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Abstract Detail



Systematics Section/ASPT

Cardinal-McTeague, Warren M. [1], Gillespie, Lynn J. [1].

Molecular phylogenetics of the tribe Plukenetieae (Euphorbiaceae s.s.): Taxonomic implications and delimitation of Tragia L.

The tribe Plukenetieae (Euphorbiaceae s.s.) is a cohesive lineage of pantropical twining lianas/vines known for their urticating trichome defenses, diversity in floral/pollen morphology, and specialized pollination syndromes. The evolution of strategic characters is hypothesized to have spurred high levels of speciation and diversity among genera (e.g. bilateral symmetry and resin/fragrance collecting bee pollination in Dalechampia ca.130 spp., vegetative urticating trichome defenses in Tragia ca. 150 spp.), but our ability to test these hypotheses is inhibited by uncertainty in the internal relationships of the tribe. Using nrDNA ITS and cpDNA trnH-psbA data we produce the first molecular based phylogenetic assessment for the tribe Plukenetieae. Our results suggest that the genus Tragia is paraphyletic and can be divided into eight distinct clades. Many of the clades reflect current sectional classifications, some of which were smaller genera subsumed into Tragia (e.g. Zuckertia Baill., Bia Klotzsch, Leptobotrys Baill.), while others must be newly named (e.g. T. sect. Tagira). The delimitations of Tragia are reinforced by differences in floral and inflorescence structure, pollen morphology, and geographic distribution. Current sampling does not fully resolve the backbone of the tribe, but is able to highlight taxonomic inaccuracies while opening up the door for future studies on the biogeography and evolution of this diversity-rich clade.

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1 - Canadian Museum of Nature, Research & Collections Division, PO Box 3443 Stn "D", Ottawa, ON, K1P 6P4, Canada

Keywords:
Plukenetieae
Euphorbiaceae s.s.
molecular phylogeny
cpDNA
nrDNA
Taxonomy
Tragia L.
delimitation.

Presentation Type: Oral Paper:Papers for Sections
Session: 5
Location: Rosedown/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 9:15 AM
Number: 5004
Abstract ID:319
Candidate for Awards:None


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