Article 22

• The name of any subdivision of a genus that includes the type of the adopted, legitimate name of the genus to which it is assigned is to repeat that generic name unaltered as its epithet, not followed by an author citation (see Art. 46). Such names are autonyms (Art. 6.8; see also Art. 7.6).
  • The subgenus that includes the type of the name Rhododendron L. is to be named Rhododendron L. subg. Rhododendron.
  • The subgenus that includes the type of Malpighia L. (M. glabra L.) is to be called M. subg. Malpighia, not M. subg. Homoiostylis Nied.; and the section that includes the type of Malpighia is to be called M. sect. Malpighia, not M. sect. Apyrae DC.
  • Art. 22.1 applies only to the names of those subordinate taxa that include the type of the adopted name of the genus (but see Rec. 22A).
  • The correct name of the subgenus of the genus Solanum L. that includes S. pseudocapsicum L., the type of S. sect. Pseudocapsicum (Medik.) Roem. & Schult. (Syst. Veg. 4: 569 (‘Pseudocapsica’), 584 (‘Pseudo-Capsica’). 1819), if considered distinct from S. subg. Solanum, is S. subg. Minon Raf. (Autikon Bot.: 108. 1840), the earliest legitimate name at that rank, and not “S. subg. Pseudocapsicum”.
• A name of a subdivision of a genus that includes the type (i.e. the original type or all elements eligible as type or the previously designated type) of the adopted, legitimate name of the genus is not validly published unless its epithet repeats the generic name unaltered. For the purposes of this provision, explicit indication that the nomenclaturally typical element is included is considered as equivalent to inclusion of the type, whether or not it has been previously designated (see also Art. 21.3).
  • “Dodecatheon sect. Etubulosa” (Knuth in Engler, Pflanzenr. IV. 237 (Heft 22): 234. 1905) was not validly published since it was proposed for a section that included D. meadia L., the original type of the generic name Dodecatheon L.
  • Cactus [unranked] Melocactus L. (Gen. Pl., ed. 5: 210. 1754) was proposed for one of four unranked (Art. 37.3), named subdivisions of the genus Cactus, comprising C. melocactus L. (its type under Art. 22.6) and C. mammillaris L. It is validly published even though C. mammillaris was subsequently designated as the type of Cactus L. (by Coulter in Contr. U. S. Natl. Herb. 3: 95. 1894).
• The first instance of valid publication of a name of a subdivision of a genus under a legitimate generic name automatically establishes the corresponding autonym (see also Art. 11.6 and 32.3).
  • Publication of Tibetoseris sect. Simulatrices Sennikov (in Komarovia 5: 91. 2008) automatically established the autonym Tibetoseris Sennikov sect. Tibetoseris. Publication of Pseudoyoungia sect. Simulatrices (Sennikov) D. Maity & Maiti (in Compositae Newslett. 48: 31. 2010) automatically established the autonym Pseudoyoungia D. Maity & Maiti sect. Pseudoyoungia.
• The epithet in the name of a subdivision of a genus may not repeat unchanged the correct name of the genus unless the two names have the same type.
• The epithet in the name of a subdivision of a genus may not repeat the generic name unaltered if the latter is illegitimate.
  • When Kuntze (in Post & Kuntze, Lex. Gen. Phan.: 106. 1903) published Caulinia sect. Hardenbergia (Benth.) Kuntze under Caulinia Moench (1802), a later homonym of Caulinia Willd. (1801), he did not establish the autonym “Caulinia sect. Caulinia”.
• When the epithet in the name of a subdivision of a genus is identical with or derived from the epithet in one of the originally included species names, the type of the higher-ranking name is the same as that of the species name, unless the original author of the higher-ranking name designated another type.
  • The type of Euphorbia subg. Esula Pers. (Syn. Pl. 2: 14. 1806) is the type of E. esula L., one of the species names included by Persoon; the designation of E. peplus L. (also included by Persoon) as type by Croizat (in Revista Sudamer. Bot. 6: 13. 1939) has no standing.
  • The type of Cassia [unranked] Chamaecrista L. (Sp. Pl.: 379. 1753) is the type of C. chamaecrista L., nom. rej., one of the five species names included by Linnaeus.
  • When the epithet in the name of a subdivision of a genus is identical with or derived from the epithet in an included species name that is a later homonym, the nomenclatural type is that of the later homonym.

Recommendation 22A

• A section including the type of the correct name of a subgenus, but not including the type of the correct name of the genus, should, where there is no obstacle under the rules, be given a name with the same epithet and type as the subgeneric name.
• A subgenus not including the type of the correct name of the genus should, where there is no obstacle under the rules, be given a name with the same epithet and type as the correct name of one of its subordinate sections.
  • When Brizicky raised Rhamnus sect. Pseudofrangula Grubov to the rank of subgenus, instead of using a new epithet he named the taxon R. subg. Pseudofrangula (Grubov) Brizicky so that the type of both names is the same.

Recommendation 22B

• When publishing a name of a subdivision of a genus that will also establish an autonym, the author should mention this autonym in the publication.