Coville's Rush - Juncus covillei
Species of Concern
(see State Rank Reason below)
MNPS Threat Rank
State Rank Reason (see State Rank above)
Rare and peripheral in Montana. Currently known from approximately a half-dozen widely scattered wetland/riparian sites in the mountainous portion of the state.
Rhizomatous. Stems erect, compressed, 6–20 cm, sometimes clumped. Leaves basal and cauline; blades flat, 1–2 mm wide; auricles acute or absent. Inflorescence congested with 3 to 7 sessile flowers in each of 1 to 3 clusters; main bract shorter or longer than the inflorescence. Flowers: prophylls absent; tepals brown to purplish with a green midstripe, 3–4 mm long, acute; stamens 6. Capsules 3–5 mm long, truncate on top; seeds without appendages (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)
We have varieties covillei
Fruits reach maturity from late August-September
Juncus is a large and difficult genus to distinguish, so a technical key should be consulted. Mature fruit is necessary for positive determination. The combination of flowers subtended by a single bract, flattened leaves, and 7-flowered heads separate J. covillei from most other rhizomatous rushes. The tepals of var obtusatus are pale brown, and the inner ones have pointed tips. In contrast, the tepals of variety covillei are dark brown, and the inner tepals have rounded tips.
BC to CA, ID and MT (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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Map Help and Descriptions
(Observations spanning multiple months or years are excluded from time charts)
Variety covillei is typically found in moist, gravelly or sandy soil along major water courses in the valley zone. In contrast, variety obtusatus is found in moist to wet, often seepy soil of slopes and meadows in the montane and subalpine zones.
Ecological Systems Associated with this Species
- Additional ReferencesLegend: View Online Publication
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- Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
- Vanderhorst, J.P. 1994. Sensitive plant surveys in the Gallatin National Forest, Montana. Unpublished report to the Gallatin National Forest. Montana Natural Heritage Program, Helena, MT. 54 pp.
- Vanderhorst, J.P. 1994. Survey for sensitive plant species on Doherty Mountain, Jefferson County. Unpublished report to the Butte District, Bureau of Land Management. Montana Natural Heritage Program, Helena, MT. 5 pp. plus appendices.