COSKUN, FATIH1*, JIANHUA LI2, and CLIFFORD R. PARKS1. 1Department of Biology, CB# 3280, Coker Hall, UNC-Chapel Hill, NC 27599-3280; 2Arnold Arboretum of Harvard University, 125 Arborway, Jamaica Plain, MA 02130. - Molecular systematics and biogeography of the genus Tilia (Tiliaceae).
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