USGS - science for a changing world

Northern Prairie Wildlife Research Center

  Home About NPWRC Our Science Staff Employment Contacts Common Questions About the Site

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.

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/plants/vascplnt/species/mhet.htm
Page Contact Information: Webmaster
Page Last Modified: Saturday, 02-Feb-2013 06:44:43 EST
Sioux Falls, SD [sdww54]