What are they? Obviously they're not just grass. Bullrushes?

Yep! This year's growth pushing through last years dead and dry stuff. I really like this one. It was a "recovered" pic, as you can see from the settings I was set for taking fast shots of birds, was just checking the light levels here I think. In any case, the graininess just adds a nice bit of texture, grit, not sure yet. In any case, in photography mistakes can net you as much as successes.