322 FREAKS OF PLANT LIFE. 



be our purpose to indicate such examples as have 

 come to our knowledge, but rather as a record of 

 facts than with any design to theorise about them. 

 In animals it has been contended that the resem- 

 blances are acquired by natural selection and the 

 survival of the fittest, such resemblances being for 

 the benefit of the organisms which acquire them. 

 The data are at present insufficient to apply such a 

 theory to plants, but the instances are sometimes so 

 striking and curious that they could not be ignored 

 as remarkable phenomena in plant life. 



Of all known plants none are more weird and 

 singular than the Cacti, with their angular succulent 

 stems, armed with spines, and the absence of leaves. 

 In many instances the flowers are large, showy, and 

 beautiful. These plants are numerous in the hotter 

 and drier parts of America. " Sometimes globular, 

 sometimes articulated, sometimes rising in tall poly- 

 gonal columns, not unlike organ-pipes." Now and 

 then attaining a very gigantic size, occasionally so 

 small that " they get between the toes of dogs." In 

 the similarly dry and arid tracts of Africa these 

 plants are absent, but their place is occupied by 

 species of Euphorbia, which resemble in form and 

 habit the Cacti of America. In our woodcut (fig. 66) 

 is represented one of these Euphorbias, growing 

 amongst rocks at the Cape of Good Hope, which is 

 entirely dissimilar from our common wood spurge 



