Populus tremula

Round-headed tree to 10 m high; bark greyish green, smooth; young shoots glabrous or with simple hairs. Buds ovoid-globose, viscid. Leaves suborbicular, 3–8 cm long and wide, both surfaces ultimately glabrous, discolorous, dark green above, blue-grey below; apex rounded, often apiculate; base truncate, rounded or cordate; margins irregularly and bluntly sinuate-lobed; leaves on suckering stems much larger. Catkins appearing before leaves; catikin-scales broadly ovate, deeply-fringed. Male catkins 5–8 cm long; stamens 5–10, sometimes more; anthers crimson. Female catkins 4–6 cm long (to c. 10 cm in fruit). Capsule dehiscing via 2 valves. Flowers spring.