Article 19

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 using 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. A tribe is designated in a similar manner, with the termination -eae, and a subtribe similarly with the termination -inae (but not -virinae).

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 based on the generic name equivalent to that type (Art. 10.6, but see Art. 19.7).

Ex. 2. The type of the family name Rosaceae Juss. is Rosa L. and hence the subfamily and tribe which include Rosa are to be called Rosoideae Endl. and Roseae DC.

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 which include Poa are to be called Pooideae Asch., Poëae R. Br. and Poinae Dumort.

Note 2. This provision 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).

Ex. 4. The subfamily including the type of the family name Ericaceae Juss. (Erica L.), irrespective of priority, is to be called Ericoideae Endl., and the tribe including this type is called Ericeae D. Don. However, the correct name of the tribe including both Rhododendron L., the type of the subfamily name Rhododendroideae Endl., and Rhodora L. is Rhodoreae D. Don (1834) not Rhododendreae Brongn. (1843).

19.5. A name of a subdivision of a family based on an illegitimate generic name that is not the base of a conserved family name is illegitimate.

Ex. 5. The name Caryophylloideae Arn. (1832), based on Caryophyllaceae Juss., nom. cons., is legitimate although it is ultimately based on the illegitimate Caryophyllus Mill. non L.

19.6. When a name of a taxon assigned to one of the above categories 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 the rule, without change of the author citation or date of publication (see Art. 32.7). However, if such names are published with a non-Latin termination they are not validly published.

Ex. 6.Climacieae” (Grout, Moss Fl. N. Amer. 3: 4. 1928), published to designate a subfamily, is to be changed to Climacioideae Grout (1928).

Ex. 7. 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 later by Grisebach (Spic. Fl. Rumel. 2: 377. 1846).

19.7. 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.

Recommendation 19A

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 in the new rank, the name should be retained, and only its termination (-aceae, -oideae, -eae, -inae) altered.

Ex. 1. The subtribe Drypetinae Griseb. (1859) when raised to the rank of tribe was named Drypeteae Hurus. (1954); the subtribe Antidesmatinae Müll. Arg. (1865) when raised to the rank of subfamily was named Antidesmatoideae Hurus. (1954).

19A.2. When a subdivision of a family is changed to another such rank, and no legitimate name is available in the new rank, its name should be based on the same generic name as the name in the former rank.

Ex. 2. Among the tribes of the family Ericaceae are Pyroleae D. Don, Monotropeae D. Don, and Vaccinieae D. Don, none of which includes the type of the family name (Erica L.). The later names Pyroloideae A. Gray, Monotropoideae A. Gray, and Vaccinioideae Endl. are based on the same generic names.