Northern Prairie Wildlife Research Center
Aquatic and Wetland Vascular Plants of the Northern Great Plains
61. Juncaceae, the Rush Family
1. Juncus L. -- Rush
9. Juncus ensifolius Wikst.
Rhizomatous perennial 1.5-6 dm tall; culms single or loosely clustered. Leaves
2-4 per culm, the blade folded along the midrib with the margins united, thus
laterally flattened and equitant (with one edge toward the culm), 1.5-6 mm wide,
incompletely cross-septate; sheaths green or reddish, with broad scarious
margins, these often prolonged as low rounded auricles to 0.5 mm long.
Inflorescence short to oblong, usually few-branched with the branches
erect or nearly so; glomerules (1)2-several (seldom more), hemispheric
to subglobose, 5- to many-flowered, to ca. 1 cm across. Flowers dark
brown, 3-4 mm long; tepals lanceolate, the outer tepals acuminate, sharp-pointed,
the inner ones shorter, acute, scarious-margined; stamens 6(3). Capsules
oblong, 1-locular, rounded to the short beak, shorter than to exceeding the
tepals; seeds ellipsoid to fusiform, 0.4-0.6 mm long and apiculate at
both ends, or sometimes to 1 mm long with a taillike appendage at one or both
ends. Jul--Sep. Margins of springs, streams, ponds and in seepage areas at moderate
to high elevations; occasional in the Black Hills and with one record from Custer
Co., MT; (SD and MT to AK, s to NM, AZ and CA, also Que. and Ont.).
Our plants, with usually 6 stamens and the anthers about equaling the filaments,
are assigned to var. montanus (Engelm.) C. L. Hitchc.
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