Systematics Section / ASPT
Sanchez-del Pino, Ivonne , Borsch, Thomas , Motley, Timothy J. .
Phylogenetic analysis of Gomphrenoideae (Amaranthaceae): Sequence data from trnL-F support a Tidestromia-Alternanthera clade.
Subfamily Gomphrenoideae is one of the two subfamilies recognized in the Amaranthaceae and traditionally characterized by having bilocular anthers. It is predominantly a New World group in mostly tropical habitats, and includes 19 genera with more than 400 species. Metareticulate pollen and rbcL sequences earlier supported the monophyly of a core subfamily Gomphrenoideae that comprises all genera except Iresine, Irenella, and Woehleria. This study includes an increased sampling of taxa within the subfamily Gomphrenoideae in order to further test the monophyly of the core Gomphrenoideae and to establish phylogenetic relationships among its genera. In addition, a greater number of representatives from Alternanthera and Tidestromia were included as compared to previous studies to test the existence of a Tidestromia -Alternanthera clade as some previous analyses based on morphology and ITS sequences suggested. Phylogenetic analysis of the subfamily Gomphrenoideae using sequence data from trnL-F of 42 ingroup taxa, and seven outgroup taxa has resolved it as monophyletic, with 99 % bootstrap support. Within the Gomphrenoideae, there are three clades. One of them includes Woehleria, a monotypic genus endemic to Cuba, and the large, widespread genus Iresine (100 % bootstrap). The remaining core Gomphrenoideae are divided into two major clades. A Tidestromia-Alternanthera clade (92% bootstrap) and a clade formed by Hebanthe, Pfaffia, Xerosiphon, Guilleminea, Froelichia, Gossypianthus, Blutaparon, and Gomphrena (87 % bootstrap). The former includes Tidestromia and Alternanthera as monophyletic groups but with little resolution among species in each genus. The latter includes a polytomy with Hebanthe, a monophyletic genus Pfaffia (90 %), a clade comprising the two species of Xerosiphon (100 %), and a clade including the remaining five genera. Xerosiphon was clearly segregated from Gomphrena, which is interesting as it has been merged with Gomphrena by most authors.
1 - New York Botanical Garden, Institute of Systematic Botany, 200th St & Kazimiroff Blvd, Bronx, New York, 10458, USA
2 - Rheinische Friedrich-Wilhelms-Universität Bonn, Nees-Institut für Biodiversität der Pflanzen, Meckenheimer Allee 170, Bonn, D-53115, Germany
Presentation Type: Paper
Location: Cottonwood C (Snowbird Center)
Date: Wednesday, August 4th, 2004
Time: 2:15 PM