The sedge above is Carex oklahomensis, Oklahoma Sedge, an endangered species in Indiana. It is somewhat similar to C. stipata, of which it has been treated as a variety in the past, but you'll notice that it doesn't have the spongy, inflated culm of C. stipata. Carex oklahomensis is found in wet meadows, marshes, and alluvial bottomlands, mostly in the plains and southern states. However, its range is thought to be increasing to the north and east. We saw this species in abundance in a wet sand flat.
Yes, it really does exist! Above is Carex lupuliformis, False Hop Sedge, a rare species in Indiana. While its range includes the entire eastern half of North America, it is said to be rare and local where it occurs. Until yesterday, anyone I had ever asked about this species said they had never seen it. You may think that this looks a lot like C. lupulina, the far more common and closely related hop sedge. The best way to tell the two apart is by looking at the achenes, which are longer than wide and not strongly knobbed on the angles in C. lupulina, but which are nearly as wide as long and strongly knobbed on the angles in C. lupuliformis.