FACULTY OF AGRICULTURAL SCIENCES AND ALLIED INDUSTRIES
INTRODUCTORY BIOLOGY UGR-121
Plant Systematic
LECTURE- 08
PLANT SYSTEMATICS
The term "Systematics" was proposed by Linnaeus in 1735.
It includes description of external morphological characters of plants or living organisms. E.g.,
morphological characters of root, stem, leaves, flowers.
This description is used to know inter-relationship among plants or living organisms.
The term systematics, taxonomy and classification are after held as synonyms but technically they
carry different meanings.
New systematics or Neo systematics or Biosystematics is a new branch. Its name was given by
Julian Huxley (1940).
New systematics includes description of all the characters (internal) including morphological
characters (external) of plants or living organisms. E.g., anatomical characters and cytological
characters. It is used to know the inter-relationship among living organisms.
Carolus Linnaeus is called father of taxonomy.
H. Santapau is called the father of Indian taxonomy.
Taxonomy is of 3 types - α, β and ω :
o In α (alpha) taxonomy, only morphological characters are used for identification and
classification of plants.
o β (Beta) taxonomy involves genetical, anatomical, cytological, palynological, physiological
and other characters.
o Analysis and synthesis of all information and types of data to develop classification system
based on phylogenetic relationship is called omega taxonomy.
Identification is to determine the exact place or position of an organism in the set plan of
classification. It is carried out with the help of taxonomic keys.
Classification is the placing of an organism or a group of organisms in category according to a
particular system and in conformity with a nomenclature system.
New systematics is mainly based on evolutionary as well as genetic relationship (experimental
taxonomy) as compared to morphological characters.
Cytotaxonomy : The use of cytological characters of plants in classification or in solving taxonomic
problems is called cytotaxonomy. Cytological characters constitute an important aid to plant
taxonomy, especially in determining affinities at the generic and intrageneric levels.
Chemotaxonomy : The use of chemical compounds present in plants for classification or in solving
taxonomic problems is called chemotaxonomy or chemical taxonomy. It is based on the chemical
constitution of plants. The basic chemical compounds used in chemotaxonomy are alkaloids,
carotenoids, tannins, polysaccharides, nucleic acids, fatty acids, amino acids, aromatic compounds etc.
Karyotaxonomy : It is based on the characters of nucleus and chromosomes. Pattern of chromosomal
bands (dark bands and light bands) is most specific character for classification of organisms.
Taxonomy is the study of principles and procedures of identification, nomenclature and classification
of organisms.
FAMILY- BRASSICACEAE
