Carex is one of the ten largest genera of flowering plants in the world, containing about 2500 species. Despite its great size and ecological importance, there has been little phylogenetic analysis within the genus. Nearly all of the classifications that do exist are strictly phenetic and, therefore, probably not natural. One probable clade within subgenus Vignea contains eight sections (about 165 species) and can be recognized by the presence of gynecandrous spikes. The clade is wide-ranging in occurrence and especially diverse in Eastern North America. We used micromorphological and anatomical data to reconstruct the phylogeny of sections within this clade. Characters include: macromorphology (especially reproductive features), culm anatomy using light microscopy, perigynia anatomy using light microscopy, and achene surface morphology using scanning electron microscopy. We polarized character states using a composite outgroup of nongynecandrous species within subgenus Vignea. Using parsimony methods, we conducted a phylogenetic analysis of these data. Our preliminary results of the sections we have studied indicate the following phylogenetic hypothesis: (Stellulatae + (Carex seorsa + ((Glareosae + Deweyanae) + (Remotae + (Cyperoideae + (Ovales + Planatae)))))). Our preliminary results also provide placement for two previously problematic species. We found that Carex seorsa, previously placed in section Stellulatae, belongs in a separate, apparently undescribed section. Our data also indicate a resolution of the controversial placement of Carex laeviculmis, placing the species in section Glaraeosae.

Key words: Carex seorsa, gynecandrous, morphology, subgenus Vignea