The Beauties of Nature, and the Wonders of the World We Live In

by Sir John Lubbock

Fig. 9.

Fig. 10. Fig. 11.

In the Salvias, the common blue Salvia of our gardens, for instance,—a plant allied to the Dead-nettle,—the flower (Fig. 9) is constructed on the same plan, but the arch is much larger, so that the back of the Bee does not nearly reach it. The stamens, however, have undergone a remarkable modification. Two of them have become small and functionless. In the other two the anthers or cells producing the pollen, which in most flowers form together a round knob or head at the top of the stamen, are separated by a long arm, which plays on the top of the stamen as on a hinge. Of these two arms one hangs down into the tube, closing the passage, while the other lies under the arched upper lip. When the Bee pushes its proboscis down the tube (Fig. 11) it presses the lower arm to one side, and the upper arm consequently descends, tapping the Bee on the back, and dusting it with pollen. When the flower is a little older the pistil (Fig. 9, p) has elongated so that the stigma (Fig. 10, st) touches the back of the Bee and carries off some of the pollen. This sounds a little complicated, but is clear enough if we take a twig or stalk of grass and push it down the tube, when one arm of each of the two larger stamens will at once make its appearance. It is one of the most beautiful pieces of plant mechanism which I know, and was first described by Sprengel, a poor German schoolmaster.

SNAPDRAGON

At first sight it may seem an objection to the view here advocated that the flowers in some species—as, for instance, the common Snapdragon (Antirrhinum), which, according to the above given tests, ought to be fertilised by insects—are entirely closed. A little consideration, however, will suggest the reply. The Snapdragon is especially adapted for fertilisation by Humble Bees. The stamens and pistil are so arranged that smaller species would not effect the object. It is therefore an advantage that they should be excluded, and in fact they are not strong enough to move the spring. The Antirrhinum is, so to speak, a closed box, of which the Humble Bees alone possess the key.

FURZE, BROOM, AND LABURNUM

Other flowers such as the Furze, Broom, Laburnum, etc., are also opened by Bees. The petals lock more or less into one another, and the flower remains at first closed. When, however, the insect alighting on it presses down the keel, the flower bursts open, and dusts it with pollen.