year of their being planted.  The first indication 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, was 700 bushels; that of the common potato exported from the United States, 1820-21, 90,889,000 bushels; in 1830-31, 112,875,000 bushels; in 1840-41, 136,095,000 bushels; in 1850-51, 106,342,000 bushels.