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Aquatic and Wetland Vascular Plants of the Northern Great Plains

29. Haloragaceae, the Water Milfoil Family

1. Myriophyllum L. -- Water milfoil

3. Myriophyllum pinnatum (Walt.) B.S.P.


Aquatic or amphibious plant with stems freely branching and rooting in mud when stranded or greatly elongating in water. Foliage leaves mostly in whorls of 3-5, partly scattered on the stem, mostly 1-3 cm long, with 3-6 remote capillary segments along each side of the midrib; emersed leaves, including those subtending flowers, 0.5-2 cm long, much surpassing the flowers and fruits, pinnatifid to shallowly toothed or seldom subentire, usually with 2-4 ascending segments or teeth on each side, the lowermost floral bracts grading into the foliage leaves; bracteoles bluntly triangular, ca. 1 mm long. Flowers perfect or imperfect; petals purplish, rounded and short-clawed, 1.5-2 mm long; stamens 4. Fruits pale, cubic-ovoid, 1.3-1.8 mm long, the mericarps with flat sides and 2 tuberculate dorsal ridges, beaked. Jul--Aug. Shallow water or mud of marshes and shores; rare, with scattered records from se ND, c SD and e NE; (MA to ND, s to FL and TX).

This species was mistaken for M. heterophyllum in this region by some previous authors.

GIF- Distribution Map

Map key


Previous Species -- Myriophyllum heterophyllum Michx.
Return to Family -- Haloragaceae - The Water Milfoil Family
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