FLOWERING PLANT

INTRODUCTION

Flower

Flower is a modified stem which functions as a reproductive organ and produces ova and/or pollen

(1) Structure of the flower:

The flower is commonly borne on short or long stalk called the pedicel. It has an upper swollen region known as receptacle (thalamus or torus).

(2) Parts of a flower:

A typical angiospermic flower consists of four whorls of floral appendages attached on the receptacle: calyx, corolla, androecium and gynoecium.

(i) Calyx: It is the outermost whorl of the flower. It is composed of leaf like green sepals. The sepals are essentially green in colour but in some cases they are coloured like petals. Such a condition of calyx is called petaloid.

(ii) Corolla: This is the second whorl of the flower and consists of a number of petals. Petals are generally brightly coloured and sometimes fragrant which make the flower to become attractive.

(iii) Androecium: It is the third whorl of flower and is the male reproductive organ consisting of stamens. Each stamen is made of filament and anther. The filament supports anther at its tip.

(iv) Gynoecium: This is the last and the fourth whorl of flower and is the female reproductive organ of the flower. It occupies the central position on the receptacle and composed of ovary, style and stigma and the component parts are called carpels.

(3) Functions of a flower

(i) Flowers are modifications of shoot to perform the function of sexual reproduction.

(ii) Flowers of most of the angiosperms are shaped variously to help diverse modes of pollination.

(iii) Flowers provide seat for germination of pollen, development of pollen tube, formation of gametes and fertilization.


(iv) The ovary part of the carpel gets transformed into fruit and the ovules are transformed into seeds after fertilization.