Systematics Section / ASPT
Padolina, Joanna .
Phylogenetic reconstruction of Phalaenopsis (Orchidaceae).
Phalaenopsis comprises approximately 60 species that occur primarily as epiphytes throughout tropical Asia and the Pacific Islands. Globally, Phalaenopsis is extremely important in the horticulture industry, ranked by the International Floriculture Quarterly Report (1995) as the second most valuable commodity of potted plants. Unfortunately, their natural populations have been exploited by unscrupulous collectors and diminished sometimes to the point of extinction. All Phalaenopsis are monopodial with short stems and succulent, fleshy leaves. The lip of the flower is always three-lobed, and the shape of the lateral lobes is taxonomically informative within the genus. Phalaenopsis has undergone various taxonomic treatments (Sweet, 1980; Christenson, 2001), however, the classification is still controversial since no molecular phylogeny has been published against which these treatments can be assessed.
In his recent revision, Christenson (2000) recircumscribed Phalaenopsis and divided it into five subgenera, two with four sections, each. He considered the species of Doritis and Kingidium to belong to Phalaenopsis, arguing that the morphological characters used to segregate these taxa were insignificant in species-level characterization. The placement of Doritis and the subgeneric grouping within Phalaenopsis is still controversial.
In order to resolve relationships in the genus, I am reconstructing a phylogeny of Phalaenopsis using DNA sequence data from several regions of the chloroplast genome that will total approximately 3000 base pairs of sequence data (including part of matK, the atpH/atpF spacer, the petD intron, and the trnD/trnE intergenic region). Preliminary results indicate that Christensonís placement of Doritis and Kingidium within Phalaenopsis is accurate, but several subgenera may need to be recircumscribed to reflect a monophyletic classification.
1 - University of Texas at Austin, Section of Integrative Biology, 1 Universiy Station, #A6700, Austin, Texas, 78712, USA
Presentation Type: Poster
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM