Page authors: Don Knoke, David Giblin
Myriophyllum hippuroides
western milfoil, western water milfoil
Specimens
Photos

Distribution: Occurring west of the Cascades crest and east in the Columbia River Gorge in Washington; British Columbia to California; introduced in Illinois.

Habitat: Ponds and slow-moving streams.

Flowers: May-October

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Wind

Description:
General:

Perennial, aquatic herbs, the stems freely branched, 1-6 dm. long.

Leaves:

Leaves 4-5 per whorl, the submersed ones 1.5-3 cm. long, pinnately dissected into 13-23 filiform segments, and gradually transitional to the linear-oblong, 10-15 mm. long, serrate bracts.

Flowers:

Inflorescence terminal, immersed to emersed, the flowers single in the axils of the bracts; sepals 4, attached to the top of the inferior ovary; petals 4, pale yellow, 1 mm. long; staminate flowers uppermost on the stem, stamens 4; stigmas very short, smooth.

Fruits:

Achene 1.5-2 mm. long.

Accepted Name:
Myriophyllum hippuroides Nutt. ex Torr. & A. Gray
Publication: Fl. N. Amer. (Torr. & A. Gray) 1(3): 530. 1840.

Synonyms & Misapplications:
(none provided)
Additional Resources:

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

WA Flora Checklist: Myriophyllum hippuroides checklist entry.

OregonFlora: Myriophyllum hippuroides information.

E-Flora BC: Myriophyllum hippuroides atlas page.

CalPhotos: Myriophyllum hippuroides photos.

USDA Plants: Myriophyllum hippuroides information.

21 photographs:
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