Binomial nomenclature

[4] But as early as 1622, Gaspard Bauhin introduced in his book Pinax theatri botanici (English, Illustrated exposition of plants) containing many names of genera that were later adopted by Linnaeus.

Although the general principles underlying binomial nomenclature are common to these two codes, there are some differences in the terminology they use and their particular rules.

In Medieval Latin, the related word binomium was used to signify one term in a binomial expression in mathematics.

First, to designate or label the species, and second, to be a diagnosis or description; however, these two goals were eventually found to be incompatible.

[10] In a simple genus, containing only two species, it was easy to tell them apart with a one-word genus and a one-word specific name; but as more species were discovered, the names necessarily became longer and unwieldy, for instance, Plantago foliis ovato-lanceolatus pubescentibus, spica cylindrica, scapo tereti ("plantain with pubescent ovate-lanceolate leaves, a cylindric spike and a terete scape"), which we know today as Plantago media.

[13] The adoption by biologists of a system of strictly binomial nomenclature is due to Swedish botanist and physician Carl Linnaeus (1707–1778).

[14] The Bauhins' genus names were retained in many of these, but the descriptive part was reduced to a single word.

Thus Gerard's Phalangium ephemerum virginianum became Tradescantia virginiana, where the genus name honoured John Tradescant the Younger,[note 1] an English botanist and gardener.

Its first stages (sometimes called "alpha taxonomy") are concerned with finding, describing and naming species of living or fossil organisms.

[28] Binomial nomenclature is thus an important part of taxonomy as it is the system by which species are named.

These include: The first part of the name, which identifies the genus, must be a word that can be treated as a Latin singular noun in the nominative case.

[40] The second part of the name, which identifies the species within the genus, is also treated grammatically as a Latin word.

From the early 19th century onwards it became ever more apparent that a body of rules was necessary to govern scientific names.

(There is also a published code for a different system of biotic nomenclature, which does not use ranks above species, but instead names clades.

As noted above, there are some differences between the codes in how binomials can be formed; for example the ICZN allows both parts to be the same, while the ICNafp does not.

The ICNafp sets out precise rules by which a personal name is to be converted to a specific epithet.

This produces specific epithets like lecardii for Lecard (male), wilsoniae for Wilson (female), and brauniarum for the Braun sisters.

[49] This explains the difference between the names of the plant Magnolia hodgsonii and the bird Anthus hodgsoni.

[51] By tradition, the binomial names of species are usually typeset in italics; for example, Homo sapiens.

[52] Generally, the binomial should be printed in a font style different from that used in the normal text; for example, "Several more Homo sapiens fossils were discovered."

A capital was also used when the name is formed by two nouns in apposition, e.g., Panthera Leo or Centaurea Cyanus.

In rare cases, this abbreviated form has spread to more general use; for example, the bacterium Escherichia coli is often referred to as just E. coli, and Tyrannosaurus rex is perhaps even better known simply as T. rex, these two both often appearing in this form in popular writing even where the full genus name has not already been given.

For example, in a paper describing the phylogeny of small benthic freshwater fish called darters, five undescribed putative species (Ozark, Sheltowee, Wildcat, Ihiyo, and Mamequit darters), notable for brightly colored nuptial males with distinctive color patterns,[65] were referred to as "Etheostoma cf.

The somewhat informal use of taxa names with qualifying abbreviations is referred to as open nomenclature and it is not subject to strict usage codes.

For names governed by the ICZN the surname is usually written in full together with the date (normally only the year) of publication.

The International Plant Names Index maintains an approved list of botanical author abbreviations.

Ranks above genus (e.g., family, order, class) receive one-part names, which are conventionally not written in italics.

In zoology, the only formal rank below species is subspecies and the name is written simply as three parts (a trinomen).

For example Harmonia axyridis f. spectabilis is the harlequin ladybird in its black or melanic forms having four large orange or red spots.