Today I bought some spiralis from an aquarium store today thinking it was a good plant for my South American biotope aquarium. I read that somewhere, so I bought it and planted it in my tank. It was labeled just 'spiralis' so I'm assuming it's vallisneria spiralis because it is grassy. Anyway, I was looking it up some more today and couldn't find a definite origin. Most of the places I looked just said 'from tropical and subtropical regions' so I'm kind of confused. Can anyone tell me for sure where the origin of this plant is?