(walnut; family Juglandaceae)
A genus of deciduous, nut-bearing trees, up to 30 m tall, that have twisting, spreading branches. They have large, oily, deeply lobed cotyledons. The leaves are compound. Male and female catkins occur on the same tree, the male catkins dangling in the wind, the female catkins upright. They produce oval, green fruits (a drupe) with a fleshy exocarp and a bony endocarp (the shell, see pericarp), which splits down the midrib. The wrinkled, woody nut is eaten fresh or pickled, and used in desserts, cakes, and confectionery. The most popular garden species are J. regia (Persian walnut), J. nigra (black walnut), and J. cinerea of N. America, the butter-nut. The wood is used for furniture. There are 21 species, occurring mainly in northern temperate regions, but extending to the tropics and native to Asia and America.
Subjects: Plant Sciences and Forestry.