Cal regular, the 5 sep separate nearly or quite to the base; cor bilabiate, the upper lip much narrower than the lower, erect, shallowly 2-lobed, the lower somewhat deflexed, 3-lobed; stamens 2 (the upper pair) or 4, the upper pair fertile, inserted at the middle of the cor-tube and included in it; lower pair of stamens sterile or fertile, inserted at the throat of the cor-tube, the basal part of the filament bent back on itself, the terminal part free, the whole resembling a forked filament; style elongate; stigmas 2, plate- like; fr fusiform to ellipsoid, commonly asymmetrical, septicidal; small annual (ours) or biennial herbs with opposite, 3-5-nerved, entire or denticulate lvs and small, white to violet fls on solitary, axillary, bractless peduncles. (Ilysanthes) 70, cosmop.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.