Changing tribal and generic concepts in Cyperaceae, new insights from phylogenomics

Despite recent advances in molecular phylogenetics, deep evolutionary relationships in Cyperaceae are not resolved. Reduction of floral morphology and complex inflorescences pose difficulties to unravel relationships based on morphology. One of the most phylogenetically informative structures in Cyperaceae is embryos. The utility of embryo characters and types in Cyperaceae systematics has been reviewed in a molecular phylogenetic context using a DNA supermatrix incorporating sequences from five plastid (matK, ndhF, rbcL, rps16, trnL-F) and two nuclear ribosomal (ETS, ITS) regions. The phylogenetic hypothesis presented includes the most extensive sampling of Cyperaceae to date. Fourteen qualitative morphological embryo characters were coded, ancestral state reconstructions were performed, and the embryo of each sampled genus was classified in a typological system based on key morphological features. Embryo morphology provides a valuable source of independent data for Cyperaceae systematics that can be used to place species with unknown affinities, when molecular data is not available, or when results of analyses are inconclusive or conflicting. This work is now being compared with the first generic level phylogenomic tree generated using the angiosperm-wide bait kit developed for Kew’s PAFTOL programme. Together, these efforts will allow generating a new molecular-based classification for the family.