CAPRIFOLIACEAE 



531 



7 and 8 p. m. : the filaments have meanwhile curved downwards, and their anthers 

 shrivelled so much as to look like little withered hooks. 



The flower has now reached its second, purely female, stage. The style 

 projects forwards above the stamens, which, as already stated, are now curved 

 downwards, and its tip has bent a little upwards. It follows that the stigma now 

 dominates the entrance to the flower (Fig. 175, 3), and a visiting hawk-moth is 

 sure to touch it with the under-side of its body, effecting cross-pollination if 

 a flower in the first stage has previously been visited. 



In the course of the day several other changes have taken place. The 

 upper- and under-lips have rolled up more or less, so that the surface. rendering 

 the flower conspicuous has become increasingly smaller. At the same time there 



1 



FjG. 175. Lonicera Periclymenmn, L. (from nature; X i). (i) Bud shortly before opening: the 

 stigma is already mature, and the stamens have dehisced, but automatic self-pollination is prevented by the 

 erect position and the greater length of the style. (2) Flower on the 6rst evening: the pollen-covered 

 anthers are in front of its entrance, the style is bent downwards so much that the stigma is not liable to be 

 touched by hawk-moths: the upper- and under-lips are but slightly cur\'ed, and are white in colour. 

 (3) Ditto, on the second evening, the style has curved upwards so much that the stigma is in front of the 

 entrance to the flower ; on the other hand, the stamens have curved downwards and the anthers are 

 shrivelled ; the upper- and under-lips are rolled back so as to occupy less space, and have become yellow, 

 a, anther; j, stigma. 



has been a gradual change of colour, the corolla, originally white inside and red 

 outside, being now bright yellow. This change is completed by the evening, so 

 that just before the fresh buds open there are no more pure white flowers to 

 be seen. 



The meaning of these facts in relation to pollination is obvious. Hawk-moths 

 are attracted from a distance by the fragrance of the flowers, when nearer by the 

 conspicuous inflorescences, and when quite close by the more clearly visible blossoms, 

 i. e. the brighter and larger red-and-white ones in the first stage. The moths there- 

 fore visit these first, and afterwards go to the duller yellow flowers in the second 

 stage, which are also smaller, owing to the rolling up of the ends of the petals. 

 The pollen of the former is thus transferred to the latter. Although the two stages 

 are so sharply outlined against the clear evening sky that it is possible to distinguish 

 them at once, yet I was not able to confirm the above explanation by direct 

 observation, for the movements of the hawk-moths which visit the flowers (Sphinx 

 ligustri Z., and S. convolvuli Z.) are so extremely rapid, and their approach is 



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