Temporal range: 49.42–0 Ma Ypresian - Recent
European hornbeam foliage
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Fagales
Family: Betulaceae
Subfamily: Coryloideae
Genus: Carpinus

Distegocarpus Siebold & Zucc

Hornbeams are hardwood trees in the plant genus Carpinus in the family Betulaceae. The 30–40 species occur across much of the temperate regions of the Northern Hemisphere.

Origin of names

The common English name hornbeam derives from the hardness of the woods (likened to horn) and the Old English beam, "tree" (cognate with Dutch ‘’Boom’’ and 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 muscled appearance of the trunk and limbs.

The botanical name for the genus, Carpinus, is the original Latin name for the European species, although some etymologists derive it from the Celtic for a yoke.[2]


Formerly some taxonomists segregated them with the genera Corylus (hazels) and Ostrya (hop-hornbeams) in a separate family, Corylaceae. However, modern botanists place Carpinus in the subfamily Coryloideae of the family Betulaceae.[3][4] Species of Carpinus are often grouped into two subgenera Carpinus subgenus Carpinus and Carpinus subgenus Distegicarpus.

However, phylogentic analysis has shown that Ostrya likely evolved from a Carpinus ancestor somewhere in C. subg. Distegicarpus making Carpinus paraphyletic. The fossil record of the genus extends back to the Early Eocene, Ypresian of northwestern North America, with the species Carpinus perryae described from fossil fruits found in the Klondike Mountain Formation of Republic, Washington.[3]


European hornbeam in Germany, during May.

Hornbeams are small, slow-growing understory trees, Carpinus betulus reaching a maximum height of 32 m.[5]: 296 

The trunk is typically smooth and gray with muscle-like fluting. hornbeam is a small, slow-growing, understory tree with an attractive natural, rounded form growing 15-30' tall and wide. The smooth, gray trunk and larger branches of a mature tree exhibit a distinctive muscle-like fluting. The dark-green leaves are coarsely serrated and often turn shades of yellow, orange and red in the fall. Its catkin flowers give the tree away as a member of the birch family. The female flowers give way to distinctive clusters of winged seeds that somewhat resemble the hops-like seeds of ironwood.

The leaves are deciduous, dark-green, alternate, simple with a coarsely-serrated margin, and typically vary from 3 to 10 cm in length. In autumn, leaves turn various shades of yellow, orange and red. Hornbeam saplings, stressed trees, and the lower branches of mature trees may exhibit marcescence—where leaves wither with Autumn but abscission (leafdrop) is delayed until Spring.

As with other members of the birch family, hornbeam 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.[6][7]


The 30–40 species occur across much of the temperate regions of the northern hemisphere, 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.[1][8][9][10][11] Carpinus betulus can be found in Europe, Turkey and Ukraine.[12]

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.[13]


Hornbeam trunk.

Hornbeams yield a very hard timber, giving rise to the name "ironwood".[14] 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.

The wood is used to construct carving boards, tool handles, handplane soles, coach wheels, piano actions, shoe lasts, and other products where a very tough, hard wood is required.

The wood can also be used as gear pegs in simple machines, including traditional windmills.[14] It is sometimes coppiced to provide hardwood poles. It is also used in parquet flooring and for making chess pieces.


Accepted species:[1]


  1. ^ a b c "Carpinus L., Sp. Pl.: 998 (1753)". World Checklist of Selected Plant Families. Royal Botanic Gardens, Kew.
  2. ^ Gledhill D. 1985. The Names of Plants. Cambridge University Press ISBN 0521366755
  3. ^ a b Pigg, K.B.; Manchester, S.R.; Wehr, W.C. (2003). "Corylus, Carpinus, and Palaeocarpinus (Betulaceae) from the Middle Eocene Klondike Mountain and Allenby Formations of Northwestern North America". International Journal of Plant Sciences. 164 (5): 807–822. doi:10.1086/376816. S2CID 19802370.
  4. ^ Forest, F.; Savolainen, V.; Chase, M. W.; Lupia, R.; Bruneau, A.; Crane, P. R. (2005). "Teasing apart molecular- versus fossil-based error estimates when dating phylogenetic trees: a case study in the birch family (Betulaceae)". Systematic Botany. 30 (1): 118–133. doi:10.1600/0363644053661850. S2CID 86080433.
  5. ^ Stace, C. A. (2010). New Flora of the British Isles (Third ed.). Cambridge, UK: Cambridge University Press. ISBN 9780521707725.
  6. ^ "Hornbeam, American (Musclewood) | Nebraska Forest Service". nfs.unl.edu.
  7. ^ . ISBN 1015282601. ((cite book)): Missing or empty |title= (help)
  8. ^ Flora of China, Vol. 4 Page 289, 鹅耳枥属 e er li shu, Carpinus Linnaeus, Sp. Pl. 2: 998. 1753.
  9. ^ Flora of North America, Vol. 3, Hornbeam, Carpinus Linnaeus, Sp. Pl. 2: 998. 1753; Gen. Pl. ed. 5, 432, 1754.
  10. ^ "Carpinus betulus L." Altervista Flora Italiana.
  11. ^ "2013 BONAP North American Plant Atlas. TaxonMaps". Biota of North America Program.
  12. ^ a b Carpinus betulus. 2.nd Ed., The Royal Horticultural Society, Dorling Kindersley Ltd, London, pp. 234, 235.
  13. ^ Miscellaneous Publication. U.S. Department of Agriculture. 1972. p. 297.
  14. ^ a b Archived at Ghostarchive and the Wayback Machine: Eichhorn, Markus; Haran, Brady (2011-12-01). "The Hornbeam's Heartbeat". test-tube.org.uk. University of Nottingham. Retrieved 2012-12-30.
  15. ^ "Carpinus fangiana". Rogers Trees and Shrubs. Archived from the original on 2011-07-15.
  16. ^ Dai, J.; Sun, B.; Xie, S.; Lin, Z.g; Wu, J.; Dao, K. (2013). "A new species of Carpinus (Betulaceae) from the Pliocene of Yunnan Province, China". Plant Systematics and Evolution. 299 (3): 643–658. doi:10.1007/s00606-012-0750-1. S2CID 16941126.
  17. ^ English Names for Korean Native Plants (PDF). Pocheon: Korea National Arboretum. 2015. p. 400. ISBN 978-89-97450-98-5. Archived from the original (PDF) on 25 May 2017. Retrieved 8 December 2016 – via Korea Forest Service.