A genus of a single species, allied to Rhodotypos, but differing in its yellow, five-petalled flowers and one-seeded carpels. It is named in honour of William Kerr, who introduced the double-flowered form of the species. He was a young Kew gardener who was sent to China in 1803 to obtain plants for the Royal Gardens. He was at Canton for some time, visited Java and the Philippines and returned to Canton, whence in 1804 he sent a collection of plants to Kew. He was appointed Superintendent of the Ceylon Botanic Garden in 1812 and died in Ceylon in 1814.