What do you understand by International Code of Botanical Nomenclature? Write its principles.

Understanding the International Code of Nomenclature (ICN)

The ICN aims to provide a standardized, internationally accepted framework for naming plants, algae, and fungi. It’s not a law, but a set of rules agreed upon by the botanical community. The core principles are designed to ensure uniqueness, stability, and universality in plant nomenclature.

Principles of the International Code of Nomenclature

1. Priority

The principle of priority dictates that the earliest legitimately published name for a taxon (a group of organisms) is the correct one. This means that if multiple names are proposed for the same plant, the oldest validly published name takes precedence. However, this principle is subject to certain exceptions, such as conservation of names for well-known species.

2. Typification

Typification is a cornerstone of botanical nomenclature. It involves designating a specific specimen (the ‘type’) as the permanent reference point for a species name. This type specimen serves as the definitive example of that species. Types can be herbarium specimens, illustrations, or even cultures. There are different types:

• Holotype: The single specimen designated as the type by the original author.
• Isotype: A duplicate specimen of the holotype.
• Syntype: One of two or more specimens cited in the original publication when no holotype was designated.
• Neotype: A specimen selected to serve as the type when all original material is lost or destroyed.

3. Effective Publication

For a name to be considered validly published, it must meet specific criteria. These include:

• The name must be accompanied by a Latin description or a clear indication of what the name applies to.
• The publication must be in a permanent, publicly accessible form (e.g., a printed book, a recognized online journal).
• The publication must adhere to the rules regarding the formation of names.

4. Legitimate Publication

Even if a name is effectively published, it must also be legitimate. This means it must conform to all the rules of the ICN, including rules regarding the correct formation of names, the use of Latin grammar, and the avoidance of names that are already in use for other taxa. Illegitimate names are rejected.

5. Rule of Independence

The names of plants are independent of the names of animals, bacteria, and other organisms. This means that the same name can be used for a plant and an animal without causing conflict. This avoids confusion across different biological disciplines.

6. Starting Dates

The ICN establishes specific starting dates for different groups of plants. Names published before these dates are generally not governed by the current rules. For example, the starting date for flowering plants (Angiosperms) is May 1, 1753, coinciding with the publication of Linnaeus’s *Species Plantarum*.

Examples Illustrating the Principles

Consider the case of the rose. Numerous cultivars exist, each with a unique name. The ICN ensures that each cultivar has a distinct, validly published name, traceable back to a type specimen. If two botanists independently name the same rose cultivar, the name published first, adhering to ICN rules, takes precedence. Similarly, if the original type specimen is lost, a neotype can be designated to maintain the stability of the name.

Principle	Description	Example
Priority	Oldest validly published name is correct.	If two names are given to the same species, the earlier one is used.
Typification	Designation of a type specimen.	A herbarium sheet serves as the holotype for a newly described species.
Effective Publication	Publication in a recognized format with a description.	A species description in a peer-reviewed journal.