The similarity between the forests of eastern North America and eastern Asia has intrigued botanists since the time of Linnaeus. However, scientific attention has been directed onto this classic disjunction pattern, now known as "the Tertiary relict disjunction", after Gray's 1859 treatment. Showing this classic pattern, the genus Tilia , the limes or lindens, includes more than 45 species in the Northern Temperate zone with a majority of the species in eastern Asia. Since the publication of the first monograph of this genus by Ventenat in 1803, many articles have discussed the relationships of Tilia species. These have been primarily based on morphological evidence. In this study, an effort is made to understand the relationships among the species of this genus using nuclear ribosomal ITS DNA sequences. Taxa are sampled from all the sections and subsections of the genus based on Engler's (1909) treatment, with representatives from North America, Europe, and western, central and eastern Asia. Phylogenetic trees are constructed based on the ITS sequences; and finally, phylogeographic patterns are generated for this genus and interpreted in the light of the fossil record.

Key words: biogeography, ITS, phylogeny, Tilia , Tiliaceae