HUTCHINSON SYSTEM OF CLASSIFICATION

Hutchinson classification | Hutchinson system of classification

Hutchinson was a british botanist in royal botanical garden kiwi. Hutchinson proposed a phylogenetic classification in his book "Family of flowering plants". The last edition of this book was printed in 1972.

In new revised classification published in 1973 small alterations were made as: Lytherales were transferred to Myrtales, in Lignosae from Herbaceae. Now Dicots include 82 orders and 342 families while Monocots include 29 orders and 69 families.

Also read - Bentham and Hooker Classification


The important points are:

1. The system is based on Bessey‘s system.

2. It is based on the assumption that flowering plants with sepals and petals, associated with other floral and anatomical characters are phylogenetically primitive, than the plants without sepals and petals.

3. This system is based on considerable knowledge of phylogeny.

4. The Monocotyledons are placed after the Dicotyledons from which they were considered to have been derived at an early stage.

5. The Ranales and Magnoliales are considered most primitive orders of the Dicotyledons, where flowers are bisexual with numerous free stamens and carpels are spirally arranged.

6. Emphasizing resemblances rather than differences, the Monochlamydeae and Gamopetalae are distributed amongst the Polypetalae according to their relationships.

7. The flowering plants are divided into smaller groups on the basis of a combination of characters and closely allied families are placed together.

8. The Gymnosperms are considered as a distinct group.

9. The families of Monocotyledons are arranged in 29 orders and he proposed new conceptions for several families resulting in more natural groupings.

10. The Butomales and the Alismatales are placed at the beginning of the Monocotyledons.

11. The Gramineae are considered as the most advanced family of the Monocotyledons which is inconsistent with the present understanding of the group.

12. He recognized 411 families of Angiosperms.

Also read - Takhtajan Classification

Hutchinsion gave some rules to determine the primitive of plants. These rules are also known as principle of phylogeny. These are 24 principle. The classification is based on principle of phylogeny was suggested by john Hutchinson in his volume 2 in 1969. He published evolution and phylogeny of flowering plants.

PRINCIPLE OF PHYLOGENY 

1. Evolution is both upward & downward. 
2. Evolution is does not necessary involved all organ of the plant at a time. 
3. Evolution has been generally consistent. 
4. Tree & shrub are more primitive than herb. 
5. In one family and genera the tree and shrub are older than climbwords. 
6. Perrenial are primitive than binnial. 
7. Aquatic flowering plants are drive from terrestrial. 
8. Collateral vascular bundle arising in a primitive condition. Ex:- dicot
9. Spiral arrangement of the leaf is a primitive condition. 
10. Hermaphrodite plant are primitive than unisexual. 
11. Simple leaf is primitive than compound leaf. 
12. Solitary flower are more primitive than flowering inflorescence. 
13. Spiral arrangement of clover part is a primitive condition. 
14. Polymerous condition is primitive than definite number. 
15. Epipetalus flower are drive from petalus form. 
16. Polypetalus is primitive than gamaepetalus. 
17. Actinomorphic is primitive than zygomorphic. 
18. Hypogamous is primitive than apigamous & perigamous. 
19. Epicarpus is primitive than syncarpus. 
20. Many carpal is primitive than syncarpus. 
21. Endospermic seed are primitive. 
22. Indefinite number of stamen is primitive condition. 
23. Superior ovary is primitive than inferior ovary. 
24. Simple fruit are primitive than aggregate fruits. 

Outline of Hutchinson system of classification

Hutchinson divided angiospermic plant in two groups monocotyledons and dicotyledons. Dicotyledons heve two sub-group Lignionaceae and herbaceae. Lignionaceae is a Woody group of plants and if have trees and shrubs herbaceae is a non-woody group of plants. It contains herb Magnoliaceae is a post primitive of lignaceae, the most advance family of this group is Boraginaceae.

Merit and De-Merit of Hutchinson classification

Merit-

1. It is most phylogenetic system of classification based on natural characterstics of plant.
2. This system is based on evolutionary tendencies and interrelationships among angiospermic plants.
3. Origin of Monocot from dicots and placement of first Dicot and then Monocot families is correct in all respect.
4. Placing of gymnosperms before angiosperms in flowering plants.
5. Reshuffling or genera and families.
6. Several big order have been broken into small orders like Rosales, Malvales, Leguminales etc.


7. Magnoliales representing orborescent plants and Ranales representing herbaceous plants which shows parellel evolution.

De-Merit-

1. This Hutchinson system of classification is not of much utility from the point of view of plant classification.
2. This is not a practical classification.