Flowers Of Tropical Africa

WE have Seen how a plant feeds and grows by means of the root, stem, and leaves; but as in the case of' all other living things the time comes when the plant gets old and dies. Fortunately, however, before this happens, the plant produces seeds, which, as you have seen, are really baby plants, and these if they fall on moist soil will grow into new plants. We have now to find out a little more about how the seed is formed in the plant, and this brings us to the study of what is at once the most interesting and most beautiful part of the plant, viz, the flower. Now, the flower has nothing to do with the feeding and growth of the plant, but is entirely concerned with the making of the seed.

Plants, like animals, grow old and die, but they do not disappear altogether, for they produce seed. The seed gets left behind and grows into a new plant. This part of a plant's work is done by the flower. Take as an example the orange flower. These grow in clusters, and some are fully open while others are buds with the small young flower folded inside. Pick off a single flower and examine it. Just below the white part of the flower you will see a kind of green cup with five little peaks on it; this is called the calyx (which means cup), and it is made up of five parts joined together called sepals. inside this cup is the white part of the flower; this part is called the corolla (meaning "crown") and is made up of five creamy white petals. Inside the corolla is a mass of yellow threads each with a little yellow knob at the end; these threads are called stamens, and the knobs, called anthers, contain a fine powder called pollen. if you shake a ripe flower over a piece of white paper you will often see the pollen which has fallen out. Lastly, in the centre of all lies the pistil; you can see this best if you carefully pull off the corolla and the stamens, or if you cut with a sharp knife right down the centre of the flower. The pistil starts as a rounded body at the bottom called the ovary; from this a stalk grows upwards called the style, ending in a knob called the stigma.

The ovary is the most important part of the flower, as it is the seed box, and contains the seeds It may be divided into different compartment has its own stigma above, communicating with it; the whole, i.e., a compartment and a stigma together, is called a carpel. And the whole pistil is accordingly said to be made up of one, two, three or more carpals. The number of carpals is always the same in each flower upon a plant; as is also the number of petals in the corolla or sepals in the calyx. But these numbers and the arrangements of the petals, sepals, etc., vary in different plants in very many different ways. Bracts are tiny leaflets often found on the flower stalk. They seem usually of very little use, but in some cases they protect and support the flower.

To sum up, the flower has the following parts: Bracts. Calyx made up of sepals. Corolla made up of petals. Stamen carrying the pollen. Pistil made up of ovary, style and stigma. The ovary is often divided into compartments called carpals. What now has each of these parts to do with the main work of the flower, that is to say, with the production of seed? The calyx outside protects the flower and holds it firmly together. The sepals may or may not be joined together; if they are separate they are generally arranged between the petals of the corolla; in a few flowers there is no calyx at all.

The corolla also protects the ovary and stamens, but it has another very important use which accounts for its beautiful color. Its purpose is to attract insects to the flower; this may seem strange but it will be explained later on The stamens produce pollen, that is the yellow dust that you can sometimes shake out of a flower. Pollen is required by the seed in order that it may ripen. The pistil is the most central and the most protected part of the flower, for it has the ovary or seed box at the bottom. This ovary contains the very precious seed and protects it when it is first formed Above the ovary is the style acting as a stalk for the stigma borne on its top end. The stigma is important as it is the means by which the pollen reaches the ovary' and so the seeds. The stigma has a small hole through which the pollen can enter; the pollen then passes down the inside of the style to the ovary to help ripen the seed. Once the pollen reaches the seed the outside of the flower may all fall away leaving the ovary, which may then become very large. In a crop of beans you can see the young flowers, then the older flowers with the bean beginning to appear, and later the flower fading away, while the bean gets larger and larger; last of all the fully-grown bean may be seen when the flower has all fallen off.