Schuster, Tanja M. , Kron, Kathleen A. .
Phylogenetic Relationships of Muehlenbeckia Meisn. (Polygonaceae) and Related Taxa Based on Molecular Characters.
The current circumscription of Muehlenbeckia (Polygonaceae) includes approximately 31 species. Muehlenbeckia have a liana or shrubby habit with an amphi-Pacific distribution restricted to the Southern Hemisphere. Species of Muehlenbeckia occur in Central and South America, Papua New Guinea, the Solomon Islands, Australia, Tasmania and New Zealand. None of the species that occur in Australasia are also distributed in the Americas and vice versa. Morphologically, the genus is usually recognized by a combination of features such as extrafloral (pit) nectaries on the petiole base, fimbriate or penicillate, trifid stigmas and a persistent, often accrescent perianth. Previous molecular analyses have shown that Muehlenbeckia belong in the strongly supported Polygonoideae. In this study, phylogenetic relationships of Muehlenbeckia are investigated with cladistic analyses of molecular characters from the gene regions nrITS, matK, ndhF and trnL-F. Twenty two species of Muehlenbeckia and nine Fallopia Adans. were included. In combined data analyses (RAxML and MP), species of Muehlenbeckia are found in two clades and most are nested within Fallopia. The American Muehlenbeckia form a strongly supported clade sister to M. australis, a species that occurs in New Zealand and the Norfolk Islands. Most Australian Muehlenbeckia and species from New Zealand also form clades. Three Australian species of Muehlenbeckia group with Atraphaxis and Polygonella with strong support. These Muehlenbeckia are characterized by not having extrafloral nectaries.
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1 - Wake Forest University, Department of Biology, PO Box 7325 , Reynolda Station, Winston-Salem, North Carolina 27109-7325, 27109, USA
2 - Wake Forest University, Department of Biology, PO Box 7325 , Reynolda Station, Winston-Salem, NC, 27109-7325, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 554/Convention Center
Date: Wednesday, August 4th, 2010
Time: 1:30 PM