What can be the use of the sticky tip that we found on the carpels? Examine the tip of the carpel of a lily which is well open, and you will very likely find some of the yellow pollen sticking to its surface. It is a curious fact that the little structures within the carpels which will become seeds cannot ripen into true seeds unless they are waked up to growth by the pollen grains. ~The sticky tip of the carpels~ (or ~stigma~, as it is called) ~catches the pollen grains and holds them; then they grow down into the carpels and carry with them the nuclei~ (see p. 92) ~that enter the undeveloped seeds. These stir the cells to divide, and after many divisions the embryos are formed and the seeds ripen.~ Sometimes the stigma has a long stalk which places it in a good position to catch the pollen grains. This stalk is called the ~style~, and is to be found in many flowers (~see~ fig. 72). The pollen dust is fine and light, and may be carried by the wind on to the stigma, as it sometimes is in poppies, and always is in pine-trees; but this is rather a wasteful way, because the wind blows so irregularly that very much pollen is lost and never reaches the stigma. In order to save some of this loss, and ~to make the pollinating more certain~, flowers have arranged their parts so as to make use of the help of insects. You know that very many flowers have sweet honey in them which the bees like, and come to collect, going from flower to flower to do so. When the bee settles on the flower it gets covered with the pollen dust, and then when it goes to the next flower and walks over it, it is almost sure to leave behind it some of the pollen sticking on the stigma. Of course, in this way also some pollen is lost, but insects are far more reliable than the wind. We now see the use of the bright coloured petals; they help to attract the bees to the flower. The flowers have made the bees and other insects their special carriers of pollen, and they pay the insect with honey, and some of the surplus pollen. Bees generally go from flower to flower of the same kind on any one day’s journey, so that the flowers get pollen from others of their own kind. This is important, for “foreign pollen” (as the pollen from quite different kinds of flowers is called) does not help the young seeds at all. We have now found a use for all the parts of the flower. [Illustration: Fig. 79. A, Violet, a two-sides flower. B, Primrose, a circular flower.]