are opposite or in whorls of three to five, simple lanceolate, and usually have serrated margins (entire in some species), 1-25 cm long, and can be either deciduous or evergreen, depending on the species.

The flowers are very decorative; they have a pendulous teardrop shape and are displayed in profusion throughout the summer and autumn, and all year in tropical species. They have four long, slender sepals and four shorter, broader