1911 Encyclopædia Britannica/Plane
PLANE. 1. In botany, the common name of a handsome tree known botanically as Platanus orientalis, a native of Greece and western Asia, a favourite shade-tree of the ancient Greeks and Romans, and introduced by the latter to south-west Europe.
Plane (Platanus orientalis).
1, Leaf, 14 nat size.
2 and 3, Base of leaf-stalk showing bud-protecting cap, about 14 nat. size.
4, Male, 5, Female inflorescence.
6, Head of fruits, about 12 nat. size.
7, A fruit with enclosed seed, cut lengthwise.
It is one of the most successful trees in London and other large towns; the smooth face of the leaf is easily washed by rain; and the periodical peeling of the bark also serves to get rid of impurities. It is a large tree with widely spreading branches and alternate, palmately five-lobed leaves, resembling those of the sycamore in shape, but quite hairless and of a brighter green. The bud in the leaf axil is protected during its development by the hollow base of the leaf-stalk, which lifts off like an extinguisher when the leaf falls in autumn. The minute, unisexual flowers are borne in dense pendulous heads, which contain either male or female flowers; the small one-seeded fruits are densely crowded in a ball, from which they gradually separate in drying, and are readily carried by the wind. The wood, which is hard and heavy, though not strong, is used in Persia and other countries of western Asia for house construction and furniture. A variety of forms are known in cultivation, the commonest being the maple-leaved (acerifolia), the London plane, which has usually three-lobed leaves; var. laciniata has very deeply much divided leaves, and var. variegata, variegated foliage. Platanus occidentalis, an allied species, is a native of the United States, being most abundant and growing to its largest size in the bottom lands of the basins of the lower Ohio and the Mississippi rivers. It was introduced into England early in the 17th century, and is occasionally met with in western and central Europe. Professor C. S. Sargent (Silva of North America) refers to it as the most massive if not the tallest, deciduous-leaved tree of the North American forest; it is known in America as sycamore and buttonwood. It differs from P. orientates in its less deeply lobed, more leathery pubescent leaves and in the usually solitary balls of fruit.
2. The name of a carpenter’s hand-tool, used for levelling and smoothing (Lat. planus, level) the surface of wood. The machine tool used for a similar purpose for metals is generally known as a planing-machine or planer.