The directions we are about to give the reader regarding this portion of his work will be understood by him only if he is fairly well acquainted with the general characters of a flowering plant and with the structure of flowers; and as it would hardly be advisable to assume such knowledge, we shall give a brief outline of this part of the subject, dealing only with those points that are essential to our purpose, and explaining the meaning of those terms which are commonly employed in the description of plants and their flowers. THE ROOT The root is that portion of the plant which descends into the soil for the absorption of the mineral food required. It really serves a double purpose, for, in addition to the function just mentioned, it fixes the plant in its place, thus forming a basis of support for the stem and its appendages. [Illustration: FORMS OF ROOTS 1. Simple fibrous. 2. Branched fibrous. 3. Tap root. 4. Tuberous root.] Roots are capable of absorbing liquids only, and all fertile soils contain more or less soluble mineral matter which is dissolved by the moisture present. This matter is absorbed mainly by the minute root-hairs--outgrowths of the superficial cells--which are to be found on the rootlets or small branches that are given off from the main descending axis. The principal forms of roots occurring in our flowering plants are:-- 1. The _simple fibrous root_, consisting of unbranched fibres such as we see in the Bulbous Buttercup and the Common Daisy. 2. The _branched fibrous root_, as that of the Chickweed and Grasses. 3. The _tap root_, which is thick above and tapers downwards, like the roots of the Dandelion, Carrot and Wild Parsnip. 4. The _tuberous root_, common among the Orchids. 5. The _creeping root_, possessed by some Grasses in addition to their fibrous roots. Besides these common forms there are roots of a somewhat exceptional character, such as the _aerial roots_ or _suckers_ which grow from the stem of the Ivy and serve to support the plant; and the roots of the Mistletoe, which, instead of penetrating the soil, force their way into the substance of certain trees, from which they derive the necessary nourishment. The student of plant life must always be careful to distinguish between roots and underground stems, for there are many examples of creeping and tuberous stems which resemble certain roots in general appearance. A true root bears no buds, and, therefore, is not capable of producing new plants. If a root creeps under the ground, as does the root of the Barley Grass, it merely serves the purpose of collecting nourishment from a wider area--a matter of considerable importance when the soil is dry and deficient in suitable mineral food. A creeping stem, on the other hand, developes buds as it proceeds, each bud giving rise to a new plant; and the creeping itself is the result of the growth of a permanent terminal bud.