Commelina paludosa Blume

A fairly common species from lower hills to the plains of Pakistan. Roots considered as an antidote for snake poison; useful in vertigo and fever etc.

Suberect or ascending herb, 20-60(-90) cm long, pubescent to subglabrous or glabrous. Leaves 5-10(-15) cm long, 2-5 cm broad, lanceolate, entire, acute, sessile, sheathing at base with fringed sheaths, 1.5-2.5 cm long. Spathes 2-3.5 cm long, folded, 1.5-2 cm broad, solitary or crowded (often so in upper axils), ob¬liquely funnel-shaped, free or fused below at the margin, subsessile to shortly pedunculate. Flowers usually pale blue, one of them nearly white. Capsules obovoid, subtrigonous, 3-loculed with 1 seed in each locule; seeds ellipsoid, lead-coloured or whitish with marbled margins, minutely dotted.

Herbs perennial. Stems often erect, simple or sometimes branched distally, to 1 m, glabrous or sparsely hispidulous. Leaves sessile; leaf sheath densely brown hispid at mouth and in a line on 1 side, sometimes either glabrous with only a few hairs at mouth or hirsute throughout; leaf blade lanceolate to ovate-lanceolate, 7--20 × 2--7 cm, glabrous on both surfaces or adaxially granular hairy and abaxially hirsute. Involucral bracts often 4--10, forming terminal heads, sessile, funnelform, ca. 2 × 1.5--2 cm, glabrous, proximal margins connate, apex acute or shortly so. Cincinnus 1; peduncle ca. 1.2 cm; flowers 1 to several, nearly included in involucral bracts; pedicels ca. 7 mm, twisted. Sepals 3--6 mm, membranous. Petals blue, 4.5--8 mm. Capsule ovoid-globose, trigonous, ca. 4 mm, 3-valved. Seeds 1 per valve, dark brown, ellipsoid, ca. 3.5 mm, slightly flattened, finely reticulate. Fl. Aug--Oct, fr. Oct--Apr.

Himalaya, India, Ceylon, Burma, Indo-China, Taiwan, Malaysia.

Distribution: Pakistan, India, Srilanka, Bangla Desh to Malaysia, Indonesia and Phillipines.

Fujian, Guangdong, Guangxi, SW Guizhou (Ceheng Xian), S Hunan, SW Jiangxi (Longnan Xian), SW Sichuan, Taiwan, SE Xizang (Mêdog Xian), Yunnan [Bhutan, Cambodia, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Sikkim, Thailand, Vietnam].

300-3500 m

Fl. Per. Aug.-October.

Forests, streamsides in ravines; near sea level to 2800 m.

Commelina obliqua Buchanan-Hamilton ex D. Don.

Đối với các định nghĩa khác, xem Rau trai.

Thài lài nước hay trai nước, tên khoa học Commelina paludosa, là một loài thực vật có hoa trong họ Commelinaceae. Loài này được Blume miêu tả khoa học đầu tiên năm 1827.

大苞鸭跖草（学名：Commelina paludosa）为鸭跖草科鸭跖草属的植物。分布于台湾岛、印度尼西亚、尼泊尔、印度以及中国大陆的福建、江西、四川、湖南、西藏、广东、广西、云南、贵州等地，生长于海拔110米至2,800米的地区，常生长在林下和山谷溪边，目前尚未由人工引种栽培。