Abstract Detail

Systematics Section / ASPT

Bell, Charles [2], Donoghue, Michael J. [1].

Taxon sampling and the relationships of Plectritis (Valerianaceae, Dipsacales).

Our analyses of 30 representatives of Dipsacales, based primarily on a battery of chloroplast genes, have yielded strong support for many major clades. Based on these analyses we reported a well supported link between Plectritis and Centranthus within the Valerianaceae. However, when the sample of taxa was expanded by the addition of a number of Valeriana species from South America, Plectritis moved away from Centranthus and instead became nested well within a large South American Valeriana clade. This result is strongly supported and is obtained using parsimony and likelihood methods. This case provides a sobering example of the importance of sufficient taxon sampling, and warns that even well supported results may be overturned when sampling is suitably expanded. The new result highlights a fascinating biogeographic pattern: western North American Plectritis species appear to have been derived, probably quite recently, from South American Valeriana. It also highlights the evolutionary recurrence of nectar spurs in Valerianaceae.

1 - Yale University, Peabody Museum of Natural History, Botany Division, 170 Whitney Ave, P.O. Box 208118, New Haven, Connecticut, 06520-8118, USA
2 - Florida Museum of Natural History, University of Florida, Gainesville, Florida, 32611-7800, USA

Keywords:
Plectritis
Dipsacales
maximum likelihood
phylogenetic theory.

Presentation Type: Paper
Session: 18-7
Location: Cottonwood A (Snowbird Center)
Date: Monday, August 2nd, 2004
Time: 2:45 PM
Abstract ID:866