CHAPTER III. Nomenclature of taxa according to their rank
SECTION 5. Names of taxa below the rank of species (infraspecific taxa)
- The name of any infraspecific taxon that includes the type of the adopted, legitimate name of the species to which it is assigned is to repeat the specific epithet unaltered as its final epithet, not followed by an author citation (see Art. 46). Such names are autonyms (Art. 6.8; see also Art. 7.6).
- The variety that includes the type of the name Lobelia spicata Lam. is to be named Lobelia spicata Lam. var. spicata (see also Art. 24 Ex. 3).
- A name of an infraspecific taxon that includes the type (i.e. the holotype or all syntypes or the previously designated type) of the adopted, legitimate name of the species to which it is assigned is not validly published unless its final epithet repeats the specific epithet unaltered. For the purpose of this provision, explicit indication that the nomenclaturally typical element of the species is included is considered as equivalent to inclusion of the type, whether or not it has been previously designated (see also Art. 24.3).
- The intended combination “Vulpia myuros subsp. pseudomyuros (Soy.-Will.) Maire & Weiller” was not validly published in Maire (Fl. Afrique N. 3: 177. 1955) because it included “F. myuros L., Sp. 1, p. 74 (1753) sensu stricto” in synonymy, Festuca myuros L. being the basionym of Vulpia myuros (L.) C. C. Gmel.
- Linnaeus (Sp. Pl.: 3. 1753) recognized two named varieties under Salicornia europaea. Since S. europaea has no holotype and no syntypes are cited, both varietal names are validly published irrespective of the facts that the lectotype of S. europaea, designated by Jafri and Rateeb (in Jafri & El-Gadi, Fl. Libya 58: 57. 1979), can be attributed to S. europaea var. herbacea L. (1753) and that the latter name was subsequently lectotypified by Piirainen (in Ann. Bot. Fenn. 28: 82. 1991) by the same specimen as the species name.
- Linnaeus (Sp. Pl.: 779–781. 1753) recognized 13 named varieties under Medicago polymorpha. Since M. polymorpha L. has neither a holotype nor syntypes, all varietal names are validly published, and indeed the lectotype subsequently designated (by Heyn in Bull. Res. Council Israel, Sect. D, Bot., 7: 163. 1959) is not part of the original material for any of the varietal names of 1753.
- The first instance of valid publication of a name of an infraspecific taxon under a legitimate species name automatically establishes the corresponding autonym (see also Art. 11.6 and 32.3).
- The publication of the name Lycopodium inundatum var. bigelovii Tuck. (in Amer. J. Sci. Arts 45: 47. 1843) automatically established the name of another variety, L. inundatum L. var. inundatum, the autonym, the type of which is that of the name L. inundatum L. (Art. 7.6).
- Pangalo (in Trudy Prikl. Bot. 23: 258. 1930) when describing Cucurbita mixta Pangalo distinguished two varieties, C. mixta var. cyanoperizona Pangalo and var. stenosperma Pangalo, together encompassing the entire circumscription of the species. Although Pangalo did not mention the autonym (see 26B.1), C. mixta var. mixta was automatically established at the same time. Since neither a holotype nor any syntypes were indicated for C. mixta, both varietal names were validly published (see Art. 26.2). Merrick & Bates (in Baileya 23: 96, 101. 1989), in the absence of known type material, neotypified C. mixta by an element that can be attributed to C. mixta var. stenosperma. As long as their choice of neotype is followed, under Art. 11.6 the correct name for that variety recognized under C. mixta is C. mixta var. mixta, dating from 1930, not C. mixta var. stenosperma. When that variety is recognized under C. argyrosperma Huber (1867), as was done by Merrick & Bates, its correct name is not C. argyrosperma var. stenosperma (Pangalo) Merrick & D. M. Bates; a combination based on C. mixta is required.
- A variety including the type of the correct name of a subspecies, but not including the type of the correct name of the species, should, where there is no obstacle under the rules, be given a name with the same final epithet and type as the subspecific name.
- A subspecies not including the type of the correct name of the species should, where there is no obstacle under the rules, be given a name with the same final epithet and type as a name of one of its subordinate varieties.
- A taxon of rank lower than variety that includes the type of the correct name of a subspecies or variety, but not the type of the correct name of the species, should, where there is no obstacle under the rules, be given a name with the same final epithet and type as the name of the subspecies or variety. On the other hand, a subspecies or variety that does not include the type of the correct name of the species should not be given a name with the same final epithet as a name of one of its subordinate taxa below the rank of variety.
- Fernald treated Stachys palustris subsp. pilosa (Nutt.) Epling (in Repert. Spec. Nov. Regni Veg. Beih. 8: 63. 1934) as composed of five varieties, for one of which (that including the type of S. palustris subsp. pilosa) he made the combination S. palustris var. pilosa (Nutt.) Fernald (in Rhodora 45: 474. 1943), there being no legitimate varietal name available.
- There being no legitimate name available at the rank of subspecies, Bonaparte made the combination Pteridium aquilinum subsp. caudatum (L.) Bonap. (Notes Ptérid. 1: 62. 1915), using the same final epithet that Sadebeck had used earlier in the combination P. aquilinum var. caudatum (L.) Sadeb. (in Jahrb. Hamburg. Wiss. Anst. Beih. 14(3): 5. 1897), both combinations being based on Pteris caudata L. Each name is legitimate, and both can be used, as by Tryon (in Rhodora 43: 52–54. 1941), who treated P. aquilinum var. caudatum as one of four varieties under subsp. caudatum (see also Art. 36.2).