Spotting

@dand and @Garon... Thank you guys. You were absolutely right. It's a hybrid form. Many thanks.

What do you mean 'the passion flower'? It definitely is a passionflower. Perhaps its not getting fertilized, that's why it is not producing fruit. There is a lot of variation in the leaves of Passiflora.

This looks just like the passion flower, however... The leaf is different and it doesn't produce fruit.

I think this is P.x violacea ( P. caerulea x racemosa), the oldest documented passionflower hybrid. This looks like Form 3.