Chestnut sedge is a nativeof the brackish and salt marshes of Florida, but is sometimes found in freshwater marshes. It is common nearly throughout the state (Wunderlin, 2003).
It is a "fringe-rush sedge". Its stem is densely tufted, to 48 in. tall, ribbed, as wide as leaf blades; leaf blades linear, narrow, rolled margins, base black or very dark brown; ligule absent; sheaths rigid, thick; bracts equal to or longer than inflorescence; inflorescences compound umbels, spikelets on branched tips; spikelets cone- to lance-shaped, to 5/8 in. long, spikelet scales spirally arranged.
There are about 25 Fimbristylis species in the U.S. with about 9 in Florida. This species is found along the Atlantic and Gulf coasts (Kartesz, 1999).