GRASSES, GRAINS, AND PLANTS. 583 



turies it has literally overspread the earth, and at the present 

 day is found growing from the Cape of Good Hope to Iceland 

 and Lapland. 



The egg-plant, the tomato, and the red pepper are esculents ; 

 and deadly nightshade, a well-known medicine, belongs to the 

 same family. The bittersweet of our own woods and fences 

 may be mentioned as the type in the Northern United States. 



The plant may be propagated by seed, in which case a vast 

 number of new varieties is originated ; or by the tubers, which 

 contain buds or germs from each of which a stem will arise, and 

 the variety continue constant. The germ will grow equally 

 well if severed from the tuber, retaining merely a small frag- 

 ment of the skin and substance ; and it submits to desiccation 

 by a hot stove without losing vitality. 



It has long been a disputed point whether it were better to 

 plant the entire tuber, or to cut it up into fragments, but no 

 accurate decision seems to have been arrived at. In conse- 

 quence, we may conclude that the practical difference is very 

 small. General custom leans towards the latter plan. It has 

 been observed that "eyes" or "germs" taken from the tubers 

 that have not been fully ripened, are more vigorous than those 

 that have been taken from such as have been very fully ripened. 

 This leads to a rule in practice, that the tubers to be planted 

 shall be those which were taken up before the stems had begun 

 to decay in autumn. 



The number of varieties is very great, and always increasing. 

 The chief distinction is that of early and late kinds. 



The peculiar characteristic of this root is the quantity of 

 starch that it contains, in combination with much water and 

 potash in its ash. The quantity of dry solid matter depends 

 much upon the state of ripeness to which it has attained. The 

 ripest leave 30 to 32 per cent of dry matter, the least ripe only 

 24 per cent. The quantity of starch varies according to variety, 

 from i of to 32 per cent ; and, according to Liebig, in the wild 

 state, this root is almost destitute of nourishing constituents. 

 Since the rot has prevailed, potatoes appear to have lost much 

 of the starch they previously possessed. The crop, also, other 

 things being equal, varies in the weight per acre, according to 

 variety, more than perhaps any other cultivated plant. The 



