Tilia is a genus of about 30 species of trees native throughout most of the temperate Northern Hemisphere. Commonly called lime trees in the British Isles, they are not closely related to the lime fruit. Other names include linden and basswood. The genus occurs in Europe and eastern North America, but the greatest species diversity is found in Asia. Under the Cronquist classification system, this genus was placed in the family Tiliaceae, but genetic research summarized by the Angiosperm Phylogeny Group has resulted in the incorporation of this genus into the Malvaceae. Tilia species are mostly large, deciduous trees, reaching typically tall, with oblique-cordate leaves across. As with elms, the exact number of species is uncertain, as many if not most of the species will hybridise readily, both in the wild and in cultivation. Limes are hermaphroditic, having perfect flowers with both male and female parts, pollinated by insects.