Cal parted to the base into upper and lower segments, the upper often wider; cor bilabiate, the upper lip usually subentire or shallowly 2-lobed, the lower entire or 3-lobed, usually elevated at the base into a prominent palate, the tube prolonged at base into a spur or sac; herbs of water or wet soil, the lvs (lf-like branches?) linear and entire or variously dissected, in most spp. provided with small bladders that catch tiny aquatic animals; fls yellow or violet, in short racemes (or apparently solitary and terminal), each subtended by a small bract. 150, cosmop.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.