Montana Field Guide

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 et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).



We have varieties covillei and obtusatus C.L. Hitchc.

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.

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.

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