THE FLOWER 243 



for insects ; the lower lip serves as a platform or 

 balcony, on which the insect alights when in the 

 act of passing its proboscis into the tube of the 

 corolla at the bottom of which the sugary nectar 

 lies. But in doing so it rubs its back against the an- 

 thers (fig. 69, I and 2 m), and when it alights upon 

 another flower it rubs its back covered with pollen 

 against the stigma (p). Self-pollination is quite im- 

 possible in this case, because the stigma develops later 

 than the stamens of the same flower, and it can 

 receive pollen only from another flower. In another 

 labiate flower, the common sage, the following curious 

 adaptation is found (the sage flower is shown in fig. 

 69). The stamens are of an unusual form, having the 

 anthers fixed to the top of a long cross-piece, which is 

 balanced on a short stalk (in fig. 69, i, a flower is shown 

 split longitudinally, with one stamen (m) ; in fig. 69, 3 

 the two stamens are shown separately) . The lower ends 

 of these cross-pieces bar the entrance to the tube of the 

 corolla, at the bottom of which, as has been already said, 

 there Hes some sugary liquid. The moment the insect 

 pushes its proboscis into the tube, it sets in motion these 

 lower ends of the cross-pieces, which like levers come 

 into position 4 from position 3 (fig. 69) . At the same 

 time the anthers descend on the back of the insect (fig. 

 69, 2 m) and cover it with pollen. 



Another still more striking method of pollination is 

 found among the orchids, where in most cases pollination 

 would be almost impossible without the agency of insects, 

 and the flowers would be doomed to continual sterility. 

 The flowers of this family are distinguished by their fan- 

 tastic shapes, for which they are so commonly grown in 

 hot-houses. It may be sufficient to mention among the 

 wild representatives of the group the butterfly orchis 

 (Platanthera) . Let us imagine such a flower with all its 

 petals torn ofi^, with the exception of the lowest which is 

 in the shape of a lip and is elongated at the base into 



