Cyperus surinamensis Rottb.
Distribution: Central U.S. to South America
Habitat: Weedy, usually moist
Florida status: Native.
Recognition: With distinctively retrorse-scabrous culm. Weedy and one of the most frequently encountered sedges in our area.
Cyperus distinctus is similar but has smooth culm and achenes with white-spongy base.
Also similar is C. virens, which has antrorsely scabrous culms