HICKORY

any of about 18 species of deciduous timber and nut-producing trees that constitute the genus Carya of the walnut family (Juglandaceae). About 15 species of hickory are native to eastern North America, and 3 to eastern Asia. Fossil remains identifiable as belonging to the genus are found in western North America, Greenland, Iceland, and Europe. Hickories typically grow to about 30 m (100 feet) tall and have a long taproot. The leaves are composed of 3 to 17 leaflets each; those of some species turn bright yellow in autumn. The male and female flowers, both of which lack petals, are borne in different clusters on the same tree, the male in hanging catkins and the female in terminal spikes of 2 to 10 flowers. The fruit is an egg-shaped nut enclosed in a fleshy husk that splits into four woody valves as it matures. The nuts of some species contain large, sweet-tasting, edible seeds; the principal edible nuts are those of the shagbark hickory (C. ovata), the shellbark hickory (C. laciniosa), the mockernut hickory (C. tomentosa), and the pecan (C. illinoensis). The nuts of the bitternut hickory (C. cordiformis) and the water hickory (C. aquatica) are bitter-tasting and inedible, because the skin covering the kernels contains tannin. The nuts of most other species are edible but are too small to be commercially important. Pecan (q.v.), the most valuable species economically, is cultivated for its flavourful nuts and its light-coloured wood. The wood of other hickories is used as fuel and for tool handles, sports equipment, furniture, and flooring.