46 POLYNESIAN RESEARCHES. 
sprouts uppermost, a small portion of dried leaves 
is laid upon each, and the whole lightly covered 
with mould. When the roots begin to swell, the 
cultivators watch their enlargement, and keep 
them covered with light rich earth, which is gene¬ 
rally spread over them about an inch in thickness. 
The yam is one of the best flavoured and most 
nutritive roots which the islands produce. The 
natives usually bake them; they are, however, 
equally good when boiled; and, as they may be 
preserved longer out of the ground than any other, 
they are the most valuable sea-stock to be pro¬ 
cured ; and it is to be regretted that they are not 
more generally cultivated. Few are reared in the 
Georgian Islands; more perhaps in the Society 
cluster; but Sir Charles Sanders’ Island is more 
celebrated for its yams than any other of the 
group. 
The umara, or sweet potato, convolvulus bata- 
tus , or chrysorizus , is grown by the natives as an 
article of food. The richest black mould is chosen 
for its culture ; and the earth is raised in mounds 
nine or ten feet in diameter, and about three feet 
high. They do not plant the roots ; but in the 
top of these mounds insert a small bunch of the 
vines, which germinating, produce the tuberous 
roots eaten by the natives. In the Sandwich 
Islands, the sweet potato is one of the principal 
means of subsistence; here it is only partially 
cultivated, and is greatly inferior to those grown 
in the northern islands, probably from the differ¬ 
ence of soil and climate. The roots are large, and 
covered with a thin smooth skin. In size, shape, 
and structure, they resemble several kinds of the 
Irish potato. The umara is very sweet, seldom 
mealy, and sometimes quite soft, but altogether 
