Binomial nomenclature

 Taxonomy is the science of classifying and identifying plants. Scientific names are necessary because the same common name is used for different plants in different areas of the world. Latin is the language used for scientific classification.

Binomial nomenclature system is the one where the name of the plant consists of two parts – genus name and species name. It is developed by Carolus Linnaeus.

Some rules framed under these codes as well as the rules set by Linnaeus are as follows:

1.     The scientific names of plants and animals should be in Latin or Greek because it is officially dead language. The use of Latin for naming also means that no-one can be offended by being forced 10 use someone else’s language.

2.     The scientific names prior to the 1.8.1758 for animals of Systema Naturae (10th Edition) and 1.5.1753 for plants of Species Plantarum by Linnaeus are not recognized.

3.     These names should be in italics when printed or separately underlined when hand written to indicate their Latin origin.

4.     The genus starts with capital letter, while species in small letter.

5.     The name of the author, first reporting it should remain in abbreviated form at the end of the scientific name and it is printed in Roman, e.g. Oriza sativa Linn. The scientific name with name of the author at the end is called complete scientific name.

6.     Only one valid name for one species is permitted and it is based on the rule of priority that is the author first effectively and validly publishing the name will be considered.

7.     In case of changing a scientific name that is double citation, the name of the second author is placed in bracket after the scientific name and the first author’s name in abbreviated form comes after that, the new name is always based on the older name and it is called the basionym.

8.     To avoid confusion no two generic names in any kingdom can be same. Specific names can however be repeated as they often qualify the generic name. For example, the specific name of both mango (Mangifera indica) and tamarind (Tamarindus indicus) are the same which mean Indian.

9.     The reporting of a new species of plant should be accompanied by a Latin description or Diagnosis.

10.  When a plant species is reported, the author should submit a herbarium sheet of the specimen (Dried plant with reproductive part placed on a sheet of paper). This is designated as type specimen (holotype, isotype, paratype, topotype, lectotype etc.). Holotype is the type specimen submitted by the original author at the time of publication. All other specimens of the same species collected at the same time are called isotypes.

11.  The specimen cited with the original description other than holotype or isotype(s) is called paratype. When the same specimen is collected from the same locality from where the holotype was collected is called topotype. In absence of a holotype, the type specimen selected from the original material by a subsequent author is called lectotype. In the absence of original type specimen, a new specimen selected from a new location by a new author is called neotype. This concept of permanent naming to a type specimen is called typification and the type specimens should be preserved in the Herbaria of all international Botanic Gardens.

Generic name: Generic name is the first word of the Binomial name. The first letter is capital. It is singular noun. The generic names are coined from different sources.

1.    The genus may be named in honor of a botanist

For ex: Linnea for Linnaeus

Adansonia- Michel Adanson

Bauhinia – Casper Bauhin

2.    In many cases generic names express some features of a plant

For ex: Pterospermum (winged seeds)

Trifolium – plant having three leaflets.

Acanthospermum- Spiny fruit

3.    Some generic names are mythological or poetic.

For ex: Theobroma (Gods food)

4.    Sometimes generic name is given after a name of a place (country, mountain or river)

For ex: Araucaria – Arauca province of Chile

Cassia – Mountain cassia from N.Syria

Salvadora – El. salvadore

Specific name: It is the second word of the Binomial name. Its first letter is small and is an adjective. The generic names are coined from different sources.

1.    It may be description of a plant.

Color of the plant or plant part, For example: alba (white), nigra (black)

Habitat of the plant, For example: aquatica(in water), arvensis (in fields)

2.    It may be in the honor of some botanist, For example: roxburghii (Vanda roxburghii)

3.    Specific name may be constructed from noun, For example: bignoniodes (Bignonia)

4.    It may be a descriptive adjective, For example: cordifolia (heart shaped leaves)

Advantages of Binomial names

These names are simple

1. These are universal names and hence remain constant in different places, languages. This avoids confusions, effective in   communication.
2. Names are governed by rules and recommendations.
3. The names are easy to remember compared to polynomials.
4. These names are self-explanatory.
5. The names are in Latin which is a dead language not used in any country, so there is no controversy.