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