The fact that you can get a drink in this way, just when you want it most, all comes of foresight on the part of the cactus. After they get down from two to four inches in the ground the roots of this cactus spread out in every direction and for a long way. They collect every bit of moisture in the soil, and they make the most of every drop of rain that falls within their reach. Then they hide all this moisture away and cling to every precious drop. Most plants, you know, evaporate a great deal of water through their leaves. But the cactus, living in a world where rains are few and far between, just can't afford to do any evaporating to speak of; so it has practically no leaves, you see, only little bits of things that you almost have to take a microscope to find. But what it lacks in leaves it makes up in spines, which defend it against the attacks of most thirsty animals, although it is believed the desert mice know the secret of getting at this water, in spite of the spines. One kind of desert plant you have no doubt met face to face, for it is used to make printing paper. It grows in the deserts of Libya and other parts of North Africa, and is called esparto grass. Like hemp, it has stems which are full of strong fibres. These stems are gathered in huge bundles, which are carried by camels to the sea, where they are sent by ship to the English paper mills. HOW THE "ROSE OF JERICHO" GOES TO SEA But there is a member of the desert plant family called the "Rose of Jericho," that doesn't wait for anybody to come after it and carry it to sea; it just picks up and sets sail for itself. It is a bush about six inches high, a native of the wastes of Northern Africa, Palestine, and Arabia. It bears a little four-petaled flower. When blossom time is over the leaves fall off and its branches, loaded with seeds, dry up, and, curling inward as they dry, form a ball. Its roots also let go of the soil, so that the strong desert winds easily pull it up and it goes bowling away toward the sea. When it gets there it tumbles in. [Illustration: THE CACTUS-WREN AND HER LITTLE FRONT DOOR Speaking of cactus spines, do you know how many of those wicked little spines the cactus-wren had to work with and tug and twist about in building that nest? About two thousand! These spines not only make the nest but defend it. You can't be too careful about your front door in Desertland. Such neighbors! ] Then this bold little traveller, who is very sensitive to moisture although he has had so little of it in his bringing up, promptly unfolds his arms and scatters his handful of seeds on the water; which is precisely the thing he took all that journey to do! For the seeds are carried far by the currents of the sea. Thus the family to which this plant belongs keeps sending out colonies into new lands. This seems to be one of the chief missions in life of plants as of other peoples.