acacia

A genus of thorny trees and shrubs found across the world's dry landscapes — Africa, Australia, the American Southwest, the Middle East. Acacias are among the toughest plants on earth: deep-rooted, drought-resistant, armed with spines, and often the only tree standing in a landscape that has defeated everything else. Many species fix nitrogen, enriching the soil beneath them and creating islands of fertility in otherwise barren ground. The flat-topped silhouette of the African acacia against an open sky is one of the most recognized shapes in the natural world.