This is a small tree or large shrub which grows in clumps or dense thickets. It is also known as desert lime, native cumquat, limebush, desert lime. When young, the plant has blue-green leaves and spines or thorns growing along the branches. More mature plants lose the spines. It is a true citrus with small very juicy fruit which appear after the July to September flowering season.
The plant is a xerophyte, a drought-tolerant plant that thrives in hot and dry climates. It is mostly found in arid and semiarid parts of Qld, NSW and SA, inland areas with 200-500 mm rainfall and clay or heavy clay soils.
It is a hardy plant that will tolerate frost, drought, alkaline soil and freezing conditions. During a severe drought, it will shed its leaves and the leafless grey green twigs carry on photosynthesis at a reduced rate.
When conditions ease, the leaves grow back. It can be slow growing initially but under ideal conditions a mature tree can reach from 2 to 8 metres. It can be grafted on to normal citrus fruit stock. It responds well to pruning, and suckering can be controlled by growing it in a tub.
The fruit ripens in late spring and summer and is ripe when it reaches approximately 1 to 2 cm and is a lime-green to bright yellow colour. It will be firm, juicy and not hard. The fruit can be cleaned and stored in the freezer for up to a year.
The close relatives of the wild lime include the rainforest limes: the finger lime Microcitrus australasica, the round lime M. australis, the Mt White lime M. garrawayi, and the Russell River lime, Microcitrus indora.
This article has been taken from the April 2001 issue of "Orchard Talk", Wide Bay Branch's Newsletter.
Citrus growers are in the limelight with the first commercial harvest of fruit developed from Australian native limes.
CSIRO Plant Industry and Australian Native Produce Industries, a company that grows and sells Australian native food, have developed plantations of new lime varieties bred from native limes.
"Australia has a range of true citrus native limes," says Dr Steve Sykes of CSIRO Plant Industry. "They include the Finger Lime, which is long and narrow like a finger and may vary from green, through pink to a dark burgundy colour when ripe; the Round Lime or 'Dooja'; and the drought tolerant Desert Lime," he says.
Dr Sykes' original aim in investigating the native limes was to find out if their useful characteristics such as disease resistance, salt tolerance and fruit colour could be bred into conventional citrus fruits.
"Our research into native limes led us in a whole new direction we never envisaged," says Dr Sykes. "We have now bred lime varieties from the native limes that can be used as fruit in their own right."
Food derived from native Australian plants and animals has risen in popularity over the last decade. Aboriginal people and early settlers used the native limes as a food source, but they have remained relatively unknown to the wider public.
"Each of the different native limes has its own unique taste. They are all relatively acidic like a lemon, but are excellent when used in sauces," says Dr Sykes. "They can also be used as an ingredient for preserves, condiments and beverages."
Three varieties, each bred by Dr Sykes at Merbein in northwest Victoria, are now being evaluated in commercial orchards in Australia.
These include the Blood Lime, a cross between a mandarin and a Finger Lime and characterised by its blood red rind, flesh and juice; the Sunrise Lime, a pear-shaped orange fruit that makes an excellent marmalade; and the Outback Lime, a cultivar of the Desert Lime with small green, juicy fruits which ripen at Christmas time.
"The advantage of our varieties of lime is that they can be propagated onto normal citrus root stocks to yield consistent and quite large volumes of fruit," says Dr Sykes.
"This is important for the native food industry that has relied on wild-collected fruits, for which consistency of supply from year to year can be a problem."
Commercial quality native limes will now be harvested from orchards, reducing the need to collect native limes from the wild, and minimising any detrimental impact on natural populations.
Andrew Beal of Australian Native Produce Industries (ANPI) was one of the first people to recognise the potential of Dr Sykes' research into native limes nearly ten years ago.
"We are always on the lookout for new and interesting Australian native foods," says Mr Beal. "Using the CSIRO Plant Industry-bred varieties of native limes, we have established over 16,000 native lime trees planted throughout the citrus growing areas of Australia."
These trees will now supply ANPI's requirements for the native lime fruit in their manufactured products which are proving very popular, especially overseas. ANPI plan to treble the number of trees in their native lime orchards to keep up with anticipated demand.
"Our largest market for native lime products is in the United Kingdom," says Mr Beal. "Our products containing the CSIRO-bred native limes are also available here under the Red Ochre brand."
"We are only just starting to see the beginning of the future for these limes. Although they were first brought to the public's attention about a decade ago, they have not been widely available."
"Now with the new varieties and commercial production, our limes will be seen on increasingly more dinner menus here and across the world," says Dr Sykes.
DATE: April 2001
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