Root carrotlike, 7-16 × 1.5-1.8 cm. Stems up to 1.5 m tall, simple, glabrous, less often white hispidulous. Cauline leaves 3-6-verticillate, sessile or subsessile; blade broadly to narrowly elliptic, linear-lanceolate, or linear, 1.8-10 × 0.2-3.2 cm, both surfaces sparsely puberulent or glabrous, base cuneate or attenuate, margin serrate or serrulate, apex acuminate, acute, or obtuse. Inflorescence a narrow panicle with branches (cymes) mostly verticillate. Hypanthium obconic or campanulate, glabrous; calyx lobes subulate, linear, or linear-triangular, 1.5-4 mm, margin entire. Corolla blue to purple, tubular or narrowly funnelform, sometimes slightly constricted at throat, 7-10 mm; tube 2.5-7 mm in diam.; lobes deltoid, 1-2 mm. Disk narrowly tubular, 2-4 mm. Style 14-20 mm, strongly exserted. Capsule obovoid or broadly obovoid, 5-8 × 3-6 mm. Seeds yellow-brown, oblong, slightly compressed, 1-1.5 mm. Fl. (Feb-)Mar-Nov, fr. May-Nov. 2n = 34, 34+2B*.
Grassy places, scrub; low elevations but up to 2000 m in south. Anhui, Fujian, N Guangdong, Guangxi, Guizhou, Hebei, Heilongjiang, Henan (Lushi, Xinyang), Hunan (Xinning, Yizhang), Jiangsu, Jiangxi, Jilin, Liaoning, E Nei Mongol, Shandong (Muping), Shanxi (Lingkong Shan), Sichuan (Ebian, Emei Shan), Taiwan, Yunnan (Yanshan), Zhejiang [Japan (including Ryukyu Islands), Korea, Laos, Russia (Far East, E Siberia), N Vietnam].