encountered. The causes of these
phenomena well merit the investigation of meteorologists.

The aspect of the Puna is singularly monotonous and dreary. The
expansive levels are scantily covered with grasses of a yellowish-brown
hue, and are never enlivened by fresh-looking verdure. Here and there,
at distant intervals, may be seen a few stunted Quenua trees
(_Polylepis racemosa_, R. P.), or large patches of ground covered with
the Ratanhia shrub[66] (_Krameria triandria_, R. P.). Both are used by
the Indians as fuel, and for roofing their huts.

The cold climate and sterile soil of the Puna are formidable impediments
to agriculture. Only one plant is cultivated in these regions with any
degree of success. It is the _maca_, a tuberous root grown like the
potatoe, and like it used as an article of food. In many of the Puna
districts the maca constitutes the principal sustenance of the
inhabitants. It has an agreeable, and somewhat sweetish flavor, and when
boiled in milk it tastes like the chestnut. As far as I am aware this
plant has not been mentioned by any traveller, nor has its botanical
character yet been precisely determined. Possibly it is a species of
Tropaeolum, but of this I am uncertain. The root is about the size of a
large chestnut. Macas may be kept for more than a year, if, after being
taken from the earth, they are left a few days to dry in the sun, and
then exposed to the cold. By this means they become shrivelled and very
hard. From these dried macas, the Indians prepare a sort of soup or
rather syrup, which diffuses a sweet, sickly sort of odor, but which,
when eaten with roasted maize, is not altogether unpalatable. The maca
thrives best at the height of between 12,000 and 13,000 feet above the
sea. In the lower districts it is not planted, for the Indians declare
it to be flavorless when grown there. Besides the maca barley is reared
in the Puna. I saw there fields of barley 13,200 feet above the sea. It
does not, however, attain full maturity, seldom even shoots into ears,
and is cut whilst green as fodder for horses.

But poor and scanty as is the vegetation of the Puna, the animal
kingdom is there richly and beautifully represented. Those regions are
the native home of the great Mammalia, which Peru possessed before
horses and black cattle were introduced by the Spaniards. I allude to
the llama and his co-genera the alpaco, the huanacu, and the vicuna.
On these interesting animals I will subjoi