Systematics Section / ASPT
Milton, Ethan F. , Weston, Peter H. , Barker, William , Barker, Robyn , Mast, Austin .
Inference of phylogenetic relationships in Hakea (Proteaceae) using morphology and four chloroplast and three nuclear DNA regions.
The Australian genus Hakea (149 spp.) is mostly composed of shrubs from dry, open, fire-swept environments. With the closely related genus Grevillea (363 spp.), Hakea forms a large lineage whose increased net diversification rate appears to have been driven by the aridification of Australia in the mid- to late-Tertiary. We infer a phylogeny for the group with morphological and DNA sequence data. We sampled 3 regions of nuclear DNA (PHYA gene and waxy loci 1 and 2) and 4 regions of chloroplast DNA (matK gene, atpB gene, ndhF gene and rpl16 intron) from a third of the species (52) in Hakea and close relatives in Grevillea (1 of 357 spp.), Finschia (1 of 4 spp.), Buckinghamia (1 of 2 spp.) and Opisthiolepis (1 of 1spp.). This sampling represents all 31 informal groups currently recognized in Hakea. In the inferred molecular phylogeny, Hakea is monophyletic with a basal split into one clade composed of the small Trineura group plus a clade composed of 6 of the informal groups previously recognized in morphological results as the "Multilineata clade" and a clade composed of the remaining species. Ecological traits (resprouting post-fire vs. not; terete vs. broad leaves) prove considerably more labile on the phylogeny than other traits traditionally used in classification of the group (prominent vs. obscure leaf venation; fruit sub-apex horned or not; pollen presenter discoid vs. conical; pollen erect vs. oblique). However, the basal split in the genus is inferred to have been between an ancestor with broad leaves and one with terete leaves, which might have left the terete leaved lineage with a greater ability to survive conditions in the central deserts of Australia.
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Mast Faculty Website
1 - Florida State University, Department of Biological Sciences, Tallahasse, Florida, 32306-1100, USA
2 - Royal Botanic Gardens, Mrs Macquaries Road, Sydney, New South Wales, 2000, Australia
3 - State Herbarium of South Australia, PO Box 2732, Kent Town, South Australia, 5071, Australia
Presentation Type: Poster:Posters for Sections
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM