14.1. In order to avoid disadvantageous changes in the nomenclature of families, genera, and species entailed by the strict application of the rules, and especially of the principle of priority in starting from the dates given in Art. 13, this Code provides, in App. II and III, lists of names that are conserved (nomina conservanda) and must be retained as useful exceptions. Conserved names are legitimate even though initially they may have been illegitimate.
14.2. Conservation aims at retention of those names which best serve stability of nomenclature (see Rec. 50E).
14.3. The application of both conserved and rejected names is determined by nomenclatural types. The type of the specific name cited as the type of a conserved generic name may, if desirable, be conserved and listed in App. IIIA.
14.4. A conserved name of a family or genus is conserved against all other names in the same rank based on the same type (nomenclatural synonyms, which are to be rejected) whether these are cited in the corresponding list of rejected names or not, and against those names based on different types (taxonomic synonyms) that are cited in that list1. A conserved name of a species is conserved against all names listed as rejected, and against all combinations based on the rejected names.
Note 1. The Code does not provide for conservation of a name against itself, i.e. against the same name with the same type but with a different place and date of valid publication than is given in the relevant entry in App. II or III, and perhaps with a different authorship (but see Art. 14.9).
Note 2. A species name listed as conserved or rejected in App. IIIB may have been pub-lished as the name of a new taxon, or as a combination based on an earlier name. Rejection of a name based on an earlier name does not in itself preclude the use of the earlier name since that name is not "a combination based on a rejected name" (Art. 14.4).
Ex. 1. Rejection of Lycopersicon lycopersicum (L.) H. Karst. in favour of L. esculentum Mill. does not preclude the use of the homotypic Solanum lycopersicum L.
14.5. When a conserved name competes with one or more names based on different types and against which it is not explicitly conserved, the earliest of the competing names is adopted in accordance with Art. 11, except for some conserved family names (App. IIB), which are conserved against unlisted names.
Ex. 2. If Weihea Spreng. (1825) is united with Cassipourea Aubl. (1775), the combined genus will bear the prior name Cassipourea, although Weihea is conserved and Cassipourea is not.
Ex. 3. If Mahonia Nutt. (1818) is united with Berberis L. (1753), the combined genus will bear the prior name Berberis, although Mahonia is conserved and Berberis is not.
Ex. 4. Nasturtium R. Br. (1812) was conserved only against the homonym Nasturtium Mill. (1754) and the nomenclatural synonym Cardaminum Moench (1794); consequently if reunited with Rorippa Scop. (1760) it must bear the name Rorippa.
14.6. When a name of a taxon has been conserved against an earlier name based on a different type, the latter is to be restored, subject to Art. 11, if it is considered the name of a taxon at the same rank distinct from that of the nomen conservandum, except when the earlier rejected name is a homonym of the conserved name.
Ex. 5. The generic name Luzuriaga Ruiz & Pav. (1802) is conserved against the earlier names Enargea Banks ex Gaertn. (1788) and Callixene Comm. ex Juss. (1789). If, however, Enargea is considered to be a separate genus, the name Enargea is retained for it.
14.7. A rejected name, or a combination based on a rejected name, may not be restored for a taxon which includes the type of the corresponding conserved name.
Ex. 6. Enallagma Baill. (1888) is conserved against Dendrosicus Raf. (1838), but not against Amphitecna Miers (1868); if Enallagma and Amphitecna are united, the combined genus must bear the name Amphitecna, although the latter is not explicitly conserved against Dendrosicus.
14.8. The listed type of a conserved name may not be changed except by the procedure outlined in Art. 14.12.
Ex. 7. Bullock & Killick (in Taxon 6: 239. 1957) published a proposal that the listed type of Plectranthus L'Hér. be changed from P. punctatus (L. f.) L'Hér. to P. fruticosus L'Hér. This proposal was approved by the appropriate Committees and by an International Botanical Congress.
14.9. A name may be conserved with a different type from that designated by the author or determined by application of the Code (see also Art. 10.4). Such a name may be conserved either from its place of valid publication (even though the type may not then have been included in the named taxon) or from a later publication by an author who did include the type as conserved. In the latter case the original name and the name as conserved are treated as if they were homonyms (Art. 53), whether or not the name as conserved was accompanied by a description or diagnosis of the taxon named.
Ex. 8. Bromus sterilis L. (1753) has been conserved from its place of valid publication even though its conserved type, a specimen (Hubbard 9045, E) collected in 1932, was not originally included in Linnaeus's species.
Ex. 9. Protea L. (1753) did not include the conserved type of the generic name, P. cynaroides (L.) L. (1771), which in 1753 was placed in the genus Leucadendron. Protea was therefore conserved from the 1771 publication, and Protea L. (1771), although not designed to be a new generic name and still including the original type elements, is treated as if it were a validly published homonym of Protea L. (1753).
14.10. A conserved name, with its corresponding autonyms, is conserved against all earlier homonyms. An earlier homonym of a conserved name is not made illegitimate by that conservation but is unavailable for use; if legitimate, it may serve as basionym of another name or combination based on the same type (see also Art. 55.3).
Ex. 10. The generic name Smithia Aiton (1789), conserved against Damapana Adans. (1763), is thereby conserved automatically against the earlier homonym Smithia Scop. (1777).
14.11. A name may be conserved in order to preserve a particular orthography or gender. A name so conserved is to be attributed without change of priority to the author who validly published it, not to an author who later introduced the conserved spelling or gender.
Ex. 11. The spelling Rhodymenia, used by Montagne (1839), has been conserved against the original spelling Rhodomenia, used by Greville (1830). The name is to be cited as Rhodymenia Grev. (1830).
Note 3. The date of conservation does not affect the priority (Art. 11) of a conserved name, which is determined only on the basis of the date of valid publication (Art. 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45).
14.12. The lists of conserved names will remain permanently open for additions and changes. Any proposal of an additional name must be accompanied by a detailed statement of the cases both for and against its conservation. Such proposals must be submitted to the General Committee (see Div. III), which will refer them for examination to the committees for the various taxonomic groups.
14.13. Entries of conserved names may not be deleted.
14.14. When a proposal for the conservation (or rejection
under Art. 56) of a name has been approved
by the General Committee after study by the Committee for the
taxonomic group concerned, retention (or rejection) of that name
is authorized subject to the decision of a later International
Botanical Congress.
14A.1. When a proposal for the conservation or rejection
of a name has been referred to the appropriate Committee for study,
authors should follow existing usage as far as possible pending
the General Committee's recommendation on the proposal.