HARMONIES OF VEGETATION. 269 



fecundation, there are others which are equally in- 

 tended for an opposite purpose. 



Though the greatest number of flowers are withdrawn from the 

 too violent action of the sun, there are others which like to ap- 

 pear in all the splendour of his rays. In these cases, the colour 

 will be found of a darker hue, either generally or only in the 

 centre of the flower, which, instead of reflecting heat, has the con- 

 trary action of absorbing it. 



15. Nature, we have already intimated, has given 

 curves to most flowers, in order to collect the heat at 

 the centre ; but she likewise employs the same curves 

 when she pleases, to dissipate it, and places their focusses 

 externally. 



It is thus that she has disposed the petals of the lily, which are so 

 many sections of a parabola. Notwithstanding the large size and 

 whiteness of its cup, the more it is expanded, the more it disperses 

 the heat of the sun; and while at midsummer, all other flowers, 

 scorched by his noon-tide rays, either close or incline towards the 

 ground, the lily, rearing its head like a king, contemplates face to 

 face, the luminary that blazes aloft in the heavens. 



16. There are flowers, such as the compound, which, 

 being in a horizontal situation, and completely exposed, 

 behold the sun, like the horizon itself, from his rising to 

 his setting. 



The common dandelion is a flower of this kind, but it possesses a 

 very extraordinary method of sheltering itself from heat ; it closes 

 whenever it becomes too powerful. It has been observed, that it 

 opens in summer at half past five in the morning, and contracts its 

 petals towards the centre at nine. The flower of the lettuce, which 

 on the contrary, is on a vertical plane, opens at seven and shuts at 

 ten. The sunflower of our gardens is said to meet the sun at its 

 rising, to follow it in its coarse, and to cherish its setting rays ; 



