Citrus australasica is a shrub or small tree to about 10 m (33 ft) tall with sharp spines up to 2.5 cm (1 in) long in the leaf axils.

[4][5][6] This species was first described by Australian botanist Ferdinand von Mueller, and was published in the first volume of his massive work Fragmenta phytographiæ Australiæ in 1858.

"[8]: 569  However, in a paper published in 1998, British botanist David Mabberley discussed the mix of morphological features present throughout the subtribe Citrineae (genera Clymenia, Eremocitrus, Fortunella, Microcitrus and Poncirus) and the ease with which species can be crossed, and subsequently restored the finger lime to Citrus.

[12]: 6  However, it is not a host to the Queensland fruit fly Bactrocera tryoni, saving Australian growers the extra burden of treatment before export.

[12]: 7 Research conducted since the 1970s indicated that a wild selection of C. australasica was highly resistant to Phytophthora citrophthora root disease, which has resulted in a cross-breeding program with finger lime to develop disease-resistant citrus rootstock.

[13] It is thought that for at least 60,000 years, First Peoples living along the east coast of Australia have been eating finger limes.

[6] The finger lime is grown on a commercial basis in Australia in response to high demand for the fruit.

With the sudden high market demand for the fruit the primary source of genetic material for propagation has been selections from wild stock.