Australia has six species of native citrus, with the most well known and cultivated species being the finger lime. The Australian finger lime (Citrus australasica) is native to the rainforests of the border ranges of SE Queensland and Northern NSW. In its natural habitat the finger lime grows as an understorey shrub or tree up to 6 metres in height on a range of soil types. Citrus is rich in vitamin C, vitamin P and calcium and is beneficial in the digestion of protein-rich foods. Citrus fruit also changes the over-acid condition of the body to an alkaline one by its heavy fruit calcium contents, which supply the bones, teeth, blood and nervous system with calcium and phosphorous. Citrus juices are a great aid to nervous persons, and are used in neurasthenia with fine results. Citrus juices relieve and prevent nervous indigestion and halitosis (bad breath) due to upset digestion.