When the calyx is divided into separate leaves, these leaves are called Sepals.
The inner flower-cup or the inner set of leaves is the Corolla (Fig. 6, C).
When the corolla is divided into separate leaves, these leaves are called Petals.
We can look upon calyx and corolla as the natural tapestry which protects the delicate organs of the flower, and serves as well, in many cases, to attract the attention of passing insects. In some flowers only one of these two parts is present; in such a case the single cup or set of floral leaves is generally considered to be the calyx.
The floral leaves may be spoken of collectively as the Perianth. This word is used especially in describing members of families where there might be difficulty in deciding as to whether the single set of floral leaves present should be considered calyx or corolla (see Lilies, Pls. XLV. and LXXX.); or where the petals and sepals can only be distinguished with difficulty, as with the Orchids.
Fig. 7.
Fig. 8.
The Stamens (Fig. 7) are the fertilizing organs of the flower. A stamen usually consists of two parts, its Filament (F), or stalk, and its Anther (A), the little sac at the tip of the filament which produces the dust-like, fertilizing substance called Pollen (p.).