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Abstract Detail


Onagraceae as a model experimental system

Wagner, Warren [1], Hoch, Peter [2].

A new classification in Onagraceae.

The plant family Onagraceae has emerged as an outstanding model system for evolutionary studies, due in large part to the efforts of Peter Raven and associates. This symposium will celebrate that legacy, summarize at least some of what we have learned, and demonstrate promising new evolutionary approaches for the future. The family has had especially intensive analyses of evolution of breeding and pollination systems, and permanent translocation heterozygosity, which have occupied numerous workers for over a century of genetic and cytogenetic analyses. Recent broad molecular phylogenetic analyses of Onagraceae support the need for changes in the family classification. We propose a revised classification of 22 genera, subdivided into two subfamilies, subfam. Ludwigioideae (only Ludwigia) and subfam. Onagroideae (the other genera), and the latter into six tribes, two with only one genus each, three with two genera each, and one (tribe Onagreae) with 13 genera. The most dramatic changes mainly involve the tribe Onagreae, from which we have segregated Gongylocarpus as its own tribe, sister to the tribes Epilobieae and Onagreae, and within which we propose changes in the delimitation of Camissonia and Oenothera. Camissonia as currently defined is broadly paraphyletic; our new classification recognizes nine generic lineages (Camissonia, Camissoniopsis, Chylismia, Chylismiella, Eremothera, Eulobus, Neoholmgrenia, Taraxia, and Tetrapteron) that in part form a grade at the base of Oenothera. Each of these lineages is well-supported by morphological and molecular data. In contrast, both molecular and morphological data suggest the need to broaden the delimitation of Oenothera to include Calylophus, Gaura, and Stenosiphon. This redefined Oenothera, strongly supported by molecular data, is marked by at least two morphological synapomorphies: presence of an indusium on the style, and a lobed or peltate stigma. Although the family has its center of diversity in the New World, especially western North America, four of the genera (Chamerion, Circaea, Epilobium, and Ludwigia) have colonized and diversified in the Old World, especially in Europe, Asia, Africa, and Australasia.

Broader Impacts:


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Related Links:
Onagraceae- The Evening Primrose Family
http://botany.si.edu/onagraceae/


1 - Smithsonian Institution, Botany, MRC-166 National Museum Of Natural History, PO Box 37012, WASHINGTON, DC, 20013-7012, USA
2 - Missouri Botanical Garden, P.O. Box 299, St. Louis, MO, 63166-0299, USA

Keywords:
Onagraceae
phylogeny
classification
Oenothera
Camissonia
Gaura.

Presentation Type: Symposium or Colloquium Presentation
Session: SY14
Location: Lenox Room/Chase Park Plaza
Date: Wednesday, July 13th, 2011
Time: 1:30 PM
Number: SY14001
Abstract ID:144


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