horn-beam, in botany: A genus of the polyandria order, belonging to the monocotyledon class of plants; and in the natural method ranking under the 50th order, Amentaceae. The calyx of the male is monophyllous and ciliated; there is no corolla, but 20 stamens. The calyx of the female is monophyllous and ciliated; no corolla; two germens, with two styles on each. The fruit is an egg-shaped nut. There are two species, viz:

1. The betulus, or common hornbeam; a deciduous tree, native of Europe and America. Its leaves are of a darkish green, and about the size of those of the beech, but more pointed and deeply serrated. Its branches are long, flexible, and crooked; yet in their general appearance very much resemble those of the beech; indeed there is so great a likeness between these two trees, especially in the shrubby and underwood state, that it would be difficult to distinguish them at the first glance, were it not for that glossy varnish with which the leaves of the beech are strongly marked. In the days of Evelyn, when topiary work was the gardener's idol, the hornbeam might be considered as deserving of those endearing expressions which that enthusiastic writer has been pleased to lavish upon it; nevertheless, Carpinus as an ornamental in modern gardening it stands low; and its present uses are few. As an underwood it affords stakes and eddies, fuel and charcoal. Its timber ranks with that of the beech and the sycamore; and the inner bark is said to be much used in Scandinavia to dye yellow. The only superior excellency of the horn-beam lies in its fitness for thorn fences for sheltering gardens, nurseries, and young plantations from the ferocities of the winter season. It may be trained to almost any height, and by keeping it trimmed on the sides it becomes thick of branches, and consequently thick of leaves; which being by their nature retained upon the plant after they wither, a horn-beam hedge occasions a degree of shelter nearly equal to that given by a brick wall. Indeed, being less reflective than that expensive screen, it affords a more uniform temperature of air to the plants which stand near it. In this point of view, too, the horn-beam is useful to be planted promiscuously, or in alternate rows, amongst more tender plants in exposed situations, in the same manner as the birch; to which it has more than one preference: namely, it is warmer in winter,—and Hanbury says, the horn-beam is peculiarly grateful to hares and rabbits; consequently it may prevent their injuring its more valuable neighbours: yet, like Evelyn, he seems to be of opinion that it is disaffected by deer. If this be really the case, the horn-beam may upon many occasions be introduced into deer-parks with singular propriety.

Of this species there are three varieties: The Eastern Horn-beam, Flowering Horn-beam, American Horn-beam. The eastern horn-beam arrives to the least height of all the sorts; about ten feet is the farthest of its growth, and it looks pretty enough with trees of the same growth. The leaves are by no means so large as the common sort; and as the branches are always closer in proportion to the smallness of the leaves, where a low hedge is wanted of the deciduous kind, this would not be an improper tree for the purpose, either to be kept sheered, or suffered to grow in its natural state. The bark of this sort is more spotted than that of the common. The flowering horn-beam is the most free shooter of any of the sorts; and will arrive to be the highest, the common horn-beam only excepted. It will grow to be thirty or forty feet high. The branches of this tree are less spotted with greyish spots than any of the other sorts. The leaves are very rough, of a dark-green colour, and are longer than the common sort. The property which the common horn-beam is possessed of, of retaining its leaves all winter, does not belong to this sort, the leaves of which constantly fall off in the autumn with other deciduous trees. American horn-beam is a more elegant tree than any of the former sorts. The branches are slender, covered with a brownish speckled bark, and are more sparingly sent forth than from any of the others. The leaves are oblong, pointed, and of a palish green, and are not nearly so rough as the common horn-beam, though the flowers and fruit are produced in the same manner.

2. The ostrya, or hop-horn-beam, a native of Italy and of Virginia. This is of taller growth than the eastern kind. It will arrive to the height of twenty feet, or more. The leaves are nearly the size of the common common sort, and some people admire this tree on account of the singular appearance it makes with its seeds, before they begin to fall. There is a variety which grows to thirty feet high, shoots freely, has long rough leaves like those of the elm, and longish yellow-coloured flowers, called the Virginian flowering hop-hornbeam.

Propagation. The common hornbeam may be propagated either by layering (at almost any time of the year), or from seeds in the following manner: In the autumn the seeds will be ripe; when, having gathered a sufficient quantity for the purpose, let them be spread upon a mat a few days to dry. After this, they should be sown in the seminary-ground, in beds four feet wide, with an alley of about two feet, and from one to two inches deep. In this bed they must remain till the second spring before they make their appearance; and all the summer they lie concealed, the weeds should constantly be plucked up as soon as they peep; for if they are neglected, they will get so strong, and the fibres of their roots will be so far struck down among the seeds, as to endanger the drawing many seeds out with them, on weeding the ground. After the young plants appear, they should constantly be kept clear of weeds during the next summer; and if they were to be now and then gently refreshed with water in dry weather, it would prove serviceable to them. In the spring following they may be taken out of these beds, and planted in the nursery, in which situation they may remain till they are of a sufficient size to plant out for standards.

The other sorts are to be propagated by layers; for which purpose a few plants for stools must be procured. The stools of the eastern hornbeam should be planted a yard, and the other sorts a yard and a half or two yards asunder. After these plants have made some young shoots, they should be layered in the autumn, and by that time twelvemonth they will have struck root; at which time, or any time in the winter, or early in the spring, they should be taken off, and planted in the nursery-way, observing always to brush up the stool, that it may afford fine young shoots for fresh layering by the autumn following. The distance the plants should be allowed in the nursery need be no more than one foot, in rows that are two feet asunder; and here they may stand, with the usual nursery care of weeding and digging the rows in winter, until they are to be finally planted out; though the Virginian hornbeam will frequently send forth two shoots, which will seem to strive for mastery in the lead. When this is observed, the weakest should always be taken away, otherwise the tree will grow forked.