E-Flora BC: Electronic Atlas of the Flora of British Columbia

Myriophyllum pinnatum (Walter) Britton, Sterns & Poggenb.
green parrot's-feather (cutleaf watermilfoil)
Haloragaceae (Water Milfoil family)

Introduction to Vascular Plants
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Distribution of Myriophyllum pinnatum
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According to Ceska and Ceska (2010), Cut-leaf water-milfoil is an "Eastern North American species with disjunct occurrences in British Columbia, Washington and Oregon. Recognized by the dark-green stems and foliage. Winter buds not seen."

Species Information

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Aquatic, either submersed or semiterrestrial perennial; stems rooting in mud, freely branched or becoming much elongated when growing in water.
In whorls of 3 to 5 or subverticillate or commonly scattered, to about 3 cm long, the submersed leaves with about 5 or more short or somewhat elongate remote capillary divisions; emersed leaves linear to oblanceolate, comb-like or sharply toothed, to 2 cm long; winter buds absent.
Perfect or unisexual in the axils of the emersed leaves; bracteoles bluntly triangular, about 1 mm long; petals purplish, 1.5-2 mm long, rounded above, with a short claw; stamens 4, anthers about 1 mm long.
Mericarps, 4, pale, 1.3-1.8 mm long, with flat sides and tiny warts on the dorsal ridges.
This eastern North American species has been identified based on a fruiting specimen collected by Frank Lomer in Port Coquitlam in 1996. There is a sterile specimen in the Royal British Columbia Museum, collected by J. K. Henry in 1918, that most probably belongs to this species.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Ponds and slough bottoms in the lowland zone; rare in SW BC, known only from the Pitt River area; S to ND, SD, MA, FL and TX.

Source: The Illustrated Flora of British Columbia


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Synonyms and Alternate Names

Myriophyllum scabratum Michx.
Myriophyllum verticillatum var. cheneyi Fassett
Potamogeton pinnatum Walt.

Taxonomic and Nomenclatural Links

Additional Photo Sources

Species References

Ceska, Oldriska and Adolf Ceska. 2010. Genus Myriophyllum (Haloragaceae) in the Pacific Northwest. Botanical Electronic News #428. Available online.

General References