The cold climate of the Puna naturally confines agriculture to very narrow limits. The only cultivated plant which grows to maturity is the Maca (a species of tropæolum), the tuberous roots of which are used like the potato, and form in many parts the chief food of the inhabitants. This plant grows best at an elevation of twelve or thirteen thousand feet, and is not planted in the lower regions, where its roots are said to be completely unpalatable. Barley is also cultivated in the Puna, but never ripens, and is cut green for forage. The animal kingdom is more amply represented; for there is no want of food on the grass-covered plains, and wherever this exists, there is room for the development of animals appropriate to the climate. [Illustration: THE LLAMA.] Thus the Llama and its near relations, the _Alpaca_, the _Huanacu_, and the _Vicuña_, the largest four-footed animals which Peru possessed before the Spaniards introduced the horse and the ox, are all natives of the Puna. Long before the invasion of Pizarro, the llama was used by the ancient Peruvians as a beast of burthen, and was not less serviceable to them than the camel to the Arabs of the desert. The wool served for the fabrication of a coarse cloth; the milk and flesh, as food; the skin, as a warm covering or mantle; and without the assistance of the llama, it would have been impossible for the Indians to transport goods or provisions over the high table-lands of the Andes, or for the Incas to have founded and maintained their vast empire. The llama is also historically remarkable as being the only animal domesticated by the aboriginal Americans. The reindeer of the north[4] and the bison of the prairies enjoyed then, as they do now, their savage independence: the llama alone was obliged to submit to the yoke of man. But the llama reminds us of the dromedary not only by a similar destiny and similar services, but also by a strong resemblance in form and structure, so as to be classed by naturalists in the same family. The unsightly hump is wanting, but the llama possesses the same callosities on the breast and on the knees, the same divided hoof and a similar formation of the toes and stomach. Thus Nature has formed in the llama a species of mountain camel, admirably adapted to the exigencies of a totally different soil and climate; and surely it is not one of the least wonders of creation to see animals so similar in many respects emerge, without any connecting links, at the opposite extremities of the globe.