Leptospermum is a genus of shrubs and small trees in the myrtle family Myrtaceae commonly known as tea trees, although this name is sometimes also used for some species of Melaleuca. Most species are endemic to Australia, with the greatest diversity in the south of the continent, but some are native to other parts of the world, including New Zealand and Southeast Asia. Leptospermums all have five conspicuous petals and five groups of stamens which alternate with the petals. There is a single style in the centre of the flower and the fruit is a woody capsule. The first formal description of a leptospermum was published in 1776 by the German botanists Johann Reinhold Forster and his son Johann Georg Adam Forster, but an unambiguous definition of individual species in the genus was not achieved until 1979. Leptospermums grow in a wide range of habitats but are most commonly found in moist, low-nutrient soils. They have important uses in horticulture, in the production of honey and in floristry. Description Plants in the genus Leptospermum range in size from prostrate shrubs to small trees, and have fibrous, flaky or papery bark. The leaves are arranged alternately and are relatively small, rigid and often aromatic when crushed. The flowers may be solitary or in groups, and have bracteoles and sepals which in most species fall off as the flower opens. There are five spreading, conspicuous petals which are white, pink or red. There are many stamens which are usually shorter than the petals and in five groups opposite the stamens, although they often appear not to be grouped. A simple style usually arises from a small depression in the ovary which has from three to five sections in most species, each section containing a few to many ovules. The fruit is a woody capsule which opens at the top to release the seeds, although in some species this does not occur until the plant, or the part of it, dies. Taxonomy and naming The first formal description of a leptospermum was published by Johann Reinhold Forster and Johann Georg Adam Forster in their 1776 book, Characteres Generum Plantarum. In 1876, George Bentham described twenty species, but noted the difficulty of discriminating between species. ("The species are very difficult to discriminate.") Of the species he named, only ten remain as valid. In 1979, Barbara Briggs and Laurie Johnson published a classification of the