Mallee manna gum facts for kids
Quick facts for kids Mallee manna gum |
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| Scientific classification | |
| Genus: |
Eucalyptus
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| Species: |
arcana
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| Synonyms | |
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Eucalyptus splendens subsp. arcana Nicolle & Brooker |
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The Eucalyptus arcana, also known as the Mallee manna gum or Carpenter Rocks gum, is a special type of mallee tree. This means it's a small, shrubby tree with many stems growing from the ground. It is only found in one place, near Carpenter Rocks in South Australia. This makes it an endemic species, meaning it naturally lives only in that specific area.
This unique gum tree has rough bark that covers its trunk and even its thinner branches. Its leaves are shaped like a spear, and its flower buds grow in groups of seven. When it blooms, it has pretty white flowers, and later, it produces fruit shaped like half a sphere.
What it Looks Like
The Mallee manna gum is usually a low, sprawling tree. It often has several stems and can grow up to about 6 metres (20 feet) tall. The bark on its main trunk and larger branches is rough and fibrous, usually grey to grey-brown. But on its thinnest branches, the bark is smooth and can be grey or cream-coloured.
Young Mallee manna gum plants, or new shoots that grow after a fire or cutting (called coppice regrowth), have stems with four sides. Their leaves are shiny and can be oval or egg-shaped, about 45 to 120 millimetres (1.8–4.7 inches) long and 13 to 55 millimetres (0.5–2.2 inches) wide, often with wavy edges.
The adult leaves are shaped like a lance, which means they are long and narrow. They are shiny green on both sides, about 80 to 150 millimetres (3.1–5.9 inches) long and 17 to 30 millimetres (0.7–1.2 inches) wide. These leaves grow on a stalk called a petiole, which is about 10 to 28 millimetres (0.4–1.1 inches) long.
The flower buds grow in groups of seven on a small stalk called a peduncle, which is about 4 to 10 millimetres (0.2–0.4 inches) long. Each individual flower bud also has its own tiny stalk, called a pedicel, up to 2 millimetres (0.08 inches) long. When the buds are ready to open, they are oval or spindle-shaped, about 5 to 7.5 millimetres (0.2–0.3 inches) long and 4 to 5.5 millimetres (0.16–0.22 inches) wide. They have a cap, called an operculum, which looks like a blunt cone. This cap is about the same length as the base of the flower, called the floral cup.
The Mallee manna gum usually flowers in February, and its flowers are white. After flowering, it produces fruit that are shaped like half a sphere or a cone. These fruits are about 6 to 7 millimetres (0.24–0.28 inches) long and 6 to 8 millimetres (0.24–0.31 inches) wide. Inside, they hold dark brown to black seeds that are egg-shaped.
How it Got its Name
The Mallee manna gum was first officially described in 1998 by two scientists, Dean Nicolle and Ian Brooker. They first called it Eucalyptus splendens subsp. arcana. They published their description in a scientific journal called the Journal of the Adelaide Botanic Gardens.
Later, in 2009, another scientist named Kevin Rule decided that this plant was unique enough to be its own species. So, he changed its name to E. arcana. The second part of its scientific name, arcana, comes from a Latin word that means "secret" or "mysterious." This name was chosen because the plant was found hidden away in dense scrubland.
Where it Lives
The Eucalyptus arcana has a very small home range. It grows on low hills in shallow, poor, red clay-loam soils that are found over limestone. You can only find it around the coastal town of Carpenter Rocks in the south-east part of South Australia.
It often grows among thick, tall shrubland. Other plants that grow with it include the Eucalyptus obliqua and Eucalyptus ovata. Some plants that were once thought to be E. splendens subsp. arcana near Moonlight Head in south-west Victoria are now known to be a different species called E. aromaphloia.
