Handkerchief tree

This is Davidia involucrata, fondly known as the handkerchief tree.
A deciduous tree from China, the spherical flower heads are typically overshadowed by the structure that envelops them. What look like large white petals dangling down are in fact large white bracts (modified leaves) that can grow up to 30 cm in length.
It is said that the white bracts resemble dangling handkerchiefs, resting doves and sometimes on a dark night, even ghosts!