 Typically, a colorful bract subtends each flower; in some species, the bract is large and showy.The calyx usually has four or five lobes; the corolla tubular, two-lipped or five-lobed; stamens number either two or four, arranged in pairs and inserted on the corolla, and the ovary is superior and bicarpellated, with axile placentation.The fruit is a two-celled capsule, dehiscing somewhat explosively.