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Eucalyptus

life science Maturity 11-13 Next article →

Eucalyptus is a massive genus of flowering plants within the Myrtaceae family.

Eucalipto (talvez Eucalyptus globulus) na zona rural de Bagé
Eucalipto (talvez Eucalyptus globulus) na zona rural de Bagé

It contains more than 700 different species. Most of these species grow as trees, though some are shrubs. Many are also known as mallees, which are plants with multiple stems growing from the ground. They are frequently called "gum trees" or eucalypts. These plants are vital to many ecosystems and economies. They are used for timber, pulpwood, honey production, and essential oils.

Eucalyptus forest2
Eucalyptus forest2

The genus is defined by a unique flowering mechanism. In most flowers, petals are the most visible part. In Eucalyptus, the sepals and petals are fused together. This fusion forms a protective cap called an operculum. The name Eucalyptus comes from the Greek words "eu," meaning well, and "kaluptos," meaning covered. This refers to how the operculum covers the stamens. As the stamens expand, they push the cap off. The flower then displays many fluffy stamens. These stamens can be white, cream, yellow, pink, or red. After flowering, the plant produces woody fruits called capsules. These are often called "gumnuts."

Close-up Eucalyptus Flower Ooty Sep25 A7CR 07608-22 zsp
Close-up Eucalyptus Flower Ooty Sep25 A7CR 07608-22 zsp

Eucalyptus plants show incredible variety in their physical forms. Their size can range from small shrubs to massive trees. The Eucalyptus diversicolor is a notable example. It is the tallest reliably measured tree in Europe. This tree is located in Portugal. It reaches a height of 72.9 meters. It also has a girth of 5.71 meters. Some species are called mallees because they stay under 10 meters tall. Other specific types include "mallets" and "marlocks." A mallet has a single thin trunk but lacks certain growth structures. A marlock is a small tree or shrub with a short, single trunk.

Eucalyptus leucoxylon1
Eucalyptus leucoxylon1

The bark of a eucalyptus is also highly diverse. Every year, these plants add a new layer of bark. The outermost layer eventually dies. About half of the species are "smooth barks." They shed their dead bark in large slabs, ribbons, or small flakes. This exposes fresh, living bark underneath. Other species keep their dead bark as it dries. Some have "stringybark," which consists of long, thick fibers. Others have "ironbark," which is hard and deeply furrowed. Ironbark is often infused with dark red or black gum resin called kino. Some species are "half-barks." These retain rough bark only on the lower part of the trunk.

Yellow Box blossoms and gumnuts
Yellow Box blossoms and gumnuts

Leaves are another important way to identify these plants. Most eucalypts are evergreen. However, some tropical species lose leaves during the dry season. Eucalyptus leaves contain many oil glands. This production of oils is a key feature of the genus. The leaves often hang downwards, creating patchy shade. As a plant grows, its leaves change through four phases. These are the seedling, juvenile, intermediate, and adult phases.

Eucalyptus tetragona - glaucous leaves close
Eucalyptus tetragona - glaucous leaves close

Seedling leaves are often opposite and waxy. Adult leaves are often lance-shaped and appear alternate. This change in leaf shape is very useful for scientists in the field.

Humans have a long history of studying these plants. The genus was first formally described in 1789. Charles Louis L'Héritier de Brutelle published this description. He used Eucalyptus obliqua as the type species. This species was collected in 1777 by David Nelson. He found it on Bruny Island. Later, in the 1800s, Ferdinand von Mueller did important work. He helped create a major account of the genus in 1867. This work was part of George Bentham's Flora Australiensis. Over time, scientists moved from studying stamens to studying buds and fruit.

Eucalyptus camaldulensis seeds00
Eucalyptus camaldulensis seeds00

Eucalyptus species are deeply connected to the environment and human industry. They are native to Australia, where they exist in every state. A few species live on islands north of Australia. Because they grow so fast, they are grown in plantations worldwide. They provide valuable resources like timber and pulp. However, they can also be dangerous. Their high flammability makes them a risk for forest fires. In some countries, people have removed them to reduce this fire danger. Understanding their biology helps us manage both their benefits and their risks.

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🖼️ Images & Media (15)
File:Eucalyptus leucoxylon1.jpg
Eucalyptus leucoxylon1.jpg
File:Eucalyptus tetragona - glaucous leaves close.jpg
Eucalyptus tetragona - glaucous leaves close.jpg
File:Close-up Eucalyptus Flower Ooty Sep25 A7CR 07608-22 zsp.jpg
Close-up Eucalyptus Flower Ooty Sep25...
File:Yellow Box blossoms and gumnuts.jpg
Yellow Box blossoms and gumnuts.jpg
File:Eucalyptus camaldulensis seeds00.jpg
Eucalyptus camaldulensis seeds00.jpg
File:Eucalipto (talvez Eucalyptus globulus) na zona rural de Bagé.jpg
Eucalipto (talvez Eucalyptus globulus) na...
File:Tasmania logging 16 Styx a tree in danger.jpg
Tasmania logging 16 Styx a tree in danger.jpg
File:Epicormic Shoots from an Epicormic Bud on Eucalyptus following Bushfire 2, near Anglers Rest, Vic, Aust, jjron 27.3.2005.jpg
Epicormic Shoots from an Epicormic Bud on...
File:Eucalyptus forest2.jpg
Eucalyptus forest2.jpg
File:Post bushfire epicormic regrowth in eucalyptus, Blue Mountains, NSW, Australia 05.jpg
Post bushfire epicormic regrowth in...
File:San Diego Firestorm 2007.jpg
San Diego Firestorm 2007.jpg
File:Fallen Eucalyptus camaldulensis limbs (1).jpg
Fallen Eucalyptus camaldulensis limbs (1).jpg

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