Commelina communis (PROSEA)
- Protologue: Sp. pl. 1: 40 (1753).
Commelina polygama Roth (1790).
- Asiatic dayflower, common dayflower (En)
- Vietnam: rau trai (ăn), thài lài trắng, cỏ lài trắng.
Native to China, nowadays distributed in India, Indo-China, China, Japan, Malaysia and the Philippines, naturalized in southern Europe, parts of Russia and eastern North America.
The aerial parts are widely used in China, Indo-China, India and Taiwan as a diuretic, a refrigerant and against diarrhoea and diabetes, and externally for boils and abscesses. In Indo-China, the juice of the crushed plant is put on inflamed eyes. In Peninsular Malaysia C. communis is sometimes used as a substitute for C. benghalensis .
An annual herb, 25-–70 cm long, often glabrescent, roots fibrous; leaves oblong-lanceolate, 2-–10 cm × 1–-3 cm, apex acute to acuminate; spathes 1–-3 together, semi-ovate, 2-–3 cm long, base cordate, apex abruptly acute, glabrous or pubescent, striate, upper raceme in spathe with 1-2 male flowers, lower raceme with 1-3 bisexual flowers, peduncle 1.5-2.5 cm long; flower 2 cm in diameter, petals blue or pale blue, fertile stamens 3, staminodes 3; capsule subglobose to oblong, 5–-6 mm × 4-5 mm, 2-celled, 4-seeded; seed semi-elliptical, dark brown. C. communis occurs in many different habitats, often in humid localities, along ditches and roadsides and has a preference for temperate climatic conditions.
- Council of Scientific and Industrial Research, 1948-1976. The wealth of India: a dictionary of Indian raw materials & industrial products. 11 volumes. Publications and Information Directorate, New Delhi, India.459, 536, 605, 952, 1124.