Nomenclatural and taxonomic comments on some taxa of Dysphania (Chenopodiaceae s. str. / Amaranthaceae s. l.)

Abstract

Following the comprehensive molecular phylogenetic results presented by Uotila et al. (2021), comments are provided on the infrageneric classification system of the genus Dysphania in its amended circumscription. Amendments and additions to the five-section scheme of Uotila et al. (2021) are proposed. In particular, the morphologically distinct lineage containing Dysphania atriplicifolia (earlier widely recognized in the monospecific genus Cycloloma as C. atriplicifolium) is recognized as a separate section, Dysphania sect. Cycloloma (Moq.) Mosyakin, comb. et stat. nov. Extensive synonymy of the section and its species is provided. The subclades revealed in the Australian clade of Dysphania sect. Dysphania are rather well characterized morphologically and were treated earlier as sections of either Chenopodium (sensu lato) or Dysphania. These subclades are recognized here as three subsections of sect. Dysphania: (1) subsect. Orthospora (R.Br.) Mosyakin, comb. et stat. nov.; (2) subsect. Dysphania; and (3) subsect. Tetrasepalae (Aellen) Mosyakin, comb. et stat. nov. The nomenclature of Dysphania graveolens (≡ Chenopodium graveolens) is discussed. It is confirmed that the name Chenopodium graveolens was first validated not by Willdenow in 1809 but by Lagasca and Rodríguez in 1802. Original specimens associated with that name in both publications belong taxonomically to the same species currently known as D. graveolens (= Chenopodium incisum Poir.). In my opinion, Art. 41.8(a) of the ICN (Shenzhen Code) is directly applicable here. Consequently, the name D. graveolens should be cited with the corrected authorship "(Lag. & Rodr.) Mosyakin & Clemants", and the new combination in Dysphania based on Chenopodium incisum (provisionally cited in POWO as "Dysphania incisa (Poir.) ined.") is unnecessary.