The term 'Tropical Herb' encompasses three plants: Sida (4 letters), YAM (3 letters), and Urena (5 letters). Sida is a genus of flowering plants in the mallow family, native to tropical regions of the world. YAM is a common name for some species of the Dioscorea genus of perennial herbaceous vines, native to tropical regions of Asia, Africa, and the Americas. Urena is a genus of flowering plants in the mallow family, native to tropical regions of the world. All three of these plants are used in traditional medicine and cuisine.