The pale green and globular ovary of a Cassine peragua flower is always visible in its centre, once the flower opens.
The whitish stamens spread from below the ovary, their anthers starting off nearly white, turning brown in decay. Where the flowers have four petals, there are four stamens when all went well. The five-petalled flowers in picture don’t fare so well in the stamen field, at least one stamen seems missing from each flower.
There is a short style upon the ovary and two-branched tiny stigmas, visible in a few cases but barely (Coates Palgrave, 2002; Schmidt, et al, 2002; Venter, 2012; iNaturalist).