Description from Flora of China
Herbs perennial, 60--100 cm tall. Stems erect, usually purplish on lower part, subterete, branched at middle, sparsely pubescent, becoming glabrescent. Branches divaricate. Leaves opposite; petiole (0.5--)1--2 cm, narrowly winged, base subauriculate and clasping; leaf blade lanceolate to oblong-lanceolate, 6--12 X 1.5--3.5 cm, abaxially with sparsely pubescent veins, adaxially glabrous, base cuneate, decurrent, apex caudate-acuminate. Umbels terminal, 6- to many flowered. Pedicel 1--1.5 cm, sparsely pubescent, glandular. Calyx 6--7 mm in fruit, parted nearly to base; lobes lanceolate, ca. 1.5 mm wide, apex acuminate-subulate; midvein raised abaxially. Anthers dorsifixed, opening by lateral slits. Capsule subglobose, 3.5--4 mm in diam.
* Grassy mountain slopes, mountain stream valleys. W Hubei, NE Hunan.