1. Taxonomic Systems in Plants
Md. Sajjad Hossain Tuhin
Student ID: 100510
4th year, 1st term
Forestry and Wood Technology Discipline
Khulna University
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2. Plant systematics
๏ฑ Classification of plants is a very ancient topics.
๏ฑ First plant classification reported in Vedas around 2000 BC.
๏ฑ Classification means the divination of something by the basis of some
properties.
Plant systematics is the branch of botany that is concerned with the naming,
identification, evolution, and classification of plants.
According to Stuessy 1990 โSystematics is a related term, sometimes used
synonymously, but involves a broader discipline of discovering phylogenetic
relationships through modern experimental methods using comparative
anatomy, cytogenetics, ecology, morphology, molecular data, or other dataโ
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3. Objectives of Taxonomy
๏ฑ Determining what is a species (or their sub-divisions, as subspecies)
๏ฑ Distinguishing these species from others through keys and descriptions
and geographic boundaries and mapping their distributions
๏ฑ Investigating their interrelationships, and
๏ฑ Determining proper names of species and higher order ranks using
international rules of nomenclature.
๏ฑ In addition, some taxonomists investigate processes of evolution that lead
to the existing pattern of species and their interrelationships.
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4. Why Classification
๏ฑ Around 400000 plant species are reported in the world now (Stearn, 1980)
๏ฑ The World Conservation Unionโs (IUCN) Red List of Plants included some 34,000
threatened species in 1997.
๏ฑ 60,000 to 100,000 plant species are currently threatened
๏ฑ 75% of the worldโs population relies on traditional medicines.
๏ฑ Globally, 80% of our plant based calorie intake comes from just 12 domesticated
plant species (8 cereals,4 tubers) though 30,000 species of plant are edible.
Need to study about all plants and for:
o Know about the ecosystem
o Conserve biodiversity
o Proper management
o Scientific study
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5. Taxonomic
System
Artificiel
300 BC. โ 1735
AD.
Natural
1600- 1883 AD.
Phylogenetic
1883- Now AD.
Classification Systems
Some literature said about another type termed as Mechanical Classification
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6. Artificiel classification
๏ฑ Oldest and first approach of classification of plants.
๏ฑ Can not describe all plants
Classification of plants into different taxa based upon one or few characteristics of
plants which is selected by authors. Such as,
๏ง Reproductive behavior
๏ง Physical appearances,
๏ง Habitat
๏ง Phenology
๏ง Cotyledon etc.
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8. SL No Name Classification parameter
01 Vedas
200 BC
Religious importance, use, medicine,
flowering and fruiting. Etc.
02 Theophrastus
ca. 300 B.C.
Size and life time(herbs, shrubs and trees)
03 Herbalists
1470-1670
Medicinal values
04 Tournefort
1700
Flower and fruit giving rise (Innovator of
genus. Distinction between genus and
species.)
05 Linnaeus
1735
Sexual behavior of plants (number, length
and union of stamens and carpels)
Basis of some artificial classification system
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9. Advantages and disadvantages of Artificial classification
Advantages
๏ฑ Simple and easy
๏ฑ Need short time and information
๏ฑ Poorly known plant can be placed easily
๏ฑ Need very few instruments
๏ฑ Specifically focus on properties of interest
Disadvantages
๏ฑ Can not grouped all plant perfectly
๏ฑ Little predictive value
๏ฑ Arbitrarily selected properties do not necessarily correlate well with each other
๏ฑ Cannot describe evolution
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11. Natural classification
๏ฑ This taxonomic system was introduced by Jean Bauhin in 1623.
๏ฑ These systems are based on natural affinities of plants.
๏ฑ It is done based on natural characteristics of plant.
๏ฑ It place together organisms that have the greatest number of shared features.
๏ฑ No single feature is not important but total features are the tools of classification.
So, classification of plants which is done based on maximum natural characteristics of
plants and not a single characteristic but total characteristics act as the key to place a
plant into a definite texa is termed as natural system of plant classification.
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12. Some important natural classification system
1. Gaspard Bauhin (1550-1624)
2. Ray ( 1627-1 705AD.)
3. Adanson (1727-1806)
4. A. L. de Jussieu ( 1748-1836)
5. Robert Brown ( 1773-1858)
6. A.P. Candole (1778-1884)
7. Alphonse (1806-1893)
8. Benthum ( 1800-1884) and Hooker (1817-1911)
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13. Sl No Name Classification parameter
01 A. L. de Jussieu
( 1748-1836)
โข No of cotyledon
โข Presence and absence of petals
โข Position of petals and stamens
02 Robert Brown
( 1773-1858)
Tissue structure
03 A.P. Candole
(1778-1884)
Characteristics of vascular tissue
04 Benthum
( 1800-1884) and
Hooker (1817-1911)
Seed characteristics of plants
Basis of some Natural classification system
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14. Advantages and disadvantages of Natural classification
Disadvantages
๏ฑ Complex than artificial
๏ฑ Need long time and more information
๏ฑ Poorly known plant can not be placed easily
๏ฑ Can not focus specifically on properties of interest
Advantages
๏ฑ More satisfactory on placing of species
๏ฑ More predictive value
๏ฑ Arbitrarily selected properties are necessarily correlate well with each other
๏ฑ can be used to predict properties, not related the classification
๏ฑ Contains more information about a species
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17. Phylogenetic classification
๏ฑ Latest system of classification of life.
๏ฑ Done in very micro scale(cells)
๏ฑ Basic of the system is the Darwin's โOrigin of Species (1859)โ
๏ฑ First introduced by August Wilhelm Eichler in 1883.
๏ฑ Goal of the system is to establish a system of classification based on the
course of evolutionary descent of its members.
๏ฑ System where it is believed that every species is come from the evolutionary
change.
So it is defined as the classification system based on phylogenetic characteristics
of a species.
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19. Advantages and disadvantages of phylogenetic classification
Advantages
๏ฑ unique name for each species eliminates confusion
๏ฑ Maximum predictive value
๏ฑ Maximum detail scientific study
๏ฑ Contains maximum information about a species
Disadvantages
๏ฑ Most Complex than others
๏ฑ Need long time and research
๏ฑ Physical appearances are neglected
๏ฑ Physically same species can be in different groups
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20. Most widely accepted systems
Arificial classification
๏ฑ Theophrastus ca. 300 B.C.
๏ฑ Linnaeus (1707-1778 AD.)
Natural classification
๏ฑ Benthum ( 1800-1884)
and Hooker (1817-1911)
Phylogenetic classification
๏ฑ Hutchinson (1884-1972)
๏ฑ Takhtajan (1980)
๏ฑ APG (Angiosperm Phylogeny Group
system) (1998,03,09)
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22. BC AD 1500 1600 1700 1800 1900 2000
Artificial
Natural
Phylogenetic
Historical Development of plant Taxonomic System
Bessey
1915
Sokal &
Sneath
1963,73
Henning
1966
APG
1998,03,09
Theophrastus
ca. 300 B.C.
Herbalists
1470-1670
Tournefort
1700
Linnaeus
1735
Bauhin
1623
Ray
1686-1704
Jussieu
1789
Candolles
1824- 73
Bentham &
Hoker
1962
Adanson
1763
Eicher
1883
Engler &
Prantl
1887-
1915
Hutchinson
1926- 69
Takhtajan
1969-97
Throne
2000
Dhlgren
1975-89
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23. Bibliography
1. Jeffrey, C. (1982). An introduction to plant taxonomy (Second edition ed.).
(C. Jeffery, Ed.) New York, United State: Cambridge University Press.
2. Sharma, O. P. (2007). Plant Taxonomy. 7 west Patel Nagar, New Delhi,
India: Tata McGraw-Hill Publishing Company Limited.
3. Stearn, W. T. (1989). Botanical Latin. (C. a. David, Ed.) London, Great
Bratin: Redwood Burn limited Trowbridge & Esher for David and Charls
limited.
4. Stewart, M. (2008). Classification of Life. 241 First Avenue North, U. S. A:
Minneapolis.
5. Stuessy, T. F. (2009). Plant Taxonomy (Second ed.). New York, U. S. A.:
Columbia University Press.
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