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 ...