Ah, well, if complex hybrids were made, as Andreas indicates,
then that would certainly account for the variation we've
seen in the photos. I was not aware that such complex hybrids
had been created....
For what it's worth, I have a specimen from Andreas which
is labeled "clone 1" and I am absolutely convinced that it
is pure N. clipeata. It is shown on my website:
Plants with Attitude.
In any case, this has been a very interesting thread of discussion!