SUGGESTIONS.--=114.= Is a puffball a plant? Why do you think so? =115.= Are mushrooms ever cultivated, and where and how? =116.= In what locations are mushrooms and toadstools usually found? (There is really no distinction between mushrooms and toadstools. They are all mushrooms.) =117.= What kinds of mildew, blight, and rust do you know? =118.= How do farmers overcome potato blight? Apple scab? Or any other fungous “plant disease”? =119.= How do these things injure plants? =120.= What is a plant disease? =121.= The pupil should know that every spot or injury on a leaf or stem is caused by something,--as an insect, a fungus, wind, hail, drought, or other agency. How many uninjured or perfect leaves are there on the plant growing nearest the schoolhouse steps? =122.= Give formula for Bordeaux mixture and tell how and for what it is used. CHAPTER XV WINTER AND DORMANT BUDS =A bud is a growing point=, terminating an axis either long or short, or being the starting point of an axis. _All branches spring from buds._ In the growing season the bud is active; later in the season it ceases to increase the axis in length, and as winter approaches the growing point becomes more or less thickened and covered by protecting scales, in preparation for the long resting season. This resting, dormant, or winter body is what is commonly spoken of as a “bud.” A winter bud may be defined as an _inactive covered growing point_, waiting for spring. _Structurally, a dormant bud is a_ =shortened axis= _or_ =branch=, _bearing miniature leaves or flowers or both, and protected by a covering._ Cut in two, lengthwise, a bud of the horse-chestnut or other plant that has large buds. With a pin separate the tiny leaves. Count them. Examine the big bud of the rhubarb as it lies under the ground in late winter or early spring; or the crown buds of asparagus, hepatica, or other early spring plants. Dissect large buds of the apple and pear (Figs. 137, 138). [Illustration: FIG. 137.--BUD OF APRICOT, showing the miniature leaves.] [Illustration: FIG. 138.--BUD OF PEAR, showing both leaves and flowers. The latter are the little knobs in the center.] _The bud is protected by firm and dry scales._ These scales are modified leaves. The scales fit close. Often the bud is protected by varnish (see horse-chestnut and the balsam poplars). Most winter buds are more or less woolly. Examine them under a lens. As we might expect, bud coverings are most prominent in cold and dry climates. Sprinkle water on velvet or flannel, and note the result and give a reason. =All winter buds give rise to branches=, _not to leaves alone_; that is, the leaves are borne on the lengthening axis. Sometimes the axis, or branch, remains very short,--so short that it may not be noticed. Sometimes it grows several feet long.