Tilia

Tilia is a genus of about 30 species of trees or bushes, native throughout most of the temperate Northern Hemisphere. The tree is known as linden for the European species, and basswood for North American species. In Britain and Ireland they are commonly called lime trees, although they are not related to the citrus lime. The genus occurs in Europe and eastern North America, but the greatest species diversity is found in Asia. In Chinese, "椴/duàn" or "椴樹/duànshù" is a general term for Tilia species. Under the Cronquist classification system, this genus was placed in the family Tiliaceae, but genetic research summarised by the Angiosperm Phylogeny Group has resulted in the incorporation of this genus, and of most of the previous family, into the Malvaceae. Tilia species are mostly large, deciduous trees, reaching typically tall, with oblique-cordate (heart-shaped) leaves across. As with elms, the exact number of species is uncertain, as many of the species can hybridise readily, both in the wild and in cultivation. They are hermaphroditic, having perfect flowers with both male and female parts, pollinated by insects. Tilia is the only known ectomycorrhizal genus in the family Malvaceae. Studies of ectomycorrhizal relations of Tilia species indicate a wide range of fungal symbionts and a preference toward Ascomycota fungal partners. The genus is generally called "lime" or "linden" in Britain and "linden", "lime", or "basswood" in North America. "Lime" is an altered form of Middle English lind, in the 16th century also line, from Old English feminine lind or linde, Proto-Germanic *lindō (cf. Dutch/German linde, plural linden), cognate to Latin lentus "flexible" and Sanskrit latā "liana". Within Germanic languages, English "lithe" and Dutch/German lind for "lenient, yielding" are from the same root. "Linden" was originally the adjective, "made from linwood or lime-wood" (equivalent to "wooden" or "oaken"); from the late 16th century, "linden" was also used as a noun, probably influenced by translations of German romance, as an adoption of Linden, the plural of Linde in Dutch and German.