The Evolution of Ericales: Recent Insights using both Morphology and Molecules
Judd, Walter S. , Waselkov, Katherine .
A phylogenetic analysis of Leucothoe s.l. (Ericaceae; Gaultherieae) based on morphological characters.
PHYLOGENETIC relationships within the genus Leucothoe (as broadly circumscribed; incl. eight species) and related taxa of Gaultherieae, Andromedeae, and Vaccinieae were investigated by a cladistic analysis based on morphological (external morphology, anatomy, chromosome number, and secondary chemistry) characters. The parsimony analysis resulted in four most parsimonious trees, all very similar, which show Leucothoe s.l. to be polyphyletic, with its species distributed among three distinct clades. Our results indicate that L. racemosa and L. recurva form a strongly supported clade, which is sister to Chamaedaphne calyculata, and these three species are likely the sister-group of the wintergreen clade (comprised of Gaultheria and Diplycosia). Leucothoe axillaris, L. fontanesiana, L. davisiae, L. griffithiana, and L. keiskei, in contrast, consistently form a monophyletic group, Leucothoe s.s., which is probably sister to the remaining members of Gaultherieae. Leucothoe grayana, the final species traditionally placed in the genus, belongs to neither of these clades and is of uncertain position, although it is never placed sister to any other species of Leucothoe. Morphological characters provide no support for the monophyly of Leucothoe, instead suggesting that it is polyphyletic, in agreement with preliminary DNA-based analyses. Thus, we redefine the genus, placing its species into three genera: Eubotrys (the E. racemosa, E. recurva clade); Eubotryoides (containing only E. grayana); and Leucothoe s.s. (the L. axillaris, L. fontanesiana, L. davisiae, L.griffithiana, L. keiskei clade). Finally, patterns of character change and geographical relationships are briefly considered.
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1 - University of Florida, Department of Botany, 220 Bartram Hall, P.O. Box 118526, Gainesville, Florida, 32611-8526, USA
Presentation Type: Symposium or Colloquium Presentation
Date: Monday, July 31st, 2006
Time: 2:45 PM