a brief introduction to plant systematics taxonomy- identification, description, classification, nomenclature. systems of plant classifications

1. INTRODUCTION TO
PLANT SYSTEMATICS
PRESENTER- RASHMI M G
1ST YEAR MSc. BOTANY
MAHARANI’S SCIENCE COLLEGE FOR WOMEN
MYSORE

2. INTRODUCTION
 TAXONOMY
The science of the classification of organisms according to their
resemblances and differences
 SYSTEMATICS
Radford (1986) defined systematics as “The study of
phenotypic, genetic and phylogenetic relationship among
taxa” and mentioned that the science of systematics posses
following essential qualities
“Taxonomy is the science of classification and
relationships of organisms
Systematics is the part of classification that involves the
arrangement of organisms into related groups”

3. OBJECTIVES,GOALS AND AIMS OF PLANT
SYSTEMATICS
 OBJECTIVES
1. To prepare a scheme of classification that provides
phenetic, natural or phylogenetic relationships among plants
2. To establish a suitable method for identification,
nomenclature and description of plant taxa
3. To provide an inventory of plant taxa that suits local,
regional and continental needs
4. To create an understanding of the evolutionary processes
5. To train the students of plant sciences in regard to the
diversity of organisms and their relationship with other
biological branches

4. OBJECTIVES,GOALS AND AIMS OF PLANT
SYSTEMATICS
 GOALS
1. To acquire the fundamental values of plant systematics
2. To know about the basic concepts and principles of
plant systematics
3. To be aware of the importance of taxonomic
relationships in plant systematics
4. To develop the knowledge of applicability of plant
systematics studies

5. OBJECTIVES,GOALS AND AIMS OF PLANT
SYSTEMATICS
 AIMS
1. To know how to collect specimens
2. To know how to prepare specimens for future preservation
3. To know how a manual should be used
4. To know how to use identification keys
5. To recognize divisions, classes, orders, families, genera and
species
6. To know how the plants are described
7. To know how the diversity in species may be related with the
regional habitat diversity
8. To become familiar with the basic taxonomic principles, and
with at least one system of plant classification

6. TAXONOMY
IDENTIFICATION
DESCRIPTION
NOMENCLATURE
CLASSIFICATION
BASIC COMPONENTS OF TAXONOMY

7. BASIC COMPONENTS OF TAXONOMY
 Classification, identification, description and nomenclature are
the four basic components of taxonomy
 Classification- is the arrangement of botanical groups with
definite circumscriptions by position and rank according to
artificial criteria, phenetic similarities, or phylogenetic
relationships
 Identification –is the determination of similarities or
dissimilarities between the two elements under identification
we make a direct comparison of the characteristic features of
a specimen with those present in the already existing keys for
identification
 Description- is the orderly recording of maximum possible
characters of a taxon, individual plant, plant part, or object
 Nomenclature- is a simple system under which the individual
taxonomic groups of plants are scientifically named

8. CLASSIFICATION
 Andrew Sugden (1984) defined the word
“classification” on Longman Illustrated Dictionary of
Botany as “ the naming of species and their
grouping into families, orders, divisions etc”
 Radford(1986) stated that “ classification is the
arrangement of groups of plants with particular
circumscriptions by rank and position according to
artificial criteria , phenetic similarities or
phylogenetic relationships”

9. RANK OF PLANT CLASSIFICATION
 Species, genus, family, order, class and division are
the 6 main ranks of plant classification in an
ascending order.
 Each rank has its subcategories , i.e. towards the
higher ranks, sub form, form, sub varieties, varieties
and subspecies are the subcategories of species,
subsection, section and sub genus re the
subcategories of genus; subtribe, tribe and
subfamily are the subcategories of family ;suborder
is the subcategory of order; subclass is the
subcategory of class; and subdivision is the
subcategory of division

10. KINGDOM
DIVISION
CLASS
ORDER
FAMILY
GENUS
SPECIES

11. RANKS OF TAXA ENDING OF RANKS EXAMPLES
Division
subdivision
-Phyta
-Phytina
Pterophyta
Pterophtina
Class
subclass
-Opsida
-Opsidae
Pteropsida
Pteropsidae
Order
suborder
-Ales
-Ineae
Rosales, asterales, rosineae
Family
subfamily
tribe
subtribe
-aceae
-oideae
-eae
-Ineae
Rosaceae,asteraceae
Rosoideae
Roseae
Rosinae
Genus
subgenus
section
Sub section
series
subseries
Us, a, um, on, es etc. Rosa, pinus
Species
subspecies

12. TYPES OF SYSTEMS OF CLASSIFICATION
Phylogenetic
system
Mechanical
system
Artificial system
Natural system

13. TYPES OF SYSTEMS OF CLASSIFICATION
 The past taxonomic literature described 3 basic
categories of systems of classification i.e. artificial
systems, natural systems and phylogenetic
systems.
 But Radford(1986) has described following four
types of the systems of classification
 Artificial classification- these system use the habit
and importance to man as the taxonomic
characters
 Some advocates of artificial systems of
classifications were Theophrastus(370-285 B.C.),
Brunfels(1464-1534)

14. • Engler
• Prantl
• Bessey
• Takhtajan
• Cronquist
• Caesalpino
• Linnaeus
• Theophrastus
• Brunfels
• A.L de Jussieu
• A.P de Candolle
• Bentham and
Hooker
Natural
system
Artificial
system
Phylogenetic
system
Mechanical
system

15. BENTHAM AND HOOKER
THEOPHRASTUS
CAROLUS LINNAEUS
BESSY

16. TYPES OF SYSTEMS OF CLASSIFICATION
 Mechanical classification- these systems used one
or a few selected taxonomic characterized to group
taxa.
 Some mechanical classifications were given by
Caesalpino(1519-1603) and Linnaeus (1707-1778)
 Natural classification- these system of
classifications used as many taxonomic characters
as possible to group taxa.
 some of natural systems of classification were
given by A.L. de Jussieu (1748-1836) , A.P. de
Candolle (1778-1841) , Bentham (1800-1884) and
Hooker( 1817-1911)

17. TYPES OF SYSTEMS OF CLASSIFICATION
 Phylogenetic classification- these system of
classification used as many taxonomic characters
as possible in addition to the phylogenetic
(evolutionary) interpretations
 Some of the phylogenetic systems of classification
were proposed by Engler (1844-1930) and Prantl
(1849-1893), Bessey (1845-1915) Hutchinson
(1884-1972), Takhtajan (1980), Cronquist (1981)

18. CONCLUSION
 The study of diversity of plants and their identification,
naming, classification, and evolution is known to be a
PLANT SYSTEMATICS
 The study of classification is known to be TAXONOMY
 The systematics is based on the idea that because of
great diversity in the biological world there exist some
‘discontinuos units’ that can be
identified,classified,described and named on the basis
of evolution.
 It is the unending field for understanding taxonomic and
evolutionary processes, principles and concepts.
REFERENCE
PLANT TAXONOMY BY O P SHARMA -2ND EDITION