All plants are abundantly supplied with means for reproducing their kind: some by seed, some by multiplication at the crown or base or by roots, others by means of underground stems; and some, as the potato, have two or more means of reproduction. In its wild or partially improved state the potato is abundantly supplied with fruit, "seed balls," borne on the top of the stalks. The seeds of a single ball will often produce many varieties of potatoes; but they cannot be depended upon to reproduce the parent stock. Farmers seldom attempt to raise potatoes from the seeds; when they do it is for the purpose of securing new varieties. The common method of reproduction is to plant a part or all of an enlarged underground stem, that is, a part of the "potato" or tuber. When the soil is reasonably porous and fertile, a strong root may start at the seed-piece and descend more or less directly into the subsoil. In most cases, however, the roots spread laterally. This is a good illustration of how plants may vary in their root habits in order to adapt themselves to their environment. Notice where the roots form on the plants you are growing. Few farmers know where they form. Distinguish the true or feeding roots from the underground stems. Determine how many tubers form on each underground stem. Dig up a hill of potatoes from the garden before school closes. [Illustration: _Fig. 272. Underground part of potato plant in mellow soil._] A single eye, with a portion of the tuber attached to furnish nourishment to the bud until sustenance can be secured from newly formed rootlets, may produce one, occasionally more, strong upright stems. A most interesting study of manifold reproduction may be made even in the winter time by planting in a fertile soil a piece of potato containing a single eye (Fig. 273). As soon as the rootlets begin to start, divide each eye and piece into two parts and re-plant. In a few days after the rootlets have again started, divide the two pieces into four and re-plant. This operation may be performed again and again, until many plants suitable for transplanting in the open may be secured from a single eye. [Illustration: _Fig. 273. Piece of tuber for planting, bearing a single eye._] Demonstrate that the potato contains starch. This can be done by applying a drop of dilute iodine to a freshly cut surface of the tuber: the starch grains turn blue-black. Five cents' worth of iodine purchased at the drug-store will be sufficient for many tests. Dilute it about one-half with water. This starch, after being changed to sugar, supplies the young plant with nourishment. Dig up the pieces you have planted and see which start first, shoots or roots.