Hornbeam Hornbeam Hornbeams are hardwood trees in the flowering plant genus "Carpinus" in the birch 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 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.
Betula pendula continues from a lateral bud. The species is monoecious with male and female catkins found in the same tree. Some shoots are long and bear the male catkins at the tip, while others are short and bear female catkins. The immature male catkins are present during the winter but the female catkins develop in the spring, soon after the leaves unfurl. The leaves have short slender stalks and are long, triangular with broad, untoothed, wedge-shaped bases, slender pointed tips and coarsely double-toothed, serrated margins. They are sticky with resin at first but this dries as they age leaving small white