DIVISION II. RULES AND RECOMMENDATIONS
CHAPTER II. STATUS, TYPIFICATION, AND PRIORITY OF NAMES
SECTION 3. PRIORITY
11.1. Each family or taxon of lower rank with a particular
circumscription, position, and rank can bear only one correct name,
special exceptions being made for 9 families and 1 subfamily for which
alternative names are permitted (see Art. 18.5 and
19.7). However, the use of separate names for the form-taxa of fungi and for morphotaxa of fossil plants is allowed under
Art. 1.3, 59.4, and
11.2. In no case does a name have priority outside the rank in which it is published (but see
Ex. 1. Campanula
R. Br. (Prodr.: 561. 1810) when treated as a genus is called
Roth (1821), a name conserved against the taxonomic (heterotypic) synonym
Delile (1813), and not Campanopsis
(R. Br.) Kuntze (1891).
Ex. 2. Magnolia virginiana
L. (1753) when raised to specific rank is called
L. (1759), not M. foetida
(L.) Sarg. (1889).
Ex. 3. Lythrum intermedium
Ledeb. (1822) when treated as a variety of
L. (1753) is called L. salicaria
Ledeb. (Fl. Ross. 2: 127. 1843), not
(Ledeb.) Koehne (in Bot. Jahrb. Syst. 1: 327. 1881).
When the two varieties constituting Hemerocallis lilioasphodelus
L. (1753), var.
L. and var. fulva
L., are considered to be distinct species, the one not including the lectotype of the species name is called
(L.) L. (1762), but the other one bears the name H. lilioasphodelus
L., which in the rank of species has priority over
(L.) L. (1762).
11.3. For any taxon from family to genus inclusive, the
correct name is the earliest legitimate one with the same rank, except
in cases of limitation of priority by conservation (see
Art. 14) or where Art. 11.7, 15,
19.4, 56, 57, or
L. (1753), Pavia
Mill. (1754), Macrothyrsus
Spach (1834) and
Spach (1834) are referred to a single genus, its name is Aesculus
11.4. For any taxon below the rank of genus, the correct
name is the combination of the
final epithet of the earliest legitimate
name of the taxon in the same rank, with the correct name of the genus
or species to which it is assigned, except
(a) in cases of limitation of priority under Art.
14, 15, 56, or
57, or (b) if the resulting combination could not be validly published under
Art. 32.1(c) or would be illegitimate under Art.
(c) if Art. 11.7, 22.1,
26.1, or 59 rules that a different combination is to be used.
Pax (in Jahresber. Schles. Ges. Vaterländ. Kultur 87: 20. 1909) when transferred to
Fenzl becomes D.
(Pax) Melch. (in Mitt. Thüring. Bot. Vereins 50: 164-168. 1943); the substitute name
. sect. Ariadna
Wendelbo (in Bot. Not. 112: 496. 1959) is illegitimate under Art. 52.1
Ex. 7. Antirrhinum spurium
L. (1753) when transferred to Linaria
Mill. is called
(L.) Mill. (1768).
When transferring Serratula chamaepeuce
L. (1753) to Ptilostemon
Cass., Cassini illegitimately (Art. 52.1
) named the species
Cass. (1826). In that genus, the correct name is P. chamaepeuce
(L.) Less. (1832).
The correct name for Rubus aculeatiflorus
T. S. Liu & T. Y. Yang (in Annual Taiwan Prov. Mus. 12: 12. 1969) is R. taitoensis
, because R. taitoensis
Hayata (1911) has priority over R. aculeatiflorus
When transferring Spartium biflorum
Desf. (1798) to Cytisus
Spach correctly proposed the substitute name C. fontanesii
because of the previously and validly published C. biflorus
L'Hér. (1791); the
combination C. biflorus
based on S. biflorum
would be illegitimate under Art.
Ex. 11. Spergula stricta
Sw. (1799) when transferred to Arenaria
L. is called
Schleich. ex Schltdl. (1808) because of the existence of the name
Michx. (1803), based on a different type; but on further transfer to the genus
L. the epithet stricta
is again available and the species is called
(Sw.) Hiern (1899).
Ex. 12. Arum dracunculus
L. (1753) when transferred to Dracunculus
Mill. is named
Schott (1832), as use of the Linnaean epithet would result in a tautonym (Art.
Ex. 13. Cucubalus behen
L. (1753) when transferred to Behen
Moench was legitimately renamed
Moench (1794) to avoid the tautonym "B. behen"
L., the epithet behen
is unavailable because of the existence of
L. (1753). Therefore, the substitute name S. cucubalus
Wibel (1799) was proposed. This, however, is illegitimate (Art. 52.1
) since the specific epithet
was available. In Silene
, the correct name of the species is
(Moench) Garcke (1869).
Ex. 14. Helianthemum italicum
Gren. & Godr. (Fl. France 1: 171. 1847) when transferred as a variety to
Thibaud ex Dunal retains its varietal epithet and is named
(Gren. & Godr.) Grosser (in Engler, Pflanzenr. 14: 115. 1903).
The final epithet of the combination Thymus praecox
Jalas (in Veröff. Geobot. Inst. ETH Stiftung Rübel Zürich 43: 190. 1970), based on T. serpyllum
Durand (Pl. Kaneanae Groenl. 196. 1856), was first used at the rank of
subspecies in the combination T. serpyllum
L. subsp. arcticus
(in Uppsala Univ. Årsskr. 1945(7): 276. 1945). However, if T. britannicus
is included in this taxon, the correct name at subspecies rank is T. praecox
Holub (in Preslia 45: 359. 1973), for which the final epithet was first used at this rank in the
combination T. serpyllum
(Ronniger) P. Fourn. (Quatre Fl. France:
841. 1938, "S.-E. [Sous-Espèce] Th. Britannicus").
The valid publication of a name at a rank lower than genus precludes any simultaneous homonymous combination
irrespective of the priority of other names with the same final epithet
that may require transfer to the same genus or species.
Tausch included two species in his new genus Alkanna
: A. tinctoria
Tausch (1824), a new species based on
in the sense of Linnaeus (1762), and A. mathioli
Tausch (1824), a nomen novum based on
L. (1753). Both names are legitimate and take priority from 1824.
Raymond-Hamet transferred to the genus Sedum
both Cotyledon sedoides
DC. (1808) and
Decne. (1844). He combined the epithet of the later name,
, under Sedum
as S. sedoides
(Decne.) Raym.-Hamet (1929), and published a new name,
Raym.-Hamet (1929), for the earlier name. Both names are legitimate.
11.5. When, for any taxon of the rank of family or below, a
choice is possible between legitimate names of equal priority in the
corresponding rank, or between available final epithets of names of
equal priority in the corresponding rank, the first such choice to be
(Art. 29, 30,
establishes the priority of the chosen name, and of any legitimate
combination with the same type and final epithet at that rank, over the
other competing name(s) (but see Art. 11.6).
A choice as provided for in Art. 11.5 is effected by
adopting one of the competing names, or its final epithet in the
required combination, and simultaneously rejecting or relegating to
synonymy the other(s), or nomenclatural (homotypic) synonyms thereof.
L. (1753) and Cardamine
L. (1753) are united, the resulting genus is called
because that name was chosen by Crantz (Cl. Crucif. Emend.: 126. 1769), who first united them.
Gillet (1876), Eccilia
(Fr. : Fr.) P. Kumm. (1871), Entoloma
(Fr. ex Rabenh.) P. Kumm. (1871), Leptonia
(Fr. : Fr.) P. Kumm. (1871),
(Fr. : Fr.) P. Kumm. (1871) are united, one of the generic names
simultaneously published by Kummer must be used for the combined genus.
Donk, who did so (in Bull. Jard. Bot. Buitenzorg, ser. 3, 18(1): 157.
, which is therefore treated as having priority over the other names.
Brown (in Tuckey, Narr. Exped. Zaire: 484. 1818) was the first to unite
L. (1753) and W. indica
L. (1753). He adopted the name
for the combined species, and this name is accordingly treated as having priority over
Baillon (in Adansonia 3: 162. 1863), when uniting for the first time
Hochst. (1845) and S. reticulatus
Hochst. (1845), adopted the name
(Hochst.) Baill. for the combined taxon. Consequently
is treated as having priority over S. reticulatus
irrespective of the genus
(Sclerocroton, Stillingia, Excoecaria or Sapium)
to which the species is assigned.
Linnaeus (1753) simultaneously published the names Verbesina alba
. Later (1771), he published Eclipta erecta
, an illegitimate name because
was cited in synonymy, and E. prostrata
, based on V. prostrata
. The first author to unite these taxa was Roxburgh (Fl. Ind., ed. 1832, 3: 438. 1832), who adopted the name
(L.) L. Therefore V. prostrata
is treated as having priority over
Ex. 23. Donia speciosa
and D. formosa
, which were simultaneously published by Don (1832), were illegitimately renamed
and C. dampieri
, respectively, by Lindley (1835). Brown (in Sturt, Narr. Exped. C. Australia 2: 71. 1849) united both in a single species, adopting the illegitimate name
and citing D. speciosa
and C. oxleyi
as synonyms; his choice is not of the kind provided for by Art. 11.5.
(G. Don) Asch. & Graebn. (1909), published with D. speciosa
listed as synonyms, is an illegitimate later homonym of C. speciosus
(Endl.) Steud. (1840); again, conditions for a choice under Art. 11.5
were not satisfied. Ford & Vickery (1950) published the legitimate
(G. Don) Ford & Vickery and cited D. formosa
as synonyms, but since the epithet of the latter was unavailable in
a choice was not possible and again Art. 11.5 does
not apply. Thompson (1990) was the first to effect an acceptable choice
when publishing the combination
(G. Don) Joy Thomps. and indicating that D. speciosa
was a synonym of it.
11.6. An autonym is treated as having priority over the name or names of the same date and rank that established it.
When the final epithet of an autonym is used in a new
combination under the requirements of Art. 11.6
, the basionym of that
combination is the name from which the autonym is derived, or its
basionym if it has one.
By describing Synthyris
(in Proc. Acad. Nat. Sci. Philadelphia 85: 86. 1933) established the name Synthyris
Benth. subg. Synthyris
(although using the designation "Eusynthyris
"), and when
this group is included in Veronica
(Benth.) M. M. Mart.
Ort. & al. (in Taxon 53: 440. 2004) has precedence over a combination in Veronica
. subg. Plagiocarpus
Ex. 25. Heracleum sibiricum
L. (1753) includes H. sibiricum
(Godr. & Gren.) Nyman (Consp. Fl. Eur.: 290. 1879) and H. sibiricum
automatically established at the same time. When H. sibiricum
is included in
L. (1753) as a subspecies, the correct name for the taxon is
(L.) Simonk. (Enum. Fl. Transsilv.: 266. 1887), not subsp.
, whether or not subsp. lecokii
is treated as distinct.
The publication of Salix tristis
Andersson (Salices Bor.-Amer.: 21. 1858) created the autonym
Aiton (1789) var. tristis
, dating from 1858. If S.
, including var. microphylla
, is recognized as a variety of S. humilis
Marshall (1785), the correct name is
(Aiton) Griggs (in Proc. Ohio Acad. Sci. 4: 301. 1905). However, if both varieties of
are recognized as varieties of S. humilis
, then the names
and S. humilis
(Andersson) Fernald (in Rhodora 48: 46. 1946) are both used.
In the classification adopted by Rollins and Shaw, Lesquerella lasiocarpa
(Hook. ex A. Gray) S. Watson (1888) is composed of two subspecies, subsp.
(which includes the type of the name of the species and is cited without an author) and subsp.
(A. Gray) Rollins & E. A. Shaw. The latter
subspecies is composed of two varieties. In that classification the
correct name of the variety which includes the type of subsp.
is L. lasiocarpa
(A. Gray) Payson (1922), not
(cited without an author) or L. lasiocarpa
(S. Watson) Rollins & E. A. Shaw (1972), based on Synthlipsis berlandieri
S. Watson (1882), since publication of the latter name established the autonym
A. Gray var. berlandieri
which, at varietal rank, is treated as having priority over var.
11.7. For purposes of priority, names of fossil morphotaxa
compete only with names based on a fossil type representing
the same part, life-history stage, or preservational state (see
The generic name Sigillaria
Brongn. (1822), established for bark fragments, may in part represent the same biological taxon as the "cone-genus"
M. J. Benson (1918), which represents permineralizations, or Sigillariostrobus
(Schimp.) Geinitz (1873), which represents compressions. Certain species of all three genera,
, and Sigillariostrobus
, have been assigned to the family
. All these generic names can be used concurrently
in spite of the fact that they may, at least in part, apply to the same
The morphogeneric name Tuberculodinium
Wall (1967) may be retained for a genus of fossil cysts even though
cysts of the same kind are known to be part of the life cycle of an
extant genus that bears an earlier name,
F. Stein (1883).
A common Jurassic leaf-compression fossil is referred to by different authors
either as Ginkgo huttonii
(Sternb.) Heer or Ginkgoites huttonii
(Sternb.) M. Black.
Both names are in accordance with the Code
, and either name can correctly be used, depending on
whether this Jurassic morphospecies is regarded as rightly assigned to the living (non-fossil) genus
L. or whether it is more appropriate to assign it to the morphogenus Ginkgoites
Seward (type, G. obovata
(Nath.) Seward, a Triassic leaf compression).
11.8. Names of plants (diatoms excepted) based on a non-fossil type are treated as
having priority over names of the same rank based on a fossil (or subfossil) type.
Siebold & Zucc. (1843), a non-fossil genus, and
Bowerb. (1840), a fossil genus, are united, the name Platycarya
is correct for the combined genus, although it is antedated by
Boalch and Guy-Ohlson (in Taxon 41: 529-531. 1992) united the two prasinophyte genera
Ostenf. (1899) and Tasmanites
E. J. Newton (1875). Pachysphaera
is based on a non-fossil type and
on a fossil type. Under the Code
in effect in 1992, Tasmanites
had priority and was therefore adopted. Under the current
, in which the exemption in Art. 11.8 applies only to diatoms and not to algae in general,
is correct for the combined genus.
The generic name Metasequoia
Miki (1941) was based on the fossil type of
(Heer) Miki. After discovery of the non-fossil species M. glyptostroboides
Hu & W. C. Cheng, conservation of
Hu & W. C. Cheng (1948) as based on the non-fossil type was approved. Otherwise, any new generic name based on
would have had to be treated as having priority over
The provisions of Art. 11 determine priority between different names applicable
to the same taxon; they do not concern homonymy. In accordance with Art. 53
later homonyms are illegitimate whether the type is fossil or non-fossil.
Ex. 34. Endolepis
Torr. (1861), based on a non-fossil type, is an illegitimate
later homonym of, and does not have priority over, Endolepis
Schleid. (1846), based on a
Ex. 35. Cornus paucinervis
Hance (1881), based on a non-fossil type, is an
illegitimate later homonym and does not have priority over C. paucinervis
Heer (Fl. Tert.
Helv. 3: 289. 1859), based on a fossil type.
Ex. 36. Ficus crassipes
F. M. Bailey (1889), F. tiliifolia
and F. tremula
Warb. (1894), each based on a non-fossil type, were illegitimate later
homonyms of, respectively, F. crassipes
(Heer) Heer (1882), F. tiliifolia
Heer (1856), and F. tremula
(Heer) Heer (1874), each based on a fossil type. The three
names with non-fossil types have been conserved against their earlier homonyms in order to
maintain their use.
11.9. For purposes of priority, names in Latin form given to
hybrids are subject to the same rules as are those of non-hybrid taxa
of equivalent rank.
The name ×Solidaster
H. R. Wehrh. (1932) antedates ×Asterago
Everett (1937) for the hybrids between
L. and Solidago
Ex. 38. Anemone
Paxton (1848) antedates A.
Decne. (1852), pro sp., as the binomial for the hybrids derived from
(Lemoine & É. Lemoine) Lemoine & É. Lemoine × A. vitifolia
Buch.-Ham. ex DC.
Camus (in Bull. Mus. Natl. Hist. Nat. 33: 538. 1927) published the name
A. Camus for a nothogenus, without a Latin description or diagnosis, mentioning only the names of the parents involved (Agropyron
L.). Since this name was not validly published under the Code
then in force, Rousseau (in Mém.
Jard. Bot. Montréal 29: 10-11. 1952) published a Latin diagnosis. However, the date of valid publication of
under this Code
) is 1927, not 1952, so it antedates the name
Cugnac (in Bull. Soc. Hist. Nat. Ardennes 33: 14. 1938).
11.10. The principle of priority does not apply above the rank of family (but see
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