Helia viridiflora

Native from Brazil to northeastern Argentina, this annual herb grows in savannas, rocky grasslands and seasonally flooded forests. It reaches about four feet tall, with unbranched or sparsely branched, cylindrical stems. Opposite leaves are oval to lance-shaped with pointed tips. White to greenish or pale yellow flowers have a funnel-shaped corolla with five spreading lobes; the stamens remain inside the tube. Elongated capsules develop after flowering and release numerous small seeds. Photographed in Peru.