XVI International Botanical Congess

Kunming Institute of Botany, Chinese Academy of Sciences - An improved understanding of the origin and intrageneric relationships of Quercus requires complete sampling of several critical southeast Asian taxa, including members of subg. Cyclobalanopsis, the monotypic Formanodendron, and several species groups of oaks endemic to SW China. An expanded ITS data set of a broad sample of Quercus, castaneoids, and trigonobalanoids was analyzed phylogenetically and rooted using several previously proposed hypotheses of relationships within Fagaceae. Preliminary trees support a basal grade of trigonobalanoids followed by several clades of castaneoid taxa. Under various rootings, Quercus s.l. was placed consistently within a grade of castaneoid taxa. Inferred relationships continue to support section Cerris as sister to the largely North American sections of Quercus.