CRUCIFER^. 37 



B. napus. L. Kale. Naturalized in a few places ; leaves 

 smooth, upper being heart-shaped and long, clasping. Native of 

 England and Holland. 



B. rapa. L, Turnip. Excellent as food for man and cattle ; 

 the several kinds are varieties. Cultivation has shown that new 

 land, or just cleared, is not essential to the production of the 

 finest turnips ; native of England. 



B. ruta-baga. Extensively cultivated as rich food for cattle, 

 being produced in great quantity compared with other articles 

 raised on equal land. It is commonly considered only a variety 

 of the following, but is made a variety of B. campestris by De 

 Candolle. 



B. oleracea. L. Cabbage, Broccoli, Cauliflower. Of too 

 much use not to be known. The varieties are many, and culti- 

 vated with considerable ease ; cabbage is, perhaps, the most 

 sure crop. Introduced from England. 



The introduction of the turnip into cultivation in England, is 

 the era from which their modern agriculture is dated. Its culture 

 deserves special attention. 



Cheiranthus. L. 14. 2. Wall Flower. 



Several species are cultivated in the gardens, or in pots, for 

 their flowers. Their beauty is too well known to need remark. 



The generic name is from the Arabic name for a plant with red 

 and sweet flowers. Loudon. 



Draba. L. 14. 1. 



D. verna. L. Whitlow Grass. Leaves radical, oblong, 

 acute, hairy ; flower-stem 2-3 inches high, ending in a raceme 

 of white flowers ; flowers in April and May, in the fields. 



Dentaria. L. 14. 2. Tooth-root, Pepper-root. 

 D. diphylla. Mx. Stem about a foot high, sends off 2 

 ternate leaves, and a raceme of white flowers ; grows in open 

 woods, and flowers in May. 



