Merremia hirta (L.) Merr.

Used medicinally to treat arthritis.

Herbs, twining or prostrate. Stems rooting at nodes or internodes, spreading hirsute to glabrous. Petiole 1-5(-20) mm; leaf blade linear, oblong-lanceolate, ovate-oblong, or ovate, 1.9-6 X 0.5-2.5 cm, sparsely appressed hirsute or glabrous, base truncate, rounded, ± auriculate to hastate, margin entire, apex obtuse, acute or slightly emarginate and mucronulate. Inflorescences 1-4(-8)-flowered; peduncle filiform, 1.5-3.5(-7.5) cm, glabrous or sparsely pubescent basally; bracts persistent, ovate, 1-2 mm, glabrous. Pedicel 5-10 mm, glabrous. Sepals elliptic or elliptic-oblong, unequal; outer 2 sepals 3-5 mm; inner 3 ca. 6 mm, margin purplish, apex obtuse. Corolla pale yellow or whitish, broadly funnelform, 0.9-1.1(-1.8) cm, midpetaline bands dark veined, glabrous outside. Stamens included; filaments dilated and pubescent basally. Ovary glabrous. Capsule broadly ovoid to globose, 6-7 mm, thinly papery, glabrous. Seeds brownish black, trigonous-ellipsoid, ca. 3 mm, glabrous or sparsely floccose at margin and hilum.

Guangdong, Guangxi, Taiwan, Yunnan [India, Indonesia, Laos, Malaysia, Myanmar, Philippines, Thailand, Vietnam; N Australia]

Open grasslands, cultivated fields, roadsides, thickets, forest margins; 0-1000 m.

Convolvulus hirtus Linnaeus, Sp. Pl. 1: 159. 1753; C. caespitosus Roxburgh; C. reptans Linnaeus, p.p.; Ipomoea linifolia Blume; I. philippinensis Choisy; Lepistemon decurrens Handel-Mazzetti; Merremia caespitosa (Roxburgh) H. Hallier; M. decurrens (Handel-Mazzetti) H. S. Kiu; Skinneria caespitosa (Roxburgh) Choisy.

Merremia hirta is a species of flowering plant in the family Convolvulaceae, native to India, southern China, Southeast Asia, Malesia, Papuasia, and Queensland. A twining herb, it is typically found in well-lit situations; grasslands, farm fields, roadsides, thickets, and forest edges, from sea level to 1,000 m (3,300 ft).