I saw this in Brazil recently and thought some of you might be interested. The first picture shows them growing submersed and the second emersed. The location is near the city of SantarÃ©m in the state of ParÃ¡. It was found in a stream which joins one of the tributaries of the Amazon close by. It is really a stream hence fluviatilis I suppose, and the water movement is actually mildly quick in which the plants were being moved gently but constantly. The major difference from our tanks was the shallowness of the water: only 3in to 6in max and any deeper, this plant was not seen. Probably this means this is a plant of the floodplain, not a true aquatic plant. The main part of the stream bed was all sandy (whitish sand) and where the plants were, it was covered thinly in brown sediments and goo. I didn't have the water test kit with me as I was on business!