The leaves (2) of the Alder are heavy and leathery. They are usually rounded at the tips, but sometimes they are square, as if a piece had been cut off. Each leaf is prettily toothed all round the edge, and the veins, which run from the centre rib to the margin, are very much raised. When the leaves are newly opened, the under-side is covered with tufts of soft down, and they are slightly sticky. Sometimes they are tinged with dull purple. These leaves are placed alternately on the stem, and while still in bud each leaf is enclosed in a pair of oval sheaths like small yellow ears. These ears do not fall off when the leaf unfolds, as do the leaf coverings of the Birch and the Beech; you will often find them at the bottom of the leaf stalk when the leaf is fully grown. PLATE V THE HORNBEAM This is a tree that many people tell you they have never noticed; even people who know the names of most of our forest trees look surprised if you ask them which is the Hornbeam (1); they have never heard of it. And yet it grows freely in England in the woods and hedgerows, and like the Beech it is invaluable for sheltering with its close bushy branches younger trees that are struggling to live. If left to grow in good soil the Hornbeam will become a tall tree over seventy feet high, but it is not usual to find such well-grown Hornbeams, because the tree is generally planted to form hedges, and as these require thickness and bushiness rather than height, the top of the tree is often cut off, so that all its strength may go to producing side-branches. Last century it was the fashion to have curious puzzle-paths made in gardens. You entered at a gap in a leafy hedge and walked on and on, and in and out between growing hedges till you came to an open space in the centre. Then the puzzle was to find your way out again, and this was sometimes very difficult. This kind of puzzle-path was called a maze, and the hedges of these mazes were frequently made of Hornbeam, because this tree will allow itself to be clipped and cut into any shape, and if its tall spreading branches are taken away, it at once puts out many small side-shoots which form a thick hedge. The Hornbeam branches have a curious habit of growing together where they cross each other. You may find two good-sized branches which are separate on the lower part of the tree, but higher up they cross and touch each other, and frequently they join together and become one branch. In the town of Ghent in Belgium there is a winding walk arched with Hornbeam: the trees have been planted so close that they meet overhead, and they have then been clipped and cut till they form a green tunnel under which you can walk for three hundred yards.