THE STOCK AND CABBAGE FAMILY. 91 



separate from the frame-like placentas (7 and 8) ; (7) 

 shows the seeds attached to them in four rows, two 

 rows being on each side ; (8) is the same with the 

 seeds removed ; (9) is a ripe seed \ (10) is a vertical 

 section, showing the embryo, the radicle being on the 

 right and the cotyledoiis on the left ; (11) is a seed cut 

 across or transversely, (a) being the radicle and (b, h) 

 the cotyledons. 



The radicle is not a true root, but develops a 

 root from its tip, and from it arises the first stem ^ 

 above upwards. The two cotyledons are really the 

 first pair of leaves, but only turn green when they 

 come up into the light, as of mustard and cress when 

 fit to eat. Between the two cotyledons is a minute 

 bud, which will in time grow up into the new plant. 



Such vegetables as all sorts of cabbages and kales, 

 the radish, turnip, etc., of this family, show how plants 

 change under cultivation, for they are all raised from 

 seed of wild plants, the roots of which are small, tough, 

 and wiry, but as soon as they grow in a rich soil, they 

 begin to get larger and " fleshy." Then by taking the 

 seed from those which have the best roots, i.c, " select- 

 ing" for about six years, fine garden vegetables are 

 secured, the seed always reproducing the good root, or 

 whatever it is that has been turned into a garden 

 crop. 



^ The first stem is called the Hypocotyl, i.e. " below the cotyledons." 

 If the plumule forms the stem, it is called the Eincotyl. 



