Buds and flowers of the morning-glory.
You have often seen the flowers of the morning-glory. These last only from early in the morning to noon, or a little after noon. In the afternoon they are all closed, and the vines look very dull without any flowers on them. But look the next morning, and you will see a plenty of these beautiful flowers. They open before most people are out of their beds. And, just as I told you about the cypress-vine, there is a new set of them every day.
It is curious to see in what way the blossom of the morning-glory opens and then shuts itself up to die. If you look in the afternoon you will find here and there a bud shaped as you see in this figure. The flower part of it, you observe, is twisted at its pointed end in a spiral manner; that is, something like a cork-screw. This bud will be an open flower the next morning.
On the following page you see the flower as it looks when it is fully opened. There are ribs running up from the lower part of the flower. Each of these ribs comes to a point at the edge. They give firmness to the blossom. They are its frame-work, its timbers. Without these ribs it could not stand like a cup on its stem, as it does now, but would hang loosely down. The open spread part of the flower is very thin, and the ribs are to it what the whalebones are to an umbrella.
Closing of the flower of the morning-glory.
In this figure you see how the flower looks as it is partly closed. The points of the ribs are all turned in toward the middle of the flower. They bend in more and more, and after a while the flower wilts and dies. Now it is curious that the ribs of the flower should be folded so differently when it closes from what they are before it opens. Before it opens they are folded in a spiral form, as you see in the figure in the preceding page. When it closes, we would suppose that they would fold up in the same form. But they do not. They bend straight over, and the points come together in the middle of the flower.
Night-blooming cereus.