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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

4. Myriophyllum verticillatum L.


Quite similar to M. exalbescens, often more robust with stems 5-25 dm long. Leaves in whorls of 4-5, with 9-13 filiform segments along each side of the midrib, 1-4.5 cm long; lower and middle nodes mostly less than 1 cm apart; winter buds present fall to early spring, clavate, yellow-green. Flowering spikes 4-12 cm long, the floral bracts much smaller than the leaves, pectinate, mostly exceeding the flowers; bracteoles minute or absent, palmately 7-lobed. Flowers perfect or the lower female and the upper male; petals reduced in female flowers, otherwise spoon-shaped, obtuse, to ca. 2.5 mm long; stamens 8. Fruits brownish, subglobose, 2-3 mm long, the mericarps rounded on the back, smooth or somewhat roughened. Jun--Sep. In much the same habitats as M. exalbescens, but restricted to fresh water; uncommon, from scattered locations in ND, e SD and nc NE; (Circumboreal, in N.Amer. s to MA, NY, IN, ne TX, NE, UT and B.C.).
GIF- Distribution Map

Map key


Previous Species -- Myriophyllum pinnatum (Walt.) B.S.P.
Return to Family -- Haloragaceae - The Water Milfoil Family

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