Page authors: Don Knoke, David Giblin
Myriophyllum spicatum
Eurasian water milfoil, spiked water milfoil

Distribution: Widely distributed throughout Washington; widely distributed throughout North America.

Habitat: Ponds, lakes, and quiet streams.

Flowers: April-October

Origin: Introduced from Eurasia

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Wind


Perennial, aquatic herbs, the stems simple or branched.


Leaves 1-3 cm. long, in whorls of 3-4, pinnately dissected into 13-23 filiform segments, abruptly reduced to the bract-like leaves of inflorescences.


Inflorescence emergent, simple; flowers single, subtended by bracts no longer than the fruit, the bracts serrulate to entire; sepals 4, attached to the top of the inferior ovary; petals 4, 2.5 mm. long, quickly deciduous; stamens 8 on the staminate flowers; stigmas short-hairy on the pistillate flowers.


Achene 2.5 mm. long, rounded.

Accepted Name:
Myriophyllum spicatum L.

Synonyms & Misapplications:
Myriophyllum spicatum L. var. spicatum [HC]
Additional Resources:

PNW Herbaria: Specimen records of Myriophyllum spicatum in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Myriophyllum spicatum checklist entry.

OregonFlora: Myriophyllum spicatum information.

E-Flora BC: Myriophyllum spicatum atlas page.

CalPhotos: Myriophyllum spicatum photos.

USDA Plants: Myriophyllum spicatum information.

14 photographs:
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