Fimbristylis castanea (Michaux) Vahl
Common misidentification: Fimbristylis spadicea (L.) Vahl
Distribution: Eastern U.S. to Mesomamerica, Caribbean
Florida status: Native
Recognition: Saltwater (often placed incorrectly under F. spadicea according to FNA). Ligule absent. Achene 1.5-2 mm long.
Fimbristylis cymosa also may occur on seaside beaches or dunes. The latter is likewise eligulate and likewise has blunt scales, but the spikelet is much smaller (2-3 mm vs. 5-20 mm), the achene is larger (1.5-2 mm vs. 1 mm long) and the inflorescence in F. castanea is usually compound (vs. usually simple in F. cymosa).
Also sometimes in brackish places, F. caroliniana has a ligule, unlike the other two species above. In F. caroliniana the leaf blades are 2-5 mm wide. The stem is flattened and scabrous distally.