200 
ON ESCULENT ROOTS. 
Yam.. 
. --^^S^ 
-Dioscorea sativa. 
treated like the common potato. In favourable seasons a tolerable crop is pro- 
duced ; and hopes are entertained that, in the course of some years the batata will be 
so far acclimatised as to be the object of successful field culture in the south of France. 
The Yam, Dioscorea sativa^ is a native 
of the east ; and is supposed to have been 
transplanted thence to the West Indies, as 
it has never been found growing- wild in 
any part of America ; while in the island 
of Ceylon, and on the coast of Malabar, it 
flourishes in the woods with spontaneous 
and luxuriant growth. It is very exten- 
sively cultivated in Africa, Asia, and 
America, for its root, which is nutritious 
and of good flavour, and is used either 
roasted or boiled as a substitute for bread. 
This root is farinaceous, and resembles the 
potato, but is of a closer texture. 
Some yams were first brought into this 
country from the West Indies, in 1733; and 
they are now occasionally imported, more, 
however, as an article of curiosity than of 
commerce. 
The yam is a climbing plant with tender stalks, of from eighteen to twenty feet in 
length ; it has smooth, sharp-pointed leaves, on long footstalks, from the base of which 
arise spikes of small flowers. The root is flat and palmated, about a foot in breadth, 
white within, and externally of a dark brown colour, almost approaching to black. 
The Winged Yam, Bios- ^^g- ^• 
corea alafa, is another species 
very generally cultivated : its 
roots attain to a larger size, 
being frequently about three 
feet long, and weighing about 
thirty pounds. Both these kinds 
are cultivated like the common 
potato. They are usually 
planted in August, and are fit 
for use in the November and 
December following. Brown * 
directs that the roots for plant- 
ing should be cut so as to leave 
a small portion of skin to each 
piece ; " for by that alone," he 
affirms," they germinate, the 
roots having no apparent buds or eyes, but casting out their weakly stems from 
every part of the surftice alike." 
* History of Jamaica. 
Different sorts of Yam root. 
