Birch, Joanne L. , Keeley, Sterling C. , Morden, Clifford W. .
Phylogenetic relationships in the Asteliaceae with an emphasis on the genus Astelia.
The Asteliaceae (Asparagales) contains 36 species with a distribution throughout the Southern Hemisphere and the Pacific. It is the second largest family in the monophyletic, but poorly resolved, “astelioid” clade in the Asparagales. Generic delimitation of the four genera in the Asteliaceae (Astelia, Collospermum, Milligania, and Neoastelia) requires critical review. The segregation of Collospermum from Astelia has been questioned as the morphological synapomorphies of Collospermum are present in some Astelia taxa. Previous authors have suggested that Milligania is a “divergent outlier” based on morphological and molecular characters and its placement in the Asteliaceae has been challenged. This study investigates the evolutionary relationships of the Asteliaceae with a focus on the genus Astelia. Gene sequence data from both the plastid (trnL, psbA-trnH, rps16, and petL-psbE) and nuclear (NIA-i3) genomes were generated for thirty-five of the thirty-six known Asteliaceae species. A phylogeny was inferred based on parsimony and Bayesian criteria. Our results indicate that Astelia as currently circumscribed is paraphyletic as Collospermum, Milligania, and Neoastelia are nested within it. The Australian endemic genera, Neoastelia and Milligania, are sister taxa. The circumscriptions of Astelia subgenera are not consistent with the evolutionary history of the genus, however, a limited number of sectional relationships recognized based on morphological synapomorphies are supported by molecular data. The implications of the phylogeny on the evolution of morphological traits in the Asteliaceae are discussed.
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1 - University of Hawaii, Botany Department, 3190 Maile Way, Honolulu, HI, 96822, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Cottonwood A/Snowbird Center
Date: Monday, July 27th, 2009
Time: 2:00 PM