Purple-wood wattle facts for kids
Quick facts for kids Purple-wood wattle |
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| Conservation status | |
| Scientific classification | |
| Genus: |
Acacia
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| Species: |
carneorum
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| Occurrence data from AVH | |
| Synonyms | |
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Acacia carnei Maiden |
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The Purple-wood Wattle (scientific name: Acacia carneorum) is a special plant. People also call it needle wattle or dead finish. It belongs to the Acacia family, which includes many types of wattle trees.
This plant grows in small groups in the far north-west of New South Wales and South Australia. It is a threatened species, meaning it's at risk of disappearing. The government lists it as vulnerable under important laws like the Environmental Protection and Biodiversity Conservation Act.
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What Does Purple-wood Wattle Look Like?
The Purple-wood Wattle is famous for its deep purple wood inside. But if you cut it and leave it out, the purple wood turns almost black after a few weeks!
From the outside, it looks like a dark green, prickly bush or a small tree. It can grow about 2 to 4 meters (6 to 13 feet) tall and spread up to 8 meters (26 feet) wide. These plants grow very slowly once they are mature. Some photos show how little they've changed in over 30 years!
Its "prickly" look comes from its pointy leaves, called phyllodes. These leaves are stiff, straight, and have four angles. They are usually 2 to 9 centimeters (about 1 to 3.5 inches) long and 1 to 2 millimeters wide. They might look a bit grey-green and have lighter veins.
The flowers are bright yellow, fuzzy balls. They are about 7 to 10 millimeters wide. They usually grow alone or sometimes in pairs, on hairy stalks.
The seed pods are about 3 to 5 centimeters (1 to 2 inches) long and 10 millimeters wide. They can be straight or slightly curved. These pods are hard and woody, covered in soft, white hairs. They have slight pinches where the seeds are inside.
Scientists have used carbon dating to find out how old these plants are. They can live for a very long time, from about 120 to 330 years! Most of the plants found are very old. This means not many new plants have grown since grazing animals like sheep and cattle were brought to Australia in the 1860s.
Besides grazing, the plant also has an ancient way of making copies of itself without seeds. This, along with changes to its home, has made it hard for new seeds to grow.
How Does Purple-wood Wattle Reproduce?
Purple-wood Wattle flowers often have female parts that mature first. Most flowers have both male and female parts. Many Acacia species cannot fertilize themselves, but we don't know for sure with Purple-wood Wattle.
The plant produces orange, woody fruits. These fruits might stay on the plant for several years after they open up. However, it's very rare for this plant to produce fruit. Studies from 2010-2012 showed that most groups of these plants still don't produce any fruit.
It's also rare for them to make pods and seeds that can grow into new plants. Only two study areas in New South Wales are known to produce seeds. Most of the time, Purple-wood Wattle makes copies of itself in a different way, called clonal reproduction.
Clonal reproduction means the plant grows new plants from its roots, like "suckers." These root suckers grow twice a year, in autumn and spring.
Clonal reproduction is the main way Purple-wood Wattle makes new plants. This method is helpful when it's hard for seeds to grow, or if something keeps the plant from flowering and fruiting. But relying only on cloning can mean the plants don't have much genetic diversity. This can make them more likely to die out if conditions change or a disease spreads. Even with low seed production, if a plant can do both sexual and clonal reproduction, it can still keep good genetic diversity. Purple-wood Wattle has been genetically isolated for a long time, even before people changed the land.
Where Does Purple-wood Wattle Live?
You often find Purple-wood Wattle growing on wide mounds of sand. It likes to grow in grasslands and woodlands with red sandy soils. It prefers shallow, chalky, and loamy soils. This includes alkaline soils, brown earths, and red duplex soils. You can usually find it on the tops or sides of sand dunes.
Purple-wood Wattle often grows near other plants like Casuarina cristata, Casuarina pauper, Alectryon oleifolius, Atriplex vesicaria, Rhagodia spinescens, and different types of Maireana plants.
Life Cycle and Pollination
Purple-wood Wattle flowers usually appear after heavy rain, no matter the time of year.
The most common pollinators for Purple-wood Wattle are wasps, native bees, flies, and butterflies. Many different insects visit the plant, but only a few of them are good at helping the plant make seeds. The plant's success is not linked to its problems with reproduction. The way its fruits are made suggests that birds might help spread its seeds. This could explain why some groups of these plants are found very far apart.
What Threats Does Purple-wood Wattle Face?
The biggest reason Purple-wood Wattle plants are not growing back is rabbits.
Rabbits chew off the bark around the plant's trunk. This is called ringbarking, and it kills the plant. Rabbits also dig burrows, which can expose the plant's roots and make sand dunes unstable.
Young suckers that grow from the roots are often eaten by animals that graze, like rabbits and farm animals. This leads to the death of young plants. Other threats include goats and kangaroos, which eat the leaves. Cattle can also stand under the trees, which can make the soil unstable.
How Purple-wood Wattle Got Its Name
Purple-wood Wattle belongs to the plant family Mimosaceae. It is part of a group called Phyllodineae.
Scientists have studied its chemicals (flavonoids) and found that it is related to A. crombiei and A. peuce.
The plant was first called Acacia carnei. Later, scientists Hall and Johnson suggested changing the name to A. carneorum. This new name honors both geologist Joseph Carne (who lived from 1855-1922) and his son, botanist Walter M. Carne (who lived from 1885-1952). This name is now widely used.
Where is Purple-wood Wattle Found?
Today, we know that groups of Purple-wood Wattle plants live in the dry areas west of the Darling River in South-east Australia. It is also expected to be found in Sturt National Park in New South Wales.
Most of these plant groups are outside of protected areas. Only about 34% of them are in conservation areas.
There are about 240 distinct genetic individuals of this plant. Most of them have more than two sets of chromosomes (they are polyploid). These groups are often separated by more than 10 kilometers (6 miles) of land where the plant cannot grow. The next small group of plants might be hundreds of kilometers away.
