The Australian Native Finger lime
The Australian Native Finger lime is easily the most fashionable and exciting citrus product currently available in the market. Demand for the new varieties of limes has been propagated by the like of "Tahitian Limes" and "Kaffir Limes" and their use in Asian cooking which has built up a tremendous following one the last few years. With the development of truly Australian cuisine and its fusion of traditional cooking with Asian influences the use of the Australian Native Finger Lime was a natural progression.

Finger Limes are an excellent source of Vitamin C and they are a great substitute for lemons and traditional non native limes. They can be used for drinks, in seafood, chicken, and meat dishes, and also desserts, cakes, biscuits and marmalade.
From: http://www.worldfeast.com.au

The Australian landscape and in particular the rainforests of the temperate, subtropical zones have recently been discovered as the home to one of the most fascinating, interesting and versatile of Australia's indigenous fruits the Australian Native Finger Lime. It is known by the botanical name of 'Microcitrus Australiasica'

The unique fruit is blessed with three characteristics which makes it a stand out as an ingredient for the use in fine cuisine and drinks:- Skin which has a distinctive bush aroma, and

The pulp of this native citrus which is about the size and shape of an adult finger consists of large individual vesicles of juice, like salmon caviar in size and texture, and

what's more, due to its wide genetic diversity, the Australian Native Finger Limes come in various colours, both inside and out - with pulp colours ranging from white to pink, lime green and lemon.

Citrus Australasica 'Rainforest Pearl'
Formerly known as Microcitrus australiasica, the Australian Native Finger Lime can reach a height of 10 metres but it generally grows from 4 metres to 6 metres in height.

It is as a native moderately drought and frost resistant and can best be described as a hardy, thorny, small tree or shrub with small glossy dark green foliage which is closely related to the domestic citrus.

The fruit is long and narrow (finger like in nature), and is a brownish red colour. It has a lime taste and is probably best used for Asian type cooking, jams, garnishes, sauces and drinks.
From http:greenfingers.com.au/services/digging_deeper/citrus/Native_Citrus.html

Microcitrus australasica
Microcitrus australasica , "Australian Finger Lime", grows to an erect tree of 10 meters. The fruits are green and cylindrical up to 50mm or 2" long and only about 20mm or 1" in diameter.

They have prominent thorns and set plenty of viable seed in their natural habitat from the Clarence River NSW, north to Brisbane Qld. Both of the native limes, that is the "Finger Lime" and the "Round Lime" have a slight taste of turpentine according to W.D. Francis in his book "Australian rain-forest trees". 

The seed is known to be slow to germinate and Nan & Hugh Nicholson claim that cuttings take "many months to develop roots". I'm a southern gardener and I'm used to lots of plants taking months to root... which is not a problem, so long as they eventually do! , "Australian Finger Lime", grows to an erect tree of 10 meters.

The fruits are green and cylindrical up to 50mm or 2" long and only about 20mm or 1" in diameter. They have prominent thorns and set plenty of viable seed in their natural habitat from the Clarence River NSW, north to Brisbane Qld. 

Both of the native limes, that is the "Finger Lime" and the "Round Lime" have a slight taste of turpentine according to W.D. Francis in his book "Australian rain-forest trees". The seed is known to be slow to germinate and Nan & Hugh Nicholson claim that cuttings take "many months to develop roots". I'm a southern gardener and I'm used to lots of plants taking months to root... which is not a problem, so long as they eventually do!

More about Australian Native Produce
Australian native produce refers to the indigenous herbs, plants and animals of Australia, a source of nourishment, flavour and medicine for the Aboriginal people. While there has been increasing awareness of some of the native fruits and plants and their uses, “bushfood” has not yet become part of the everyday pantry supplies of the average Australian cook.

Herbs such as lemon myrtle, native pepperberry and native aniseed are strong in flavour and add a distinctive taste of the bush to any dish. Fruits like the riberry or lilli pilli, Kakadu plums, quandongs, ‘bush tomatoes’ or akadjura, native finger limes and lemon aspen can be made into jams, chutneys or used in sauces. Native meats include crocodile, kangaroo and emu. And the bark of the paperbark tree is perfect to wrap around meat or seafood or even green vegetables prior to baking, steaming or grilling. Greens include native parsley and warrigal greens, a native spinach that is grown in other parts of the world, including France.

There are a number of companies supplying native Australian ingredients and some retail outlets, including The Essential Ingredient and Five Star Gourmet Foods in Sydney.