172 BOTANY 
are some of the means by which the visits of unsuitable 
insects are prevented :— 
1. Isolation.—The bladderwort (Utricularia) flower 
floats on the surface of the water, so that none but 
flying insects can reach it. 
2. Sticky juices, secreted at each node of the stem 
in certain species of catchfly, prevent creeping insects 
from reaching the flower. 
3. Hairs in the salvia, act as a barrier to insects 
that would not be strong enough to work the lever. 
A hairy stem may serve the same purpose. 
4. The structure of the flower in some eases pre- 
vents the entrance of any but an insect large enough to 
do the work of pollination. In the snapdragon, for 
instanee, it requires a heavy insect to depress the lower 
lip sufficiently to open a way into the flower. 
5. Closure during the hours of light protects the 
flower of the evening primrose against many ereeping 
insects that are abroad in the daytime. 
Animals other than insects, as for instance, slugs 
and birds, also pollinate flowers, as was seen in the 
ease of the fuchsia. 
1. In the clianthus (kaka-beak), the so-called red 
kowhai, the tui was originally the chief agent of 
pollination. On thrusting his tongue to the base of the 
keel, into which the pollen had been shed, he would 
cause the brush-like style to sweep out the pollen on 
to his forehead. The stigma, which is at the end of 
the style, would, however, first strike the bird, so that 
it would receive pollen that might have been brought 
from another flower. 
2. The rewarewa (Knightia eaxcelsa) (Fig. 109), 
under natural conditions, is pollinated by tuis and 
other native birds. The anthers are pressed close 
against vertical grooves towards the top of the style. 
Into these grooves the pollen is shed, being well pro- 
tected by the perianth tube, which does not open till 
