About the nomenclature of the complicated ruderal species Rumex pulcher s.l. (Polygonaceae)

Abstract Rumex pulcher is a species native to central and southern Europe, the Mediterranean area, and western Asia, growing mainly in ruderal habitats. It is a highly variable species, with six subspecies currently recognized (i.e., R. pulcher subsp. anodonta , subsp. cassius , subsp. pulcher , subsp. raulinii , subsp. suffocatus , and subsp. woodsii ). In addition, there are the Linnaean R. divaricatus and Lojacono‐Pojero's R. usticanus , both of which are often considered heterotypic synonyms of R. pulcher , and several varieties and forms described by C. Haussknecht, which are synonymized with some accepted subspecies of R. pulcher . With the exception of R. suffocatus (basionym of R. pulcher subsp. suffocatus ) and R. pulcher f. anodonta (basionym of R. pulcher subsp. anodonta ), the names are still untypified and are examined and lectotypified here on specimens deposited at G, JE, PAL, and RO, whereas an illustration by Tilli is designated as the lectotype of the Linnaean R. divaricatus . Rumex usticanus is considered a synonym (syn. nov.) of R. obtusifolius subsp. obtusifolius ; R. divaricatus is a synonym of R. pulcher subsp. woodsii . Haussknecht's infraspecific names are considered heterotypic synonyms of R. pulcher subsp. raulinii ( R. pulcher f. macrodon ) or R. pulcher subsp. woodsii ( R. pulcher var. oligomicrodonta , var. microdon , and var. micropleiodontus ). Haussknecht's R. pulcher f. anodonta is accepted as separate taxon at subspecies rank ( R. pulcher subsp. anodonta ). Finally, the type of R. pulcher subsp. woodsii confirms the occurrence (as an old record) of this taxon in the region of Latium (central Italy) where, up to now, it was strangely considered a doubtful record. Further specimens, found at RO and identified as R. pulcher (without specifying any subspecies), confirm the recent occurrence of R. pulcher subsp. woodsii in the Italian region of Latium.