A VERY INTELLIGENT PLANT 265 



doubt, from deer and wild oxen and beavers, but 

 later on from the sheep and cows and goats 

 and donkeys which followed in the wake of ag- 

 gressive civilisation. Under these circumstances, 

 most of the soft-leaved and unprotected plants 

 got eaten down and killed off ; but any shrub 

 which showed a nascent tendency to develop 

 stout spines or prickles on their branches must 

 have been favoured by nature in the struggle for 

 existence. The consequence was that in the 

 end our upland slopes and open spaces all over 

 Western Europe came to be occupied by nothing 

 but strongly armed plants brambles, thistles, 

 blackthorns, may-bushes, nettles, butcher's-broom, 

 and the various kinds of furze, all of which can 

 hold their own with ease against the attacks of 

 quadrupeds. Indeed, there is one not uncom- 

 mon English herb, the little purple-flowered rest- 

 harrow, which very well illustrates this curious 

 connection between the production of thorns 

 and the habit of growing in much - browsed- 

 over spots ; for when it settles in enclosed and 

 protected fields it produces smooth and unarmed 

 creeping branches, but when it happens to 

 find its lot cast in places where donkeys and 

 rabbits abound, it defends itself against the dreaded 

 enemy by covering its shoots with stout woody 

 prickles. 



Still, to the end of its days, the developed gorse 

 plant never entirely forgets that it is the remote 

 descendant of trefoil-bearing ancestors ; for not 

 only does every young gorse begin life with trefoil 



