– slender-leaved pondweed, western pondweed, threadleaf-pondweed
Distribution: Only known from Whatcom County in Washington; Alaska south to California, east to the Rocky Mountains; east across Canada to the Atlantic Coast and Greenland.
Habitat: Lakes, ponds, slow moving waters.
– fennel-leaved pondweed, sago pondweed, sago-pondweed
Distribution: Both sides of the Cascades in Washington; common throughout North America; Eurasia
Habitat: Shallow, fresh to brackish water.