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| Species: | Myriophyllum spicatum L., Eurasian milfoil, Eurasian water-milfoil |
| Family: | Haloragaceae |
| Eurasian milfoil,
an invasive non-native plant, is one of the worst
aquatic plant pests in North America. Like native aquatic milfoils, it
has feather-like underwater leaves and emergent flower spikes. Usually
leaf shape and size can be used to distinguish it from other milfoil
species. However, Eurasian milfoil is a variable species, often making
it difficult to identify without chemical or DNA analysis. Because it
is an extremely invasive plant, it is important to distinguish Eurasian
milfoil from the native milfoils. Every effort should be made to
prevent the spread of this plant. |
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| Leaf:
Two types. Submersed leaves: 2-4 cm long,
feather-like, arranged in whorls of 4 around the stem. The
leaves are often square at the tip and typically have greater than 14
leaflet pairs per leaf. On mature plants the leaflets are closely
crowded along the midrib. Emergent leaves: tiny (1-3 mm long) smooth
edged to toothed, located on the flower spikes with one leaf beneath
each flower, leaves shorter than flowers.
Stem: Long, often abundantly branched stems form a reddish or olive-green surface mat in summer. Flower: Tiny. On reddish emergent spikes 4-8 cm long. Female flowers lack petals, 4 petals on male flowers, 8 anthers. Fruit: Up to 3 mm in diameter, divided into 4 chambers, with 1 seed per chamber. Root: Many, fibrous, from the plant base. Roots often develop from plant fragments. Propagation: Plant fragments; rhizomes. Sprouting from seed is rare. Importance of plant: This invasive plant spreads rapidly, crowding out native species, clogging waterways, and blocking sunlight and oxygen from underlying waters. Distribution: Native to Eurasia and northern Africa, but is a widespread weed in North America. Found in many lakes and rivers throughout Washington. Habitat: Lakes, rivers, and ponds. Tolerates a wide range of water conditions. May be confused with: Northern milfoil (Myriophyllum
sibiricum) which Photographs: Closeup photo of Myriophyllum spicatum leaflets Line Drawings: Myriophyllum spicatum |
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Go to Aquatic Weed Control Home Page Email Aquatic Weed Control Aquatic Weed Control Seattle, Washington (866) 4-MILFOIL Toll Free (206) 772-6036 Local (206) 374-2979 Fax www.awc-america.com ©2004 Aquatic Weed Control LLC No part of this online utility may be used, duplicated, or copied without the express written permission of Aquatic Weed Control LLC except for personal use by private homeowners. Photos and drawings are compyrighted by thier respective owners. See WA DOE web site for owner, copyright, and source information. |
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has fewer than 14
leaflet pairs per leaf, generally has stouter stems, and produces
winter buds. When lacking flower stalks, Eurasian milfoil is also
easily confused with most other milfoils.