Hi Donald,
I am not sure I am the right person to answer this, as I didn't even know there was a "Plant Photos Forum". LOL
When I think of watermarks, TRUGANINI doesn't immediately come to mind because the watermark is so small. One could almost call it a slightly extended threat, except that the cool thing about this flower area is that it is raised above the rest of the flower tissue. Coming out of the throat is this stark white thick area has needs to be called something, because it is so distinctive. I am not sure any photo could accurately capture it.
I will see if I can get a closer image of what I am trying to explain.....but it won't be today....raining heavily.
Thanks,
Steve