The Book of Household Management by Mrs. Beeton

designed, not only to support the plant by fixing it in the soil, but also to fulfil the functions of a channel for the conveyance of nourishment: it is therefore furnished with pores, or spongioles, as they are called, from their resemblance to a sponge, to suck up whatever comes within its reach. It is found in a variety of forms, and hence its adaptation to a great diversity of soils and circumstances. We have heard of a willow-tree being dug up and its head planted where its roots were, and these suffered to spread out in the air like naked branches. In course of time, the roots became branches, and the branches roots, or rather, roots rose from the branches beneath the ground, and branches shot from the roots above. Some roots last one year, others two, and others, like the shrubs and trees which they produce, have an indefinite period of existence; but they all consist of a collection of fibres, composed of vascular and cellular tissue, without tracheae, or breathing-vessels. The stem is the grand distributor of the nourishment taken up by the roots, to the several parts of the plant. The seat of its vitality is said to be in the point or spot called the neck, which separates the stem from the root. If the root of a young plant be cut off, it will shoot out afresh; if even the stem be taken away, it will be renewed; but if this part be injured, the plant will assuredly die.