Montana Field Guide

Fibrous-rooted annual. Stems ascending to erect, 4–20 cm, tufted. Spikelet 4–10 mm long with numerous flowers. Scales brown with hyaline margins and a lighter midrib, 2–2.5 mm long. Flowers: bristles 0 to 7, equaling or exceeding the achene; stigmas usually 2. Achenes grey to brown, smooth, obovate, lenticular, ca. 1.5 mm long with a broad, low tubercle 0.1–0.2 mm high (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Eleocharis ovata - Ovate Spikerush
*Life Cycle: Annual; lacks rhizomes.
*Achene: gray to brown, obovate, lenticular, and about 1.5 mm long.
*Scales: longer than the achene,2-2.5 mm long.
*Stigma: 2

Eleocharis acicularis - Ovate Spikerush
*Life Cycle: Perennial; rhizomatous.
*Stems: 1-25 cm tall.
*Achene: gray, honeycombed, obovoid, and about 1.0 mm long.
*Scales: longer than the achene, 1.5-2.5 mm long.
*Stigma: 3

Eleocharis bella - Delicate Spikerush, SOC
*Life Cycle: Annual; lacks rhizomes.
*Stems: 1-8 cm tall.
*Achene: whitish, honeycombed, obovoid, nearly round in cross-section, 0.5-1.0 mm long.
*Scales: about 1.0 mm long.
*Stigma: 3

Eleocharis elliptica - Slender Spikerush
*Life Cycle: Perennial; rhizomatous.
*Stems: 10-14 cm tall.
*Achene: yellow, honeycombed, obovoid, and 1.0-1.5 mm long.
*Scales: longer than the achene, 2-3 mm long.
*Stigma: 3

Eleocharis rostellata - Beaked Spikerush, SOC
*Life Cycle: Perennial; tufted.
*Stems: 10-80 cm long, erect or arching and able to root at the tip to form new plants.
*Achene: green-gray, obovoid, and 2-6 mm long.
*Scales: longer than the achene, about 2.0 mm long.
*Stigma: 3

Vernally wet to shallowly submersed soil on the margins of ponds, lakes, sloughs; valleys (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).