Oxalis purpurea flower

The leaflet margins of Oxalis purpurea have uneven allocations of short white hairs. The lower leaflet surfaces are purple. Maybe that leaf colouring brought about the specific name of purpurea as the flowers vary in colour.

The outside of the funnel-shaped corolla tube is yellow as the inside. The upper petal parts of the withered flower have turned dark blue, the lower yellow parts only paled. Maybe lying on the ground as the one in picture does not impair the ability of the ovary to develop into a fruit (Manning, 2007; iSpot).