Atia Eisa, Atia M. , Hilu, Khidir .
Phylogeny of PhleumL. (Poaceae, timothy grass): species and polyploid evolution.
Phleum L. (Poaceae, timothy grass) comprises about 15 species of worldwide distribution. It includes annual and perennial species with diploid and polyploid cytotypes based on x=7. The species are morphologically quite variable, contributing to difficulties in the assessment of species boundaries. A comprehensive systematic study for the genus is lacking. We present the first molecular phylogeny for the entire genus using the nuclear internal transcribed spacer (ITS) and the plastid trnL-F and psbJ-petA sequences to assess species relationships. Three major clades were recovered that coincide with the morphology-based sectional classification. The fourth clade consists of two morphologically different species, tetraploid P. panculatum and diploid P. nodosum. These two species are traditionally placed in different sections, and lack morphological synapomorphies. Polyploidy appear to have evolved in one of the three major clade/sections, whereas the other two remain diploid. We also conducted a detailed morphological study of a number of vegetative and reproductive characters for all the species. Floret features are mapped on the tree to discern character evolution and their potential implication in the taxonomy of Phleum.
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1 - Desert Research Center, Ecology and Range mangment, 1 mathaf Elmatariya st., Cairo, Egypt
2 - VIRGINIA TECH, Department Of Biology, 2119 Derring Hall, BLACKSBURG, VA, 24061-0406, USA
Presentation Type: Poster:Posters for Sections
Location: Khorassan Ballroom/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 5:30 PM