Sorry to start off with a rant. This whole plant thing is frustrating me more than it should, especially since my plants all seem to be doing well now. I'm just one of those people that like to know as much as I can about what I'm doing and it bothers me it is so difficult to ID plants. I know lighting and whether a plant is submersed can change a plant's appearance but often I see multiple pictures that look absolutely nothing alike for the same species of plant. To the actual question. I bought a tall stem plant at PetCo about a month ago. It was labeled ludwigia (water primrose) but it didn't say what kind. I'm starting to wonder if it is truly ludwigia. I'll get a picture and post when I get home today. It was in a bunch and I didn't bother separating it but I believe they are individual stems. The whole plant is a lighter green color including the stem. The stem is also a little thicker compared to most of the ludwigia pictures I've seen. Since starting CO2 injections it has grown like crazy, probably 3 or 4 inches in the last week or so and is now touching the water surface. The leaves are longer and more narrow than a repens, with a rounded tip and slightly serrated along the edge. Most of the leaves are an inch or slightly longer. I found the pic below which looks very similar and was listed as Limnophila aromatic, but every other picture of Limnophila aromatic shows a plant with long narrow red leaves.