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 ppeus 
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 
K 
