A small deciduous tree 20 ft high, with long-stalked, pinnate leaves consisting usually of three or five leaflets, which are 11⁄2 to 21⁄2 in. long, ovate or obovate, stalkless, entire, downy on both sides. Flowers in erect panicles 3 or 4 in. long, small and of no beauty; the male panicles much denser than the female. Fruits reddish, oval, 3⁄4 in. long.
Native of Central Asia, N. Afghanistan, and N.E. Persia, long cultivated and naturalised over the Mediterranean region and more recently grown commercially in other parts of the world, e.g., California; said to have been in cultivation in Britain in 1570, and certainly introduced before 1770, the erroneous date given in ‘Don’s Miller’. This is the tree that produces the well-known pistachio-nuts, the kernels of which are eaten raw, or cooked, or made into confectionery. It has not much beyond its economic interest to recommend it, for it needs the protection of a warm wall, and even then is occasionally injured by cold; with us its fruits are never developed. In warm climates the leaflets are as much as 31⁄2 in. long by 21⁄2 in. wide.
The natural stands in Soviet Central Asia occur in semi-desert areas at 2,000 to 6,500 ft. Their productivity is low, partly because male trees make up more than half the total and partly because they have been much damaged by overgrazing (Tseplyaev, Forests of the USSR, Eng. ed. (1965), p. 470). The best commercial stands consist of selected female varieties grafted on P. atlantica or P. terebinthus, intermixed with males (or with male branches grafted on them).