CHAPTER XLIII
HOW FLOWERS PROTECT THEIR NECTAR
A WHOLE volume could be written on the marvellous contrivances of flowers, but we must be content to describe a few. It is a wonderful subject, and one which you yourselves will be able to study quite easily.
Have you ever wondered why cup-shaped flowers—the harebell, the snowdrop, and many others—droop their heads? It is because they would become filled with rain or dew if they did not do so, and thus their nectar would be spoiled, and insects would no longer visit them. For the same reason daisies will close their petals when dark clouds come up, and will remain closed until the sun shines again. Have you ever seen a flower of the white dead nettle? It actually protects its nectaries with one of its petals, which overhangs the others, and acts like a little umbrella.
The ordinary nasturtiums (Plate XXXVII.) have the edge of the three lower petals cut into fine strips. These keep the rain from the nectar, which is situated at the end of the long spur. You will notice that hive bees are not often seen on nasturtiums, for their tongues are not long enough to reach the nectar; so these flowers depend more on humble-bees for fertilisation. The nasturtium is a flower which illustrates very well what was said about “honey-guides” just now, for all the lines on the petals point to where the nectar is to be found.
Some flowers have to protect their honey from certain insects, who wish to take it without fertilising the flower in return. Ants, for instance, are very fond of honey; and, as you can easily imagine, they are so small that they can creep right down to the nectaries without dusting themselves with pollen, or fertilising the flower. So certain flowers—like the primrose—have their stalks covered with multitudes of tiny hairs. These serve as a barricade to the ant, and prevent it from climbing to the flower above. The cross-leaved heather has its stalk and calyx covered with sticky hairs, so that not only are the little thieves prevented from getting to the flower, but they are actually held prisoners as well.