flower

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Reproductive unit of an angiosperm (flowering plant), typically consisting of four whorls of modified leaves: sepals, petals, stamens, and carpels. These are borne on a central axis or receptacle. The many variations in size, colour, number, and arrangement of parts are closely related to the method of pollination. Flowers adapted for wind pollination typically have reduced or absent petals and sepals and long, feathery stigmas that hang outside the flower to trap airborne pollen. In contrast, the petals of insect-pollinated flowers are usually conspicuous and brightly coloured.

Structure
The sepals and petals form the calyx and corolla respectively and together comprise the perianth with the function of protecting the reproductive organs and attracting pollinators.

The stamens lie within the corolla, each having a slender stalk, or filament, bearing the pollen-containing anther at the top. Collectively they are known as the androecium (male organs). The inner whorl of the flower comprises the carpels, each usually consisting of an ovary in which are borne the ovules, and a stigma borne at the top of a slender stalk, or style. Collectively the carpels are known as the gynoecium (female organs).

Types of flower
In size, flowers range from the tiny blooms of duckweeds scarcely visible to the naked eye to the gigantic flowers of the Malaysian Rafflesia, which can reach over 1 m/3 ft across. Flowers may grow either individually or in groups called inflorescences. The stalk of the whole inflorescence is termed a peduncle, and the stalk of an individual flower is termed a pedicel. A flower is termed hermaphrodite when it contains both male and female reproductive organs. When male and female organs are carried in separate flowers, they are termed monoecious; when male and female flowers are on separate plants, the term dioecious is used.

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