Systematics/Phytogeography / Taxonomie/ Section
Tippery, Nicholas P. , Les, Donald H. , Padgett, Donald , Jacobs, Surrey .
Taxonomic revision of Villarsia (Menyanthaceae) in Australia: Molecular and morphological evidence.
The aquatic and wetland plant family Menyanthaceae consists of five genera that are distributed worldwide. Phylogenetic analyses using both molecular and morphological data consistently have resolved two monotypic genera with boreal distributions, Menyanthes and Nephrophyllidium, as a clade sister to the remaining genera. Two of the latter, Liparophyllum (1 sp.) and Villarsia (18 spp.), are restricted to the southern hemisphere, and species of Nymphoides (40-50 spp.) are found worldwide. Analysis of combined molecular (nrITS, trnK/matK, rbcL) and morphological data resolved several relationships that were inconsistent with current generic circumscriptions under a criterion of monophyly, among which the most conspicuous was the paraphyly of Villarsia relative to Nymphoides. Circumscriptions of these genera have fluctuated historically, with species in Australia (where both Nymphoides and Villarsia are the most diverse) belonging entirely to one or the other genus according to different authors. Recent sampling of nearly all species of Villarsia and of the most morphologically diverse and broadly distributed species of Nymphoides revealed heretofore undescribed relationships, wherein Villarsia resolved to three clades: two native to Australia and one, containing the type species V. capensis, comprised of only South African taxa. Species of Nymphoides resolved to a single clade, with the exception of the anomalous species N. exigua. Revised taxonomic designations have been provided for species of Villarsia in Australia and for N. exigua, in order to reflect the phylogenetic relationships that were recovered in our study. Several distinguishing morphological characters were found to support these relationships, particularly aspects of seed shape and vestiture.
Log in to add this item to your schedule
1 - University of Connecticut, Ecology & Evolutionary Biology, 75 North Eagleville Road, U-3043, Storrs, Connecticut, 062693043, USA
2 - Bridgewater State College, Department of Biological Sciences, Bridgewater, Massachusetts, 02325, USA
3 - Royal Botanic Gardens, Mrs Macquaries Road, Sydney, New South Wales, 2000, Australia
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM