CHAP. VI.J CABBAGE. 129 



crops for several years in succession, without 

 manuring, or at least without renewing the soil. 

 This is called the rotation of crops ; and in fix- 

 ing the order of this rotation, plants differing 

 as much as possible in their habits should be 

 chosen to succeed each other; as, for example, 

 onions may be succeeded by lettuces, carrots 

 by peas, potatoes by cabbages, turnips by spi- 

 nach, &c. 



The Cabbage Tribe. — Few persons unac- 

 quainted with botany will be able to believe 

 that broccoli, cauliflowers, cabbages, Scotch or 

 German greens, Brussels sprouts, and Savoys, 

 not only all belong to one genus, but are ac- 

 tually varieties of one species of a genus, viz. 

 Brassica oleracea ; and that the turnip, the 

 Swedish turnip, and the rape (the seed of which 

 is used for oil), belong to other species of the 

 same genus. The cabbage, in its wild state, 

 is a biennial which grows naturally on the sea- 

 coast in different parts of England, and is a 

 tall straggling plant with loose leaves, and 

 rather pretty yellow cruciferous flowers. The 

 borecole, or kale, is the first improvement ef- 

 fected by cultivation ; and the cauliflower the 

 last. Indeed, it is impossible to imagine a 

 greater difference between any species and va- 

 riety, than exists between the cauliflower and 

 the original wild cabbage plant. All the va- 

 rieties of the cabbage tribe require a soil which 

 has been enriched w T ith abundance of animal 

 manure; and, when decaying;, they have alia 

 peculiarly offensive smell, like that of putrid 

 meat, from the large quantity of nitrogen that 

 they contain. 



K 



