Aquatic and Wetland Vascular Plants of the Northern Great Plains
61. Juncaceae, the Rush Family
1. Juncus L. -- Rush3. Juncus balticus Willd. -- Baltic rush
Strongly rhizomatous perennial; culms slender and tough, dark green, 3-9 dm tall, appearing leafless, arising in rows from thick, brown to black rhizomes. Leaves, except for the involucre, comprised of basal sheaths only, these brown to reddish-brown; involucral leaf terminal, erect, terete, resembling a continuation of the culm. Inflorescence appearing lateral, subcapitate and dense to spreading and diffuse, extending outward 1-7 cm; bracteoles obtuse to mucronate, 1-2 mm long. Flowers borne singly on pedicels, dark brown to purplish-brown, 3.5-5 mm long; tepals acute, hyaline-margined, the inner ones slightly to considerably shorter than the outer; stamens 6. Capsules ovoid, 3-locular, shorter than to surpassing the perianth; seeds obliquely ovoid-ellipsoid, grayish-brown, ca. 0.6 mm long, apiculate at both ends. Jun--Aug. Wet meadows, ditches, seepage areas and shores; common, often abundant; (Circumboreal, in N.Amer. s to NY, PA, OH, IN, IL, MO, n TX, NM and CA; also S.Amer.).
Most plants of this region are var. montanus Engelm., with the outer tepals short-acuminate, the inner tepals acute to obtuse and nearly equaling the outer ones, and with the capsules shorter than to about equaling the inner tepals. In the eastern part some populations of var. littoralis Engelm. are encountered. These plants have the outer tepals acuminate and longer than the acute to obtuse inner ones, and the capsules exceeding the inner tepals. As expected, plants intermediate between these varieties are also found.
Juncus balticus, inflorescence. |
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