General: Perennial aquatic herb without roots; stems very slender, floating, submerged or creeping along the bottom, leafy, up to 1 m long and 1 mm or more thick.
Leaves: Alternate, numerous, 1-5 cm long, pinnatifid, divided into 2 parts at the base and then again repeatedly but unequally into more than 20 flattened ultimate segments, the segments circular in cross-section, narrowed and pointed towards the tips, margins bristly; bladders numerous, borne on the leaves and 1-3 mm wide; winter buds egg-shaped or more elliptic, 1-2 cm long, with hyaline bristles.
Flowers: Inflorescence of 6-20 flowers in lax racemes at the end of stalks 6-20 cm long; corollas yellow, the lower lips saddle-shaped,1-2 cm long with well-developed cylindric spurs, upper lips shorter than the lower lips;
Lakes and ponds in the lowland, steppe and montane zones; common S of 55degreeN in BC, less frequent northward; amphiberingian, N to AK, YT and NT, E to NF and S to MO, VA, TX, MX and CA; E Asia.
