186 THE VEGETABLE WORLD. 
filaments of the stamens are bent backwards on themselves, under 
the pressure of the floral envelope; but as soon as full bloom takes 
place the filaments unroll and the pollen is projected to a distance 
of thirty or forty inches or more. This movement is simply the 
result of the elasticity of the organs. In the Rue, at the moment 
of fecundation, each of the numerous stamens constituting the 
andraczeum, bends itself over the stigma, deposits the pollen there, 
and resumes its former position. Here is an individual and really 
spontaneous movement. 
In the Passion-flower the styles are at first erect, but at the 
moment of the opening of the anthers, they are observed to curve 
downwards, and lower themselves towards the stamens, and: then 
to rise up and resume their former position. 
In the flower of the Barberry, if a stamen is touched with the 
point of a pin, it is brought close to the pistil by a sudden move- 
ment, and then, in a little time, resumes its former position ; and 
this it will do again if fresh irritation is produced. A phenomenon 
of irritability is shown here, which does not exist in the other 
cases just specified. 
The hairs which cover the styles of the Campanula show a very 
singular property. They fold back on themselves, like the finger 
of a glove, the end of which is pushed inwards, and they draw 
with them into this retreat the grains of pollen, the fall of which 
they thus determine. 
In a pretty little plant of New Holland, known under the name 
Leschenanthia, the stigma is in the form of a cup, and it is edged 
with rather long hairs. At the moment of the anthers opening; 
part of the pollen falls into the cup of the stigma, which contracts 
in order to grasp them, whilst the hairs approach each other so 48 
to prevent the exit of the fertilising dust. 
In the facts we have just pointed out, the organs themselves 
act to produce the fecundation of the flower. But this physiological 
action is often facilitated by the concurrence of exterior agents. 
The wind has power to transport the pollen to a certain distance, 
and thus favours the fecundation of the flowers in mon@ci0us, 
diecious, or polygamous plants. Insects, while flitting from flower 
to flower, often become the active instruments of vegetable 
fecundation. 
