Sedges have edges goes the old saying. Stems on sedges are triangular and can be felt by rolling them between your fingers.
The sedge grows to be about 1-3.5 feet tall. Relatively large green-to-black spike-like inflorescence, with long, bright green strap-like leaves growing from a clump below. Stems clump-forming to 3' tall, stout, shorter than leaves. Leaf blades to 3/8" wide. Sheaths loose, papery.