NOMENCLATURE OF TAXA ACCORDING TO THEIR RANK
NAMES OF FAMILIES AND SUBFAMILIES, TRIBES AND SUBTRIBES
19.1. The name of a subfamily is a plural adjective used as a noun; it is formed in the same manner as the name of a family (Art. 18.1) but by adding the termination ‑oideae instead of ‑aceae.
19.2. Names intended as names of subfamilies, but published with their rank denoted by the term “suborder” (subordo) instead of subfamily, are treated as having been published as names of subfamilies (see also Art. 18.2), unless this would result in a taxonomic sequence with a misplaced rank-denoting term.
Ex. 1. Cyrilloideae Torr. & A. Gray (Fl. N. Amer. 1: 256. 1838) and Sphenocleoideae Lindl. (Intr. Nat. Syst. Bot., ed. 2: 238. 1836) were published as “suborder Cyrilleae” and “Sub-Order ? Sphenocleaceae”, respectively.
Note 1. If the term “subfamily” is simultaneously used to denote a rank different from “suborder”, a name published for a taxon at the latter rank cannot be considered to have been published as the name of a subfamily.
19.3. The name of a tribe or subtribe is formed in the same manner as the name of a subfamily (Art. 19.1), except that the termination is ‑eae for a tribe and ‑inae (but not ‑virinae) for a subtribe.
19.4. The name of any subdivision of a family that includes the type of the adopted, legitimate name of the family to which it is assigned is to be formed from the generic name equivalent to that type (Art. 10.9; but see Art. 19.8).
Ex. 2. The type of the family name Rosaceae Juss. is Rosa L. and hence the subfamily and tribe assigned to Rosaceae that include Rosa are to be called Rosoideae Endl. and Roseae DC., respectively.
Ex. 3. The type of the family name Gramineae Juss. (nom. alt.: Poaceae Barnhart, see Art. 18.5) is Poa L. and hence the subfamily, tribe, and subtribe assigned to Gramineae that include Poa are to be called Pooideae Asch., Poeae R. Br., and Poinae Dumort., respectively.
Ex. 4. The type of the family name Ericaceae Juss. is Erica L. and hence the subfamily and tribe assigned to Ericaceae that include Erica are to be called Ericoideae Endl. and Ericeae D. Don, respectively, the priority of any competing names notwithstanding. The subfamily that includes Rhododendron L. is called Rhododendroideae Endl. However, the correct name of the tribe of Ericaceae that includes both Rhododendron and Rhodora L. is Rhodoreae D. Don (in Edinburgh New Philos. J. 17: 152. 1834), not Rhododendreae Brongn. (Énum. Pl. Mus. Paris: 127. 1843).
Note 3. A name of a subdivision of a family that includes the type of the adopted, legitimate name of the family to which it is assigned, but is not formed from the generic name equivalent to that type, is incorrect but may nevertheless be validly published and may become correct in a different context.
Ex. 5. When published, the name Lippieae Endl. (Gen. Pl.: 633. 1838) was applied to a tribe of Verbenaceae J. St.-Hil. that included Verbena L., the type of the family name, as well as Lippia L. Although originally incorrect, Lippieae may become correct if used for a tribe of Verbenaceae that includes Lippia but excludes Verbena.
19.5. The name of any subdivision of a family that includes the type of a name listed in App. IIB (i.e. a name of a family conserved against all unlisted names, see Art. 14.5) is to be formed from the generic name equivalent to that type (Art. 10.9), unless this is contrary to Art. 19.4 (see also Art. 19.8). If more than one such type is included, the correct name is determined by precedence in App. IIB of the corresponding family names.
Ex. 6. A subfamily assigned to Rosaceae Juss. that includes Malus Mill., the type of Malaceae Small (Fl. S.E. U.S.: 495, 529. 1903) listed in App. IIB, is to be called Maloideae C. Weber (in J. Arnold Arbor. 45: 164. 1964) unless it also includes Rosa L., i.e. the type of Rosaceae, or the type of another name listed in App. IIB that takes precedence over Malaceae. This is so even if the subfamily also includes Spiraea L. and/or Pyrus L. because, although Spiraeoideae Arn. (in Hooker & Arnott, Bot. Beechey Voy.: 107. 1832) and Pyroideae Burnett (Outlines Bot.: 695, 1137. 1835) were published earlier than Maloideae, neither Spiraeaceae nor Pyraceae is listed in App. IIB. However, if Amygdalus L. is included in the same subfamily as Malus, the name Amygdaloideae Arn. (in Hooker & Arnott, Bot. Beechey Voy.: 107. 1832) takes precedence because Amygdalaceae Marquis (Esq. Règne Vég.: 49. 1820) is listed in App. IIB with priority over Malaceae.
Ex. 7. Monotropaceae Nutt. (Gen. N. Amer. Pl. 1: 272. 1818) and Pyrolaceae Lindl. (Syn. Brit. Fl.: 175. 1829) are both listed in App. IIB, but Pyrolaceae is conserved against Monotropaceae. Therefore, a subfamily including both Monotropa L. and Pyrola L. is called Pyroloideae Beilschm. (in Flora 16(Beibl. 1): 72, 109. 1833).
19.6. A name of a subdivision of a family formed from an illegitimate generic name is illegitimate unless and until that generic name or the corresponding family name is conserved or protected.
Ex. 8. The name Caryophylloideae Arn. (in Hooker & Arnott, Bot. Beechey Voy.: 99. 1832), formed from the illegitimate Caryophyllus Mill. non L., is legitimate because the corresponding family name, Caryophyllaceae Juss., is conserved.
Ex. 9. Thunbergioideae T. Anderson (in Thwaites, Enum. Pl. Zeyl.: 223. 1860), formed from Thunbergia Retz., nom. cons. (in Physiogr. Sälsk. Handl. 1(3): 163. 1780), became legitimate when the generic name was conserved against its earlier homonym Thunbergia Montin (in Kongl. Vetensk. Acad. Handl. 34: 288. 1773) (see App. III).
19.7. When a name of a subdivision of a family has been published with an improper Latin termination, such as ‑eae for a subfamily or ‑oideae for a tribe, the termination must be changed to accord with Art. 19.1 and 19.3, without change of authorship or date (see Art. 32.2). However, if such a name is published with a non-Latin termination, it is not validly published.
Ex. 10. ‘Climacieae’ Grout (Moss Fl. N. Amer. 3: 4. 1928), published to designate a subfamily, is to be accepted as Climacioideae Grout (1928).
Ex. 11. Melantheen (Kittel in Richard, Nouv. Elém. Bot., ed. 3, Germ. Transl.: 727. 1840), published to designate a tribe, is not to be accepted as “Melanthieae Kitt.” because it has a German rather than a Latin termination. The name Melanthieae was validly published by Grisebach (Spic. Fl. Rumel. 2: 377. 1846).
19.8. When the Papilionaceae are included in the family Leguminosae (nom. alt.: Fabaceae; see Art. 18.5) as a subfamily, the name Papilionoideae may be used as an alternative to Faboideae.
19A.1. When a family is changed to the rank of a subdivision of a family, or the inverse change occurs, and no legitimate name is available at the new rank, the name should be retained, with only the termination (‑aceae, ‑oideae, ‑eae, ‑inae) altered.
19A.2. When a subdivision of a family is changed to another such rank, and no legitimate name is available at the new rank, its name, Art. 19.5 permitting, should be formed from the same generic name as the name at the former rank.
Ex. 1. The subtribe Drypetinae Griseb. (Fl. Brit. W. I.: 31. 1859) when raised to the rank of tribe was named Drypeteae Small (Man. S.E. Fl.: 775. 1933); the subtribe Antidesmatinae Müll. Arg. (in Linnaea 34: 64. 1865) when raised to the rank of subfamily was named Antidesmatoideae Hurus. (in J. Fac. Sci. Univ. Tokyo, Sect. 3, Bot. 6: 322, 340. 1954).