28 SOUTH AFRICAN FLOWERING PLANTS. 



and as the pivot is not in the middle of the rod, 

 but much nearer the lower end, if you touch the 

 spoon-like, empty anther-cells and force them down- 

 wards a little way, the two upper anther-cells will 

 swing down a very long way, as shown by their 

 positions at the end of the dotted lines in Fig. 

 15 (L). 



This is exactly what a bee does. It alights on 

 the lip, puts its head down to reach the honey at the 

 bottom of the tube of the corolla, depresses the lower 

 anther-cells, and the upper ones filled with pollen 

 come down and strike the bee on the back, giving 

 it a shower of pollen in so doing (II.). 



On its retiring the anthers swing back again into 

 the place under the hood. 



Then the forked stigma projecting forwards is 

 pretty sure to hit the bee just where it has received 

 the pollen from some other flower. 



In the Desert near Cairo there are some Salvias, 

 but as there are very few insects, the Salvias have 

 learnt to do without them, for the two stigmas have 

 grown very long, and curl backwards till they are 

 touching the anthers, which thus pollinate them at 

 once. This is called '* self-fertilization," of which I 

 shall say more presently. 



The common yellow - flowered Oxalis ccr'nua 

 described in the introduction is remarkable for having 

 three kinds of flowers. Though the corollas are the 



