iv ON PLANT LIFE 129 



fertilisation by Humble Bees. The stamens 

 and pistil are so arranged that smaller species 

 would not effect the object. It is therefore 

 an advantage that they should be excluded, 

 and in fact they are not strong enough to 

 move the spring. The Antirrhinum is, so to 

 speak, a closed box, of which the Humble 

 Bees alone possess the key. 



FURZE, BROOM, AND LABURNUM 



Other flowers such as the Furze, Broom, 

 Laburnum, etc., are also opened by Bees. 

 The petals lock more or less into one an- 

 other, and the flower remains at first closed. 

 When, however, the insect alighting on it 

 presses down the keel, the flower bursts open, 

 and dusts it with pollen. 



SWEET PEA 



In the above cases the flower once opened 

 does not close again. In others, such as the 

 Sweet Pea and the Bird's-foot Lotus, Nature 



