Page:Popular Science Monthly Volume 73.djvu/201

Rh tropical beauty is here assembled. The flame tree of Madagascar, named from the brilliant color of the flowers, is a wondrous sight in March and April, the whole tree being a mass of red which hides the dark-green foliage. From India there is a tree, Saraca indica, with a profusion of brilliant orange-yellow flowers; and from tropical America various trees of the genus Brownea, especially interesting because of the graceful clusters of pendant young leaves. The leaves droop when young and tender, thus presenting very little surface for injury by the overhead sun. As they grow older a horizontal position is assumed and the red color is lost. It is supposed that the red coloring matter acts as a screen which protects the living substance of the young leaves just as the red glass in a photographer's dark-room window protects the sensitive plates from injury by light.

Among the most interesting plants are the bamboos, of which many different kinds are cultivated, some native, others imported from peninsular India or from other parts of Asia. Some interesting studies have been made at the gardens on the rate of growth of bamboo stems. These spring up almost as if by magic. To measure the growth from day to day no expensive auxanometer is needed, but only a tape measure and a coolie to climb an adjacent tree with the end of the tape. A day's growth is measured not in millimeters but in feet or inches. Bamboo stems are hollow, as are most grasses—for bamboos are but grasses—and are wonderfully strong considering the weight and the amount of material in them. Indeed, the principle of the hollow cylinder so well known to engineers was long understood by the Asiatics, who use bamboos for building purposes.

Of economic plants in the garden there seems almost no end. The balmy breezes of Ceylon may v/ell be spice-laden. Ceylon cinnamon is known the world over. The various peppers, as black pepper, long pepper, betel pepper, are woody climbers. A handsome grove of nutmeg trees is planted near the entrance—the trees about seventy years old. On the ground under the trees may be found the seeds, i. e., the nutmegs, and around them a covering, the aril of the botanist, which forms the spice known as mace. Clove trees may be seen also; it is the young flower buds of the tree which are dried to make the cloves of commerce. In the garden one may see the plants which furnish vanilla, citronella oil, tea, indigo, pineapple, ramie, sisal hemp and sago. Almost countless trees there are of economic importance. A few may be named, as those which furnish coffee, chocolate, cola, cocoanut, Brazil nut, camphor, rubber, gamboge and other tropical products.

In speaking of economic plants mention must be made of the experiment station which is really a part of the garden, although situated across the river. As a matter of fact nearly all the world lies across the river from the Peradeniya gardens, as these are situated in a bend of the stream which flows first north, then west, then south