Spermacoce (or False Buttonweed) is a genus of flowering plants in the Rubiaceaefamily. 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.
The species are herbs or small shrubs with small- to medium-sized, four-lobed flowers arranged in capitate inflorescences. Some have a brightly coloured calyx and are eye-catching, particularly the Australian species. The corolla is variable in colour, often white, but also all shades of blue, pink and maroon. The fruit is usually a two-seeded capsule, sometimes a schizocarp or nut.