anthers? Why is the corolla white, while the rest of the plant is green?

The honey of course serves to attract the Humble Bees by which the flower is fertilised, and to which it is especially adapted; the

white colour makes the flower more conspicuous; the lower lip forms the stage on which the Bees may alight; the length of the tube is adapted to that of their proboscis; its narrowness and the fringe of fine hairs exclude small insects which might rob the flower of its honey without performing any service in return; the arched upper lip protects the stamens and pistil, and prevents rain-drops from choking up the tube and washing away the honey; the little teeth are, I believe, of

no use to the flower in its present condition, they are the last relics of lobes once much larger, and still remaining so in some allied species, but which in the Dead-nettle, being no longer of any use, are gradually disappearing; the height of the arch has reference to the size of the Bee, being just so much above the alighting stage that the Bee, while sucking the honey, rubs its back against the hood and thus comes in contact. first with the stigma and then with the anthers, the pollen-grains from which adhere to the hairs on the Bee's back, and are thus carried off to the next flower which the Bee visits, when some of them are then licked off by the viscid tip of the stigma.1

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 function

1 Lubbock, Flowers and Insects.

less. In the other two the anthers or cells pro

ducing 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

Fig. 9.

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. 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.

SWEET PEA

In the above cases the flower once opened does not close again. In others, such as the Sweet Pea and the Bird's-foot Lotus, Nature

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