Description from Flora of China
Tittmannia stachydifolia Turczaninow, Bull. Soc. Imp. Naturalistes Moscow 7: 156. 1837; Mazus simadusMasamune; M. villosus Hemsley; Vandellia stachydifolia Walpers.
Perennials, 10-50 cm tall, white villous. Rhizomes short. Stems erect, rarely ascending, terete, basally woody with age. Basal leaves short petiolate; leaf blade spatulate. Stem leaves opposite or upper ones alternate, sessile, elliptic to obovate-lanceolate, 2-7 cm, papery, margin irregularly serrate. Racemes terminal, lax, 2-20 cm; bracts triangular-ovate, ca. 1 mm. Pedicel shorter than or as long as calyx. Calyx funnelform, 5-10 mm, to 1.6 cm in fruit, over 1 cm in diam.; lobes slightly longer than tube, lanceolate-triangular, apex narrowly acute, conspicuously 10-veined. Corolla blue-purple, 1.5-2 cm; tube almost as long as lips; lower lip yellow-punctate, large, spreading flat, papillate glandular hairy, middle lobe smaller than other lobes and suborbicular; upper lip short, lobes narrowly triangular, apex acute. Ovary apically long hirsute. Capsule ovoid, 2-3.5 mm, flattened. Fl. Apr-Jun, fr. Jul-Sep.
Trailsides, grassland, wet places at edge of forests; below 1500 m. Anhui, Guangdong, Hebei, Heilongjiang, Henan, Hubei, Jiangsu, Jiangxi, Jilin, Liaoning, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Zhejiang [Korea, Mongolia, Russia].