Chenopodium rugosum Aellen, 1928

Mosyakin, Sergei L. & Romaschenko, Konstantin, 2021, On Chenopodium rugosum (Chenopodiaceae), an enigmatic taxon described by Aellen from Siberia, Phytotaxa 496 (2), pp. 208-212 : 209-210

Chenopodium rugosum Aellen , a later homonym of C. rugosum Raf.

The bibliographic and nomenclatural search performed by Sergei Mosyakin, however, demonstrated that the name Chenopodium rugosum proposed by Aellen (1928) cannot be used, even in a hypothetical case of its actual application to a species or infraspecific taxon worth taxonomic recognition. That name is, unfortunately, a later homonym of a long-

forgotten but validly published name C. rugosum Rafinesque (1830: 208) . That earlier name, however, was not listed in the International Plant Names Index ( IPNI 2021 –onward), Plants of the World Online ( POWO 2021 –onward) or any other nomenclatural database that we consulted before March 2021.

The name Chenopodium rugosum first appeared in the second volume of Rafinesque’s Medical Flora ( Rafinesque 1830), in the book section entitled “Lexicon of Medical Equivalents: or Alphabetical Enumeration of all the medical Plants of the United States omitted in the 100 selected articles, with additions and corrections, &c.” (pages 181–276). The original text containing the name stated as follows: “Correct in the article of Ch. anthelminthicum [sic!], two species equally medical are blended under that name. The southern and western species, which I now call Ch. rugosum, Raf. is well described by Elliott, it is really perennial, stem furrowed 4 or 5 feet high, leaves rugose, glandular beneath, &c.” ( Rafinesque 1830: 208). The article referred to in the protologue is, undoubtedly, Article 21 in Rafinesque (1828: 103–106) with the description of and comments on C. anthelminticum Linnaeus (1753: 220) , accompanied by Plate 21. The reference to the description of the species by Elliott means the description of C. anthelminticum in the first volume of A Sketch of the Botany of South Carolina and Georgia ( Elliott 1821: 331).

Thus, the name Chenopodium rugosum was apparently coined by Rafinescue for some southern robust forms of Dysphania anthelmintica (L.) Mosyakin & Clemants (2002: 382) (= Chenopodium anthelminticum ). However, Rafinesque clearly indicated that he corrected his earlier concept of C. anthelminticum as described in the first volume of the Medical Flora ( Rafinesque 1828: 103–106) and illustrated there on Plate 21. He also indicated, although briefly, the diagnostic characters of the species that he now accepted as C. rugosum , distinguishing it from C. anthelminticum sensu stricto, and also commented that the description of C. anthelminticum sensu Elliott (1821: 331) is referable (at least mainly) to his new species. Because of that the name C. rugosum Raf. was validly published and is also legitimate under the current Shenzhen Code ( Turland et al. 2018).