Dear gods, what flower is this below! What's his playboy ~ thank you ...

The double-petalled Rehmannia glutinosa (scientific name: Kerria Japonica (L L.)) is a variety of the deciduous shrub Rehmannia glutinosa, with a height of 1 m to 1.5 m, green branchlets, stripes and slightly twisted; The leaves are triangular-ovate, tapering at the apex, nearly round at the base, 2 cm to 5 cm long, with double serrations on the edge, bright green on the surface and light and slightly hairy on the back; Golden yellow flowers on the lateral branches, double petals, 3 cm to 4.5 cm in diameter, achene brown-black.