Systematics Section / ASPT
Whitten, W. M. , Williams, N. H. , Dressler, Robert L. , Gerlach, Guenter , Pupulin, Franco .
Generic relationships of Zygopetalinae (Orchidaceae: Cymbidieae).
THE neotropical orchid subtribe Zygopetalinae (Orchidaceae: Cymbidieae) contains over 400 species of showy orchids with diverse vegetative, inflorescence, and floral habits; no cladistic analysis of the group has been attempted, and orchid taxonomists disagree over subtribal/generic delimitation and generic relationships. Existing observations indicate all species are probably pollinated by euglossine bees, but pollination mechanisms and site of pollinarium attachment vary among taxa. Some gullet-shaped flowers (e.g., Chondroscaphe) are deceit flowers with a false sepaline nectary that deceive male and female bees seeking nectar, whereas other species ( Dichaea; Kefersteinia) are pollinated by fragrance-collecting male euglossine bees. We used combined molecular data sets (nrITS, matK, trnL-F) to estimate phylogenetic relationships among 99 species. The trees reveal a weakly supported grade of taxa with prominent pseudobulbs and plicate or convolute leaves successively sister to the morphologically anomalous Cryptarrhena and Dichaea (both of which have been placed in separate subtribes by various authors) plus the Huntleya clade. The highly supported Huntleya clade includes species with reduced or absent pseudobulbs, conduplicate leaves, and single-flowered inflorescences. As in many orchid groups, gross floral traits (e.g., gullet deceit flowers) are homoplasious, and often vegetative/habit characters are more congruent with clades defined by molecular data. Six new genera created to accommodate morphologically definable, monophyletic groups, and a revised classification and key to genera of the Chondrorhyncha complex is presented.
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1 - University of Florida, Department of Botany, Florida Museum of Natural History, P.O. Box 117800, Gainesville, Florida, 32611-7800, USA
2 - Florida Museum of Natural History, University of Florida, P.O. Box 117800, Gainesville, Florida, 32611-7800, USA
3 - Botanischer Garten Muenchen Nymphenburg, Menzinger Str. 65, Munich, 80638, Germany
4 - Jardin Botanico Lankester, Universidad de Costa Rica, P.O. Box 1031-7050, Cartago, , Costa Rica
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM