Hornbeam

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Hornbeam
European Hornbeam foliage
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Fagales
Family:	Betulaceae
Genus:	Carpinus L.
Species
Carpinus betulus—European Hornbeam Carpinus caroliniana—American Hornbeam Carpinus cordata—Sawa Hornbeam Carpinus faginea Carpinus fangiana Carpinus fargesii—Farges' Hornbeam Carpinus japonica—Japanese Hornbeam Carpinus laxiflora—Aka-shide Hornbeam Carpinus orientalis—Oriental Hornbeam Carpinus putoensis—Putuo Hornbeam Carpinus tengshongensis† Carpinus tschonoskii—Chonowski's Hornbeam Carpinus turczaninowii—Turkzaninov's Hornbeam

Hornbeams are relatively small hardwood trees in the genus Carpinus (Cár-pi-nus). Though some botanists grouped them with the hazels (Corylus) and hop-hornbeams (Ostrya) in a segregate family, Corylaceae, modern botanists place the hornbeams in the birch subfamily Coryloideae. The 30–40 species occur across much of the north temperate regions, with the greatest number of species in east Asia, particularly China. Only two species occur in Europe, and only one in eastern North America.

Origin of names

The common English name of "hornbeam" derives from the hardness of the woods (likened to horn) and the Old English "beam", a tree (cognate with German "Baum". The American hornbeam is also occasionally known as blue-beech, ironwood, or musclewood; the first from the resemblance of the bark to that of the American Beech Fagus grandifolia, the other two from the hardness of the wood and the muscular appearance of the trunk respectively. The botanic name for the genus, Carpinus, is the original Latin name for the European species.

Identification

The leaves are deciduous, alternate, and simple with a serrated margin, and typically vary from 3–10 cm in length. The flowers are wind-pollinated pendulous catkins, produced in spring. The male and female flowers are on separate catkins, but on the same tree (monoecious). The fruit is a small nut about 3–6 mm long, held in a leafy bract; the bract may be either trilobed or simple oval, and is slightly asymmetrical. The asymmetry of the seedwing makes it spin as it falls, improving wind dispersal. The shape of the wing is important in the identification of different hornbeam species. There are typically 10–30 seeds on each seed catkin.

Associated insects

Hornbeams are used as food plants by the larvae of some Lepidoptera species including Autumnal Moth, Common Emerald, Feathered Thorn, Svensson's Copper Underwing and Winter Moth (recorded on European Hornbeam) as well as the Coleophora case-bearers C. currucipennella and C. ostryae.

Applications

Hornbeams yield a very hard timber, giving rise to the name Ironwood. Dried heartwood billets are nearly white and are suitable for decorative use. For general carpentry, hornbeam is rarely used, partly due to the difficulty of working it. Its hardness has however lent it to use for carving boards, tool handles, handplane soles, coach wheels, piano actions and other situations where a very tough, hard wood is required, perhaps most interestingly as gear pegs in simple machines, including traditional windmills. It is sometimes coppiced to provide hardwood poles. It is also used in parquet flooring and for making chess pieces.

See also

• Acer carpinifolium, a.k.a. Hornbeam Maple