button-wood, in botany: A genus of plants belonging to the class of *tetrandria*, and order of *monogynia*; and in the natural system arranged under the 47th order, *flabella*. The corolla is monopetalous and funnel-shaped, and there are two bidentate teeth. The species are eight, *tenue*, *verticillata*, *hirta*, *articulata*, *stricta*, *hispidia*, *procumbens*, and *spinae*.