This is not the beginning of a Gardenia thunbergia flower, but its end. The corolla has been lost; the narrow tips at the top are the calyx remains that will persist.
The texture at the base of the cylindrical structure already shows something of the surface roughness of the fruit-to-be. It will continue to bulge more as it grows to dimensions of 7 cm in length and half that in width.
Note the way the leaves are attached below the developing fruit (Coates Palgrave, 2002).