So it does seem that it most likely was grown emerged in the greenhouse. That would explain the die off of most of the original leaves. The colors of the original leaves are just as you described, with green tops and purple undersides.
I thought a true aquatic plant was one that couldn't grow emerged.
Two 1 GA desktops, a 5 gallon, a 2.5 gallon, a 10 gallon, a 20 gallon, a 25 gallon, and two 75 gallon tanks, all planted.
I am an expert on algae, so ask me if you have questions. I know how to grow it, just not how to get rid of it.