1 88 Introduction to Botany. 



its long proboscis to the bottom of the tube and secures 

 the nectar ; and while it is tarrying briefly at each flower, 

 keeping itself poised by the swift vibration of its wings, it 

 is pretty certain to touch with its proboscis both anthers 

 and stigmas, which stand close together at about the same 

 height near the mouth of the corolla. Both cross and self 



Fig. 104. 



Sphinx moth and flower of Datura stramonium, posed to show the relative lengths 

 of the flower and of the moth's proboscis. Reduced rather more than one-half. 



pollination might be brought about in this way, but, as 

 Darwin has shown, the foreign pollen would probably 

 possess the greater potency, and cross fertilization would 

 be apt to result. Figure 104 is a photograph of a sphinx 

 moth and Datura flower, posed to show the relative lengths 

 of the moth's proboscis and the corolla tube. 



138. Cross Pollination of Salvia. — In the Salvias, or 

 sages, we find several contrivances working together for 

 a common end. The corolla is tubular below and two- 

 Hpped above, the lower lip serving as an alighting place 

 for bees, and the upper forming a protective covering for 

 the stamens and style. There are two stamens of peculiar 

 construction set one on either side of the mouth of the 



