i62 COLIN CLOUT'S CALENDAR. 



.-',11 our principal grains and food-stuffs. The reason is 

 that the crucifcrs have never learned to lay up a separate 

 store of albumen beside the seed-leaves of their embryo, 

 nor even to fill the seed-leaves themselves with starches 

 to maintain the young plant in the earlier stages of its 

 stru<Tn-linfr existence. On the other hand, those cabbage- 

 worts which deviate slightly from the central charlock- 

 type may be utilised in certain other ways, in accordance 

 with the nature of the deviation. Here, for example, 

 growing on the edge of the turnip-field, is the undoubted 

 wild ancestor of the turnips themselves— the meadow 

 navew. Its leaves are still rough and hairy, so we can 

 do little with them in the way of greens, though when 

 young and tender they are not unpleasant, with their 

 slightly bitter spinach flavour : but its root is larger and 

 rounder than that of the charlock ; and here the primi- 

 tive husbandman shrewdly saw his practical chance of 

 an edible vegetable. By neglecting leaves or seeds, and 

 selecting the most favourable variations in the root, he 

 at last succeeded in producing a modified turnip, from 

 which later agriculturists have again developed the still 

 larger, coarser, and rounder swedes. Moreover, though 

 the seeds are but small and poor, they contain a con- 

 siderable proportion of oil ; and by concentrating atten- 

 tion on this peculiarity, to the neglect of all others, we 

 have managed also to evolve independently from the 

 same parent stock another variety, the rape-seed, from 

 which we express colza oil. Each of these plants re- 

 mains exactly alike in foliage and flowers, because we 

 have expended no selective action upon those points ; 

 but in the parts on which selection has been definitely 

 exercised they differ widely from one another, and from 



