Any of us can be "experts" if we just compare pics with no reference to geography or size metrics.I am not expert, so I would like to know more too from people in the know.
The pic I posted was taken at the Bolivan plateau in Laos. Exul comes from around Krabi Island in Thailand, so no were near these. In some ways this reminds me of insigne, but the plant is nothing like that species. I have often wondered are we really confusing different species under the name gratrixianum?
Yes time of year is a biggy if you don't have geography on your side.Whew! I thought I was alone in thinking it looked more like exul than gratrixianum. Another factor which would keep them distinct in the wild would be time of flowering. In my greenhouse the gratrixianums all flower much earlier in the season (autumn) and the exuls later (spring), and I don't think I have ever seen an overlap (not in my greenhouse in any case).