Flower parts and Types of Flower

Aug 09, 2022, 16:45 IST

About flower and parts of flowers

A flower is a highly condensed and modified shoot of angiosperms meant for sexual reproduction (Goethe, 1790). The study of flowers and flowering plants is called anthology. Like a branch, it arises in the axis of a bract.

PARTS OF A FLOWER

A flower has two parts, pedicel and floral leaves. The stalk of flowers is called the pedicel, The distal upper part of the pedicel which becomes somewhat swollen and receptive is called the thalamus or torus. The thalamus receives floral leaves i.e., the modified special leaves. Since the floral leaves are usually arranged in whorls, so they are simply called whorls. Flowers exhibit wide variation in size, shape, color, and arrangement of floral parts. However, all flowers have the same basic plan.

WHORLS OF FLOWER

An angiospermic flower consists of four whorls-calyx, corolla, androecium and gynoecium. The former two are called accessory or nonessential organs while the latter two are referred to as essential or reproductive organs.

Calyx: It is the first whorl and first accessory organ. It is a small, green, photosynthetic, and protective structure. Its unit is called sepal. When sepals are united, the calyx is said to be gamosepalous but when sepals are free, the calyx is called polysepalous.

Corolla: It is the second whorl and second accessory organ. It is somewhat large, colored, and attractive. The color of the corolla determines the color of the flower. Its unit is called a petal. When petals are united, the corolla is said to be gamopetalous but when petals are free, the corolla is called polypetalous. When sepals and petals are undifferentiated, they are called perianth. Its unit is called tepal. Tepals may be sepaloid or petaloid. When tepals are united, the perianth is called gamosepalous or gamophyllous but when tepals are free, the perianth is said to be polysepalous or polyphyllus.

Androecium: Androecium (Gk. Andros: male; Oikos: home) is the third whorl and first essential organ. It is called the male reproductive organ. Its unit is called the stamen. Stamen is a highly modified special leaf, known as microsporophyll. Each stamen has got three parts; filament, anther, and connective. The filament is a basal, thin, and sterile stalk-like part. The anther is the upper, lobed, and fertile part, connected with filament by connective. Each anther has usually two lobes and such anther is called the dithecous or bi-celled anther. But in the members of the family Malvaceae, another has one lobe and is called monoecious. Each anther lobe has two pollen sacs or microsporangia placed longitudinally. Each pollen sac has many, minute, dusty and haploid pollen.

Gynoecium: Gynoecium (Gk. Gynae: female; Oikos: home) is the fourth, central and last whorl, and second essential organ. It is also called the female reproductive organ. Its unit is called carpel or megasporophyll. A typical carpel has three parts; ovary, style, and stigma. The ovary is the basal, swollen, and fertile part. On its inner wall, there is a parenchymatous tissue known as the placenta. It bears one or more ovules (megasporangia). Style is a thin, elongated stalk-like structure while stigma is a terminal receptive part.

Read the theory form NCERT text book and try to solve the questions for

reference read Physics Wallah NCERT Solutions for class 12 Biology

NCERT Solutions for class 12 Biology