This shows us not only that different species are specialised to grow under different conditions, but that even two individual plants of the same species may be growing within a few feet of each other, and yet have quite a different appearance owing to the influence of their immediate surroundings. There are many such cases to be seen in the hedgerows. If the hedge runs from east to west, it will cast a shadow over the side lying to the north. Notice ~how different is the general appearance of the plants on the bleak side from that of those on the south~. You may also find that some species which grow on the south side do not grow on the north at all, or only in far smaller numbers. It is quite worth while making out lists of all the plants you can find on one side and the other of the hedge if it is a big, well-established one, and comparing the numbers and condition of the two sets of plants. [Illustration: Fig. 137. A, Dead Nettle which has grown up through the hedge. B, the same after being cut back with all the others. Side branches have begun to sprout now that it is well lighted and the top has been cut off.] As we noticed before, hedges are not entirely natural, and as ~man therefore forms a part of the plants’ environment~, it is quite interesting to ~see how they respond to his influence~. For example, we may study the effect of his trimming the hedge. In a hedge which had been left for some time to itself, the plants would have long, thin stems, bare at the base, where no leaves would develop, as they would be cut off from the light by all the other plants. Then comes the “hedger and ditcher,” and cuts them all back, leaving often only a few inches of nearly leafless stem. What is the result? Soon on these bare stumps leaves begin to sprout now that the light can get at them and the top is cut off, and many short side-branches come out, also bearing leaves, so that where before were only long, bare stems carrying the top tufts of leaves out to the light, we now have short, thickly clustered plants of bushy appearance (~see~ fig. 137). Soon, however, the race for light begins again, and the plants grow taller in their attempt to overtop each other. Notice also how the hawthorn (or whatever woody plant it may be which makes the hedge) responds when its leafy shoots are cut away. Many hidden and sleeping buds in the brown woody stem now get their chance and wake to active life. It is this continual cutting back which makes the hedge so thick with many short branches. [Illustration: Fig. 138. Bulrushes growing in a wet ditch.]