Maclura Nutt. (1818) contains only 1 species, M. pomifera (Raf.) C.K. Schneid., the osage orange, from North America, in the family Moraceae.

Description Tree to 20m, the twigs with spines in the leaf axils and milky sap. The leaves are alternate, deciduous, rounded at the base, slender-pointed, hairy, not toothed or lobed. The flowers are unisexual, with males and females on different plants. The male flowers are in catkin-like spikes, with 4 sepals, no petals, and 4 stamens. Female flowers are in round heads, with 4 sepals, the 2 inner narrower than the 2 outer, 1 carpel, and a long, undivided style. Pollination is by wind. The fruits are large, round, green, to 12cm across, with each seed surrounded by fleshy sepals.

Key Recognition Features The large, green fruits remain on the tree after the leaves have fallen, and then lie on the ground. They exude milky juice when cut open.

Evolution and Relationships Cudrania Tréc., from China and Japan southwards to Australia, is closely related to Maclura and sometimes united with it; it has similar but smaller fruits, which ripen orange. x Macludrania, the hybrid between Maclura and Cudrania, was raised in France; it has large, orange fruits.

Ecology and Geography In scrub and along hedges and roads; native of southwestern Arkansas, southeastern Oklahoma, and Texas, and naturalised elsewhere northwards to New York state.

Comment The genus is named after William Maclure (1763–1840) an American geologist. The wood was used for bows and war clubs, and the trees were planted as hedges in the midwest.

Maclura pomifera (Raf.) Schneid., family Moraceae Osage Orange Bow Wood Deciduous tree, native to south and central United States, Arkansas and Oklahoma south to Texas. The bark has been used in tanning leather, but also yields a yellow dye, and the Osage Indians used the wood to make weapons. Cultivated as hedging around the Mississippi, and as an ornamental in eastern states and sometimes in Europe. Height to 12m (40ft). Male and female flowers are on separate trees. They open in June, males about 1.5-2.5cm (3/5-1in) across, females with shorter stalk but about the same size and green. Fruit is large, about 7.5-12.5cm (3-5in) across and very heavy, ripening yellow and falling in November. When broken it exudes a white milky sap. Z5.