Pictures posted by me and Gurcharan ji in this thread are belong to the 'purple' variety. The stems, fruits and sometimes leaves have the coloration. These are always cultivated and i have not seen in wild.
This purple form is botanically known as Basella rubra (Synonym: Basella alba var. rubra).
The green form of 'pasalai keerai' is wild and all parts (lvs, stems, fruits) of the plant are green. It is Basella alba (or B. alba var. alba).
Vijayasankar Raman, Ph.D.Post Doctoral Research Associate
National Center for Natural Products Research
Thad Cochran Research Center
University of Mississippi, Oxford, MS 38677
Phone: +1 662 915 1018