THE PLANT AND ITS ENEMIES 95 



number of plants which bear a fair similarity to 

 the true Nettle, such as the Red and the Yellow 

 Nettle, the Betony, the Gipsywort. One can 

 scarcely think that it is entirely chance which 

 has ordered this remarkable repetition of one 

 suggestive form. 



Whether anything which may be called pro- 

 tective resemblance exists among plants is at 

 present an open question, but certain succulent 

 species are very curious in this connection. The 

 most striking of these plants is Mesembryanthemum 

 tnmcatum, a South African species which flourishes 

 in desert regions. The whole of this quaint 

 vegetable consists of succulent shoots which grow 

 close to the ground, and these so strongly re- 

 semble the stones among which they nestle as to be 

 most perfectly hidden. Even after a close exam- 

 ination it is impossible to distinguish the plant 

 from the stones. Several allied species are also 

 remarkable on account of their rock-like appear- 

 ance, which, whether it be accidental or not, can 

 hardly fail to cause the plants to be overlooked 

 time and again. A few of the Cacti may also be 

 said to bear a strange resemblance to their 

 environment, most striking of all in this direction 

 being the Cereus monstruosus. This plant, which 

 produces oddly-shaped stems, is coloured in such 



