Description from Flora of China
Evolvulus emarginatus N. L. Burman, Fl. Indica 77. 1768; Convolvulus reniformis Roxburgh; Ipomoea reniformis (Roxburgh) Choisy.
Herbs perennial, prostrate; axial parts sparsely hirtellous or glabrescent. Stems rooting at nodes, becoming tuberculate. Petiole 0.2-3.7 cm; leaf blade reniform to broadly ovate, 0.5-3.5 X 0.6-3.5 mm, glabrous or sparsely appressed pilose, base cordate, margin entire or coarsely crenate, apex obtuse to broadly rounded or slightly emarginate. Inflorescences subsessile, 1(-3)-flowered; bracts unequal, ovate to linear, pubescent, apex acute. Pedicel 2-4 mm. Sepals obovate to circular or subquadrate, ± pubescent abaxially, margin long ciliate; outer 2 sepals 2.5-3 mm, apex obtuse, hoodlike and distinctly mucronate; inner 3 sepals 3-6 mm, deeply emarginate. Corolla yellow, tubular-campanulate, 5-9 mm, midpetaline bands distinctly 5-veined, purplish tinged outside, inside pubescent basally; limb slightly 5-lobed. Filaments pubescent basally. Ovary glabrous. Capsule enclosed by persistent calyx, brown-black, ± globular, 5-6 mm, longitudinally grooved, glabrous, apiculate. Seeds grayish brown, ca. 2.5 mm, glabrous. 2n = 30.
Weedy in fields, roadsides, grasslands, on clay to sandy soils, forest floors; 0-200 m. Guangdong, Hainan [India, Indonesia, Malaysia, Myanmar, Nepal, Philippines, Sri Lanka, Thailand; Africa].