|
|
||||||||
|
(American Journal of Botany. 2009;96:1896-1906.) doi: 10.3732/ajb.0800404 © 2009 Botanical Society of America, Inc. |
What's this? |
Systematics and Phytogeography |
Plant Biology Department, 109 Carrigan Drive, University of Vermont, Burlington, Vermont 05405 USA
ABSTRACT
Carex aquatilis is a highly diverse and geographically widespread member of one of the largest genera of flowering plants, Carex, and is ideally suited for the study of the role of hybridization and niche partitioning in ecological speciation. Phylogenetic analyses of nuclear ITS and ETS 1f and chloroplast psbA-trnH DNA sequences support the monophyly of a broadly defined Carex aquatilis-Carex lenticularis lineage, which includes C. aquatilis and C. lenticularis and their allies within section Phacocystis. However, neither taxon is monophyletic as currently circumscribed. The C. aquatilis lineage includes C. aquatilis and four morphologically and molecularly distinct salt-tolerant maritime taxa with which C. aquatilis s.s. is reported to form stabilized homoploid hybrids. The C. lenticularis lineage includes a paraphyletic C. lenticularis and seven allied species from both the New and Old World. The data provided here allow recognition of four species within the North American endemic C. lenticularis and suggest a neotropical origin for the C. lenticularis lineage with subsequent radiation and divergence through northwestern North America to Asia and via northeastern North America to Europe and southern South America. Evolutionary rate analyses indicate an origin for the C. aquatilis-C. lenticularis group around 1.89 million years ago during the early Pleistocene.
Key Words: biogeography Carex Cyperaceae ecological speciation hybridization molecular phylogeny rates analysis systematics
Received for publication 4 December 2008. Accepted for publication 19 June 2009.
FOOTNOTES
1 The authors thank all the scientists who assisted with this research, especially C. Paris, L. Standley, M. Waterway, S. Schmitz, J. Cayouette, staff at the herbaria that provided research materials, and numerous botanists whose generous efforts to collect specimens for this research helped to give it such wide geographic and taxonomic breadth.
2 Author for correspondence (Julie.Dragon{at}uvm.edu); present address: Department of Biology, University of Vermont 109 Carrigan Dr., Burlington, VT 05405-0086 USA
![]()
CiteULike
Complore
Connotea
Del.icio.us
Digg
Facebook
Reddit
Technorati
Twitter What's this?
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |