Originally Posted by Inga
That could be it. Hard to say for sure. In your photo the leaves seem narrower and maybe slightly rounder. I know that water parameters can make a difference in the way the plant grows. Wisteria is very narrow and sparce in my tank where as in a friends tank it is thick and lush. I would like very much to get more. Maybe mine will fill out enough that I can break apart the plant a bit and space it out?
If you Google this species, you will find photos almost as different as night and day. Echinodorus will grow quite differently in different tanks; even in mine I have the same species including daughter plants from the same parent that grow differently. AQssuming I am right that this is an Echinodorus--and the leaf structure and crown once I saw it is what I base that on--this is the only species with leaves like yours.
You could separate the root "clumps" if you want. If they don't come apart easily, don't force them. But often I can get 4 or 5 plants from one "plant" when I buy it. You mentioned long roots previously, so that usually lets you separate.