"Other plants have thick, fleshy tap-roots. These live for two seasons, and called Biennials. The tap- root is a sort of storehouse of food for the plant, to feed it when it wakes up after its winter sleep.
"Trees and shrubs live for many years, and are called Perennials. They have fibrous roots, but these fibres are really thick and woody.""You must remember, Norah," said Willie, "that, whatever the class of root may be, the actual feeders are the delicate root-hairs. These root-hairs are absorbent, and absorb the dissolved earth-food from the soil.""Take the stem next," said Fred. "This is the part of the plant which grows upwards into the air, and bears the leaves and flowers. But I want you to think only of the leaves now. Can you tell me the different parts of a leaf, Norah?""Let me see," said Norah. "It has a footstalk and a blade; the ribs and veins spread through the blade.
"Oh, and I remember, too, that the surface of the leaf is closely set with breathing pore," she added.