Gonolobus riparius

Native to Colombia and northern Venezuela, this climbing subshrub has twining stems that release milky sap when damaged. Rounded, slightly grooved young branches are covered with hairs. Opposite, pointed leaves have deeply heart-shaped bases, smooth upper surfaces and fine hairs beneath. Groups of stalked flowers develop between the leaf bases. Green flowers spread nearly flat, with five pointed, oblong lobes and gently wavy edges. A small central crown surrounds the compact reproductive structures. Photographed in Colombia.