684 JOURXAL OF THE ROYAL HORTICULTURAL SOCIETY. 



being straight, have a right-angular bend, and their extremities tT\'isted 

 spirally. The pistil, which is included within them, has its style coiled 

 in a corresponding manner. Just below the stigma is a tuft of hair upon 

 the style. On looking at an expanded flower from the front it will be 

 noticed that the wing petal on the left is smaller than the one on the 

 right, and that the orifice of the spirally twisted end of the keel petals 

 projects over the left or smaller of the two wing petals. 



An insect, e.g. the hive bee, always alights upon the smaller wing 

 petal. The mngs have peculiar depressions upon their inner surface, 

 which catch hold of corresponding elevations on the exterior surface of 



Fig. 299.— Fruit of Stork's-bill {Erodium), showing 

 spirally twisted awn-like beak. (Phot, ad nat.) 



the keel. The result is that, by acting as the power of the lever, the 

 weight of the insect depresses the smaller petal ; the force is communi- 

 cated by the grip-like action of this petal to the spiral keel, which, by 

 being dragged downwards, causes the spirally twisted style to pass up the 

 hollow coil, so that the stigma now protrudes out of the orifice of the 

 snail-shell " shaped extremity of the keel. The tuft of hair on the 

 style sweeps the pollen from the cluster of anther-cells in its passage out- 

 wards, through the middle of which it passes, and deposits it upon the 

 back of the bee which is there ready to receive it.* It is thus roughly 



* The reader is recommended to take the first opportunity of examining a flower 

 of the Scarlet Runner ; and if he will raise and depress the /c/7-hand wing, holding it 

 between the forefinger and thumb, he can imitate the action of a bee, so that the 

 stigma will protrude and retire with every movement of the wing. 



