LIFE HISTORIES OF FAMILIAR PLANTS 



supply of water. Fig. 97 shows them half an 

 hour later ; the mock orange is seen to have 

 almost half collapsed, owing to the evaporation of 

 water from its tissues. Fig. 98 depicts them again 

 six hours later. The orpine looks very much the 

 same as it did in Fig. 96 ; but the mock orange 

 presents a very different appearance. Finally, 

 Fig. 99 shows the branches twenty-six hours later. 

 The orpine is there seen just beginning to show 

 signs of exhaustion. However, it only needs a 

 little moisture quickly to regain its former appear- 

 ance : but as much could not be said of the mock 

 orange. 



It is obvious, from the experiment thus illus- 

 trated, how well equipped are these succulent 

 plants for growing in the dry and stony places 

 they inhabit ; hence, too, their popular name 

 ^^ stonecrops." These plants are the ^' cacti," as it 

 were, amongst British plants, our native " vegetable 

 camels " ; although they bear no relationship to 

 the true cacti, which are entirely exotic. How 

 very differently, though, do they conduct their 

 economy when compared with the desert-loving 

 cacti. Here we find httle or nothing in the way of 

 protective devices, such as irritating hairs and sharp 

 spines. 



Why are not these succulent plants likewise 

 protected ? The answer is, that in the clefts of 

 the high rocks and on walls, where the stonecrops 

 grow, the plants have had few or no dangerous 

 enemies to contend with in their habitat. Also, as 

 they chiefly throw up their branches in the 



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