190 THE FERTILISATION OF FLOWERS. [parr 1. 
If it dehisced along with the other four stamens of its own 
whorl and then withered, its pollen would lie useless in the lower 
part of the carina, a little in front of its middle point, and would 
never be pressed forward ; but since it grows to the same length as 
the inner stamens and dehisces simultaneously with them, its 
pollen unites in great part with that of the two neighbouring 
stamens (5 and 7 in 1, Fig. 62), and is heaped with it above the 
style. 
The inner whorl of stamens and the inferior stamens of the 
outer whorl dehisce and wither a short time before the vexillum 
expands. The position which the organs occupy at this time 
within the carina may be easily seen by holding the carina up to 
the light, and is represented in 2, Fig. 62. 
The carina still forms a much compressed sheath, closely 
surrounding the style and the pollen of all the ten stamens which is 
heaped above it. It is kept horizontal by the action of two equal 
and opposite forces. The column of stamens with the contained 
style possesses a tension upwards, so that if it be freed from the 
surrounding petals it springs up close to the perpendicular vexillum. 
The claws of the ale and of the two petals which form the carina 
- possess a downward tension, and if the upward pressure of the style 
is removed, they suddenly bend downwards and place the ale and 
carina in a vertical position. The ale are kept in connection 
with the carina by means of a bulging protuberance at the base 
and near the upper border of each (h’, 3, 5, 6), which les in the 
angle between the upper border of the carina and another pro- 
tuberance directed outwards and upwards from each half of the 
carina near its base (h, 7). 
The opposite tensions balance one another so long as the upper 
borders of the carina cohere together (7, 5) and the pouched lobes of 
the alee (m, 5) meet one another above the staminal column. 
As soon, however, as an insect places its feet upon the alee and 
thrusts its head beneath the vexillum, the pouched lobes of the alv 
slip down below the staminal column (m, 6); at the same time the 
union between the upper borders of the carina is ruptured from 
behind forwards by the pressure of the essential organs in its posterior 
part, and as soon as the splitting reaches the tip of the style the 
two opposite forces are set free, and the staminal column springs 
upwards while the alz and carina spring downwards. If we hold 
the flower in one hand, and press down the tip of the carina with 
a needle or a pencil-point, we see clearly the split spreading 
forwards, and the pouched lobes of the ale separating, so that the 
