family Myrtaceae in the Proceedings of the Linnean Society of New South Wales. Although there have been revisions to their groupings, their paper allowed a systematic examination of species in the genus Leptospermum. In 1989, Joy Thompson published a complete revision of the genus. In 2000, O'Brien et al. published yet another revision, using matK-based evidence to suggest that Leptospermum is polyphyletic, and should be split into persistent, Western non-persistent, and Eastern non-persistent fruiting plants, with Leptospermum spinescens as an outlier. However, neither phylogeny has been universally accepted. Current estimates recognize about ninety species of Leptospermum. The common name tea tree derives from the practice of early Australian settlers who soaked the leaves of several species in boiling water to make a herbal tea. Distribution and habitat Most Leptospermum species are endemic to Australia where most are found in southern areas of the country. They are most common in moist, nutrient-poor soils although they sometimes occupy other situations. Leptospermum laevigatum is usually found growing on beach sand and L. riparium growing in Tasmanian rainforest on the edges of rivers. Leptospermum amboinense extends from Queensland to Southeast Asia and three species, L. javanicum, L. parviflorum and L. recurvum are endemic to southeast Asia. L. recurvum is only found on Mount Kinabalu in Sabah. Leptospermum scoparium is one of the most widespread in the genus and occurs in New South Wales, Victoria, Tasmania and New Zealand, where it is one of the most widespread and important native shrub species. Ecology In Australia, Leptospermum species are sometimes used as food plants by the larvae of hepialid moths of the genus Aenetus, including A. lewinii and A. ligniveren. These burrow horizontally into the trunk then vertically down. Uses Use in horticulture Most Leptospermum species make desirable garden plants. The hardiest species (L. lanigerum, L. liversidgei, L. polygalifolium, L. rupestre, L. scoparium) are hardy to about to ; others are sensitive to frost. They tolerate most soils, but many suppliers specify ericaceous (i.e. lime-free) compost with good drainage and full sun. Established plants are drought tolerant. They are often found as hedge plants on the west coast of the United States, and some species are popular for cultivation as bonsai. Many cultivars exist. Use in floristry These flowers are also grown in double cultivars and are used in floral designs. However, they do not last when out of water and the single flowers do not