Ostrya

Ostrya 

(hop-hornbeam), a genus of deciduous monoecious trees of the family Betulaceae. The trees are 10–25 m tall and have longitudinally fissured bark. The leaves are alternate and irregularly double-toothed. The staminate flowers have no perianth and are arranged in a single cylindrical catkin along the longitudinal axis. The pistillate flowers have a plain perianth and are arranged in two’s in reduced dichasia, which are gathered, in turn, into short, thick catkins. Each pistillate flower is surrounded by a pitcher-shaped membranous involucre formed of concresced bracts, giving the cone-shaped female catkin a resemblance to the female inflorescences of hop plants. The involucre is closed when fruits are present; the fruits are nuts.

There are five species (according to other sources, ten) of hophornbeam, distributed in the northern hemisphere. The species O. carpinifolia occurs in the USSR; it grows wild in the mixed forests of the Caucasus. A tree reaching 15 m in height (sometimes to 22 m), it has double-toothed, short-petioled leaves and rough, scaly bark. The bark is a source of dyes and is used for tanning leather. The wood is valuable, but the reserves of this relict species are not great. The American hop-hornbeam (O. virginiana) is cultivated in the European USSR and in the Caucasus.

REFERENCE

Derev’ia i kustarniki SSSR, vol. 1. Moscow-Leningrad, 1951.

V. N. GLADKOVA