Page:Popular Science Monthly Volume 60.djvu/406

398 and uppermost of all the leaves—and ends its life as the lowest in the cluster. The shape and size of the cluster of leaves vary somewhat with the age of the tree, but some species differ greatly from others in this respect. Species like the assai, the palmito and the royal palm have long petioles folding completely around the trunk, and shed the lowest leaves as fast as these leaves pass maturity. The clusters of fronds upon palms of this kind are always fresh looking, for they never have dead fronds dangling against their trunks. (See Fig. 1.) Certain other species have the habit of retaining the dead or half-dead fronds for a certain length of time, and these fronds, as they get older, bend downward more and more until they lie against the trunk of the tree. Such palms have nearly round clusters of fronds. The great forests of carnaúba or carandá palms along the Paraguay river look like forests of gigantic clover blossoms growing on straight stems.

The fronds of palms are extensively used by the lower classes in the tropical parts of South America for thatching their houses. Along the seashores, where the coco palms are grown, the leaves are cut as regularly as the nuts, and are used for covering the roofs and often for making the walls of the humble homes of the fishermen. In the Amazonas valley the entire leaves of the ubussú are best adapted to thatching; for this purpose they are frequently carried a hundred miles or more in canoes.

The young leaflets of palms are widely used in the manufacture of certain kinds of cheap straw hats. The leaflets of the tucúm palm yield an excellent fiber—one of the strongest known.

On account of certain peculiarities of its leaves I may here mention the jacitára (Desmoncus), the long, slender, clambering or sprawling palm already spoken of. The jacitára is not precisely a climbing palm but it comes as near to it as a palm can come. Its full-grown stem is hardly larger than a lead pencil but it reaches a length of a hundred feet or more, and it is therefore impossible for it to stand upright. Shortly after it starts from the ground it topples over and rests against whatever happens to be at hand. It has no tendrils and does not wind about its supports, but the structure and habits of its fronds contribute effectively to its ability to support itself against or upon its neighbors.

The accompanying illustration (Fig. 14) shows the growing end of one of these clambering palms, and beside it is shown the structure of the tips of the fronds. The recurved hooks at the frond tip are quite stiff and are fastened to the midrib with thickened inflexible joints. In the unopened or embryonic fronds the leaflets all point forward toward the tip or external end of the leaf. At the end of these undeveloped leaves are three or four pairs of leaflets, which, like all the rest, point forward. When the frond unfolds, the terminal