Broad-leaf Buttonweed is a genus of flowering plants in the family Rubiaceae. It comprises about 275 species found throughout the tropics and subtropics. Its highest diversity is found in the Americas, followed by Africa, Australia and Asia.
Broad-leaf Buttonweed is a terrestrial, tufted to erect herb, up tot 60 cm tall. Roots are fibrous, white or brown. Stems are quadrangular, solid, hairy. Stipules are present, collar like. Leaves are simple, not lobed or divided, opposite, stalkless, elliptic to ovate, hairy on both sides, tip pointed, base narrow, pinnately veined. Flowers are bisexual, grouped together in an axillary, stalkless glomerule. They are white tinged with blue to pale purple, funnel-shaped, outside hairy. Flower-tube is 2-3 mm, velvety in throat, petals triangular, 1-1.5 mm. Fruit is a capsule, opening apical slits or pores. Broad-leaf Buttonweed is probably native to tropical America, naturalized in Asia and Africa. It is found in the Himalayas, at altitudes of 200-2000 m, and also in Peninsular India.
The plant is considered to be emetic. The aerial parts of the plant are taken as a febrifuge. and are also considered to be stimulant and tonic. Externally, the leaves are applied in poultices to treat headache - they appear to have a cooling effect on the head and so allay the pain somewhat. They are also used as a poultice on wounds and sores.