Osage orange is a medium-sized tree with a short trunk, dense, round, or irregular crown, milky sap, and stout thorns.
Leaves are alternate, simple, 3–6 inches long, 2–3 inches wide, broadest below the middle; margins lacking teeth; upper surface dark green, shiny; lower surface paler, with some hairs along the veins.
Bark is brown to orange, deeply grooved with age, ridges rounded, interconnecting, often peeling into long, thin strips; exposed roots (and wood) bright orange.
Twigs are slender, green, turning light orange-brown, young twigs hairy, becoming smooth later; sap milky; spines stout, straight, about ½ inch long, emerging above the leaf attachment.
Flowers May–June. Male and female flowers minute, in dense clusters about 1 inch across, each produced on separate trees; no petals.
Fruits September–October, large, yellowish green, fleshy or pulpy, 4–5 inches across; surface resembling a brain; juice milky, sticky, bitter. Numerous seeds small, flattened, imbedded in the fruit.
