四孔草 si kong cao

Commelina cristata Linnaeus, Sp. Pl. 1: 42. 1753; Cyanotis cavaleriei H. Léveillé & Vaniot; C. racemosa C. B. Clarke.

Herbs annual; roots fibrous. Stems creeping, often branched, 10--35 cm. Leaves all cauline; leaf blade oblong, lanceolate, ovate-lanceolate, or narrowly elliptic, 2--8 × 0.8--2 cm, abaxially glabrous or sparsely arachnoid. Cincinni often solitary, terminal or also axillary if 2 together; peduncle absent or to 9 cm; bracts 1--1.5 cm. Sepals connate at base, linear-lanceolate or oblanceolate, ca. 5 mm, abaxially hirsute along midvein and at margin. Petals blue or purple, 4--5 mm. Filaments blue lanate. Capsule columnar, trigonous, ca. 2.5 mm, hirsutulous at apex. Seeds gray-brown, pitted. Fl. Jul--Aug, fr. Sep--Oct.

By streams in ravines or open humid places; near sea level to 2000 m. W Guangdong (Xinxing Xian), Guangxi, SW Guizhou, Hainan, Yunnan [Bhutan, Cambodia, India, Indonesia, Laos, Malaysia, Myanmar, Philippines, Sikkim, Sri Lanka, Thailand, Vietnam].

The root is used as a medicine for the relief of swelling and snakebite.