BugwoodWiki Article

Eurasian water-milfoil
Myriophyllum spicatum L.

Overview

Appearance
Myriophyllum spicatum is a submersed aquatic plant that invades lakes, ponds, and other aquatic environments throughout the United States. The plants are rooted and the stems grow up to the water surface, usually reaching 3-10 ft. (0.9-3 m) in length and can be as much as 30 ft. (9.1 m) long.
Foliage
Leaves are bright green, finely dissected, and whorled. The delicate leaflets give this plant a feathery appearance.
Flowers
Myriophyllum spicatum has both male and female flowers on the same inflorescence. The female flowers are basal while the male flowers are located distally. The female flowers have a 4-lobed pistil and lack sepals and petals. The male flowers have 4 pink petals and 8 stamens.
Fruit
The very small globular fruit of Myriophyllum spicatum are indehiscent, and contain 4 seeds.
Ecological Threat
Myriophyllum spicatum requires stagnant to slowly moving water and can tolerate brackish conditions. It forms dense mats of leaves restricting light availability, leading to a decline in the diversity and abundance of native macrophytes. In addition, Myriophyllum spicatum displaces the native species of watermilfoil and reduces habitats for fish spawning and feeding. It is native to Europe, Asia, and northern Africa.

Resources

Image Sets
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Maps


EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org

EDDMapS Distribution

State Invasive List - This map identifies those states that list this species on their invasive species list. For more information, visit Invasive.org

State Invasives List

Invasive Listing Sources

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Subclass: Rosidae
Order: Haloragales
Family: Haloragaceae
Genus: Myriophyllum

Other System Links

Plants: MYSP2
Bayer: MYPSP
GRIN: 400094
ITIS: 27039
NPDN Pest: PCDABBD
NPDN Host: 36432

Synonyms and Other Names

Other Common Names:
spiked watermilfoil

Categories

Category: Aquatic
Category: Forbs/Herbs