Abstract Detail

Systematics Section / ASPT

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

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

Known best as a source of economically important fibers and oils (from the cultivated flax, L. 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 four regions of the chloroplast genome (trnL intron, trnL-F intergenic spacer,trnK 3' intron, and rbcL) indicate that the blue-flowered linums are sister to a predominantly yellow-flowered lineage, and that these lineages initially diversified in Eurasia. Members of both the blue and yellow-flowered lineages appear to have independently colonized North America. The subsequent diversification of the yellow-flowered linums in North America gave rise to several specialized lineages generally given generic status: the serpentine endemic Hesperolinon and the morphologically distinct species Sclerolinon digynum and Cliococca selaginoides. The phylogeny to date indicates that the South American and South African species of Linum may be derived from North American ancestry. Given this phylogenetic resolution and the comparatively low level of sequence divergence within the yellow-flowered flaxes (relative to the blue-flowered group), recent dispersal events may provide a likely explanation for the amphi-tropical and amphi-Atlantic distribution of yellow-flowered Linum.

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

Keywords:
Linum
Linaceae
biogeography
Bayesian phylogenetic inference
South America
South Africa
North America
phylogenetic inference
Cliococca
Sclerolinon
Hesperolinon
trnL intron
trnL-trnF IGS
trnK 3' intron.

Presentation Type: Paper
Session: 30-1
Location: Cottonwood B (Snowbird Center)
Date: Tuesday, August 3rd, 2004
Time: 8:15 AM
Abstract ID:804