Hornbeam

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. 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. 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. 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. Hornbeams are small to medium-sized trees, Carpinus betulus reaching a height of 32 m. The leaves are deciduous, alternate, and simple with a serrated margin, and typically vary from 3 to 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.