The flower looks similar to the various wendtii flowers shown on Jan Bastmeijer's pages. If all your pictures are of the same cultivar, it certainly shows the famous wendtii variability due to growth condtions. I have a variety that is even browner when submersed---a dark chocolate brown on top and a dark red underneath. I got it as the "red" wendtii. I notice that the above plant does not have red underneath. Emersed it looks just like a wendtii I have that is very different submersed.
I think the best way to differentiate vareities is to grow them submersed.