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Abstract Detail


Systematics Section

Mast, Austin [1], Jones, Eric [1], Barker, Robyn [2], Barker, William [2], Weston, Peter H. [3].

The Phylogeny and Age of the Woody Australian Genus Hakea (Proteaceae) and the Evolution of its Leaf and Fire Persistence Features.

The Australian genus Hakea (149 spp.) is composed of trees and shrubs that mostly occupy dry, open, fire-prone environments. With the closely related genus Grevillea (363 spp.), Hakea forms a large lineage that reaches its greatest diversity the Southwest Australian Floristic Region, a global biotic hot spot. We infer a phylogeny for Hakea with 46 morphological characters and sequences from 4 regions of chloroplast DNA (matK gene, atpB gene, ndhF gene and rpl16 intron) and 3 regions of nuclear DNA (PHYA gene and waxy loci 1 and 2) from a taxonomically even sampling of 55 spp. (a third of the total). In the inferred chloroplast phylogeny, Hakea is monophyletic with a basal split into one small clade with primitively broad leaves that we recognize as the enlarged section Conogynoides and one large clade with primitively terete leaves that we recognize as the enlarged section HakeaHakea is unexpectedly young; the mean inferred age for the crown group is only 10 million years. We infer the synapomorphy for the group (thick, walled woody follicles) to have arisen in the southwestern corner of Australia at this time. While there is considerable lability in resprouting ability and leaf shape in the group, we find mixed support for prior hypotheses of evolutionary correlations. Resprouting ability is not significantly correlated with leaf shape or serotiny at a threshold of p=0.05. However, resprouting species have a higher rate of change from terete to broad leaves than the reverse, and serotinous species have a higher rate of change from resprouting to non-sprouting than the reverse.


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1 - Florida State University, Department of Biological Sciences, Tallahasse, Florida, 32306-1100, USA
2 - State Herbarium of South Australia, PO Box 2732, Kent Town, South Australia, 5071, Australia
3 - Royal Botanic Gardens, Mrs Macquaries Road, Sydney, New South Wales, 2000, Australia

Keywords:
Hakea
Australia
phylogeny
molecular dating
Leaf evolution
Serotiny
resprouting
fire adaptation.

Presentation Type: Oral Paper:Papers for BSA Sections
Session: 56
Location: Cottonwood C/Snowbird Center
Date: Wednesday, July 29th, 2009
Time: 9:00 AM
Number: 56005
Abstract ID:335


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