Arrangement of plants in an orderly sequence based upon their similarities and relationship in hierarchy such as species, genus, family, order, class and division in conformity with the nomenclatural system The closely related plants are kept within a group and unrelated plants are kept far apart in separate groups.

1. Bentham and Hooker’s
classification of plant kingdom
Vimal priya SUBRAMANIAN

2. CLASSIFICATION
Arrangement of plants in an orderly
sequence based upon their similarities
and relationship in hierarchy such as
species, genus, family, order, class
and division in conformity with the
nomenclatural system
The closely related plants are kept

3. NEED FOR CLASSIFICATION
 Classification makes the study of organisms
easy
 It helps us to understand the inter relationship
among different groups
 It also helps to understand the diversity better
 It helps to understand the evolution of
organisms

4. TYPES OF CLASSIFICATION

5. 1. Artificial
2. Natural
3. Phylogenetic classification
Types of classification

6. 1. Artificial system
1.It was based on a few superficial characters.
2.In 1753, Carolus Linnaeus of Sweden published his book “
Species Plantarum” - description of 7,300 species.
3.He divided the plants into 24 classes based on number,
union, length and certain other characters of stamens.
4.Also known as Sexual system of classification.
5.Importance of floral characters.

7. Drawback of Artificial system
1. Improper grouping
• Close resembling plants – widely separated groups
• Totally unrelated plants – placed in same group
Example:
Plants belonging to Zingiberaceae of Monocotyledons and
that of Anacardiaceae of Dicotyledons had been placed in
one group called Monandria, [have only one stamen]
2. No importance was given to either natural or phylogenetic
relationships among different groups of plants.

8. 1. includes all the important characters
2. the plants are classified according to their related
affinities.
3. More number of characters are taken into
consideration in this system. mainly based on
direct observation of plants.
But does not bring out the evolutionary relationships
among different groups of plants.
2. Natural system

9. HISTORY OF BENTHAM AND HOOKER SYSTEM
OF CLASSIFICATION

10. George Bentham (1800-1884) and Sir Joseph Dalton Hooker
(1817-1911), two English Botanists, carried out researches at
the Royal Botanical Garden of Kew and established the
important natural system of classification.
Genera Plantarum – 1862-1883
HISTORY OF NATURAL SYSTEM OF CLASSIFICATION

11. Royal Botanical Garden, Kew, London

13. MODERN CLASSIFICATION
Plant Kingdom
Cryptogamae Phanerogamae
Thallophyta Bryophyta Pteridophyta
Angiosperms
(ovules enclosed)
Gymnosperms
(ovules naked)
Dicotyledonae Monocotyledonae
Bentham and Hooker (1862)
Algae, Fungi, LIchens
Microspermae
Epigynae
Coronarieae
Calycinae
Nudiflorae
Apocarpae
Glumaceae
7 Series
3 Sub class

14. Phanerogams (Seed plants)
202 natural orders
7569 Genera / 97205 species
Gymnosperms
44 Genera
415 species
Monocotyledons
3 families
• Gnetaceae
• Coniferae
• Cycadaceae
Dicotyledons

15. Dicotyledonae
Polypetalae Gamopetalae
Thalamiflorae Disciflorae Calyciflorae
Inferae Heteromerae Bicarpellate
Monochlamydae

16. Class - Dicotyledonae
Sub class- Polypetalae
Sub class- Gamopetalae
Thalamiflorae Disciflorae Calyciflorae
Inferae Heteromerae Bicarpellate
Order: 3 3 4
Family: 9 12 24
Order: 6 4 5
Family: 34 23 27
Total: 84 families
Total: 45 families
Subclass
Monochlamydae
Series
Series

17. Class - Dicotyledonae
Sub class
Polypetalae
Sub class
Gamopetalae
Subclass
Monochlamydae
1. Curvembryae
2. Multiovulate aquaticae
3. Multiovulate terrestres
4. Microembryae
5. Daphnales
6. Achlamydosporeae
7. Unisexuales
8. Polemoniales
9. Ordines anomali
Total: 41 families
8 Series (No orders)

18. Class I. DICOTYLEDONS :
Includes 14 series; 25 orders (Cohorts) and
165 families (natural orders)
Key Characteristics
 Tap root system
 Presence of two cotyledons in the seed
 Flowers are either pentamerous or tetramerous
 Pollengrains are with three pores or furrow
 Reticulate venation in leaves
 Presence of vascular bundles arranged in rings
the stem tissue

19. Sub Class 1. POLYPETALAE – 3 series
 Sepals and petals distinct, petals free
Series 1. Thalamiflorae
 Flowers hypogynous, stamens many, disc absent
 6 Orders – Ranales, Parietales, Polygalineae, Caryophyllineae, Guttiferales and
Malvales
 34 Families
Series 2. Disciflorae
 Flowers hypogynous, disc present below the ovary
 4 Orders- Geraniales, Ollacales, celastrales and Sapindales
 23 Families
Series 3. Calyciflorae
 Flowers perigynous / epigynous; inserted into disc.
 5 orders- Rosales, Myrtales, Passiflorales, Ficoidales and Umbellales
 27 Families
 Total number of families under Polypetalae: 84

20. Sub Class 2. GAMOPETALAE
Sepals and petals distinct, petals united
Series 1. Inferae
 Ovary Inferior
 3 orders; Rubiales, Asterales, Campanales
Series 2. Heteromerae
 Ovary usually superior
 Stamens in one or two whorls, Carpels more than 2
 3 orders; Ericales, Primulales, Ebinales
Series 3. Bicarpellate
 Ovary usually superior
 Stamens in one whorl; Carpels two
 4 orders; Gentinales, Polemoniales, Personales and Lamiales

21. Sub Class 3. MONOCHLAMYDEAE
 Also called as Incompletae or Apetalae
 Flowers are incomplete, apetalous, perianth lacking or if
present not differentiated into sepals and petals
 Either calyx or corolla or both absent
 Flowers bisexual or unisexual
No orders; Includes 8 series
 Curvembryae – Embryo coiled, ovule usually one
 Multiovulate aquaticae – Aquatic plants, ovules many
 Multiovulate terrestres – Terrestrial plants, ovules many
 Microembryae – Embryo minute
 Daphnales – Carpel one; Ovule one.
 Achlamydosporeae – Ovary inferior, unilocular,ovules 1-3
 Unisexuales – Flowers unisexual
 Ordines anomaly – uncertain relationship

22. Class - Monocotyledons
7 series/34 orders; 1495 Genera; 18576 species
Key Characteristics
• Fibrous root system
• Single cotyledon
• Flowers trimerous
• Pollengrains with single pore or furrow
• Parallel venation in leaves
• Presence of vascular bundles throughout the stem tissue
7 series
1.Microspermae
2. Epigynae
3. Coronarieae
4. Calycinae
5. Nudiflorae
6. Apocarpae
7. Glumaceae

23. Series 1. Microspermae
 Inner perianth petaloid
 Ovary inferior, Seeds many; very minute
 3 orders; Hydrocharideae, Burmanniaceae, Orchidaceae etc.,
Series 2. Epigynae
 Perianth biseriate,
 Inner perianth petaloid
 Ovary often inferior, Seeds large – few to many
 7 orders; Scitamineae, Bromeliaceae, Haemodoraceae, Irideae, Amaryllideae,
Taccaceae, Dioscoreaceae etc.,
Series 3. Coronarieae
 Perianth biseriate,
 Inner whorl petaloid, Ovary superior
 8 orders; Roxburghiaceae, Liliaceae, Pontederiaceae, Philydraceae, Xyridaceae,
Mayaceae, Commelinaceae and Rapateaceae
Series 4. Calycinae
 Perianth biseriate,
 Sepaloid, Ovary Superior, Carpels united
 3 orders; Flagellariaceae, Juncaceae, Palmae etc.,

24. Series 5. Nudiflorae
 Perianth absent /represented by scales
 Ovary Superior
 5 orders; Pandaneae, Cyclanthaceae, Typhaceae, Aroideae, Lemnaceae.
Series 6. Apocarpae
 Perianth in one or two whorls or absent
 Ovary Superior; Apocarpous
 Carpels free, one or more
 3 orders; Triurideae, Alismaceae, Naidaceae
Series 7. Glumaceae
 Flowers minute, Borne in the axils of bracts as spikelets
 Perianth absent or modified into scales
 Glumaceous, bracts large,
 Ovary one loculed; superior
 5 orders; Eriocauleae, Centrolepideae, Restiaceae, Cyperaceae,
Gramineae.

25. Merits
It is a natural system, based on actual examination of
specimens
Observations recorded by themselves and not based on
existing literatures
Description of all the genera of seed plants is accurate,
precise and complete
202 families or orders were recognized.
Key characters given for identification are very useful

26. Merits
Placement of monocotyledonae after the dicotyledonae
appears to be in accordance with the evolutionary
trends; a position approved by all present day
taxonomists.
Many countries follow this system for the arrangement
of plant specimens in their herbaria
This system shows affinity to modern concepts of
evolution.
Eg: The order Ranales, given a primitive position in this
system.
Recent taxonomic findings also indicate that the
members of Ranales are the most primitive living
angiosperms.

27. Demerits
It does not bring about the phylogenetic relationship of various
groups of plants.
The position of ‘gymnospermae’ in between dicot and monocot
is not correct. Placed only for convenience
Unrelated families are grouped nearer.
Eg: two unrelated families Podostemaceae and Laurineae are
grouped nearer.
• Some closely related families are separated and
placed in different groups.
Several important floral characters are not considered.
Unfortunate introduction of the group
Monochlamydeae

28. Distinguishing key characters