Ostrya virginiana

American hophornbeam is a small deciduous understory tree growing to 18 m (59 ft) tall and 20–50 centimetres (8–20 in) trunk diameter. The bark is brown to gray-brown, with narrow shaggy plates flaking off, while younger twigs and branches are smoother and gray, with small lenticels.[5][7] Very young twigs are sparsely fuzzy to thickly hairy; the hairs (trichomes) drop off by the next year.[8]

The leaves are ovoid-acute, 5–13 cm (2–5 in) long and 4–6 cm (1 ¹⁄₂–2 ¹⁄₄ in) broad, pinnately veined, with a doubly serrated margin. The upper surface is mostly hairless, while the lower surface is sparsely to moderately fuzzy (rarely densely hairy).[5][7]

The flowers are catkins (spikes) produced in early spring at the same time as the new leaves appear. The staminate (male) catkins are 2–5 cm (³⁄₄–2 in) long,[5] and arranged in groups of 1–4.[7] The pistillate (female) catkins are 8–15 mm (⁵⁄₁₆–¹⁹⁄₃₂ in) long, containing 10–30 flowers each.[5]

Pollinated female flowers develop into small nutlets 3–5 mm (¹⁄₈–³⁄₁₆ in) long fully enclosed in a papery sac-shaped involucre 10–18 mm (³⁄₈–¹¹⁄₁₆ in) long and 8–10 mm (⁵⁄₁₆–³⁄₈ in) wide.[5] The involucre changes from greenish-white to dull brown as the fruit matures.[7]

American hophornbeam is similar to its close relative American hornbeam (Carpinus caroliniana), which can be distinguished by its smooth bark and nutlets enclosed in open, three-lobed bracts.[7]

• 
  Bark of a mature tree
• 
  Male catkins hanging from the branches in spring (United States Botanic Garden)
• 
  Leaf color in autumn
• 
  Two trees in winter with some dried leaves still hanging on their branches (marcescence)
• 
  An exceptionally large trunk

There are two subspecies:

• Ostrya virginiana subsp. guatemalensis (H.J.P.Winkl.) A.E.Murray – central and southern Mexico, Guatemala, Honduras, El Salvador[9]
• Ostrya virginiana subsp. virginiana – eastern half of United States, eastern Canada

Populations along the Atlantic coast have slightly smaller leaves, and are sometimes separated as O. virginiana var. lasia Fernald.[5]

The buds and catkins are important source of winter food for some birds, notably ruffed grouse (Bonasa umbellus).[7] Additionally, the nutlets and buds are eaten by birds, deer, and rabbits.[1]

It is grown as an ornamental plant and is sometimes used as a street tree.

Its wood is very resilient and is valued for making tool handles and fence posts.

Being a diffuse porous hardwood and having extremely high density and resistance to compression, it is an excellent material for the construction of wooden longbows.

• Metzger, F. T. (1990). "Ostrya virginiana". In Burns, Russell M.; Honkala, Barbara H. (eds.). Hardwoods. Silvics of North America. Washington, D.C.: United States Forest Service (USFS), United States Department of Agriculture (USDA). 2 – via Southern Research Station (www.srs.fs.fed.us).

Wikimedia Commons has media related to Ostrya virginiana.

• Bioimages: Ostrya virginiana.
• University of Wisconsin – Green Bay. Trees of Wisconsin. Ostrya virginiana.
• Virginia Tech Dendrology. Ostrya virginiana Fact Sheet.
• University of Connecticut. Plants Database. Ostrya virginiana.
• Trees, Shrubs, and Woody Vines of North Carolina. Hophornbeam (Ostrya virginiana).
• Yale University. Cyber Flora. Ostrya virginiana.