The document outlines the rules of nomenclature for plant specimens as framed by the International Code of Botanical Nomenclature (ICBN), discussing various types of taxa and their classifications. Key concepts include the type method, types of specimens (holotype, isotype, lectotype, etc.), and the principles of priority and citation. The emphasis is on the importance of typification for stabilizing scientific plant names.

1. TAXONOMY-TYPE CONCEPT(18/4/20)
By N.SANNIGRAHI, ASSOCIATE PROFESSOR
ICBN has framed a number of rules of nomenclature of plant specimens.
Some of these are-
i. Ranks & endings of Taxa,
ii. Principle of Priority,
iii. Type Method,
iv. Citation of author,
v. Synonyms and related definitions,
vi. Names of Cultivated plants,
vii. Latin diagnosis,
viii. Effective & Valid Publication,
ix. Choice of names when the taxon rank is changed,
x. Choice of names when same rank is changed,
xi. Retention of names of divided taxa

2. • Xii. Retention of names of taxa on transference,
• Xiii. Rejection of names
• Xiv. Names of different taxa
The type method is a legal device to provide the
correct name for a taxon.A type specimen is a
herbarium sheet(Rarely drawing or photograph)
of a specimen which was used by the author to its
authentic description. According to Article 9 of
ICBN, the type of a genus is a species(The type
genus vernonia is V.noveboracensis(L.) Michx.)

3. • And the type of a family is a genus (e.g. Aster is the type genus of
the family-Asteraceae).
• Several kinds of types have been recommended by the ICBN to
make the nomenclature more scientific, accessible and holistic. They
are as follows:
• Holotype:It is a specimen used by the author in the original
publication as the nomenclatural type.
• Isotype: It is a duplicate specimen of the holotype if from the same
collection , with the same locality, date & number as the holotype.
• Lectotype: when the holotype was not designated or destroyed or
lost, a specimen selected by a competent researcher from the
original material studied by the author of the species.
• Neotype: It is a specimen selected to serve as a substitute for the
holotype when all material, on which the name of the taxon was
based, is missing.

4. • Nomenclatural type: It is the element with which the name of a
taxon is permanently associated.
• Syntype: It is one of the two or more specimen cited by the
author of a species when no holotype was designated; or
syntype is any of the two or more specimens originally
designated as types.
• Paratype or Co-types: It is a specimen other than the Isotype or
holotype. If two or more specimen have been cited as types by
the author, the remaining cited specimens are called Paratypes
or Co-types.
• Topotypes: It is a specimen collected from the same locality
from where the holotype was collected.
• The ICBN has greatly emphasised on the typification of the
taxa in order to bring about the stabilization f the names
having binomial landmark. THANK YOU