n of it is the change
in the leaves, which gradually turn to a yellow hue, have a sickly
appearance, and at length drop off at the surface of the earth. The
stock or "coco head," as it is called, below ground, having become
rotten, nothing but a soft pulpy mass remains. In some fields every
third or fourth root is thus affected, in others much greater numbers
are destroyed, so much so that the field requires to be almost
entirely replanted, by which not only an expense is entailed, but a
heavy loss sustained, from the field being thrown out of its regular
bearing. The black coco seems to suffer less than the white.

Another species, the Taro (_Arum Colocasia_, _Colocasia esculenta_ and
_macrorhizon_), is an important esculent root in the Polynesian
islands. In the dry method of culture practised on the mountains of
Hawaii, the roots are protected by a covering of fern leaves. The
cultivation of taro is hardly a process of multiplication, for the
crown of the root is perpetually replanted. As the plant endures for a
series of years, the tuberous roots serve at some of the rocky groups
as a security against famine. It is also extensively cultivated in
Madeira and Zanzibar, and has even withstood the climate of New
Zealand. It is grown also in Egypt, Syria, and some of the adjacent
countries, for its esculent roots. A species is cultivated in the
Deccan, for the sake of the leaves, which form a substitute for
spinach. Farina is obtained from the root of _Arum Rumphii_ in
Polynesia.

SWEET POTATOES.

The batatas, or camote of the Spanish colonies (_Convolvulus batatas_,
Linn; _Batatas edulis_, of Choisy, and the _Ipomaea Batatas_ of other
botanists), belongs to a family of plants which has been split into
several genera. It is a native of the East Indies, and of
intertropical America, and was the "potato" of the old English writers
in the early part of the fourteenth century. It was doubtless
introduced into Carolina, Georgia, and Virginia soon after their
settlement by the Europeans, being mentioned as one of the cultivated
products of those colonies as early as the year 1648. It grows in
excessive abundance throughout the Southern States of America, and as
far north as New Jersey, and the southern part of Michigan. The
varieties cultivated there are the purple, the red, the yellow, and
the white, the former of which is confined to the South.

The amount of sweet potatoes exported from South Carolina in 1747-48,
wa