Horticultural and botanical nomenclature


by Dick Brummitt, RBG Kew updated April 2009

Name endings in Taxonomic hierarchy:

Division Spermatophyta
Class Dicotyledones
Subclass Rosidae
Order Rosales
Family Rosaceae
Subfamily Rosoideae
Tribe Roseae also Macadamieae, Proteeae
Subtribe Rosinae
Genus Rosa etc.
Subgenus Rosa subgen. Rosa etc.
Section Rosa sect. Rosa, Cassiorhodon etc. (sing. nouns) ; Rosa sect. Synstylae, Caninae etc. (plur. adject.)
Subsection Rosa subsect. Pimpinellifoliae etc. (plur. adject.)
Series Rosa ser. Stylosae etc.
Species Rosa stylosa
Subspecies Rosa stylosa subsp. gallica
Variety Rosa stylosa var. glabra
Subvariety Rosa stylosa subvar. alba
Forma Rosa stylosa forma variegata

Permissible alternatives to -aceae for families

Family Name


Some example of recommendation listed in the International code of Botanical Nomenclature (ICBN).

32 A.1 Names of persons and also of countries and localities used in specific epithets should take the form of nouns in the genitive (clusii, porsildiorum, saharae) or of adjectives (clusianus, dahuricus).

23 A.2 The use of genitive and the adjectival form of the same word to designate two different species of the same genus should be avoided (e.g. Lysimachia hemsleyana Oliv. and L. hemsleyi Franch.).

20 A.1 (a)To use Latin terminations inso far possible.

20 A.1 (b) avoid names not readily adaptable to the Latin language.

Making Epithets agree with Generic Names

1st declension

2nd declension


3rd declension




Any gender

Group A epithets




But note that nearly all names ending in –ma are neuter, e.g. Eriosma, Fissistigma

E.g. Smilax (f)
Styrax (m)
Thlaspi (n)
And the epithet will follow rules for feminine, masculine, or neuter given previous columns.

Group B epithets ending in -is




Note that the –is ending as in geographical epithets ending in –ensis changes to –e neuter genera

Group B epithets not ending in -is




These epithets not ending in –a, -us, -um or –is are simple and never change

Generic names which look masculine but are treated as feminine



Alnus glutinosa


Arbutus arizonica


Buxus baelarica


Carpinus caroliniana

(beware of Carpinus betulus, an exception to the exception, which is correct because Betulus is a noun (referring to a precious stone in Roman times) here used in apposition and not an adjective. It should not be corrected to C.betula.).

Cedrus atlantica


Cissus antarctica


Cornus florida


Cupressus macrocarpa


Elaeagnus latifolia


Eucalyptus aggregata


Fagus sylvatica


Ficus sylvatica

(Note again an exception to the exception - Ficus sycamorus in which Sycamorus is a pre-Linnaean name used as a noun in apposition which does not change according to the gender of the generic name.)

Fraxinus angustifolia

(Another exception to the exception is Fraxinus ornus, in which Ornus is again a pre-Linnean name used as a noun in apposition, as indicated by the original author, Linnaeus 1753, who spelt it with a capital O.)

Juniperus procera


Malus domestica


Morus nigra


Pinus nigra


Platanus x acerifolia


Prunus armeniaca

(Exceptions again P. cerasus and P. laurocerasus have epithets which are pre-Linnaean names used as nouns in apposition.)

Pyrus pyrifolia


Quercus petraea


Sorbus intermedia

(Note exception again: Sorbus aria and S.aucuparia are both, I think derived from pre-Linnaean names used as nouns in apposition, in these cases conveniently making the epithet look as if they agree with other epithets in the genus such as intermedia)

Ulmus procera


It is usually said that generic names were used by the Romans for trees, and they made all trees feminine.

Formation of epithets from Personal surnames

Such epithets may be nouns in the genitive case e.g. Rosa smithii means the Rose of Smith. Or they may be adjectives e.g. Rosa smithiana means the Smithian Rose.

If the genitive nouns they do not have to agree with the genus name, so we could have Rosa smithii and Polygonum smithii. However, adjectives must agree with the genus name, so we would have Rosa smithiana, Acanthus smithianus or Polygonum smithianum.

Genitive nouns epithets, however, vary according to the person honored. Rosa smithii would be named after a male Smith. Rosa smithiae would be named after a female Smith.

The spelling of all such epithets also depends on whether the personal name ends in -er, or a vowel, or neither.

Name not ending in –er or a vowel e.g. Bentham

Name ending in –er e.g. Hooker

Name ending in –a e.g. Balansa

Name ending in another vowel e.g. Clarke or Lindley

Genitive (male person)




clarkei, lindleyi

(2 male people)




clarkeorum, lindleyorum

Genitive (female person)




clarkeae, lindleyae

(2 female people)




clarkearum, lindleyarum


benthamiana (or –us or –um)

hookeriana (or –us or –um)

balansaeana (or –us or –um) (not often used)

clarkeana, lindleyana (or –us or –um)











The name for the subdivision of a genus or of a species which includes the type of the name of the genus or species is called an autonym. These names repeat the name of the genus or the epithet of the species name, and are written without an author.

Rhododendron L. subgen. Rhododendron
Ranunculus ficaria L. var. ficaria

Author citations

Note 'Authors' , not 'Authorities'

Developed naturally from Linnaeus on, usually using abbreviations, such as L. for Linnaeus, DC. for De Candolle etc. Now names need to be expanded to include initials. A standard list, Authors of Plant Names, was published in 1992 giving unique citations for over 30 000 authors, and has been widely followed. Modern surnames are usually not abbreviated unless very long.

New combinations and 'nomina nova'

1.Bellis anglica Smith 1800 (sp.nov.)

2.Crepis anglica (Smith) Robinson 1850 (comb. nov.)
Basionym: Bellis anglica Smith

3. Bellis europaea subsp. anglica (Smith) Taylor 1875 (stat. nov.)
Basionym: Bellis anglica Smith

4. Bellis europaea var. anglica (Smith) Harris 1900 (stat. nov.)
Basionym: Bellis anglica Smith

5. Aster europaea f. anglica (Smith) Jones 1925 (comb. et stat. nov.)
Basionym: Bellis anglica Smith

But if in 1950 Brown decides 'anglica' is a good species and belongs in Anthemis, and there is already a different species called Anthemis anglica, he can rename it with a new epithet and publish a 'nomen novum'

Replaced synonym: Bellis anglica Smith.


Holotype: A single element (specimen or illustration) to which a name has been attached from the time of its original description.

Isotype:A duplicate of a holotype specimen (not illustration)

Syntype: One of two or more specimen cited in the protologue when there was no holotype. Isosyntype. A duplicate of a Syntype.

Lectotype: A specimen or illustration chosen from among the original material when no holotype exists. Isolectotype. A dupliucate of a lectotype specimen

Paratype: A specimen cited in the protologue additional to the holotype or syntypes cited there.

Lectoparatype: One of the original types not selected as lectotype.

Neotype: A specimen or illustration which is not part of the original material but which is chosen as a replacement type when all the original material is missing.

Epitype: A specimen or illustration additional to an existing type, chosen to supplement the latter if it is found to be inadequate for proper taxonomic interpretation.

Horticultural nomenclature

A cultivar name includes a Latin names at generic , specific or infraspecific rank followed by a cultivars epithet.

A cultivar epithet may be more than one word and is written in non-italic script enclosed by single quotes and with major words with capital initials.

Achillea 'Martina'
Pisum sativum 'Consort'
Cedrus libani subsp. atlantica 'Mount Saint Catherine'

Sometimes cultivar-group name may be placed in brackets between the Latin part and the cultivar epithet e.g. Hydrangea macrophyllla (Hortensia Group) 'Ami Pasquier'

A cultivar epithet must contain a noun and not be adjectival ('Large White' is not acceptable)

After 1 january 1959 a cultivars epithet must be in a modern language, not Latin.

What is a cultivar

A Cultivar is a taxon that has been selected for a particular attribute or combination of attributes, and that is clearly distinct, uniform and stable in its characteristics and that, when propagated by appropriate means, retains those characteristics.

Hybrids: as formula, Primula floribunda x P. verticillata can be a-z or with female parent first or as binomial with x in front e.g. Skimmia confusa for S. japonica x S. anquetila.

Generic hybrids: Formula still allowed e.g. Agrostis L. x Polypogon L. Nothogeneric names allowed also e.g. x Agropogon

sports: can be in cultivation or in the wild.

clones (cuttings): from abnormal growth (tertological). For example witches broom on Picea Abies caused by a bacteria or virus can be propagated to produce dwarf conifers. Fasciation on stem can also be propagated like in Cactus.

Graft Chimeras: e.g. + Laburnocystisus. Also some Camelia.

Chimeras: Like leaf variegation

Tetraploids: Induced with a chemical Colchicine that produces polyploid plants.

Albinos: White flowered forms are very common.

Double flowered: This is the result of the reversion of stamen and carpels into leaves or petals. It often result in abnormal and sterile flowers.


A nomenclatural standard is the herbarium specimen or illustration of a cultivars which forms a permanent record of the distinguishing characteristics of that cultivars. A description and its designation should accompany the standard and most importantly its location must be published. These principles are published in the International Code of Nomenclature for Cultivated Plants (ICNCP)

Using a standard specimen can help fix a name and act as a reference point when the application of a plant name has become confused.

Some images of the standard specimen are available online in www.rhs.org.uk

ICRA: International Cultivars registration authorities

The ICRA produce checklist of names, give forms to register new cultivars names, can advice on names to use. They don t ask for any fees.

The ICRA are listed by Genera on this link

Patent, Trade designation, trade marks and preferred selling names

Patents are used to protect a cultivars and give them Plant breeders Rights (PBR). They have to be applied in each country where the cultivars will be distributed. Patent documentation act as the standard specimen of the name. Patent involve fees.

Trade designation or trade marks are not to be used under the ICNCP. They are names that will help selling the plants but are not the name of the cultivars.


Some Horticultural societies run trial where cultivars can be grown together and compared. This can be very useful in sorting names and producing the right documentation.


Index Herbariorum

International Code of Botanical Nomenclature ICBN

International Code of Nomenclature for Cultivated Plants ICNCP

International Cultivars Registration Authorities ICRA

IPNI (International Plant Name Index)


Home Page

Name endings

Alternative endings


Epithets and Generic names


Epithets and Surnames


Author citations

New combination


Horticultural Nomenclature

What is a cultivar







Label analyses

spot the errors


Label analyses

Coprosma 'Pacific Night' (HUTPAC) Coprosma 'Hutpac' Pacific Night'

Patented under the name Hutpac so Hutpac is the cultivars name and Pacific Night a preferred selling name.

Helichrysum RUBY CLUSTER Helichrysum 'Blorub' Ruby Cluster

Patented under the name Blorub so Blorub is the cultivars name and Ruby Cluster a preferred selling name

Mikado Gold Syngonanthus chrysantus

Mikado is a trademark this plant is not a cultivars just a botanical species of Eriocaulaceae Syngonanthus chrysnanthus from Brasil.

Vulcan Palm Brighamia insignis 'Kirsten' Vulcan Palm

Vulcan Palm is a trade mark but this plant has been patented under the name Kirsten. It is a botanical species but was given Plant Breeders Right to support its conservation Program in Hawaii.

Spigelia 'Wisley Jester' Spigelia marilandica 'Wisley Jester'

This is the correct name though it hasn t been registered with the corresponding ICRA.

Spot the errors

1. Acanthus longifolia Acanthus longifolius

2. Allium officinalis Allium officinale

3. Rosa spinosa var. rubrifolium Rosa spinosa var. rubrifolia

3. Rhododendron farrerii Rhododendron farreri

5. Rubus hookeranus (named after Mrs Hooker) Rubus hookerianus

6.Potentilla smithi (named after John Smith) Potentilla smithii

7. Rosa jekyllae (named after Gertrude Jekyll) Rosa jekylliae

8. Pinus nigra maritima Pinus nigra L. var. maritima

9. Malus domesticus Malus domestica

10. Aralia fortuni (named after Charles Fortune) Aralia fortunei

11. Narcissus lopezianus (named after Sara Lopez) Narcissus lopezianus

12. Genista cv. 'Picos de Europa' Genista 'Picos de Europa'

13. Buddleja 'Purple Beauty' Buddleja 'Purple Beauty'

14. Polygonum affinis 'Red Rocket' Polygonum affine 'Red Rocket'

15. Thalictrum aquilegifolium Thalictrum aquilegiifolium

16. x Crindonna (Crinum x Amaryllis belladonna) x Amarcrinum

17. Acaena rosaefolia Acaena rosifolia

18. Heucherella x tiarelloides (Heuchera brizoides x Tiarella cordifolia) x Heucherella tiarelloides

19. Poterium balansai (named after Balansa) Poterium balansae

20. Carya 'Pride of the Mississipi delta' Carya 'Pride of the Mississipi Delta'



Label analyses

spot the errors