Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east across most of North America to the Atlantic Coast.
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.
Publication: Sp. Pl. 2: 992. 1753.
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.
