Glabrous perennial. Stems erect, branched, 25–80 cm. Leaf blades lanceolate, 5–25 cm long. Inflorescence a narrow, leafy-bracted panicle with erect, branches and flowers in whorls of 20 to 25. Flowers perfect; outer tepals 1–2 mm long. Fruit 3–5 mm long; inner tepals ovate-deltoid with a callosity on each and denticulate margins. Achene reddish brown, 2–3 mm long (
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).