Distribution: Occurring on both sides of the Cascades crest in Washington; circumboreal; widely distributed throughout North America except in Central Plains, Gulf Coast, and Southeast.
Habitat: Shallow, standing or slowly moving water.
Conservation Status: Imperiled/Vulnerable in Washington (WANHP)
Submersed plants with very slender stems, commonly creeping along the bottom.
Leaves numerous, alternate, 0.5-2 cm. long, 3-parted and the base, then 1-3 times dichotomous, the segments slender and flat, the ultimate ones blunt; specialized branches distinct from the leaves bear bladders 2-4 mm. wide.
Flowers 2-4 in a lax raceme at the end of an emergent peduncle 6-20 cm. long; calyx deeply 2-lobed, the lobes entire; corolla bilabiate, yellow, the proper tube very short, the spur 8-12 mm. long; upper lip entire, half as long as the lower; lower lip nearly entire, about as long as the spur, the base prominently raised; stamens 2, ovary superior.
Capsule on an erect pedicel.