The Wych Elm forms a trunk of large size, from 80 to 120 feet or more in height, with a girth of 50 feet, and covered with rough bark that is often corky. Its long slender branches spread widely with a downward tendency, the downy forking twigs bearing their leaves in a straight row along each side. The leaves are somewhat oval in general form, but the two sides of the midrib are unequal in size and shape. Their edges are doubly or trebly toothed, and the surfaces are rough and harsh to the touch. The hairs that cover the strong ribs on the under surface serve for the protection of the breathing pores from dust. On leaves of the pendulous form of this tree, grown in the London parks and gardens, these hairs will be found to be quite black with the soot particles gathered from the air. Trees need carbon, but in this gross form they are too often suffocated by it. In March or April the brownish flowers are produced in bunches from the sides of the branches. They are a quarter of an inch long, bell-shaped, their edges cut into lobes, and finely fringed. The ovary, with its two awl-shaped styles, is surrounded by four or five stamens with purple anthers. They appear in March or April, before the leaf-buds have opened, and are dependent on the wind for the transfer of pollen. The fruit is an oblong _samara_, about an inch long. This consists of a single seed in the centre, invested by a thin envelope, which is extended all round as a light membranous wing, which gives it buoyancy and enables it to float through the air to a little distance. These seeds are not produced until about the thirtieth year of the tree's life, and though they are ripened almost annually thereafter, good crops are biennial or triennial only. It has often been stated that the Wych Elm does not send up suckers, but it does, though not invariably; it does so chiefly as the result of root-pruning or some other check to the extension of the root-system. [Illustration: Wych Elm.] [Illustration: _Pl. 34._ Bole of Wych Elm.] [Illustration: _Pl. 35._ Wych Elm--winter.] [Illustration: _Pl. 36._ Common Elm--summer.] [Illustration: _Pl. 37._ Bole of Common Elm.]