Ionta, Gretchen M. , Judd, Walter S. , Nicolas, Antoine N. , Michelangeli, Fabian A. .
Introduction to the Miconieae of the Greater Antilles: II. Clidemia sect. Sagraea.
Clidemia, like many of the traditionally recognized taxonomic groups within Miconieae (Melastomataceae), has proven to be non-monophyletic based on recent DNA-based phylogenetic analyses by Michelangeli et al., which placed most Clidemia species within a paraphyletic grade, giving rise to a nested Leandra s. str. + Pleiochiton clade. Clidemia species were characterized historically by the presence of a suite of characters, mainly "axillary" inflorescences (axillary, or terminal but deflexed into a pseudo-axillary position), elongate external calyx lobes, and blunt petals; these characters are not unique to Clidemia, but together they defined the genus. The Clidemia grade of Michelangeli and collaborators comprises a mix of several genera including Clidemia, Miconia and Leandra species, many of which lack the suite of characters that traditionally defined Clidemia. Within the Clidemia grade, a weakly supported yet well-defined clade of ca. 80 spp. (traditionally recognized as Clidemia sect. Sagraea or as the genus Sagraea, including a few species placed in Ossaea) is characterized by true axillary inflorescences (present in all species) and stalked, furrowed glands (present in all species but sometimes highly modified; absent in other Miconieae, including other Clidemia species); this clade contains nearly all of the Antillean species of Clidemia along with continental taxa. Of the ca. 50 Antillean species in Clidemia sect. Sagraea, 40% fall within a well-supported (96% BS) clade comprised solely of Antillean taxa, the "Greater Antillean Sagraea clade", characterized by inflorescences reduced in size and flower number (single-flowered in the C. fuertesii complex), and the presence of irregularly branched dendritic hairs. Members of this clade, like many Antillean melastomes, are important components of montane forests. The group is particularly diverse in areas of high endemism such as the Massif de la Hotte (Haiti), Cordillera Central, and Sierra de Bahoruco (Dominican Republic); some species are restricted to a single mountain range. Diversity, relationships between taxa, biogeographic patterns, and potential speciation mechanisms within the Antillean Sagraea clade are presented.
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1 - University of Florida, Department of Biology, 220 Bartram Hall, P.O. Box 118526, Gainesville, FL, 32611-8526, USA
2 - University of Florida, Department of Biology, 220 Bartram Hall, P.O. Box 118526, Gainesville, FL, 32611, USA
3 - New York Botanical Garden, Cullman Program for Molecular Systematics Studies, 200th Street and Kazimiroff Boulevard, Bronx, New York, 10458, USA
Clidemia sect. Sagraea.
Presentation Type: Oral Paper:Papers for Sections
Location: 556B/Convention Center
Date: Wednesday, August 4th, 2010
Time: 4:45 PM