Sheathed Sedge - Carex vaginata

Species of Concern
Native Species

Global Rank: G5
State Rank: S2?
(see State Rank Reason below)

Agency Status
MNPS Threat Rank:

External Links

State Rank Reason (see State Rank above)
Rare in Montana, where it is currently known from one area in the northwest corner of the state, which is at the southern edge of the species' range. Additional data on population levels and trends are needed.
General Description
Long-rhizomatous. Stems erect, 10–40 cm. Leaves glabrous, basal and lower-cauline; blades 2–4 mm wide. Inflorescence of 3 to 4 well-separated spikes; the lowest bract shorter than the inflorescence, sheathing. Spikes unisexual; the uppermost male, narrow, 1–2 cm long; the lower female, ascending, pedunculate, 1–3 cm long, cylindric. Perigynia ascending, green to brown, narrowly elliptic, glabrous, 3–5 mm long with a beak 0.5–1.2 mm long; stigmas 3. Female scales with a green midstripe and hyaline margins, shorter than the perigynia. Achene 3-sided, nearly filling the perigynium (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Fruit mature in July.

Diagnostic Characteristics
Diagnostic characters of Carex vaginata include the rhizomatous habit, well-developed basal stem leaves, bracts with inflated sheaths, female flowers with 3 stigmas, and perigynia without hairs and with definite short beaks. A hand lens or microscope and technical key are needed for positive identification.

Species Range

Range Comments
Circumboreal south to MT, WI and NY. Known only from Lincoln County (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 7

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)


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Citation for data on this website:
Sheathed Sedge — Carex vaginata.  Montana Field Guide.  .  Retrieved on , from