[HeyPK]

The third picture plant is in the very large sedge family. I am not sure it is hair grass. It might be. See if it grows submersed.

The fourth picture plant is not Hemianthus. The leaves are shaped differently, and there are too many of them in a whorl. Also, the leaves of hemianthus are thin and translucent, whereas these leaves look thicker. The plant looks vaguely familiar, but I can't place it. If it can grow submersed, then you have got something new!

Plants 1 and 2 don't look like they belong underwater, but you never know.

Were all these plants found completely submersed? Did they look like they have been submersed for some time or just recently because of higher water levels?

 

[HeyPK]

Eleocharis is also in the sedge group. There are a lot of Eleocharis species in this country, and I am sure that not all of them have been tested to see if they make good aquarium plants. Then there are all the other genera in the sedge family. Cyperus, Carex, etc. There could be some good aquarium plants in there, somewhere. Members of the Rush family, Juncaceae, not Limbaugh) look like sedges to us non-experts and Juncus repens has been found to be a good aquarium plant. There are 3 or 4 other aquatic species of Juncus that need to be investigated.

Happy hunting!

 

[HeyPK]

I know what your second plant is, Steve. It is yellow dock aka curled dock, Rumex crispus. I doubt that it can grow underwater. It is common here in Mississippi, and it looks strictly terrestrial to me. I don't recognize your second plant. Was it under water when you found it?