Acacia

The wattle is a type of tree or bush.

Many grow in Australia. They have bright yellow flowers.

These flowers can be small and round. Some plants have leaves that look like flat stems.

These plants make pods to hold their seeds. Some people eat the seeds. They can be made into flour. The seeds have a lot of protein. This helps people stay strong.

Acacia plants are often called wattles. Most of these trees and shrubs grow in Australia.

These plants have many different looks. Some have bipinnate leaves. This means the leaves are made of many small parts. Other plants have phyllodes. These are parts that look like leaves but are actually stems.

The flowers are very pretty. They grow in clusters called spikes or heads. Most flowers are golden-yellow or creamy-white.

They have many tiny parts called stamens. After the flowers fade, the plant makes a pod. This pod holds the seeds.

Many animals use the acacia. Some butterflies eat the leaves. Even some reptiles eat the sap. People can use these plants, too. Aboriginal Australians have used the seeds for food. They can grind them into flour. The seeds have a lot of protein. This helps people stay healthy. Some wood is used to make tools or even music instruments. Many species are also grown for wood or paper.

Acacia plants are often called wattles. These plants include many different types of shrubs and trees. Most of them belong to the pea family. While they once grew in Africa and South America, most species are now found in Australia. They are also found in places like New Guinea and Southeast Asia.

These plants are very important to the land they live in. In Australia, acacia forests are the second most common type of forest. They cover about 8% of the total forest area in that country.

Each acacia plant has its own special way of growing. Some plants have bipinnate leaves, which are leaves made of many small parts. Other plants have phyllodes. These are stems that look and act like leaves. The flowers grow in shapes like spikes or cylindrical heads. These clusters hold many tiny flowers that are golden-yellow or creamy-white. Each small flower has more than 10 stamens. After the flowers finish blooming, the plant grows a fruit called a pod. These pods can be flat or shaped like a cylinder.

People have studied these plants for a very long time. A man named Philip Miller first gave the genus its name in 1754. In 1913, two scientists named Nathaniel Lord Britton and Addison Brown worked on the plant names. There was even a big debate about how to group them. Scientists argued about whether to use the name Acacia or Racosperma. In 2011, a big meeting in Melbourne, Australia, decided to keep the name Acacia for the largest group of species.

There are many different facts about how many acacias exist. As of January 2025, there are more than 1,080 accepted species. Most of these are native to Australia. Some species are very old, with pollen fossils found from 25 million years ago. In South Africa, some species were brought in to help hold sand dunes in place. One species called Acacia mearnsii was planted in 1864 to get tannins from its bark. Today, two million hectares of these plants are grown in plantations for business.

Acacia plants connect to many parts of nature and human life. Many animals rely on them to survive. For example, the imperial hairstreak butterfly feeds on at least 25 different species. Some reptiles even eat the sap from the plants. Humans have also used them for a long time. Aboriginal Australians have ground the seeds into flour to make cakes. These seeds have 25% more protein than many common cereals. People also use the wood for tools, fuel, or even making music instruments.

Acacia is a large genus of shrubs and trees within the Mimosoideae subfamily. These plants belong to the Fabaceae family, which is commonly known as the pea family. While the genus originally included species from Africa and South America, it is now primarily used for plants found in Australasia. Many species also grow in New Guinea, Southeast Asia, and the Indian Ocean. These plants are incredibly diverse and play vital roles in their environments. In Australia, acacia forests are the second most common forest type. They cover approximately 8% of the total forest area in the country.

Physically, acacia plants show a variety of leaf structures. Many species have bipinnate leaves, which means the leaves are divided into many small leaflets. In some mature plants, these leaves are reduced to structures called phyllodes. A phyllode is a flattened leaf stalk that functions like a leaf.

The flowers of the acacia are often quite striking. They grow in clusters called spikes or cylindrical heads. These clusters can appear singly, in pairs, or in groups called racemes. Each cluster contains many tiny golden-yellow or creamy-white flowers. Each individual flower has four or five sepals and petals, plus more than 10 stamens. The style, a thread-like part of the flower, is longer than the stamens. After flowering, the plant produces a fruit known as a pod. These pods can be flat or cylindrical and contain seeds with a fleshy aril at the end.

The history of naming the acacia has been complex for botanists. Philip Miller first validly named the genus in 1754 in his book, *The Gardeners Dictionary*. Later, in 1913, scientists Nathaniel Lord Britton and Addison Brown selected a specific African species as the lectotype. A lectotype is a single specimen chosen to represent the name of a group. For a long time, scientists believed the genus contained about 1,352 species. However, in 1986, a scientist named Leslie Pedley argued that the genus was not monophyletic. A monophyletic group is one that includes an ancestor and all its descendants. Pedley suggested splitting the genus into three separate groups: Acacia, Senegalia, and Racosperma.

This split caused a significant scientific debate between different regions. One group of over 900 species was mainly native to Australia and nearby islands. This group was not closely related to the smaller African group that held the original type species. Because of this, there was a disagreement over which group should keep the name Acacia. Australian botanists wanted to keep the name for their large group of plants. They proposed a new type species, *Acacia penninervis*, to allow the majority of species to remain under the Acacia name.

In 2005, a decision was made to conserve the name Acacia for the Australian component. This decision was upheld at the 2011 International Botanical Congress in Melbourne.

The fossil record shows that acacia-like plants have existed for millions of years. Fossil seed pods similar to acacia have been found in the Eocene of the Paris Basin. Other fossils, named *Leguminocarpon*, have been found in Hungary from the late Oligocene. In Switzerland, fossils of *Acacia parschlugiana* and *Acacia cyclosperma* have been identified from Tertiary deposits. The oldest fossil pollen for an acacia species in Australia dates back 25 million years to the late Oligocene.

Today, there are more than 1,080 accepted species of acacia recognized by Plants of the World Online as of January 2025.

Acacia species interact deeply with their local ecosystems. They serve as a common food source and host plant for various animals. For instance, the imperial hairstreak butterfly, *Jalmenus evagoras*, feeds on at least 25 different acacia species. Some reptiles, such as the native house gecko in Australia, feed on the plant's sap. Various insects, known as Hemiptera, also consume the sap.

Humans also find many uses for these plants. Aboriginal Australians have traditionally harvested seeds to grind into flour for cakes. These seeds are very nutritious, containing up to 25% more protein than many common cereals. They also use the timber for making tools, weapons, fuel, and musical instruments.

Beyond traditional uses, acacia has significant economic and environmental impacts. Many species are grown in large plantations for commercial purposes. For example, two million hectares of commercial plantations have been established worldwide. Species like *Acacia mangium* and *Acacia mearnsii* are used for wood products, firewood, and fodder. The bark of the black wattle is also used to produce tannins. Tannins are substances used in the tanning industry to make leather. However, some species can also be problematic. In South Africa, at least 16 introduced acacia species are considered invasive. This means they can spread out of control and disrupt the local environment.