Amaranthus commutatus A. Kern., 1924

Raus, Thomas, 2022, Taxonomic, nomenclatural and floristic review of Amaranthaceae of Greece and neighbouring countries, Willdenowia 52 (3), pp. 335-357 : 341

7. Amaranthus commutatus A. Kern. in Oesterr. Bot. Z. 25: 194. 1875.

Remarks — As already mentioned under Amaranthus blitum above, A. commutatus is a designation with no nomenclatural value, referring to a non-existent taxon. Its concept was investigated by the monographer Thellung on authentic material collected by Anton Kerner von Marilaun in Hungary and deposited in WU. Thellung (1914: 326) revealed the protologue as referring to a fictitious species, namely a taxonomic chimaera of A. graecizans (“ A. angustifolius silvester ” sensu Thellung ) and A. blitum (“ A. lividus ascendens ” sensu Thellung ). Kerner’s original collections, seen by Thellung (1914: 326), turned out to undoubtedly represent A. blitum , and the character of irregularly rupturing fruits (not truly circumscissile), pointing toward A. graecizans , was identified by Thellung as an artefact due to improper plant pressing. The name A. commutatus A. Kern. ex Hayek ( Hayek 1924: 162) is utilizable as a synonym of A. blitum (see above). However, there is no existing taxon behind “ A. commutatus A. Kern. ” that would be available for any kind of typifying action. Iamonico (2020) arrived at the same conclusion, and his idea to substantiate the name A. commutatus as a “species incertae sedis” is not feasible because this would require an existing taxon behind it, which is not the case. The name A. commutatus was rightly not in use, after 1875, in subsequent basic sources on European vascular plants. Surprisingly, “ A. commutatus A. Kern. ” survived and is currently preliminarily accepted in the Euro+Med PlantBase ( Iamonico 2015a), confined to Bulgaria as “alien with unknown status”, not native, although described from Hungary and recorded by distributed exsiccata from adjacent W Romania ( Beck 1909: 181). In parallel, it is given as native to Australia ( Govaerts 1995: 203), more precisely Queensland (“This species is accepted, and its native range is Australia. Native to: Queensland ”; POWO 2022). Iamonico (2020: 193) conjectured the similarity of the Australian A. rhombeus R. Br. (3-tepaled flower, circumscissile fruit) as the reason for this but at the same time excluded A. commutatus as a possible synonym of A. rhombeus . The critical Australian Plant Name Index ( Chapman 1991) does not at all include or synonymize the name “ A. commutatus ”. In short, it is a rare oddity in botanical literature: monographers and compilers of online checklists and atlases argue on the internet about the imaginary native range of an imaginary taxon!