Orchid Biology: Darwin`s Contrivances 150 Years Later
Endara, Lorena , Judd, Walter , Whitten, William , Neubig, Kurt , Williams, Norris .
Morphological cladistic analysis and character evolution of Scaphosepalum (Orchidaceae).
Scaphosepalum is a clade that encompasses 49 species of the Pleurothallidinae, a Neotropical orchid subtribe of ca. 4000 species. Preliminary molecular phylogenies of the Pleurothallidinae placed Scaphosepalum sister to Platystele, Teagueia, Dryadella, Specklinia and Sarcinula but morphological synapomorphies that support the generic circumscription of Scaphosepalum were lacking. We performed morphometric analyses to search for morphological synapormophies that define each genus. An average of 89 macro-morphological characters were scored for each taxon. Maximum Parsimony (MP) and Maximum Likelihood (ML) methods were used to reconstruct the morphology-based phylogeny. Character evolution was also analyzed using ML methods and the molecular phylogeny of the group. In addition to the traditional characters used to distinguish Scaphosepalum (non resupinate flowers with sepals crowned by an osmophore), our work indicates that the genus is distinguished from its close relatives by the ventral presentation of the pollinia, a consequence of the outgrowth of the column and a lip hinged by a flap to the column foot. These characters are reversals from Dryadella. Additional synapomorphies of Scaphosepalum include the arcuate column, petals that subtend the clinandrum, lips reflexed in the middle, longitudinal dentate lamellae on the lip, and non-resupination.These characters are probably associated with changes in pollination mechanisms relative to the other genera.
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1 - University of Florida, Florida Museum of Natural History and Department of Biology, Dickinson Hall, Gainesville, FL, 32611, USA
2 - University Of Florida, Department Of Botany, 220 Bartram Hall, PO Box 118525, Gainesville, FL, 32611-8525, USA
3 - University Of Florida, Florida Museum Of Natural History, PO BOX 117800, Gainesville, FL, 32611-7800, USA, 352/273-1964
4 - University of Florida, Florida Museum of Natural History, 385 Dickinson Hall, Gainesville, FL, 32611-7800
Presentation Type: Symposium or Colloquium Presentation
Location: Franklin B/Hyatt
Date: Wednesday, July 11th, 2012
Time: 3:45 PM