“It is like a spoon,” said Tom. “It is,” said his uncle; “and can you see any reason for it being so shaped? “You cannot? Well, I must tell you. All plants whose leaves are all at the ground have leaves shaped something like this. The primrose and cowslip are good examples. We have seen that plants, like the pea, climb up so that their leaves and green parts may get as much light and air as possible. And if you look at any tree, such as the horse-chestnut, ash, elm, or beech, you will notice that their leaves are spread out so as to catch as much light as possible.” Uncle George then drew a circle. [Illustration] 1 and 2. Diagram to show Leaf arrangement of Daisy. 3. Head of Daisy split. 4. Outer Floret. 5. Inner Floret. “Now, boys,” he said, “I want you to try to fill that circle with leaves so shaped that they will fill it without covering one another. The best way to do so is to make them broad at the end. If you make them broad at the base and narrow at the end, they overlap and rob each other of light and air. Now you can see why the leaves of the daisy are so shaped. “Take up a daisy and split it down the centre with your knife. You will notice that the daisy is _not_ a flower, but a collection of tiny flowers, or florets, all packed closely together upon a pad or disc, and surrounded outside by many little green things like small leaves. These little leaf-like things are called _bracts_.” [Illustration: London Pride, showing Leaf arrangement.] “There are two distinct kinds of florets,” said Frank, looking at the split daisy with his lens. “Yes,” said Uncle George, “you will see them better if you remove one of each with a pin, and examine them separately.” “The outer florets are very large and white,” said Frank. “They are very flat, while the inner ones are yellow and round. They are very like small crocus flowers. What is that small two-headed thing that comes out in the centre of each floret?” “That is the part which leads to the seed-vessel. Can you see the seed-vessel at the bottom of each floret?” “Yes,” said Tom, “it is large and round. On the top of it and all round the petal part of the floret there are long silky hairs.” “In flowers of this kind, when the seeds are ripe they are carried away by the wind,” said Uncle George. “The petal part withers, but the tuft of hairs remain. They are to the seed what sails are to a ship. They are much better seen in some other flowers related to the daisy, such as the thistle. “Now cut open the seed-vessel and see how many seeds it contains.” “There is only one, I think,” said Frank. “You think correctly,” said his uncle. “Each seed-vessel holds a single seed.” “The seed-vessel in the large white floret is small and flat,” said Tom. “It is,” said Uncle George. “In fact, the outer florets seldom produce seeds.” “Then what is the use of them?” Tom asked.