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."

General:
Aquatic, either submersed or semiterrestrial perennial; stems rooting in mud, freely branched or becoming much elongated when growing in water.

Leaves:
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.

Flowers:
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.

Fruits:
Mericarps, 4, pale, 1.3-1.8 mm long, with flat sides and tiny warts on the dorsal ridges.

Notes:
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

If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.

Illustration Source:  The Illustrated Flora of British Columbia

Synonyms and Alternate Names:
Myriophyllum scabratum Michx.
Myriophyllum verticillatum var. cheneyi Fassett
Potamogeton pinnatum Walt.