_Budding._--If a given tree, for example, produces a kind of fruit which is of excellent quality, it is possible sometimes to attach parts of the tree to another strong tree of the same species that may not bear good fruit. This is done by _budding_. A T-shaped incision is cut in the bark; a bud from the tree bearing the desired fruit is placed in the cut and bound in place. When a shoot from the embedded bud grows out the following spring, it is found to have all the characters of the tree from which it was taken. [Illustration: Steps in tongue grafting. _a_, the two branches to be formed; _b_, a tongue cut in each; _c_, fitted together; _d_, method of wrapping.] Grafting.--Of much the same nature is grafting. Here, however, a small portion of the stem of the closely allied tree is fastened into the trunk of the growing tree in such a manner that the two cut layers just under the bark will coincide. This will allow of the passage of food into the grafted part and insure the ultimate growth of the twig. Grafting and budding are of considerable economic value to the fruit grower, as it enables him to produce at will, trees bearing choice varieties of fruit.[34] Footnote 34: For full directions for budding and grafting, see Goff and Mayne, _First Principles of Agriculture_, Chap. XIX, Mayne and Hatch, _High School Agriculture_, pp. 159-165, or Hodge, _Nature Study and Life_, pages 169-179. Other Methods.--Other methods of plant propagation are by means of runners, as when strawberry plants strike root from long stems that run along the ground; layering, where roots may develop on covered up branches of blackberry or raspberry plants; slips, roots developing from stems which are cut off and placed in moist sand; from tubers, as in planting potatoes; and by means of bulbs, as the tulip or hyacinth. All of the above means of propagation are asexual and are of importance in our problem of plant breeding. [Illustration: Plant breeding plots. (Minnesota Experiment Station.)]