Members of the sedge family have leaves that are composed of a blade, sheath, and ligule. The leaf sheath is closed and the ligule is often absent, and when present is tiny. Stem structure is often triangular.This 3-page fact sheet was written by D. E. P. Telenko, Ramon Leon, J. Bryan Unruh, and B. J. Brecke, and published by the UF Department of Environmental Horticulture, December 2014.
http://edis.ifas.ufl.edu/ep492