Essay on the Natural System of Classification of Plants

Essay on the Natural System of Classification of Plants as suggestes by Bentham and Joseph Dalton Hooker. Natural system of classification is that in which all natural characters of plants both vegetative and reproductive are taken in to consideration as the basic of classification principally the plants are grouped according to their related characters. This system of classification is aptly of practical utility which ascertain the name of plants but provides the plants it specific taxon in relation to their affinities to other.

All modem systems of classification are natural. Which was proposed by different botanist viz John Ray, A.P. de Candole, and Lindley etc. Out of which Bentham and Hooker’s classification is widely used as most Natural System of Classification of Plants.

Bentham and Hooker’s System:

George Bentham (1800-1884) and Sir Joseph Dalton Hooker (1817-1911) were great plant explorer and geographer associated with royal botanical gardens and adopted a very comprehensive system of classification in their jointly published book genera pantarum.

This classification is based on the assumptions of de Candoll’s classification. Their classification is purely natural as the knowledge of phyllogenicity was not detected and there was not the knowledge of theory of descent.

There classification is based on the assumptions of de Candolle’s classification there classification is purely natural as the knowledge of phyllogenicity was not detected and there was not the knowledge of theory of descent.

There genera plantarum was accepted through out the British Empire and the U.S.A and well adopted by all the botanists of the continent.

Feature of Classification:

i. This includes the names and descriptions of all genera of seed plant known so far and classified accordingly.

ii. The plant kingdom comprises about 97205 species of seed plantsunder 202 orders in which orders treated now as families.

iii. This orders further grouped under several cohorts, now treated as orders.

iv. This orders further grouped under several cohorts, now treated as orders.

v. They placed first dicotyledons, then gymnosperms and lastly the monocotyledons.

vi. They classify dicotyledonsinto 165 order gymnosperms into 3 orders and mono cotyledons into 34 orders.

vii. They devide dicotyledons in to 3 divisions and 14 series which further divided into cohorts and orders.

viii. The dicots started with family ranunculadceae, with free sepals and petals and indefinite number of stamens and carpels are free. The dicots e4nds with family labiatae with fused swpals and petals with definite number of carpels and stamens.

ix. Monocots divided into seven series. Which are directed grouped into orders without interpretation of cohorts.

Orders with epigenous flowers, i.e. orchidaceous and scitaminae were kept first, follower by orders with petaloid hypogynous flowers, i.e. liliaceae. Then kept palmaceae and araceae, finally ended with graminal and cyperaceae.

Summary of Classification:

There system is regarded as the most natural system convenient and suitable system for practical utility and is followed in most of the herbaria for following reasons.

i. Every genes and species was studies from the actual specimens available in the British and continental herbaria and their descriptions were based on their detailed studies and dissections.

ii. The description made in the florea is based on actual examination of specimens.

iii. The work is not a mere compilation of the previous system but is in essence a refinement of those by de Candolle’s system.

iv. In the division polyetalae the new series disciflorale is interpolated between thalamiflorel and calyciflorade of decondolles system.

v. Grmnosperms treated as a third taxon and placed betweem the dicots and monocots.

vi. The genera were divided into sub-genera to which were assigned all the relevant and important species.

vii. Ranales are placed first in the dicot which is very reasonable.

viii. Monocots flow dicots, but the keeping gymnosperms in between is an a normally but it is justified according to them.

ix. Monochlamydae is considered as highly evolved and polypetalous is the most primitive.

Besides above features Bentham and hookers classification was not treated flowering plants expensively on the basis of phylogenetic relationship but it are sure that the classification is natural one.