Descriptions : HerbSmall herb, with 4-angled stems; leaves opposite, ovate, serrate; flowers pedicellate, solitary in axils of leaves (or in cymes, if "leaves" are considered bracts); calyx tubular with 5 lobes, 5 keels, glabrous except some hairs on keels; corolla bilabiate, 2 upper lobes and 3 lower lobes; tube purple except yellow patch on lower side, lobes with white; stamens 4, upper and lower pairs; each lower stamen with short spur-like appendage from filament; ovary glabrous; style filiform; stigma bilamellate; fruit a septifragal capsule with 2 valves and septum; seeds numerous, small.
