What is a genus of bitter herbs or shrubs having eight stamens and a two-celled ovary (as the Seneca snakeroot, the flowering wintergreen, etc.); milkwort called?

polygala — A genus of bitter herbs or shrubs having eight stamens and a two-celled ovary (as the Seneca snakeroot, the flowering wintergreen, etc.); milkwort. (Webster's 1913.)