Annual glabrous herbs. Leaves simple, ovate-orbicular, crenate to lobed, long petiolate. Flowers borne in axils of upper leaves. Bracts subulate, spinose, spreading or deflexed. Calyx infundibuliform, in fruit much enlarged with membranous-reticulate broad spreading lobes. Corolla bilabiate; upper lip emarginate or entire, straight; lower lip 3-lobed, median lobe clearly larger; tube with an internal oblique annulus. Stamens 4, anterior pair longer; thecae bilocular, divergent. Nutlets clearly triquetrous, apically truncate.