Flower: Parts and Functions | Biology

In this article we will discuss about the parts and functions of a flower.

Parts of a Typical Flower:

A typical flower consists four whorls of floral appendages, attached on the receptacle, i.e., calyx, corolla, androecium and gynoecium. Of these, the two lower whorls, i.e., calyx and corolla are sterile and considered as non-essential/accessory/helping whorls and the two upper whorls, i.e., androecium and gynoecium are fertile and are considered as essential or reproductive whorls.

Different whorls of a flower are given below:

(i) Calyx:

It is the outermost whorl of floral leaves. An individual leaf segment is called sepal. The sepal are essentially green, but in some cases they are coloured like petals, is called petaloid. They are protective in function. They may fall immediately after the flower opens or may remain persistent and protect the developing fruits.

(ii) Corolla:

This is a second whorl of floral leaves that arise inner to calyx. Individual leaf of corolla is called petal. Petals are brightly coloured and fragrant, which make the flower attractive. They attract insect pollinators and help in pollination.

Petals and sepals together form the floral envelope. The floral envelope including both calyx and corolla is called perianth. An individual member of perianth, when sepals and petals are not clearly differentiated is called tepal.

(iii) Androecium:

It is the third whorl of floral appendages that arise inner to corolla. The individual apparatus is the stamen, which represents the male reproductive organ.

Each stamen consists of an anther and a filament, usually anthers are bilobed and contain four microsporangia, but sometimes they have only one lobe and two microsporangia.

The point of stamen, which connects the anther and the filament is called connective. Its main function is the production of microspores, i.e., pollen grains containing male gametes within the anther lobe.

(iv) Gynoecium/Pistil:

It is the fourth and the last whorl of floral appendages, which represents the female reproductive organ and consists of three parts, i.e., ovary, stigma and style.

These are given below:

(a) Ovary is the basal swollen part of the carpel, which bears one or several ovules.

(b) Stigma is the receptive spot, which lodges the pollen grains.

(c) Style is the connection between the stigma and the ovary.

It helps body part in production of megaspores, fruits and seeds.

Functions of a Flower:

Following are the functions of flower:

(a) Flowers are the modifications of shoot that perform the function of sexual reproduction.

(b) The fertile leaves become microsporophyll’s and megasporophylls, which bear anthers and ovules respectively. The anthers produce pollen grains and ovules possess eggs.

(c) Flowers are variously shaped to help diverse mode of pollination.

(d) They provide seed for germination of pollen, development of pollen tube, formation of gametes and fertilisation.

(e) Floral parts get transformed into fruits and seeds after fertilisation.

(f) Flowers also help in dispersal of seeds and fruits.