There's a zillion variants of quadrangularis out there.. And it's rather difficult to tell them apart.

Looks like the picture on http://www.pwbelg.clara.net/seeds/Seedpics/Passiflora_quadrangularis.jpg is correct as if I remember right, there's 6 "bumps" on the leaf-stem of quadrangularis.

The biggest problem for me has been getting the seeds to sprout then keeping the seedling alive for more than about 4 months. Perhaps you will have better luck than I.