Have a few photos of some of the Rush on my place. I don't know the specific varieties but if I had to guess I would guess the smallest one pictured is one of the spike rush varieties and the larger specimens are one of the soft rush varieties.
The last picture is of a clump that I don't remember if it is from one of the spike rush plugs I transplanted last fall from my old pond or something that the birds have brought in. It looks just like what is in my forage pond. If it is the same spike rush that is in my old pond, it is a much better environment because it is getting bigger than that in my old pond (which is in a pure clay bank so is possible).
First three pictures are from my old pond.
I'm just shooting in the dark about the varieties. Maybe some of the experts can help out.