plant anatomy

Flower, the characteristic reproductive structure of angiosperms. As popularly used, the term “flower” especially applies when part or all of the reproductive structure is distinctive in colour and form.
petuniaPink variegated flowers of a common garden petunia (Petunia ×atkinsiana).(more)
lilacCommon lilac (Syringa vulgaris).
In their range of colour, size, form, and anatomical arrangement, flowers present a seemingly endless variety of combinations. They range in size from minute blossoms to giant blooms. In some plants, such as poppy, magnolia, tulip, and petunia, each flower is relatively large and showy and is produced singly, while in other plants, such as aster, snapdragon, and lilac, the individual flowers may be very small and are borne in a distinctive cluster known as an inflorescence. Regardless of their variety, all flowers have a uniform function, the reproduction of the species through the production of seed.
The sepals and petals together make up the perianth, or floral envelope. The sepals are usually greenish and often resemble reduced leaves, while the petals are usually colourful and showy. Sepals and petals that are indistinguishable, as in lilies and tulips, are sometimes referred to as tepals.