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Merit d merit..hchinson ..takhtajan ..bassaey


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relative merits and demerites of major systems pf classification:takhtajan, bassaey.hutchinson

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Merit d merit..hchinson ..takhtajan ..bassaey

  1. 1. Relative merits and demerits of major systems of classification: Takhtajan , Bassaey , Hutchinson Presented by : Panchal Rita C. sem : 2 Department of Life sciences, H.N.G.U., Patan
  2. 2. Content Takhtajan Systems Of Classification. Bassaey Systems Of Classification. Hutchinson Systems Of Classification.
  3. 3. Takhtajan Systems Of Classification Takhtajan ( 1910 to 2009 ) proposed evolutionary system of classification in " system and phylogeny of Flowering Plants (1966)" and revised in 1987. The latest revised edition of his classification published in " Diversity and Classification of Flowering Plants ( 1997)". His latest classification is according to ICBN.
  4. 4. Merits Dicots discussed prior to monocots. Dicots begin with most primitive living angiosperm Magnoliales. The families are small and homogeneous units made up of closely related genera. Cyperaceae and Gramineae are placed under separate orders.
  5. 5. Demerits The main demerits is extremely narrowly defined taxa , that has resulted in the un warranted splitting of the related groups. For example Papaveraceae kept away from order Capparales. Malvales have 10 orders , but based on palynology , embryology these can be divided into two orders Malvales and Tiliales.
  6. 6. Bassaey Systems Of Classification Bassaey ( 1845 - 1915 ) a student of Asa Gray was the first American Taxonomist to introduce phylognetic system of classification.
  7. 7. Merits The Gymnosperm which stand between the dicots and Monocots in Bentham and Hooker's system have not been considered. Order Asismatales among monocots and Ranales among dicots are placed at the base , because these two orders have been regarded as most primitive. Similarly Orchidaceae and Composite have been placed at the top , because of their being most advanced among monocots and dicots respectively.
  8. 8. Demerits Placing of monocots before dicots is not justified. Inclusion of families are Typhaceae , Sparganiaceae, Pandanaceae in Alismatales is not sound , as these families are supposed to be derived from Liliaceous ancestors. Similarly Najadaceae is placed under Tiliales.The family is more allied to Helobiales rather than Liliales.
  9. 9. Hutchinson Systems Of Classification He proposed a phylogenetic system of classification in his " The Families of Flowering Plants.” He published his revised classification in " British Flowering Plants."
  10. 10. Merits It is most phylogenetic system of classification based on natural characteristic of Plants. Cytological, anatomical, paleobotanical , studies have been considered for treatment of families. Placing of gymnosperm before angiosperm in Flowering plants. Many Families have been raised to the rank of orders legumiosae family raised to order Leguminales.
  11. 11. Demerits It is based on habit only and Lamiaceae and Verbenaceae are placed away from each other. There is no hypothesis for pro angiosperms. Magnoliaceae mentioned as most primitive family and according to other authors Winteraceae is the most primitive family which vessel less. In herbaceae , Lamiaceae is regarded advanced over Asteraceae . Infact Asteraceae have been treated as most advanced family of dicotyledons.
  12. 12. Reference Text book of Botany Angiosperms by: B.P.Pandey https:// 
  13. 13. Thank You