Systematics Section / ASPT
Ickert-Bond, Stefanie, M. , Wen, Jun , Pigg, Kathleen B. .
Resolving phylogeny within the family Altingiaceae: implications from anatomy of infructescences and molecular data sets.
The circumscription of the Altingiaceae includes Liquidambar L., Altingia Noronha and Semiliquidambar H.T. Chang. Morphological characters traditionally used to delimit these taxa are few and sometimes ambiguous, and their underlying anatomical basis has never been comprehensively documented or analyzed. Likewise, in many previous molecular studies all species have not been represented. In this study the phylogenetic relationships and geographic disjunctions within the Altingiaceae were investigated using two complementary sources of data, morphology and anatomy of infructescences and new molecular data from the nuclear starch synthase gene (GBSSI, or waxy) and the chloroplast trnL-trnF intergenic spacers. The anatomical study demonstrated many previously undocumented characters of fruit wall structure, resin duct distribution, seed anatomy and seed surface and carpel wall micromorphology. Some characters support the traditional segregation of species into Altingia and Liquidambar, while others are confined to the species level. Infructescences of Liquidambar can be characterized by thin outer fruit walls (7-8 cell layers), as compared to well-developed, thick walls (20-30 cell layers) that are sometimes suberized in Altingia. Innermost carpel walls are mostly single-layered, but vary in the shape and lignification of cells comprising this layer. Rarely, the innermost carpel wall comprises up to 8 cell layers (A. poilanei). Previous phylogenetic analyses of several chloroplast and nuclear genes nest Altingia within Liquidambar. Our present GBSSI and trnL-trnF results confirm this relationship, but also suggest a split into a basal clade of the North American L. styraciflua and the western Asian L. orientalis sister to a clade of the rest of Altingiaceae. Within the second larger clade two subclades can be recognized one with L. formosana, sister to A. poilanei and A. chinensis, and a second subclade with L. acalycina sister to A. siamensis and A. gracilipes.
1 - Arizona State University, School of Life Sciences, PO Box 874501, Tempe, Arizona, 85287-4501, USA
2 - Field Museum, Botany Department, 1400 S. Lake Shore Dr., Chicago, Illinois, 60605-2496, USA
Presentation Type: Paper
Location: Cottonwood C (Snowbird Center)
Date: Wednesday, August 4th, 2004
Time: 4:45 PM