A new phylogeny of Rumex (Polygonaceae) adds evolutionary context to the diversity of reproductive systems present in the genus

Rumex is a unique member of the Polygonaceae family of plants. A source of intrigue for Rumex lies in the diversity of the reproductive systems associated with this genus. Four previously circumscribed subgenera and some two-hundred species comprise the collective Rumex genus. These species exhibit monoecious, dioecious, synoecious (hermaphroditic), and polygamous reproductive systems. Moreover, some of the dioecious species contain heteromorphic sex chromosomes, a phenomenon that is very rare in angiosperms. Apart from these confirmed morphological and phytogeographical distinctions, two of the four described subgenera, Rumex subg. Acetosa and Rumex subg. Acetosella, are distinctive in their sex chromosome systems. For this study, we used three chloroplast markers, rbcL, trnH-psbA, trnL-F, and dense taxon sampling, to reconstruct the most comprehensive molecular phylogeny of Rumex to date. The reconstructed phylogeny for this work resolves six major clades and one large grade in Rumex subg. Rumex. In addition, the species with known dioecious reproductive systems are resolved within a broader clade termed “the dioecious clade”. These results suggest that the species with divergent reproductive systems are more closely related to each other than to other species comprising the rest of the Rumex genus. Furthermore, some species with known synoecious reproductive systems are resolved in a single clade which is also nested within “the dioecious clade”. These results imply a possible reversal occurring over time which suggests the highly plastic nature of the reproductive systems in Rumex species.

Methods

These data were generated in order to study the evolution (phylogeny) of the plant genus Rumex (Polygonaceae).
The data are composed of chloroplast DNA sequences.
These sequences were generated using DNA primers and PCR, followed by Sanger Sequencing.
These data re not related to human subjects.