LIFE HISTORIES OF FAMILIAR PLANTS 



circumstances are favourable. Now I will ask you 

 to look at Figs. 46, 47, and 48 (Plates 29, 30, and 

 31); I may inform you that the movements 

 exhibited from Fig. 45 to Fig. 48 occurred in 

 about one second. The photograph, Fig. 45, hav- 

 ing been taken, a slight breath of air through the 

 lips was blown at the plant. The results depicted 

 in Figs. 46, 47, and 48, therefore, were brought about 

 entirely without touching the plant or even shak- 

 ing the pot — simply by blowing upon it slightly. 



Now, when upon our approach to a plant it 

 suddenly folds up its leaves and assumes an alto- 

 gether different attitude we very naturally ask, in 

 wonder, why it acted so. Of course, in the case 

 of our "woolly bear" caterpillar, and also our 

 hedgehog, it was obvious that they derived pro- 

 tective advantages from their movements ; but 

 what practical use can this strange manoeuvre of 

 the sensitive plant serve in its economy ? 



Well, when a plant, without the slightest 

 warning, closes together its leaflets and, as it were, 

 " shuts up shop " in this summary fashion, we are 

 naturally rather startled by the performance, and 

 wonder what will happen next ; and any grazing 

 animal would have the same feeling. In tropical 

 countries where such sensitive plants are found 

 they frequently cover large tracts of land, and 

 wandering, grazing animals come upon them ; 

 indeed, may be often attracted towards them by 

 their bright green foliage. But what happens ? 

 The very first plants an animal approaches droop 

 their tempting leaves, sensitive even to the 



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