Northern Prairie Wildlife Research Center
Northeast Wetland Flora
Field Office Guide to Plant Species
Myriophyllum spicatum L.
- Family: Water-milfoil (Haloragaceae)
- Flowering: July-September
- Field Marks: This water-milfoil is distinguished by having all leaves borne in whorls, with
6-11 pairs of divisions per leaf. The flowers are in whorls in terminal spikes.
- Habitat: Quiet water.
- Habit: Submerged aquatic herb.
- Stems: Branched or unbranched, usually purple but drying white, smooth, up to 2 feet long.
- Leaves: All in whorls, each leaf divided into 6-11 pairs of linear segments, smooth, each leaf up to 1 1/2 inches long.
- Flowers: Borne in whorls and crowded into terminal spikes, each spike up to 4 inches long, subtended by ovate to oblong, toothed bracts, the upper part of the spike with male flowers only, the lower part with female flowers only.
- Sepals: 4, green, united below, minute.
- Petals: 4, green, free from each other, minute, or absent.
- Stamens: 8.
- Pistils: Ovary superior, smooth.
- Fruits: Spherical, with 4 grooves, smooth or warty, up to 1/8 inch long.
- Notes: This species is sometimes considered the same as M. exalbescens. The nutlets are eaten by waterfowl. This species is introduced from Eurasia and is replacing native submerged aquatic species.
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