ABSTRACT
DESCRIPTION : Trees, often with broad rounded crowns, the bark smooth when young, flaking or furrowed in age. LEAVES: two, on opposite sides of the stem, 2–6 inches long, 2–6 inches wide, palmately lobed (i.e. the lobes and veins arising from a single basal point), with 3–9 lobes, the lobes with few to many teeth; leaf blades (and stalks) smooth and hairless; leafstalks long, sometimes as long as the blade; leaves often brilliantly colored in fall. FLOWERS: emerging with or before the leaves in spring, small, greenish-yellow or sometimes flushed with red, in few-flowered flat-topped clusters, erect or drooping; male and female flowers in separate clusters, on the same or different trees; sepals usually 5; petals 0 or 5; stamens 3–12; ovary free of the sepal tips, 2-celled. FRUITS: a characteristic pair of winged seed, on long drooping stalks, the fruits floating to earth, rotating like a helicopter.
