I thought these photos of some of our aquarium plants growing in their Amazonian habitat might be of interest. The photos were taken by Claus Christensen during some of his collecting trips; Claus was formerly the CEO of the famous Tropica nursery in Denmark.
Photo 1 shows Echinodorus grandiflorus
growing emersed along the banks of a river [not sure it is the Amazon itself]. For half the year the rivers flood the surrounding forest, and these plants then grow in their submersed form. Photo 2 is another river with emersed plants, not sure what the plant in the foreground is but E. grandiflorus is in the back.
Photo 3 I included to show the normal river/stream bed, devoid of plants because it is too dark; the famous caiman is prowling the substrate. We talk of plants and fish a lot, but of course the truth is that most of the watercourses in Amazonia are plant-less; the fish remain among twisted branches, roots and leaf litter. During the wet season though when the rivers flood thousands of square miles of the forest up to 35 feet in depth, the fish move into these heavily planted areas to spawn.