Spiny trees are a type of tree that are characterized by their sharp thorns or spines. Acacias are a genus of trees and shrubs that are part of the subfamily Mimosoideae of the family Fabaceae, commonly known as the legume, pea, or bean family. Acacias are native to tropical and subtropical regions of the world, particularly Africa, Australia, and South America. They are often used for ornamental purposes due to their attractive foliage and fragrant flowers.