Nomenclature

Anything that becomes known to human intelligence needs a name, so that ideas about it can be communicated — this art of naming objects is the science of nomenclature. Every living organism is known by a particular name, and biology recognises two broad categories of names:

1. Vernacular / local / common names — Widely distributed organisms accumulate a large number of common names. The pansy (Viola tricolor), grown in gardens across Europe and America, has roughly fifty different common English names. In a multilingual country like India, almost every useful plant has local names that differ from language to language and even dialect to dialect — in Ayurveda alone, the mango (Mangifera indica) is known by more than fifty different Sanskrit names. Common names are therefore useful locally, but they have limited value for universal, cross-language communication, which is why a single unambiguous name for each organism became essential.

2. Scientific names — Scientists assign a single scientific name to every known organism to avoid the confusion caused by multiple common names. Because these names follow a fixed system, they serve as a means of international communication. Early naming used long, many-word (polynomial) names, but Carl Linnaeus introduced the two-part (binomial) system, in which a scientific name consists of exactly two epithets. He introduced this system in his book Species Plantarum, published in 1753. The International Code of Botanical Nomenclature (ICBN) was set up to standardise and confirm such scientific names; following the XIX International Botanical Congress held in Shenzhen, China in July 2017 (often called the "Shenzhen Code"), the ICBN was renamed the International Code of Nomenclature for Algae, Fungi, and Plants (ICNAFP), published on 26 June 2018.

The binomial system follows a fixed set of rules, illustrated by the scientific name of the sunflower, Helianthus annuus — here Helianthus is the genus (generic epithet) and annuus is the species (specific epithet):

• The name is made up of two Latin or Greek words.
• The generic epithet is a simple noun; it comes first and begins with a capital letter.
• The specific epithet is a descriptive adjective; it comes second and begins with a small (lowercase) letter. …