We noticed that nature provides that most of the flowers shall be cross pollinated. This is particularly true of the flowers of the fruit trees, and for this reason it is impossible to get true varieties of fruit from seed. For example, if we plant seeds of the wine sap apple, the new trees produced from them will not produce the same kind of apple but each tree will produce something different and they will very likely all be poorer than the parent fruit. This is because of the mixture of pollens which fertilize the pistils. Knowing this fact the nurseryman plants apple seeds and grows apple seedlings. When these get to be the size of a lead pencil he grafts them, that is, he digs them up, cuts off the tops away down to the root and then takes twigs from the variety he wishes to grow and sets or splices these twigs in the roots of the seedlings and then plants them. The root and the new top unite and produce a tree that bears the same kind of fruit as that produced by the tree from which the twig was taken. These are a few of the reasons why it is well to know something about flowers and their work. [Illustration: FIG. 76.--FLOWER OF A LILY. Notice how the stigma and the anthers are kept as far as possible from each other to guard against self-pollination and to insure cross-pollination.] [Illustration: FIG. 77. Bud and flower of jewel-weed, or "touch-me-not." _A._ Interior of bud. Stamens are seen, but there appears to be no pistil. _B._ Section of bud showing the pistil concealed behind the stamens. _C._ Bee entering flower comes in contact with stamens and is loaded with pollen. _D._ Same bee entering older flower. The stamens have ripened and been pushed off by the lengthened pistil, which is brushed by the back of the bee, and thus is pollinated. This is a contrivance to insure cross-pollination.] [Illustration: FIG. 78. _A._ Pistillate flower of strawberry. _B._ Perfect flower of strawberry. (Drawing by M.E. Feltham.)] FRUIT The pistil develops and forms the fruit of the plant. This fruit bears seed for the production of new plants. This fruit may be a dry pod like the bean or pea, or it may be a fleshy fruit like the apple or plum. Now the developing pistil or fruit may be checked in its work of seed production by insects and diseases, and to secure good fruit it is in many cases necessary to spray the fruits just as the leaves are sprayed, to keep these insects and diseases in check. The fruits of most plants, like the leaves, need light and air for their best development, and it sometimes happens that the branches of the fruit trees grow so thick that the fruits do not get sufficient light and air. This makes it necessary to thin the branches or in other words to prune the tree. Some trees also start more fruit than they can properly feed and as a result the ripened fruits are small and the tree is weakened. This makes it necessary to thin the fruits while they are young and undeveloped. PART II