Schuster, Tanja M. , Kron, Kathleen A. .
A Preliminary Study of Phylogenetic Relationships of Muehlenbeckia Meisn. (Polygonaceae) Based on Morphological Characters.
Muehlenbeckia is one of 48 named genera in Polygonaceae and comprises approximately 31 species with a liana or shrubby habit. They are predominantly found in disturbed and xeric habitats and some are used as ornamentals. Muehlenbeckiaís distribution is amphipacific, with species occurring 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 recognized by a combination of features such as extrafloral (pit) nectaries on the petiole base, fimbriate or penicillate, trifid stigmas and a persistent, baccate perianth. The ocreae, so characteristic for Polygonaceae, are often not persistent. Flowers may be unisexual and/or bisexual on an individual plant. Molecular analyses show that Muehlenbeckia belong in the strongly supported Polygonoideae and are included in a clade that also comprises Fallopia Adans. and Reynoutria Houtt. In this study, phylogenetic relationships of Muehlenbeckia are investigated with cladistic analyses of 48 morphological characters. Twenty Muehlenbeckia, two Fallopia and one Reynoutria species were used for this study. Despite high levels of plasticity, leaf shape and habit are phylogenetically informative characters for determining species relationships in Muehlenbeckia. Additional phylogenetically useful characters are inflorescence type and features of the achenes and endosperm.
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1 - Wake Forest University, Department of Biology, PO Box 7325 , Reynolda Station, Winston-Salem, North Carolina 27109-7325, 27109, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Magpie A/Cliff Lodge - Level B
Date: Tuesday, July 28th, 2009
Time: 8:45 AM