Meudt, Heidi M. .
Phylogeographic patterns in the Australasian genus Chionohebe (Veronica s.l., Plantaginaceae) based on AFLP and chloroplast DNA sequences.
The Hebe complex (Plantaginaceae) is the largest and arguably the most fascinating flowering plant radiation in New Zealand, comprising nearly 100 species ranging from tiny herbs to large, woody shrubs. Five allied genera (Chionohebe, Hebe, Heliohebe, Leonohebe and Parahebe), some of which extend into other areas of the Southern Hemisphere, plus two Australian relatives (Derwentia and Detzneria), make up the monophyletic Hebe complex, which is nested within the genus Veronica in molecular phylogenies. Despite recent systematic studies, many important questions remain regarding taxonomy, biogeographical patterns, and character evolution within the Hebe complex. This is especially true for Chionohebe, a genus of six species all found in high-elevation habitats of the South Island of New Zealand. Two of these species, C. densifolia and C. ciliolata, are also disjunct in alpine Australia. There are many floral and vegetative morphological characters that separate the five pulvinate, cushion-forming species of Chionohebe from the prostrate subshrub C. densifolia. In contrast, it is very difficult to distinguish the cushion species based on morphology. The most recent taxonomic treatment relies heavily on leaf trichomes, which are extremely variable with respect to kind, amount, and distribution on leaf surfaces.
To infer the evolutionary relationships among the species of Chionohebe, phylogenetic analyses were performed on AFLP data and the chloroplast DNA (cpDNA) marker rpoB-trnC. AFLP profiles were generated from 170 individuals (and cpDNA sequences for a subset of these) representing multiple populations of all Chionohebe species from throughout their geographic ranges in New Zealand and Australia. These phylogenies allow interpretation of phylogeographic patterns, as well as a deeper understanding of the relationship of Chionohebe to other genera in the Hebe complex (especially Parahebe and Leonohebe). Additionally, these data provide a molecular framework that will guide future morphological studies, ultimately leading to a taxonomic revision of Chionohebe.
Log in to add this item to your schedule
Museum of New Zealand Te Papa Tongarewa Botany website
1 - Museum of New Zealand Te Papa Tongarewa, Botany, PO Box 467, Wellington, New Zealand
Presentation Type: Oral Paper:Papers for Topics
Location: Lake Michigan/Hilton
Date: Tuesday, July 10th, 2007
Time: 2:45 PM