Let us choose, for example, a harebell. On the outside we find five separate green parts, and if we examine a bud which has not yet opened we shall find that these fold quite tightly over the inner portions of the flower and protect them, as they do in the rose and in almost all flowers (~see~ fig. 69). In this they correspond to some extent to the bud scales, and their special work is that of ~protection~. In all harebells and roses there are five of these parts, but in the wallflower you will find only four, and in poppies two, and so on. There are different numbers of them in the different kinds of flowers. They are also of different shapes and sizes; sometimes each of the five parts is free, and sometimes they are all joined up together to form a true cup, as in the primrose (~see~ fig. 72). These outer green protective parts have a special name, and are called the ~calyx~ or cup, while each of the separate parts which makes the cup is called a ~sepal~. [Illustration: Fig. 70. Buds of the Rose; A with the calyx covering the inner parts, B with the petals opening out.] [Illustration: Fig. 71. Flower of the Rose, with separate petals.] Directly within the calyx we come to the parts which are generally bright and prettily coloured, and which give the chief beauty to the flower. In the harebell which we are examining these parts are joined up to form a bell, but in the rose they are each separate (~see~ fig. 71). In both harebell and rose we find five of these parts, and the same number in the primrose, where you will find that they are joined up at the base to form a long, narrow tube, and then spread out separately like those of a rose. Both in the harebell and primrose, where they are joined up, we can tell the number of parts which go to make the whole bell or tube (and this is nearly always the case in bell flowers), while, of course, where the parts are free it is quite easy to count them, and we find that for each kind of flower their number is always fixed. For example, we find five in the harebell, rose, primrose, and many others, four in the poppy, wallflower, cress, and so on. These parts are called the ~petals~, and in almost all flowers you will find that they are bright and pretty, and stand out from the surrounding green leaves, so that they are easily seen. When the cups or bells hang down they may protect the parts within from the rain, but that is not generally their chief work. The ~first duty of the petals is to be attractive~. You will understand better why this is so after we have gone further into the flower. [Illustration: Fig. 72. Primrose flower cut open, showing the stamens (~s~) attached to the tube formed by the petals.] [Illustration: Fig. 73. Flower of Speedwell, with only two stamens (~s~).]