Q. How Linnaeus classify the plant kingdom?
Linnaeus classified the plant kingdom into 24 classes in his famous work 'Genera Plantarum' (1737) and 'Species Plantarum' (1753). In species plantarum, he diagnosed nearly 6000 species under 1000 genera. This work is still considered to be the mast important in the botanical world. It would not be out of place to mention that Linnaeus proposed Binomial Nomenclature in this book and that is why Species
Plantarum and the date 1 May 1753 have been chosen by the modern botanists as the starting point of the present day botanical nomenclature. For the first time he used two names in Latin for an individual organism i.e. a generic name and a specific name. This was the foundation stone in development of binomial system of nomenclature.
The outline of the classification proposed by Linnaeus is as under:
Class I Monandria - One stamens e.g. Canna, Salicornia
Class I1 Diandria - Two stamens e.g. OEea, Veronica
Class I11 Triandria - Three stamens e.g. many grasses
Class IV Tetrandria - Four stamens e.g. Protea, Galium
Class V Pentandria - Five stamens e.g. Ipomoea, Campanula
Class VI Hexandria - Six stamens e.g. Narcissus, Lilium
Class VII Heptandria - Seven stamens e.g. Trientalis, Aesculus
Class VIII Octandria - Eight stamens e.g, Vaccinium, Dirca
Class IX Enneandria - Nine stamens e.g. ~ aurusB, utomus
Class X Decandria - Ten stamens e.g. Rhododendron, Oxalis
Class XI Dodecandria - Eleven to Nineteen e.g. Asarum.
Class XI1 Icosandria - Twenty or more stamens attached to Calyx e.g. Opuntia
Class XI11 Polyandria - Twenty or more stamens attached to receptacle e.g. Tilia, Raunculus
Class XIV , Didynamia - 2 stamens short and 2 long, e.g. Merltho (Mint)
Class XV Tetradynamia- 2 stamens short and 4 stamens long e.g. Brassica (Mustard)
Class XVI Monadelphia - Stamens formingone bundle only, c.g. Hibisc11.s
Class XVII Diadelphia - Stamens forming in 2 bundles, e.g. Pisurn (Pea)
Class XVIII Polyadelphia - Stamens forming many bundles, e.g . Bombrr.~
Class XIX Syngenesia - Anthers are fused but filament are free (Syngenesious condition) e.g. Many composites such as sunflower
ClassXX Gynandria - Stamens adnate to the gynoecium e.g. Orchids
Class XXI Monoecia - Plants monoecious Male and Female flowers are borne on the same plant e.g. CtcurbitaM, orus
Class XXII Dioecia - Plants Dioecious Male and Female flowers are borfie on different plants e.g. Papaya
Class XXIII Polygamia - Plant Polygamous, male female and bisexual flowers are borne on the same plant e.g. Mango
Class XXIV Cryptogamia - Flower concealed e.g. Algae, Lichen, Fungi, Music (Moss), Filicinae (Fern) etc.
Linnaeus followed Tournefort in arrangement of plants in the classification and introduced further modifications and ideas of his owp. But his classification was artificial because he has considered only one major character as an aid for delimitation of taxa from each other irrespective of their relationship. By using only one criterion different families of monocotyledons and dicotyledons have come
together in one class. He also knew this and pointed out that such artificial system has been followed in order to simply present a practical and easy method to identify and place all known plants of that period. Linnaeus, therefore, never asserted that system proposed by him is perfect and natural. Later in his life he started pointing out that instead of one, group of characters should be taken into consideration.
The evolutionary concept was not clear during Linnaeus period and Darwin's theory of evolution was brought to light nearly a century later than Linnaeus. Despite several limitation Linnaeus has contributed excellent knowledge of living kingdom.