KECENT OBSEEYATIONS ON THE FEKTILISATION OF PLANTS. 339 
appear, when they have arrived at maturity, to break suddenly 
out of the opening bud, the filament elongating in a moment to 
several times its original length, the anther bursting at the 
same time, when the slightness of its attachment to the fila- 
ment causes the least breath of wind to sweep the whole of the 
light dusty pollen out of its case, some of which must neces- 
sarily reach the neighbouring stigmas in the same ear, provided 
there is not enough wind to blow it completely away. In rye 
and oats this extraordinarily rapid lengthening of the filaments 
is even more conspicuous than in wheat. Hence the importance 
attached by farmers to comparatively calm sunny weather at 
the critical period when the corn is in flower. 
These two examples furnish good illustrations of the structure 
which prevails in those flowers that are fertilised by the wind. 
They are generally of very simple structure, and rarely brightly 
coloured, since bright colours would be of no advantage to 
them. The quantity of pollen is usually very large, and the 
structure of the male flowers such that it is dispersed by the wind 
with the greatest facility, this being brought about by the 
slender ‘‘ versatile ” filaments of the wheat and by the lightly 
hanging catkins of the hazel, the willow, and other early-flowering 
shrubs, which appear before the leaves, and hence at a period 
when there is no obstruction to the free dissemination of the 
pollen. 
In the majority of flowers, however, the structure of the 
pollen, or the arrangement relatively to one another of the pistil 
and stamens, is such that fertilisation could not be effected by 
the wind alone. Sometimes the pollen-grains themselves are 
too large and heavy to be thus conveyed, or they are united 
together by fine threads or even into dense masses; or the 
position of the stigmatic portion of the pistil is evidently not 
adapted for the pollen to reach it in this way ; and Nature then 
employs as the agent in fertilisation the services of insects or 
of other small animals. This opportunity is afforded by the 
visits of insects to the flowers in search of the honey or nectar 
which forms an important portion of the food of many classes. 
The mode of attraction to the flowers which serve them for 
food is mainly two-fold, scent and colour ; in other words, those 
properties which chiefly render flowers attractive to our own 
senses. The honey or other sweet juice is generally stored in 
small glands or receptacles, which together form the “ nectary,” 
the position of which is extremely variable ; the deep pits at the 
base of the corolla in the crown imperial, the small scroll-like 
petals of the hellebore, the bottom of the spur in orchises and 
the larkspur, the prolongations of two of the stamens which 
project into the spur of the violet and pansy, very frequently 
minute glands at the base of the stamens or pistil, &c. Nature 
