Northern Prairie Wildlife Research Center
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.
Previous Species -- Myriophyllum heterophyllum
Return to Family -- Haloragaceae - The Water
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