In the current rules for
botanical nomenclature (which apply retroactively), tautonyms are explicitly prohibited. The reason for prohibiting tautonyms is not explained in current or historical botanical nomenclatural codes, but it appears to have resulted from concerns over a century ago that identical taxon names could result in confusion where those names share identical spelling and identical capitalization. One example of a former botanical tautonym is 'Larix larix'. The earliest name for the
European larch is
Pinus larix L. (1753) but
Gustav Karl Wilhelm Hermann Karsten did not agree with the placement of the species in
Pinus and decided to move it to
Larix in 1880. His proposed name created a tautonym. Under rules first established in 1906, which are applied retroactively,
Larix larix cannot exist as a formal name. In such a case either the next earliest validly published name must be found, in this case
Larix decidua Mill. (1768), or (in its absence) a new epithet must be published. However, it is allowed for both parts of the name of a species to mean the same (
pleonasm), without being identical in spelling. For instance,
Arctostaphylos uva-ursi means
bearberry twice, in Greek and Latin respectively;
Picea omorika uses the Latin and Serbian terms for a
spruce. Instances that repeat the genus name with a slight modification, such as
Lycopersicon lycopersicum (Greek and Latinized Greek, a rejected name for the
tomato) and
Ziziphus zizyphus, have been contentious, but are in accord with the Code of Nomenclature. In April 2023, a proposal was made to permit tautonyms in botanical nomenclature on a non-retroactive basis, noting that tautonyms have been allowed in zoological and bacteriological codes for decades without incident, and that allowing tautonyms would simplify botany's nomenclatural code while eliminating certain naming problems and preserving the epithets originally assigned to species. == See also ==