Hillgrove box facts for kids

The Hillgrove box (scientific name: Eucalyptus retinens) is a special type of tree found only in the Northern Tablelands area of New South Wales, Australia. It's known for its interesting bark, which is rough and flaky on its main trunk and bigger branches, but smooth on the thinner ones. This tree also has long, spear-shaped leaves, and its flowers are white. After the flowers, it grows unique cup-shaped fruits.

Hillgrove Box: A Unique Australian Tree

The Hillgrove box is a fascinating tree that can grow quite tall, usually reaching about 20 to 25 meters (about 65 to 82 feet) high. It has a special woody swelling at its base called a lignotuber. This lignotuber helps the tree regrow if it gets damaged, for example, by fire.

What Does the Hillgrove Box Look Like?

Bark and Size

The bark on the main trunk and larger branches of the Hillgrove box is rough. It can be fibrous, meaning it looks like threads, or flaky, peeling off in pieces. This rough bark is usually grey. However, the bark on the thinner branches is smooth and can be grey or greenish.

Leaves and Flowers

Young Hillgrove box plants and new shoots that grow after the tree has been cut back have square stems. Their leaves are directly attached to the stem without a stalk (this is called sessile). These young leaves are about 35 to 100 millimeters (1.4 to 3.9 inches) long and 25 to 80 millimeters (1 to 3.1 inches) wide. They grow in pairs, with their bases wrapping around the stem.

As the tree gets older, its adult leaves change. They are shiny green on both sides and have a shape like a spear or a gentle curve. These leaves are quite long, from 90 to 300 millimeters (3.5 to 11.8 inches), and 10 to 40 millimeters (0.4 to 1.6 inches) wide. They narrow down to a leaf stalk, called a petiole, which is about 12 to 40 millimeters (0.5 to 1.6 inches) long.

The tree's flower buds grow in groups of seven where the leaves meet the stem (called the leaf axil). Each group of buds sits on a stalk about 5 to 17 millimeters (0.2 to 0.7 inches) long. The individual buds are oval or oblong, about 7 to 10 millimeters (0.3 to 0.4 inches) long. They have a rounded or cone-shaped cap, known as an operculum, which covers the flower before it opens. When they bloom, the flowers are white.

Fruit and Seeds

After the flowers, the Hillgrove box produces a woody fruit. This fruit is a type of capsule, which means it's a dry fruit that opens to release seeds. The fruits can be cup-shaped, cylindrical, or like half a sphere. They are about 5 to 10 millimeters (0.2 to 0.4 inches) long and 7 to 10 millimeters (0.3 to 0.4 inches) wide. When the fruit opens, its parts (called valves) stick out above the rim.

How Did It Get Its Name?

Scientists have a special way of naming and classifying all living things; this is called taxonomy. The Hillgrove box was officially described and named in 1990 by two botanists, Lawrie Johnson and Ken Hill. They published their findings in a science journal called Telopea.

The specific part of its scientific name, retinens, comes from a Latin word that means "retaining" or "holding back." This name was chosen because of the tree's persistent bark, which stays on the trunk rather than shedding completely.

Where Does the Hillgrove Box Grow?

The Hillgrove box tree is found in a specific part of New South Wales, Australia. It likes to grow on the edges of steep gorges or on top of steep ridges. You can find it in the eastern areas of the Northern Tablelands.