Burke, Janelle , Sanchez, Adriana , Kron, Kathleen A. , Luckow, Melissa .
Placing the woody tropical genera of Polygonaceae: A hypothesis of character evolution and phylogeny.
Among the genera in Polygonaceae Juss., the affinities of the tropical genera have been the least well-studied in a phylogenetic context. Traditionally the woody tropical genera are placed in the Polygonoideae Eaton as two tribes: Triplarideae C.A. Mey. and Coccolobeae Dumort. Recent studies based on molecular phylogenies have suggested most genera of these tribes fall within a more broadly-defined Eriogonoideae Arn. A phylogenetic study was undertaken with expanded sampling of the tropical genera using five plastid markers (psbA-trnH, accD-psaI, matK, ndhF, and rbcL,), nuclear ribosomal DNA (ITS) and morphology. Results support the placement of nine of twelve genera of the Triplarideae and Coccolobeae within Eriogonoideae s.l., where these genera form a paraphyletic assemblage giving rise to Eriogonoideae s.s. Interestingly those tropical genera with distributions in the Paleotropics are excluded from Eriogonoideae s.l. Traditional characters used to delimit these two tribes are not useful for defining monophyletic groups. The six-tepal condition is derived from the five-tepal condition, and unisexual flowers have arisen multiple times in different sexual systems. The key vegetative character for Polygonaceae, the ocrea, is defined narrowly here as a synapomorphy for subfamily Polygonoideae and provides a useful character to diagnose the two subfamilies.
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1 - Cornell University, Department of Plant Biology, L.H. Bailey Hortorium, 412 Mann Library Building, Ithaca,, New York, 14853-5908, USA
2 - Wake Forest University, Department of Biology, PO Box 7325, 226 Winston Hall, Winston-Salem, North Carolina, 27109-7325, USA
3 - Cornell University, L.H. Bailey Hortorium, Department of Plant Biology, Ithaca, New York, 14853, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Magpie A/Cliff Lodge - Level B
Date: Tuesday, July 28th, 2009
Time: 8:30 AM