mi] THE FERTILISATION OF FLOWERS. 51 
in passing over the flower-head one insect fertilises 
several florets. There are nearly ten thousand known 
species of this order, but the structure of the flower 
is tolerably uniform, and can be well observed in the 
Daisy or Feverfew. In the latter the stamens are 
united so as to form a tube, enclosing the pistil. The 
pistil is furnished at top with a brush of hairs. The 
anthers ripen before the stigmas, and shed the pollen 
on their inner surface, so that it is deposited in the 
tube on the top of the immature stigmas which it 
cannot affect. The pistil as it ripens elongates and 
pushes up the pollen, which is thus brought in the 
way of insects. By means of the brush every pollen 
grain is swept out before the stigmas ripen. When 
this has been effected, the stigmas raise themselves 
from the tube, and assume a position as in fig. 60. 
Fic. 63. 
The flowers of the various species of Harebell 
(Campanula) are more or less inverted, and among 
the most graceful objects of our native flora. At first 
both pistil and stamens are immature, the stamens 
clasping the pistil (fig. 61). The anthers ripen, shed 
their pollen on the style, and shrivel up. Insects 
visiting the flower clasp the style, and thus remove 
the pollen. The pistil then elongates, and the stigmas 
