54 CLOSED FLOWERS. 
the Antirrhinum, or Snapdragon, is completely closed, 
and only a somewhat powerful insect can force its way 
in. The flower is in fact a strong box, of which the 
Humble-bee only has the key. The Linarias are another 
case of this kind. The Campanulas, again, are open 
flowers, but the stamens are swollen at the base, 
and in close contact with one another, so that they 
form the lid of a hollow box in which the honey is 
secreted. In some species the same object is effec- 
ted by the stamens being crowded together, as in 
some of the white ranunculuses of the Alps. In 
other cases, the flower forms a narrow tube, still 
further protected by the presence of hairs, sometimes 
scattered, sometimes, as in the white dead nettle, 
forming a row. 
In others, as in some species of Narcissus, Primula, 
Pedicularis, &c., the tube itself is so narrow that even 
an ant could not force its way down. 
In others, again, asin some of the Gentians, the 
opening of the tube is protected by the swollen head 
of the pistil. 
In others, as in clover, lotus, and many other 
Leguminose, the ovary and the stamens, which cling 
round the ovary in a closely-fitting tube, fill up almost 
the whole space between the petals, leaving only a 
very narrow tube. 
Lastly, in some, as in Geraniwm robertianum, 
Innwm catharticum, &c., the main tube itself is 
divided by ridges into several secondary ones. 
