Acacias are trees and shrubs in the genus Acacia. Acacias can be found naturally on every continent on Earth except for Antarctica, and they are deliberately cultivated for a variety of purposes. The most iconic acacias are probably those adapted to the harsh environment of the African savanna, but with over 800 species in this genus, acacias are in fact quite diverse.
There are two main types of acacia. One type produces small, feathery leaves which are ideally suited to hot climates. When conditions are favorable for photosynthesis, the leaves can twist to expose the maximum amount of surface area to the sun, but when the weather gets harsh, the leaves can fold up to reduce their exposed surface area, reducing the risk of being burned. Other acacias have specialized flattened stems, instead of leaves. Many species also have thorns, and all species produce clusters of flowers with multiple stamens which cause them to appear very fuzzy.
These members of the pea family are primarily found in tropical and subtropical regions. Thanks to the thorns, they are sometimes known as thorntrees, and some people may also refer to acacias as wattles. In the natural environment, acacias can become very important, because they provide food and shelter for a wide variety of animals. Some African acacias even form symbiotic relationships with creatures like ants, establishing a habitat for the ants in return for protection from insect pests.
The shoots and seeds of some acacia species are used in Asian cuisine, and acacia honey is also prized in many regions for its mild, light flavor. Acacia honey is very slow to crystallize, making it appealing to honey producers who wish to ship their honey. Some acacias are used for their hardwood timber, while others can be treated to extract tannins and various gums. Commercially useful acacia species are actively cultivated in many regions of the world, especially in harsh environments where conventional agriculture would not be successful.
Acacias can also be used ornamentally. A number of species are quite decorative, and the thorns can be a deterrent to unwanted visitors. However, people who wish to use acacias as decorative plants may want to be aware that some people are allergic to acacia pollen. Acacias produce a great deal of pollen when they are healthy, and people with such allergies may experience watery eyes, a runny nose, or difficulty breathing when exposed.