Fruits (page 1)

Fruit formation is stimulated by the fertilization process described in a prior lesson. In the two photographs above you can see the beginning stage and ending stage of the angiosperm reproductive cycle. The Bunchberry flower appears early in the spring and by mid-summer parts of the flower have been transformed into a bright red fruit cluster. An individual fruit, of a flowering plant, always contains at least one mature ovary. Maturation includes enlargement and modification of the ovary wall and ovary contents. Completion of this developmental process forms a simple fruit derived from a single ovary. Other plants produce fruits formed by the fusion of several ovaries found on the same flower. This second process, of ovary fusion and maturation, forms an aggregate fruit. A third kind of fruit results from the maturation and fusion of ovaries of separate flowers of the same plant. This process forms a multiple fruit. It is also common to find simple, aggregate and multiple fruits to contain not only modified ovaries but also modified floral (perianth) structures including parts of the calyx, corolla and receptacle. These are called accessory fruits. Fruits without accessory floral parts are known as true fruits. As this lesson continues we will learn the names of the simple, aggregate and multiple fruits and how their individual structure is related to the flower from which they originated.