Carex is a vast genus of more than 2,000 species of grass-like plants in the family 'Cyperaceae', commonly known as sedges (or seg, in older books). Other members of the family 'Cyperaceae' are also called sedges, however those of genus 'Carex' may be called true sedges, and it is the most species-rich genus in the family. The study of Carex is known as caricology.

The leaves of Carex comprise a blade, which extends away from the stalk, and a sheath, which encloses part of the stalk.

The defining structure of the genus 'Carex' is the bottle-shaped bract surrounding each female flower.

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