Systematics of Carex section Laxiflorae

Carex section Laxiflorae includes some of the most common and ecologically important sedges in forests of eastern North America, as well as several narrowly endemic species. The section is currently comprised of 16 species in North America, but is in great need of taxonomic revision. Morphometric analyses indicate that several species in eastern North America contain previously undocumented diversity, and traditional sequencing methods provide evidence that section Laxiflorae is not monophyletic. However, the phylogenies produced by traditional sequencing of six different regions (ETS1f, ITS, trnL-trnF, atpB-rbcL, rpS16, and rpL16) display conflicting gene tree topologies and very low support values, thus, failing to fully resolve intra and inter sectional relationships. To overcome this challenge, we constructed ddRAD libraries of 31 putative taxa and sent the libraries for paired-end 150 base pair sequencing on an Illumina NextSeq 550 machine. We are using this genomic-wide sequence data to test whether morphologically defined species are supported by molecular data, to detect hybridization, and to clarify the phylogenetic relationship of section Laxiflorae to North American members of sections Paniceae and Bicolores.