CHAPTER III. Nomenclature of taxa according to their rank
SECTION 2. Names of families and subfamilies, tribes and subtribes
- 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.
- 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.
- 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.
- A tribe is designated in a similar manner, with the termination -eae, and a subtribe similarly with the termination -inae (but not -virinae).
- 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 based on the generic name equivalent to that type (Art. 10.6; but see Art. 19.8).
- 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.
- 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.
- Art. 19.4 applies only to the names of those subordinate taxa that include the type of the adopted name of the family (but see Rec. 19A.2).
- 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 assigned to Ericaceae that includes Rhododendron L. is called Rhododendroideae Endl. However, the correct name of the tribe assigned to Rhododendroideae that includes both Rhododendron and Rhodora L. is Rhodoreae D. Don (1834), not Rhododendreae Brongn. (1843).
- 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 based on the generic name equivalent to that type (Art. 10.6), 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.
- A subfamily assigned to Rosaceae Juss. that includes Malus Mill., the type of Malaceae Small (1903), listed in App. IIB, is to be called Maloideae C. Weber (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. (1832) and Pyroideae Burnett (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. (1832) takes precedence as Amygdalaceae Marquis (1820) is listed in App. IIB with priority over Malaceae.
- Monotropaceae Nutt. (1818) and Pyrolaceae Link (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 Kostel. (1834).
- A name of a subdivision of a family based on an illegitimate generic name is illegitimate unless and until that generic name or the corresponding family name is conserved.
- The name Caryophylloideae Arn. (1832), based on the illegitimate Caryophyllus Mill. non L., is legitimate because the corresponding family name, Caryophyllaceae Juss., is conserved.
- Thunbergioideae T. Anderson (1860), based on Thunbergia Retz., nom. cons. (1780), became legitimate when the generic name was conserved over its earlier homonym Thunbergia Montin (1773) (see App. III).
- 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 the author citation or date (see Art. 32.2). However, if such a name is published with a non-Latin termination it is not validly published.
- “Climacieae” (Grout, Moss Fl. N. Amer. 3: 4. 1928), published to designate a subfamily, is to be changed to Climacioideae Grout (1928).
- However, 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.”, as it has a German rather than a Latin termination. The name Melanthieae was validly published by Grisebach (Spic. Fl. Rumel. 2: 377. 1846).
- 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.
- 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 in the new rank, the name should be retained, with only the termination (-aceae, -oideae, -eae, -inae) altered.
- When a subdivision of a family is changed to another such rank, and no legitimate name is available in the new rank, its name, Art. 19.5 permitting, should be based on the same generic name as the name in the former rank.