Noone has the right to the plants. All they can do is discover a new one and they get to name it.
There are some shops selling 10+ varieties of Wendtii. I will bet that many of those are the same for example:
You saw my brown in the tank earlier.
These are browns and greens I used to grow emersed but I could now sell them as Wendtii 'var rainbow'
Tropica produce and sell 4 different varieties which are all actually different as detailed earlier.
Aquafleur only produce and sell 2 varieties: Green and brown. both different
I would tend to think that if all the others with 'de witt' and 'rose' and 'red' were real, then Tropica would more than likely produce and sell at least one of them
Its one of those 'grey' areas just as sucking loach may be used as a descriptive to sell plecs, CAEs and Otos in different shops.
In that case it is the same name but different fish.
AC