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Northern Prairie Wildlife Research Center

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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

2. Myriophyllum heterophyllum Michx.

Submersed aquatic with simple or branching, rather robust stems to 8 mm thick, usually red-tinged, 3-10 dm or more long; winter buds produced at the plant base or from rhizomes, not clavate, green. Foliage leaves in whorls of 4-6 or some scattered, 1.5-5 cm long, with 5-14 divisions on each side of the midrib. Flowering spikes green to reddish, 5-30(40) cm long; bracts in whorls of 4 or some occasionally offset, smaller than the foliage leaves and distinct from them, laminate, oblong-lanceolate to ovate-lanceolate, 3-12 mm long, serrate or the lower ones usually pectinate but with a laminate central portion, with 4-8 ascending teeth or segments, eventually reflexed; bracteoles triangular to ovate, spinulose, to 1.2 mm long. Flowers perfect and imperfect; petals of male and perfect flowers pale, 1-3 mm long; stamens 4. Fruits olive, subglobose, 1.5-2 mm long, the mericarps rounded or with 2 undulate keels on the dorsal side, otherwise smooth to papillate, conspicuously beaked with the recurved stigma. Jun--Aug. Stream pools and ponds; rare, with collections from Brookings Co., SD; (Que. and ME to SD, s to FL, TX and NM).
GIF- Distribution Map

Map key

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

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