Fig. 119. (a) Flower of the Gorse after the insect’s visit, showing the inner parts exposed; (b) young flower nearly ready to be visited.
First examine a flower so that you know how it is arranged. At the back lies the big petal, or “standard,” as in the pea; there are two side wings, and in the front the two petals close together forming the “keel.” The two-sidedness of this flower is very well marked. Inside the keel you will find ten stamens, all joined to form a tube except the back one, which is free, and inside them lies the carpel with its curved style. When the stamens are ripe they are so fitted that they lie inside the keel of the petals in a bent form, and when they are pressed from above they fly out with a little explosion and scatter the pollen dust about. Now watch a bee alighting on the flowers; he presses the two front petals with his legs to open them to get at the honey, and the stamen explosion covers him all over with pollen. Then he goes to the other flowers, but perhaps the next one he visits has already exploded and the ripe stigma is exposed in the front of the flower, and as he settles he touches it with his furry body all covered with pollen, and leaves some on it. If you watch the bees doing this yourself, you will find out a number of things which I have not told you, while you may notice how some of the bees are lazy and enter the wrong side of the flower, others are stupid and go to flowers which have already been visited several times, and therefore are of no use, while other bees which come late may open up buds which were not ready for them and steal the honey before the stamens are ripe enough to smother them with pollen. I have watched them opening buds which were still so tightly closed that it took them all their strength to get in. But we must not stop too long with one flower, for almost every flower has some special arrangement of its own, and all are worth study.
Fig. 120. The two kinds of Primrose flowers, A, with long style and stamens low in the petal tube; B, short style, with stamens at the mouth of the petal tube.
The primroses and cowslips are interesting, as they have two kinds of flowers. It you gather a bunch of primroses and look into them you will find that in some you can see the little central green ball of the stigma, and in others at the top of the tube are the five small anthers. These two kinds of flowers make an arrangement which ensures that the pollen from the one kind of flower reaches the stigma of the other. A big fly like the wasp-fly, and several others, visit these flowers most frequently, and carry the pollen from flower A (see fig. 120) to the stigma of B, and the pollen of B to the stigma of A.
Fig. 121. A, Flowerhead of the Daisy; (b) a single little flower from the side with big petals fused together; (c) a single little flower from the middle with very small petals.
As we noticed before, the chief duty of the petals is to act as flags to attract the visiting insects by their bright colours. Now we find that some flowers club together, and grow clustering closely on one head, so that it is sufficient for a few of them to have the flag petals which attract the insect to the group, as it goes from one to the other when once it is there. When a few of the flowers do this, the rest can economise in petals and have quite small ones, and yet all the same they have a good chance of insect visits. Such an arrangement as this is found in the daisy (see fig. 121). A single daisy is not one flower, but a whole bunch of flowers, in which some of the outer flowers of the bunch (see fig. 121 (b)) form big petals, while all the inner ones (fig. 121 (c)) are quite small and inconspicuous, and by themselves would hardly attract any visitors. Just the same thing happens in the cornflower, sunflower, and very many members of the daisy family. The big outer petals attract the insect, and once on the head of flowers it walks about over them, and they all get the benefit.