Abstract Detail

Systematics Section / ASPT

McDill, Joshua [1], Simpson, Beryl [1].

Phylogeny of the Flaxes: Evolutionary Relationships and Biogeography in Linum (Linaceae).

Known best as a source of economically important fibers and oils (from the cultivated flax, Linum usitatissimum), Linum includes approximately 200 species and is distributed throughout the temperate and subtropical regions of the world. Bayesian and Maximum Parsimony analyses of sequences from five regions of the chloroplast genome (trnL intron, trnL-F intergenic spacer, trnK intron, rbcL, and ndhF) indicate that the yellow-flowered flaxes (which have diversified in North America, South America, South Africa, and the Mediterranean region) are sister to a blue-flowered lineage that is essentially confined to Eurasia. Ancestral area calculations and the phylogeny to date indicate that both of these lineages initially diversified in Eurasia and colonized North America independantly. The South American and South African radiations of yellow-flowered Linum appear to be descended from North American ancestry. Several specialized lineages traditionally given generic status - the Californian serpentine endemic Hesperolinon and the morphologically distinct monotypic genera Sclerolinon (North America), Cliococca (South America), and Radiola (Europe) - are nested among the yellow-flowered linums. In addition to improving our understanding of the relationships among flaxes throughout the world, the phylogenies provide a framework for examining the evolution of breeding systems in Linum, and for potential future taxonomic revision.

1 - University of Texas at Austin, Plant Resources Center and Section of Integrative Biology, 1 University Station A6720, Austin, Texas, 78712, USA

Keywords:
Linum
flax
Hesperolinon
Sclerolinon
Cliococca
Radiola
Biogeography
trnL-F
rbcL
trnK
ndhF
trnL intron
Linaceae.

Presentation Type: Poster
Session: 33-92
Location: Salon C, D & E - Gov Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 12:30 PM
Abstract ID:393