Ostrya virginiana (American Hophornbeam), is a species of Ostrya native to eastern North America, from Nova Scotia west to southern Manitoba and eastern Wyoming, southeast to northern Florida and southwest to eastern Texas and northeastern Mexico. Other names include eastern hophornbeam, hardhack (in New England), ironwood, and leverwood.
It is a deciduous understory tree growing to 18 m tall and 0.2–0.5 m trunk diameter. The bark is brown to gray-brown, with small shaggy plates flaking off. The leaves are ovoid-acute, 5–13 cm long and 4–6 cm broad, with a finely serrated margin. The flowers are catkins produced in spring at the same time as the new leaves appear; the male catkins are 20–50 mm long, the female 8–15 mm long. The fruit is a small nutlet 3–5 mm long fully enclosed in a papery white involucre 1–1.8 cm long, with 10–30 involucres on each catkin.
Populations along the Atlantic coast have slightly smaller leaves, and are sometimes separated as O. virginiana var. lasia Fernald.
The buds and catkins are important source of winter food for some birds, notably Ruffed Grouse (Bonasa umbellus).
Ostrya is a genus of eight to ten small deciduous trees belonging to the birch family Betulaceae. Its common name is Hophornbeam in American English and Hop-hornbeam in British English. It may also be called ironwood, a name shared with a number of other plants.
The genus is native in southern Europe, southwest and eastern Asia, and North and Central America. They have a conical or irregular crown and a scaly, rough bark. They have alternate and double-toothed birch-like leaves 3–10 cm long. The flowers are produced in spring, with male catkins 5–10 cm long and female catkins 2–5 cm long. The fruit form in pendulous clusters 3–8 cm long with 6–20 seeds; each seed is a small nut 2–4 mm long, fully enclosed in a bladder-like involucre.
The wood is very hard and heavy; the name Ostrya is derived from the Greek word 'ostrua', "bone-like", referring to the very hard wood. Regarded as a weed tree by some foresters, this hard and stable wood was historically used to fashion plane soles.
Ostrya species are used as food plants by the larvae of some Lepidoptera species including Winter Moth (Operophtera brumata), Walnut Sphinx (Amorpha juglandis) and Coleophora ostryae.