The leaves are opposite, palmately lobed with five lobes, 7–14 cm (2.8–5.5 in) long and 8–20 cm (3.1–7.9 in) (rarely 25 cm (9.8 in)) across; the lobes each bear one to three side teeth, and an otherwise smooth margin. The leaf petiole is 8–20 cm (3.1–7.9 in) long, and secretes a milky juice when broken. The autumn colour is usually yellow, occasionally orange-red. The flowers are in corymbs of 15–30 together, yellow to yellow-green with five sepals and five petals 3–4 mm (0.12–0.16 in) long; flowering occurs in early spring before the new leaves emerge. The fruit is a double samara with two winged seeds; the seeds are disc-shaped, strongly flattened, 10–15 mm (0.39–0.59 in) across and 3 mm (0.12 in) thick. The wings are 3–5 cm (1.2–2.0 in) long, widely spread, approaching a 180° angle. It typically produces a large quantity of viable seeds. Under ideal conditions in its native range, Norway Maple may live up to 250 years, but often has a much shorter life expectancy in North America, sometimes only 60 years. Especially when used on streets, it can have insufficient space for its root network and is prone to the roots wrapping around themselves, girdling and killing the tree. Norway Maples often cause significant damage and cleanup costs for municipalities and homeowners when branches break off in storms as it is fast-growing and does not have strong wood.