44() CHARACTER OF VEGETABLE VITALITY. CHAP. XT. 



. the day. It has been observed also, that the flowers 

 of plants that are removed from a warmer to a 

 colder climate expand at a later hour in the latter. 

 A flower that opens at six o'clock in the morning at 

 Senegal, will not open in France or England till 

 eight or nine ; nor in Sweden till ten. A flower 

 that opens at ten o'clock at Senegal will not open 

 in France or England till noon or later, and in 

 Sweden it will not open at all. And a flower that 

 does not open till noon or later at Senegal, will not 

 open at all in France or England. This seems as if 

 heat or its absence were also an agent in the open- 

 ing and shutting of flowers ; though the opening of 

 such as blow only in the night cannot be attributed 

 either to light or heat. 

 Vegetable But the opening or shutting of some flowers 



weather- 

 glass, depends not so much on the action or the 



stimulus of light as on the existing state of the at- 

 mosphere, and hence their opening or shutting 

 betokens change. If the Siberian Sowthistle shuts 

 at night, the ensuing day will be fine; and if it opens, 

 it will be cloudy and rainy. If the African Mari- 

 gold contines shut after seven o'clock in the morn- 

 ing, rain is near at hand. And if the Convolvulus 

 arvensis, Calendula jluvialis, or Anagallis arvemis, 

 are even already open, they will shut upon the ap- 

 proach of rain, the last of which from its peculiar 

 susceptibility has obtained the name of the Poor 

 Man's Weather-glass. 

 Nutation. But some flowers not only expand during the 



