The leaves vary greatly in size, those growing on a tree being much larger than those produced by a bush. They range from two to four inches in diameter, and are always in pairs--springing from the sides of the branch exactly opposite to each other. The general form of the leaf is kidney-shaped, but it is cut up into five lobes, which are more or less toothed. They are downy when young, of a deep green colour, but too frequently this is disguised by a thick layer of road-dust. In October they turn to a rich yellow, and the Maple is then prominent even in a distant view, for the bright colour of the foliage makes the tree stand out prominently, in strong contrast with the still deep green of the Oaks or Firs beyond. The Maples are among the trees that have complete flowers, although in this case they happen to be greenish yellow. They are about a quarter of an inch across, have narrow sepals and narrower petals, eight stamens, and a two-lobed flattened ovary, that develops into the pair of broad-winged "keys," or samaras. These are individually much like those of the Ash, but unsymmetrical and curved, half an inch long, with their bases joined together. Sometimes in late summer these "keys" take on a colouring of deep crimson, previous to turning brown as they ripen. As a rule the contained seeds take eighteen months to germinate, though a few may start growth the first spring. The Common Maple is thought to be indigenous only from the county of Durham to the southern coast, and in Ireland. In Scotland it is only an introduced plant that has become naturalized. The Great Maple, Sycamore, or False Plane (_Acer pseudo-platanus_) is not a native tree, but it appears to have been introduced from the Continent as far back as the fifteenth century, so that it has had time during the intervening centuries to get well established among us, and by means of its winged seeds to distribute itself to remote corners of our islands. It appears to be fond of exposed situations, growing to a large size even near the sea, where the salt-laden gales destroy all other deciduous trees. Recently in Ireland we ascended a hill where the planting of pines and other trees had resulted in comparative failure, and found that the wind-borne seeds of the Sycamore had produced a large number of young trees, which will probably serve later as nurses for more desirable timber-producers. The close-grained, firm wood, which can be worked with ease, is not highly esteemed. [Illustration: Sycamore.] [Illustration: _Pl. 46._ Leaf-buds of Sycamore.] [Illustration: _Pl. 47._ Bole of Sycamore.]