Description from Flora of China
Commelina nudiflora Linnaeus, Sp. Pl. 1: 41. 1753; Aneilema nudiflorum (Linnaeus) R. Brown; Tradescantia malabarica Linnaeus.
Herbs annual. Roots fibrous, slender, less than 0.3 mm in diam., glabrous or tomentose. Rhizomes absent. Stems numerous, diffuse, creeping proximally, simple or branched, 10--50 cm, glabrous. Leaves nearly all cauline, sometimes 1 or 2 basal; leaf sheath mostly less than 10 mm, hirsute throughout, sometimes glabrous except for a hirsute line along mouth slit; leaf blade linear or lanceolate, 2.5--10 × 0.5--1 cm, glabrous or sparsely hispid on both surfaces, apex obtuse or acuminate. Cincinni several, in terminal panicles, or solitary, with several densely arranged flowers; peduncle slender, to 4 cm; proximal involucral bracts leaflike but smaller than leaves, distal ones less than 10 mm; bracts caducous; pedicels slender, straight, 3--5 mm. Sepals ovate-elliptic, ca. 3 mm. Petals purple, obovate-orbicular. Fertile stamens 2; filaments bearded proximally; staminodes 2--4; antherodes 3-sect. Capsule ovoid-globose, trigonous, 3--4 mm. Seeds 2 per valve, yellow-brown, deeply pitted, or shallowly pitted and radiate white verrucose. Fl. and fr. (Jun--)Aug--Sep(--Oct).
Wet places by water, rarely among grass; low elevations (to 1500 m in Yunnan). C Anhui (Shucheng Xian), Fujian, Guangdong, Guangxi, S Henan (Tongbai Xian), WC Hunan (Xuefeng Shan), N and S Jiangsu, Jiangxi, C and E Shandong (Laoshan Xian, Tai Shan), C Sichuan (Emei Shan, Guanghan Xian), S and W Yunnan [Bhutan, Cambodia, India, Indonesia, Japan, Laos, Malaysia, Myanmar, New Guinea, Philippines, Sikkim, Sri Lanka; Indian Ocean and Pacific Islands].