Q. Show the Natural selection of taxonomist?

Natural selection associated with successful reproduction maintains a basic similarity of the reproductive feature of flowers, fruits and seeds within the various species, genera and families. We have already discussed these concepts in Unit 5. This general constancy makes the structures ideal for charactensing taxonomic groups. You should know {hat floral feature of a plant are fundamental in defining natural groups, because of being more constant than vegetative features. Dicots have tetramerous and pentamerous flowers, while monocots have trimerous flowers. Reproductive characters are numerous and provide more features to differentiate taxa. Modifications in floral morphology can be related to the mode of pollination or specialised reproduction. Wind pollinated taxa frequently have unisexual reduced flowers that are individually inconspicuous. Corollacolor, pollinator guides and structure of floral whorls, stamen number, another position, ovary position, number of carpels, number and position of perianth parts, type of inflorescence and fruit and seed type contribute to the reproductive features of the plants. The mature fruits of the mustard species (Cruciferae) and carrot species and their relatives (umbelliferae) have diagnostic character. In. cruciferae the fruit is silique or silicle and in umbelliferae the fruit is a Schizocarp.

These families should include mature fruits to insure identification. Similarly flower type and fruit are important in the classification of the Rosa species (Rosaceae). The flowers are usually actinomorhic e, rigynous to epigynous and fruit are fleshy pome. The carollas and stamens of the figworts (Scrophulariaceae) provide much information for classification at various taxonomic ranks within the family. The corolla consists of bilabiate 4-5 connate petals and androecium commonly of 4 didynamous epipetalous stamens that are alternate with the lobes.