PROTECTION OF THE POLLEN, 32$ 



panula, and others, while the over-shad ow- 

 ing corolla keeps off rain, the air has free ac- 

 cess underneath to blow the pollen to the 

 stigma. Nor is this drooping caused by the 

 weight of the flowers, for the fruit in most 

 of them is much heavier, and yet stands 

 erect on the very same stalk. The papi- 

 lionaceous flowers in general spread their 

 wings in fine weather, admitting the sun and 

 air to the parts within ; whereas many of 

 them not only close their petals at night, but 

 also derive additional protection from the 

 green leaves of the plant folding closely about 

 them. Convolvulus arvensis, t. 312, Ana- 

 gallis arvensh, t* 529, Calendula pluvialis, 

 and many others, are well known to shut iu> 

 their flowers against the approach of rain; 

 whence the AnagalUs has been called the 

 Poor Man's Weather-glass. It has been ob- 

 served by Linnaeus that flowers lose this fine 

 sensibility, either after the anthers have per- 

 formed their office, or when deprived of them 

 artificially ; nor do I doubt the fact. I have 

 had reason to think that, during a long con- 

 tinuance of wet, the sensibility of the Ana- 

 gallis is sometimes exhausted ; and it is evi- 



