Tilia is a genus of about 30 species of trees, native throughout most of the temperate Northern Hemisphere, in Asia (where the greatest species diversity is found), Europe and eastern North America; it is not native to western North America. Under the Cronquist classification system, this genus was placed in the family Tiliaceae, but genetic research by the APG has resulted in the incorporation of this family into the Malvaceae. The trees are generally called lime in Britain and linden in parts of Europe and North America (where they are also known as basswood). Tilia species are large deciduous trees, reaching typically 20â€“40 m tall, with oblique-cordate leaves 6â€“20 cm across, and are found through the north temperate regions. The exact number of species is subject to considerable uncertainty, as many or most of the species will hybridise readily, both in the wild and in cultivation.