Description from Flora of China
Herbs, 15-50 cm tall. Stems erect, quadrangular, simple or branched above middle, subglabrous. Petiole 1-2 cm; leaf blade oblong-ovate to ovate, 3-5 X 1.5-2.5 cm, subglabrous, margin coarsely serrate. Racemes often terminal; bracts linear, 2-5 mm. Pedicel 1-2 cm. Calyx ellipsoid, 1.3-1.9 X ca. 0.8 cm, green or purple-red at apex and margin, 5-winged; wings decurrent, ca. 2 mm wide, becoming ca. 3 mm wide in fruit; lips subtriangular, 1.5-1.7 cm, sometimes apically lobed. Corolla 2.5-4 cm, exceeding calyx by 1-2.3 cm; tube pale violet, upper side yellow; lower lip lobes purple-blue, middle lobe with a yellow patch near base, oblong to suborbicular, ca. 10 X 8 mm, subequal; upper lip pale blue, erect, broadly obovate, 1-1.2 X 1.2-1.5 cm, emarginate. Stamens unappendaged. Capsule narrowly ellipsoid ca. 12 X 0.5 mm. Seeds yellow. Fl. and fr. Jun-Dec.
Usually cultivated in S China but sometimes occurring by roadsides or in fields; below 1200 m. Fujian, Guangdong, Guangxi, Taiwan, Yunnan, Zhejiang [Cambodia, Laos, Thailand, Vietnam].