Hornbeam

Hornbeam
European hornbeam foliage
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Fagales
Family:	Betulaceae
Genus:	Carpinus L.
Synonyms
Distegocarpus Siebold & Zucc

Hornbeams are relatively small hardwood trees in the genus Carpinus. Though some botanists grouped them with the hazels (Corylus) and hop-hornbeams (Ostrya) in a segregated 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, only one in eastern North America, and one in Mesoamerica. Carpinus betulus can be found in Europe, Turkey and Ukraine.

Origin of names

The common English name "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

Hornbeam trunk

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. Typically, 10–30 seeds are 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, walnut sphinx, 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, shoe lasts, and other uses 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.

Hornbeam has been listed as one of the 38 substances used to prepare Bach flower remedies, a kind of alternative medicine promoted for its effect on mental or emotional health. However, according to Cancer Research UK, "there is no scientific evidence to prove that flower remedies can control, cure or prevent any type of disease, including cancer".

Species

Accepted species

1. Carpinus betulus L. — European hornbeam - widespread across much of Europe; Turkey, Iran, Caucasus; naturalized in a few places in US.
2. Carpinus caroliniana Walter — American hornbeam - Quebec, Ontario, eastern half of US
3. Carpinus chuniana Hu - Guangdong, Guizhou, Hubei
4. Carpinus cordata Blume — Sawa hornbeam - Primorye, China, Korea, Japan
5. Carpinus dayongiana K.W.Liu & Q.Z.Lin - Hunan
6. Carpinus eximia Nakai - Korea
7. Carpinus faginea Lindl. - Nepal, Himalayas of northern India
8. Carpinus fangiana Hu - Sichuan, Guangxi
9. Carpinus hebestroma Yamam. - Taiwan
10. Carpinus henryana (H.J.P.Winkl.) H.J.P.Winkl. - southern China
11. Carpinus japonica Blume — Japanese hornbeam - Japan
12. Carpinus kawakamii Hayata - Taiwan, southeastern China
13. Carpinus kweichowensis Hu - Guizhou, Yunnan
14. Carpinus laxiflora (Siebold & Zucc.) Blume — Aka-shide hornbeam - Japan, Korea
15. Carpinus lipoensis Y.K.Li - Guizhou
16. Carpinus londoniana H.J.P.Winkl. - southern China, northern Indochina
17. Carpinus luochengensis J.Y.Liang - Guangxi
18. Carpinus mengshanensis S.B.Liang & F.Z.Zhao - Shandong
19. Carpinus microphylla Z.C.Chen ex Y.S.Wang & J.P.Huang - Guangxi
20. Carpinus mollicoma Hu - Tibet, Sichuan, Yunnan
21. Carpinus monbeigiana Hand.-Mazz. - Tibet, Yunnan
22. Carpinus omeiensis Hu & W.P.Fang - Sichuan, Guizhou
23. Carpinus orientalis Mill. — Oriental hornbeam - Hungary, Balkans, Italy, Crimea, Turkey, Iran, Caucasus
24. Carpinus paohsingensis W.Y.Hsia - China
25. Carpinus polyneura Franch. - southern China
26. Carpinus pubescens Burkill - China, Vietnam
27. Carpinus purpurinervis Hu - Guizhou, Guangxi
28. Carpinus putoensis W.C.Cheng — Putuo hornbeam - Zhejiang
29. Carpinus rankanensis Hayata - Taiwan
30. Carpinus rupestris A.Camus - Yunnan, Guangxi, Guizhou
31. Carpinus shensiensis Hu - Gansu, Shaanxi
32. Carpinus shimenensis C.J.Qi - Hunan
33. †Carpinus tengshongensis W.C.Cheng - Zhejiang but probably extinct
34. Carpinus tropicalis (Donn.Sm.) Lundell - Mexico, Central America
35. Carpinus tsaiana Hu - Yunnan, Guizhou
36. Carpinus tschonoskii Maxim. — Chonowski's hornbeam - China, Korea, Japan
37. Carpinus turczaninowii Hance — Turkzaninov's hornbeam - China, Korea, Japan
38. Carpinus viminea Wall. ex Lindl. - China, Korea, Himalayas, northern Indochina

See also

• Acer carpinifolium, hornbeam maple