Cameron, Kenneth M. , Meyer, Gary , White, Ingelia , Buitrago, Elsy .
Once bitten, twice shy: molecular systematics of Dracula (Pleurothallidinae; Epidendroideae; Orchidaceae).
The genus Dracula contains at least 120 species distributed in cloud forest habitat from Chiapas, Mexico to central Peru. It was established as distinct from Masdevallia in 1978 to distinguish those species exhibiting a highly elaborate labellum, which is thought to mimic fungi in order to attract pollinators. Systematic studies of Dracula have been hampered by poor collections, high morphological variability within species complexes, relatively stereotyped floral and leaf morphology, and the likelihood of hybridization between species. The objectives of this phylogenetic study were to test the monophyly of the genus and sections as currently proposed, and to determine whether characters other than flower structure, such as fruit morphology, are potentially valuable indicators of inter-species relationships. Gene sequence data from both the plastid (matK, ycf1, trnL-F, psbA-trnH) and nuclear (ITS) genomes were generated for more than 200 samples representing nearly every known species in the genus. Our results concur with earlier molecular studies that demonstrated Dracula to be monophyletic with the exception of the unusual taxon D. xenos, which is embedded within Masdevallia. The species of Dracula with crested ovaries (subsection Costatae) are closely related, suggesting descent from a common ancestor, and the species of Dracula section Dodsonia, characterized by a flattened labellum, upright inflorescence, and upwardly creeping growth of the rhizome, show a similarly strong relationship. We also have found molecular evidence of natural hybrid origin for at least two species (D. kareniae, D. aphrodes), and suspect that other examples exist. Further molecular studies within and among this and other pleurothallid orchid genera are sorely needed.
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1 - University of Wisconsin, Madison, Herbarium and Department of Botany, Birge Hall, 430 Lincoln Dr., Madison, WI, 53706, USA
2 - Colombian Orchid Imports , 538 Waller St., San Francisco, CA, 94117, USA
3 - Windward Community College, Department of Natural Sciences, 45 - 720 Keaahala Road, Kaneohe, HI, 96744, USA
4 - Universidad Nacional de Colombia, Instituto de Ciencias Naturales, Bogota, AC, Colombia
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Cottonwood A/Snowbird Center
Date: Monday, July 27th, 2009
Time: 4:15 PM