Finally stems, leaves, and all are pressed into a dense hard convex mass, making, in the case of _Raoulia eximia_, an excellent and appropriate seat for a tired botanist. Within the plant is a peat made of rotting leaves and branches, which holds water like a sponge, and into which the final branchlets send roots. Thus the plant lives in great measure on its own decay, and the woody main root serves chiefly as an anchor. The vegetable sheep are not inaptly named, for at a distance a shepherd might be misled.” The genus _Raoulia_ belongs to the daisy family, and furnishes another illustration of the remarkable diversity of this largest and probably most recent of the families of flowering plants, which appears to have originated in the Andes and now covers the world. In Damaraland, Southwest Africa, the most remarkable desert plant was discovered years ago, growing in a sandy and stony plain where the rainfall for fourteen years has not averaged more than two and a quarter inches annually. There are sea fogs, however, upon the condensation of which upon sheets of glass the discoverers of _Welwitschia mirabilis_ relied for some of their scanty water supply. The plant, whose woody stem is deep buried in the ground with only the top appearing above the surface, looks not unlike “the burnt crust of a loaf of bread.” To this only two large leaves are attached. These are many feet long and split into several sections which undulate over the ground very like the tentacles of an octopus. With such strange products of the desert scattered over the plains it is little wonder that _Welwitschia_ caused a sensation only equaled by the discovery of _Rafflesia_ in the rain forest of Sumatra. While deserts seem to be the most unfavorable places in which plants can exist, and their very existence in many deserts is often a precarious affair, it should be kept in mind that the soil of such places is often by no means sterile. As we found in the section of this book on “How Plants Get Their Food,” water is absolutely necessary for the absorption of food through the root hairs. Where, as in an oasis in the desert, water is locally plentiful a luxuriant vegetation springs up, and one of the most fertile parts of our Southwest was transformed from a desert by irrigation. Then, too, in many deserts there is a pronounced rainy season during which there is a marvelous development of showy flowering herbs that die down as rain ceases or becomes too slight, to wait for another opportunity to make the desert blossom into often gorgeous coloring.