"Grandmamma," said Jack, "there is a poor-looking flower like a small stock in the garden; it smells so sweet."
"It is a stock—the night-flowering stock. The flower is dull-coloured and insignificant; but it has a powerful odour. You must not suppose that the sweet scent of flowers is for our pleasure alone. The perfumes are of great use to the plants themselves, and to the insects that live on honey."
"Of what use can they be to the plants?" asked Mary.
"The perfume is chiefly due to a kind of oil found in the blossoms of plants, and sometimes in the leaves as well. Lavender, rosemary, thyme, and herbs used in cooking, are examples of plants whose leaves as well as flowers possess this ethereal oil, as it is called. Caterpillars do not like the taste of these oils, and leave these highly-scented plants alone. It is, however, generally the flowers only that smell; and now you can guess why they are protected by their fragrance. What is the most important part of the flower?"
"Yes; and as the cattle will not eat the flowers, the seed is safe from them."
"But they eat flowers in hay," said Jack.
"True; but by the time the grass is cut many seeds have ripened and have dropped out of their husks; and when flowers are dry, as they are in hay, they lose their particular scent and the oil with it. But the very perfume which keeps away the enemies of the flower attracts its friends the insects, whose sense of smell is very keen."
"Why do flowers want insects?" asked Annie.
"Because they want their yellow dust taken from one flower to another, to ripen their seeds, or to fertilize them, as it is called. The seeds are far better if they are ripened by the pollen or dust of another blossom than by the pollen of their own flower. The bees, as you know, get covered with this dust as they visit one flower after another; some of it sticks to the bees, but a great deal of it drops off as they rub against the flowers."