Also bears tubers; the D, Spore showing the two spiral vegetative shoots have bands of the perinium.
The tubers of Ipomaea Batatas are rich in starch and sugar, and, as the "sweet potato," form one of the most widely distributed foods in the warmer parts of the earth.
The large tubers are often gashed to cause them to dry more quickly.
Jalap has been cultivated for many years in India, chiefly at Ootacamund, and grows there as easily as a yam, often producing clusters of tubers weighing over 9 lb; but these, as they differ in appearance from the commercial article, have not as yet obtained a place in the English market.
All plant life has a remarkably large proportion of subterranean growth, because of the necessity of getting moisture from the earth and not from the air; hence roots and tubers are unusually well developed.