Mostly deciduous trees. Buds brown and hairy in winter. Leaves alternate (rarely opposite), pinnate with an odd or even number of leaflets, sometimes aromatic; stipules absent. Flowers unisexual but both sexes on the same plant. Male flowers forming catkins on previous year's growth, each flower with 3-40 stamens. Female flowers forming spikes on new twigs. Perianth 4-lobed (occasionally reduced or absent). Pollination is by wind. Carpels 2, fused together. Ovary inferior with 1 chamber and 1 apical ovule, style short, stigmas 2. Fruit a nut or drupe.
The relatives of this family are uncertain but it is often associated with the Anacardiaceae; it is also well represented in the Tertiary fossil floras of America and Eurasia.
Best known commercially for the edible walnut and pecan; oils extracted from these nuts are used in cosmetics, soap, foods, cooking oil and paints. Trees of several species provide excellent fine-grained timber, especially the hickories and walnuts and there is also some demand for the charcoal.
Trees with pinnate exstipulate leaves; flowers in catkins; ovary inferior, producing a nut fruit.
9 genera and about 62 species, mostly north temperate but also subtropical, extending into the southern hemisphere.
Source: (1997). Juglandaceae. In: . Horticultural Flora of South-eastern Australia. Volume 2. Flowering plants. Dicotyledons. Part 1. The identification of garden and cultivated plants. University of New South Wales Press.