How to Write Binomial Names

1. Binomial names are usually typeset in italic, e.g. Zea mays, ;

or any other font different from that used in the normal text, e.g. “Zea mays is a facultative long-night plant.”

2. when handwritten, each part of a binomial name should be underlined, e.g. Zea mays.

3. The genus name is always written with a initial capital letter, the specific epithet is never with an initial capital.

4. When used with a common name, the scientific name often follows in parentheses, e.g. “Maize (Zea mays) has 10 chromosomes.”

5. The binomial name should generally be written in full.  The exception to this is when several species from the same genus are being listed, or the same species is mentioned repeatedly, in which the genus is written in full when it is first used, but may then be abbreviated to a capital initial and a full stop.  e.g.  Zea diploperennis and Z. perennis are perennial, while Z. mays, Z. luxurians and Z. nicaraguensis are annual.

In care cases, this abbreviated form has spread to more general use, e.g. Escherichia coli is often referred to just E. coli, and Tyrannosaurus rex is better known as T. rex.

6. The abbreviation ‘sp.’ is used when the actual specific name cannot or need not be specified.  The abbreviation ‘spp.’ indicates plural form.  These abbreviations are not italicized or underlined.  e.g. Canis sp. means “an unspecified species of the genus Canis”, while Canis spp. Means “two or more species of the genus Canis”

7. Infraspecific name

When use a connecting term ( subsp., var., c.f., f. etc ), it is customary to italicize all three part of such a name, but not the connection term.

a. ‘subsp.’, plurals ‘subspp.’ for subspecies, e.g longbean - Vigna unguiculata subsp. Sesuipedalis

b. ‘var.’ for varietas (variety) , e.g Broccoli - Brassica oleracea var. botrytis

c. ‘subvar.’ for subvarietas (subvariety) , e.g Chinese cabbage – Brassica rapa subvar. pekinensis

d. ‘cv.’ for cultivated varietas (variety) , e.g Durian -  Durio zibethinus cv. D24, or Durio zibethinus ‘D24’

e. ‘f.’ for forma (form) , e.g Bishop’s cap cactus - Astrophytum myriostigma f. quadricostata

f. ‘subf.’for subforma (subform) , e.g. Saxifraga aizoon subf. surculosa

8. The abbreviation ‘cf.’ comes from the Latin word conferre, which means “compare to”.   It is used when the identification is not confirm, e.g. Crovus cf. splendens, indicates “a bird similar to the house crow but not certainly identified as this species.”

9. The symbol ‘†’ placed before or after the binomial name indicates that the species is extinct, e.g. † Nelumbo aureavallis.

10. A hybrid is often named with few options :

a. normal botanical name, e.g. Iris albicans

b. a ‘x’ placed before the specific epithet for interspecific hybrid, e.g. Citrus x floridana ( C. aurantiifolia x C. japonicas )

c. a ‘x’ placed before the generic name for intergeneric hybrid, e.g. x Heucherella tiarelloides ( Heuchera sanguinea x Tiarella cordifolia )

11. A graft-chimaera :

a. a ‘+’ placed in between both parents. e.g. Crataegus + Mespilus

b. a ‘+’ placed before a newly-formed name for intergeneric grafting. e.g. + Crataegomespilus (Crataegus + Mespilus)

c. a cultivar name is given for interspecific grafting, e.g. Syringa ‘Correlata’ ( Syringa vulgaris + Syringa x chinensis )

ICZN, International Code of Zoological nomenclature

ICN, International Code of Nomenclature for alge, fungi and plants ( formerly ICBN )

ICNCP, International Code of Nomenclature for Cultivated Plants

ICNB, International Code of Nomenclature of Bacteria

ICTV, International Committee on Taxonomy of Viruses

Derivation of Binomial Names

Generic names

Generic names must be a word which can be treated as a Latin singular noun in the nominative case. 

Generic names are nouns that can come from anywhere. They can even be meaningless strings of letters, as long as they can be put into a Latin form and pronounced as if they were Latin. In practice, they tend to come from a few main sources.

a.       Classical Latin plant names :

Acer, “sharp” (maple),

Quercus , “oak tree” (oak),

Ilex, “evergreen oak” (holly).

b.      Classical Greek plant names :

Anemone , “daughter of the wind” (anemone),

Rhododendron, “rose of the tree” (rhododendron),

Carya, “nut” (hickory),

Hieracium, “hawk” (hawkweed),

Myrica, “fragrance” (wax myrtle).

c.       Names from Latin and Greek myths :

Andromeda (an Aethiopian king in Greek mythology),

Calypso (a nymph in Greek mythology),

Iris (a goddess in Greek mythology),

Liriope (a Boeotian naiad in Greek mythology),

Narcissus (a Boeotian hunter in Greek mythology),

Nyssa (a nymph in Greek mythology).

d.      Modern names made from one or more Greek words :

Chrysanthemum (chrysos “gold” + anthemon “flower”),

Lycopodium (lukos “wolf” + podion “foot”),

Philodendron (philo “love” + dendron “tree”),

Podocarpus (podos “foot” + karpos “fruit”),

Stenotaphrum (stenos “narrow”+ taphros “trench”), and many others.

This is probably the largest category of plant generic names.

e.       Latinized names of famous botanists and other people :

Albizia (Filippo degli Albizzi),

Camellia (Georg Joseph Kamel),

Cunninghamia (James Cunningham),

Forsythia (William Forsyth),

Gardenia (Alexander Garden),

Halesia (Stephen Hales),

Kalmia (Pehr Kalm),

Linnaea (Carl Linnaeus),

Magnolia (Pierre Magnol),

Serenoa (Sereno Watson),

Sequoia (Sequoyah),

Torreya (John Torrey),

Wisteria (Caspar Wistar),

Woodwardia (Thomas Jenkinson Woodward), and many others.

Probably the second largest category of generic names.

f.       Names from other languages :

Catalpa (Catawba - Catawba, Native American),

Musa (mauz - Arabic),

Nelumbo (Nelum - Sinhalese),

Nuphar (nīlōtpala - Sanskrit).

g.       Names from other sources :

Aquilegia (aquila “eagle”) – medieval Latin

Liatris (blazing star) – unknown origin,

Trilisa (deer’s tongue-an anagram of Liatris) – unknown origin,

Taxodium (Latin taxus “yew” ; Greek eidos “similar to”) -  mixture of Latin and Greek

I	masculine		feminine		neuter
	singular	plural	singular	plural	singular	plural
Nominative	-us / -er	-i	-a	-ae	-um	-a
Genitive	-i	-orum	-ae	-arum	-i	-orum

  

	masculine		neuter
	singular	plural	singular	plural
Nominative	-is	-es	-e	-ia
Genitive	-is	-ium	-is	-ium

Specific epithets

The second word, which identifies the species within the genus, must be a word treated grammatically as a Latin word.

The specific epithet plays one of three grammatical roles: 

1) an adjective modifying the genus name in gender

These adjectives must agree with the genus name in gender (masculine, feminine, or neuter), number (singular or plural), and case (for example, nominative or genitive) :

Lansium domesticum (langsat) - neuter

Nandina domestica (sacred bamboo) – feminine

Passer domesticus (house sparrow) – masculine

2) a noun in the genitive case meaning “of x” (where x is the noun that forms the epithet).  These genitives often commemorate the first collector of a species, in honour of a person, place of origin, or any descriptions of the species :

Acer palmatum – in allusion of the palm-like leaves of “Japanese maple”

Calocephalus brownie – “cushion bush” described by botanist Robert Brown

Caltha palustris – “marigold” of the marsh

Mangifera indica - “manggo” originated from India

Quercus alba – white coloured “oak”

3) a noun “in apposition to,” or placed next to, the generic name

These nouns are to be in apposition to the genus name in gender :

Acer negundo, “Negundo maple” (box elder);

Adiantum capillus-veneris, “Venus’s-hair adiantum;”

Aesculus pavia, “pavia buckeye” (red buckeye);

Diospyros kaki, “kaki diospyros” (Japanese persimmon) ;

Zephyranthes atamasco, “atamasco zephyranthes” (Atamasco lily).