84 PLANTS AND ANIMALS 
(Pinus), or Reed-mace (Typha), we note the small size 
of the flowers and the great abundance of pollen. Com- 
pare these with insect-fertilized flowers, such as Butter- 
cup (Ranunculus), Flax (Linum), Snapdragon (Antir- 
rhinum), or one of the Orchids. In these the flowers 
are much larger owing to the increased size of the 
petals, which are of brilliant colour and of various 
shape. Pollen is mostly much reduced in quantity, 
since insects flying direct from flower to flower afford 
a far more economical mode of distribution than is 
offered by the wind. The pollen grains, moreover, are 
sticky and covered with tiny spines or knobs, to render 
them more liable to adhere to the body or head of an 
insect; the pollen grains of wind-fertilized flowers 
being, on the other hand, smooth, dry, and dust-like. 
Again, these insect-pollinated flowers usually possess 
little glands which secrete nectar, the sugary syrup 
which by digestion in a bee’s body becomes honey. 
Here, then, is the inter-relation established: the insect 
helps the plant by carrying its pollen from flower to 
flower, and in its turn is helped by the provision of 
delicious food. And what about the showy petals, and 
the fragrance that so often marks these entomophilous 
flowers? They are advertisements, designed to catch 
the attention of the necessary insects as they fly about. 
Not only does the corolla by its bright colour attract 
insects, but markings of various shapes and tints upon 
the petals are generally held to be honey-guides— 
sign-posts directing the insects to the nectar and to 
the pollen. These are especially conspicuous in many 
of the irregular flowers to which reference will be 
made shortly, in which the insects are encouraged to 
approach the flowers in a particular way. An example 
