I recently collected some plants from a natural warm spring system that feeds 5 ponds. The water is mid 60s and doesn't freeze over in the winter. One of the plants looks like some kind of cabomba or hornwort. Almost like your cliche plastic plant. Another looks like some kind of grass stem plant. Like giant hair grass, but it is some kind of skinny leaved stem plant. The last seems to be a mexican oak leaf variant. Has similar leaves to an oak leaf, but it is smaller and more petite. All plants were found in a foot deep warm spring creek that feeds the ponds. The water has very low turbidity and is crystal clear. I successfully grew theses plants in my aquarium way back in the day before I really knew much about planted tanks or how to properly care for plants. I never found out what species they were. I hope someone has a definite answer.