Section Ovales, with approximately 90 New World species, comprises one of the largest groups in the sedge genus Carex. Preliminary investigations using nrDNA (ITS) and cpDNA (rpl16 intron) sequences have revealed that the section contains a monophyletic clade that includes most of the section’s Great Plains and Eastern North American species. ITS and rpl16 alone are insufficient to resolve relationships within this clade. The study presented here is an investigation of relationships within this clade using combined analysis of sequence data and amplified fragment length polymorphism (AFLP) data. AFLP’s are shown to be largely congruent with ITS in a sampling that crosses the range of the section. Combined analysis demonstrates that the traditional subsections of Ovales have some correlation with phylogenetic relationships of the eastern species. The broad North American concept of subsection Festucaceae is not supported by phylogenetic study, however; and evidence of convergence in vegetative characters associated with floodplain species suggests that the traditional subsection Tribuloideae is also circumscribed too broadly. The data presented will be used to infer changes in chromosome number associated with speciation in the section and to explore geographic and morphological evolutionary trends.

Key words: AFLP, Carex, Cyperaceae, ITS, Ovales, rpl16