NOMENCLATURE OF TAXA ACCORDING TO THEIR RANK
NAMES OF TAXA ABOVE THE RANK OF FAMILY
16.1. The name of a taxon above the rank of family is treated as a noun in the plural and is written with an initial capital letter. Such names may be either (a) automatically typified names (Art. 10.10), formed from a generic name in the same way as family names (Art. 18.1; but see Art. 16.4) by adding the appropriate rank-denoting termination (Art. 16.3 and 17.1), preceded by the connecting vowel ‑o- if the termination begins with a consonant; or (b) descriptive names, not so formed, which may be used unchanged at different ranks (see also Art. 6 Note 3).
Ex. 1. Automatically typified names above the rank of family: Lycopodiophyta, formed from Lycopodium; Magnoliophyta, from Magnolia; Gnetophytina, from Gnetum; Pinopsida, from Pinus; Marattiidae, from Marattia; Caryophyllidae and Caryophyllales, from Caryophyllus; Fucales, from Fucus; Bromeliineae, from Bromelia.
Ex. 2. Descriptive names above the rank of family: Angiospermae, Anthophyta, Ascomycetes, Ascomycota, Ascomycotina, Centrospermae, Chlorophyta, Coniferae, Enantioblastae, Gymnospermae, Lycophyta, Parietales.
16.2. For automatically typified names, the name of the subdivision or subphylum that includes the type of the adopted name of a division or phylum, the name of the subclass that includes the type of the adopted name of a class, and the name of the suborder that includes the type of the adopted name of an order are to be formed from the same generic name (see also Art. 16.4) as the corresponding higher-ranked name.
Ex. 3. Pteridophyta Schimp. (in Zittel, Handb. Palaeont., Palaeophyt.: 1. 1879) and Pteridophytina B. Boivin (in Bull. Soc. Bot. France 103: 493. 1956); Gnetopsida Prantl (Lehrb. Bot., ed. 5: 194. 1883) and Gnetidae Pax (in Prantl, Lehrb. Bot., ed. 9: 210. 1894); Liliales Perleb (Lehrb. Naturgesch. Pflanzenr.: 129. 1826) and Liliineae Rchb. (Deut. Bot. Herb.-Buch: xxxvii. 1841).
16.3. Automatically typified names end as follows: the name of a division or phylum ends in ‑phyta, unless it is referable to the fungi in which case it ends in ‑mycota; the name of a subdivision or subphylum ends in ‑phytina, unless it is referable to the fungi in which case it ends in ‑mycotina; the name of a class in the algae ends in ‑phyceae, and of a subclass in ‑phycidae; the name of a class in the fungi ends in ‑mycetes, and of a subclass in ‑mycetidae; the name of a class in the plants ends in ‑opsida, and of a subclass in ‑idae (but not ‑viridae). Automatically typified names with a termination not in accordance with this rule or Art. 17.1 are to be corrected, without change of authorship or date of publication (see Art. 32.2). However, if such names are published with a non-Latin termination they are not validly published.
Ex. 4. ‘Cacteae’ Juss. ex Bercht. & J. Presl (Přir. Rostlin: 238. 1820, formed from Cactus L.) and ‘Coriales’ Lindl. (Nix. Pl.: 11. 1833, formed from Coriaria L.), both published for taxa at the rank of order, are to be corrected to Cactales Juss. ex Bercht. & J. Presl (1820) and Coriariales Lindl. (1833), respectively.
Ex. 5. Ptéridées (Kirschleger, Fl. Alsace 2: 379. 1853–Jul 1857), published for a taxon at the rank of order, is not to be accepted as “Pteridales Kirschl.” because it has a French rather than a Latin termination. The name Pteridales was later validly published by Doweld (Prosyll. Tracheophyt., Tent. Syst. Pl. Vasc.: xi. 2001).
Note 1. The terms “divisio” and “phylum”, and their equivalents in modern languages, are treated as referring to one and the same rank (Art. 3.1). When “divisio” and “phylum” are used simultaneously to denote different non-consecutive ranks, this is to be treated as informal usage of rank-denoting terms (see Art. 37.8; see also Art. 37 Note 1).
16.4. At ranks higher than order, the word elements ‑clad-, ‑cocc-, ‑cyst-, ‑monad-, ‑mycet-, ‑nemat-, or ‑phyt-, which are genitive singular stems of the second part of a name of an included genus, may be omitted before the rank-denoting termination. Such names are automatically typified when their derivation is obvious or is indicated in the protologue.
Ex. 6. The name Raphidophyceae Chadef. ex P. C. Silva (in Regnum Veg. 103: 78. 1980) was indicated by its author to be formed from Raphidomonas F. Stein (Organismus Infus. 3(1): x, 69, 152, 153. 1878). The name Saccharomycetes G. Winter (Rabenh. Krypt.-Fl., ed. 2, 1(1): 32. 1880) is regarded as being formed from Saccharomyces Meyen (in Arch. Naturgesch. 4: 100. 1838). The name Trimerophytina H. P. Banks (in Taxon 24: 409. 1975) was indicated by its author to be formed from Trimerophyton Hopping (in Proc. Roy. Soc. Edinburgh, B, Biol. 66: 25. 1956).
Note 2. The principle of priority does not apply above the rank of family (Art. 11.10; but see Rec. 16A).
16A.1. In choosing among typified names for a taxon above the rank of family, authors should generally follow the principle of priority.