PROTECTION OF THE POLLEN. 195 



duced in Sweden when the flowering season has been 

 wet. The same great observer also remarks, what 

 yearly experience confirms, that Cherry-trees are more 

 certainly fruitful than Pear-trees, because in the for- 

 mer the opening of the anthers is, in each blossom, 

 much more progressive, so that a longer period elapses 

 for the accomplishment of the fertilization of the ger- 

 men, and there is consequently less chance of its being 

 hindered by a few showers. 



To guard against the hurtful influence of nocturnal 

 dews or drenching rains, most flowers either fold their 

 petals together, or hang down their heads, when the sun 

 does not shine ; by which, their internal organs are 

 sheltered. In some which always droop, as the Snow- 

 drops, the Fritillary, the Crown Imperial, various spe- 

 cies of Campanula, and others, while the over-shad- 

 owing corolla keeps off rain, the air has free access 

 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 v--ry same stalk. The papilionace- 

 ous flowers in general spread their wings in fine weath- 

 er, admitting the sun and air to the parts within, where- 

 as 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. The 

 common Bindweed, as well as the Anagallis arvensis, 

 and many others, are well known to shut up their flow- 

 ers against the approach of rain ; whence the Anugal- 

 lish-AS been called the Poor Man's Weather-glass. It 

 has been obseived by Linnieus that flowers lose this 

 fine sensibility, either after the anthers have perform- 

 ed their office, or when deprived of them artificially ; 

 nor do I doubt the fact. I have had rea.. on to think that, 



