Nomen illegitimum

Nomen illegitimum(Latinforillegitimate name) is a technical term used mainly inbotany.It is usually abbreviated asnom. illeg.Although theInternational Code of Nomenclature for algae, fungi, and plantsuses Latin terms as qualifiers for taxon names (e.g.nomen conservandumfor "conserved name",andnomen superfluumfor "superfluous name" ), the definition of each term is in English rather than Latin.The Latin abbreviations are widely used by botanists and mycologists.

Achras sapotais both aNomen illegitimumand anomen superfluumand is properly calledManilkara zapota

Definition

Anomen illegitimumis avalidly published name,but one that contravenes some of the articles laid down by theInternational Botanical Congress.The name could be illegitimate because:

• (article 52) it was superfluous at its time of publication, i.e., the taxon (as represented by thetype) already has a name, or
• (articles 53 and 54) the name has already been applied to another plant (ahomonym).

For the procedure of rejecting otherwise legitimate names, seeconserved name.

The qualification above concerning the taxon and the type is important. A name can be superfluous but not illegitimate if it would be legitimate for a differentcircumscription.For example, the family nameSalicaceae,based on the "type genus"Salix,was published byCharles-François Brisseau de Mirbelin 1815. So when in 1818Lorenz Chrysanth von Vestpublished the name Carpinaceae (based on the genusCarpinus) for a family explicitly including the genusSalix,it was superfluous: "Salicaceae" was already the correct name for Vest's circumscription; "Carpinaceae" is superfluous for a family containingSalix.However, the name is not illegitimate, sinceCarpinusis a legitimate name. IfCarpinuswere in future placed in a family where no genus had been used as the basis for a family name earlier than Vest's name (e.g. if it were placed in a family of its own) then Carpinaceae would be its legitimate name. (See Article 52.3, Ex. 18.)

A similar situation can arise when species are synonymized and transferred between genera.Carl Linnaeusdescribed what he regarded as two distinct species of grass:Andropogon fasciculatusin 1753 andAgrostis radiatain 1759. If these two are treated as the same species, the oldest specific epithet,fasciculatus,has priority. So when Swartz in 1788 combined the two as one species in the genusChloris,the name he used,Chloris radiata,was superfluous, since the correct name already existed, namelyChloris fasciculata.Chloris radiatais an incorrect name for a species in the genusChloriswith the same type as Linnaeus'sAndropogon fasciculatus.However, if they are treated as separate species, and Linnaeus'sAgrostis radiatais transferred toChloris,thenChloris radiatais its legitimate name. (See Article 52.3, Ex. 15.)

Examples

Rhodotorula rubra(Demme) Lodder, 1934(different fromRhodotorula rubra(Schimon) F.C. Harrison, 1928)is anom. illeg.and now calledRhodotorula mucilaginosa(A. Jörg.) F.C. Harrison, 1928

• "The generic nameCainitoAdans. (1763)is illegitimate because it was a superfluous name forChrysophyllumL. (1753),which Adanson cited as a synonym. "
• "The nameAmblyantheraMüll. Arg. (1860)is a later homonym of the validly publishedAmblyantheraBlume (1849)and is therefore unavailable for use, althoughAmblyantheraBlumeis now considered to be a synonym ofOsbeckiaL. (1753)."
• "The nameTorreyaArn. (1838)is anomen conservandumand is therefore available for use in spite of the existence of the earlier homonymTorreyaRaf. (1818)."

See also

• Correct name (botany)
• Valid name (zoology)
• Nomen dubium
• Glossary of botanical terms
• Glossary of scientific naming
• Nomen conservandum