Dooja facts for kids

Quick facts for kids Australian round lime
Scientific classification
Genus:	Citrus
Species:	australis

The Citrus australis, also known as the Dooja, round lime, Australian lime, or Australian round lime, is a large shrub or small tree. It grows tasty fruit. You can find it in the edges of forests in the Beenleigh area and further north in Queensland, Australia.

This tree can grow up to 20 meters (about 65 feet) tall. Its fruits are round or slightly pear-shaped, about 2.5 to 5 centimeters (1 to 2 inches) wide. They have a thick green or yellow skin and light green inside. In 1889, a book called The Useful Native Plants of Australia said that its "acid juice" makes a nice drink.

About the Australian Round Lime

The Australian round lime is part of the Rutaceae family, which includes all citrus fruits. It has many names like Australia sweet, dooja, Gympie lime, native lime, native orange, or round lime.

There are three main types of native limes in Australia:

• The Australian finger lime (Microcitrus australasica)
• The Australian desert lime (Ermocitrus glauca)
• The Australian round lime (Citrus australis)

Other types of Microcitrus also grow in Australia. These native limes can mix with other citrus types. This mixing can create new plants with special features. For example, they might become better at handling dry weather, salty soil, or diseases.

What the Plant Looks Like

In nature, the Australian round lime tree can reach about 20 meters (65 feet) tall. Its small branches have sharp thorns. The leaves are usually oval-shaped with pointed tips. Each leaf is about 3 to 4 cm long and 2 to 3 cm wide.

The tree produces white or pinkish-white flowers. The fruit has a thick outer skin and a yellowish-white inside. Inside the fruit, there's a slender spine about 1 cm long. You'll find only a few seeds and many firm, pale green juice sacs. Sometimes, these juice sacs look twisted because they are packed so tightly inside the fruit. It can take about three years for a young plant to start growing fruit.

How it's Different from Other Limes

The Australian round lime often has a pear-like shape. It is a bit narrower at the top and wider at the bottom. This is different from the perfectly round shape of many other limes. It is also smaller, about 2 to 5 cm (1 to 2 inches) wide. This makes it easy to tell apart from common limes, which are usually bigger.

These limes also have a lot of yellow oil inside their juice sacs. This is another way they differ from other common citrus fruits. The Australian round lime has larger juice sacs near its center, which produce this oil. Limes with more oil usually have bigger leaves. For example, the Australian round lime has an oil yield of 0.3-0.5%. Its leaves are about 3 to 4 cm long.

The essential oils in the leaves of different citrus plants are also unique. The Australian round lime is special because it has a lot of a-pinene. It has very little limonene, which is common in the Australian finger lime.

Where it Grows and How it's Grown

The Australian round lime grows in southeast Queensland, Australia. You can find it in the lowland sub-tropical rainforests, especially north of Brisbane. This lime grows slowly and needs protection when it's young. The thorns on its stems help protect it from wild animals.

It's important to keep the soil moist for this plant to grow well. This is especially true during dry seasons. Even so, it's a tough plant and can handle winter weather. It can even tolerate some frost. Animals that eat the fruit help spread its seeds.

Growing in Other Places

The Australian round lime can also be found in places like California in the United States. Even though it takes time for the plant to grow roots, you can start new plants from stem cuttings. You can also graft (attach) a piece of the Australian round lime onto another citrus plant's root system. This helps the plant grow more fruit.

Uses of the Australian Round Lime

The Australian round lime is full of good things for you! It has energy, protein, fiber, and important minerals like calcium, iron, and potassium. Because of this, it's still used in cooking in Australia today.

You can eat the fruit raw, but it's quite sour. It's more often used in cooking to make marmalades or to add a lime flavor to dishes. The peels can be cut into strips to decorate pastas. They can also be ground up to add a subtle flavor to sauces. It tastes great with seafood too! The flowers bloom in spring, and the fruits are ready from November to March. They turn greenish-yellow when ripe.

Comparing with Other Limes

The Australian round lime is often compared to the Citrus australasica (Australian finger lime). The finger lime also grows in similar areas and is used for juices or jams. While the finger lime is great for making preserves, the Australian round lime is better for adding flavor to dishes.

Another common comparison is with the Tahitian lime. The Tahitian lime is also used for marmalades and juices. However, its skin is rough, so you might not use the whole lime. The Australian round lime has a drier inside than the Tahitian lime. But you can cut it in half or use it whole to flavor many meals.

Other Uses

The Australian round lime also produces special oils from its juice sacs. These oils can be used as an essential oil because they have a unique and pleasant smell. The oils can also be used in cleaning sprays. Many cleaner sprays contain a chemical called limonene, which often comes from limes.

The Australian round lime can also be used to create hybrids. Hybrids are new plants made by crossing two different types of plants. Since the Australian round lime is a strong native Australian species, it's useful for creating new citrus varieties. For example, the Sydney hybrid is a mix of the Australian round lime and the Australian finger lime. It mostly grows in Australia. The Sydney hybrid looks a lot like the Australian finger lime in its leaf size and fruit shape. Its fruit is longer, about 3 x 5 cm, and rounded at the end. It's also very good at handling dry conditions.

While the wild trees can grow very tall, you can also grow the Australian round lime in a garden. It will usually stay a smaller shrub or tree, about 3 to 6 meters (10 to 20 feet) tall. When the plant is young, it has many thorns for protection. But as it grows older, it becomes less prickly, making it easier to care for. The wood of the Australian round lime is fine-grained. This makes it good for making cabinets and for engraving.

History of the Australian Round Lime

The Australian round lime belongs to a group called Microcitrus. This group also includes other limes like the New Guinea lime. Scientists believe that the Australian round lime has evolved over millions of years. It came from an older type of citrus that changed and developed into new species in Australia and New Guinea.

This evolution happened in two main stages. The first stage was millions of years ago in East and Southeast Asia. This stage gave us limes like the citron and mandarin. The second stage happened later in Oceania (which includes Australia). This stage led to the Australian species we know today, like the Citrus glauca, Citrus australasica, and the Citrus australis.