A sedge is a plant in the Cyperaceae family. These plants are monocotyledonous, or flowering plants. The broad Cyperaceae family group includes about 5,500 varieties of sedges. These are widely distributed around the world, but tropical South America and Asia are believed to be the two main locations with the most diverse number of plant varieties. A sedge is able to grow and even thrive in all kinds of soils and climates, but most sedges can be found in locations with poor soil, or more particularly, in marshes or wetland areas.
Sedges, at first glance, often are mistaken for grasses or rushes, but sedges differ from rushes or other grasses in that their stems have strong, triangular cross-sections. The leaf sheath generally is closed, and its leaves grow in ranks of three. Grasses have hollow stems with nodes where leaves sprout in a more open fashion, in ranks of two. Rushes have solid stems but are round. Rush leaves are flat but also ranked in threes and tend to grow in a spiral fashion, basally arranged.
A sedge produces only single seeds from its flowers and is either unisexual or bisexual, meaning that each flower contains either a female or male part, but not both. There is a rhyme that many botany and horticulture students have been taught in order to remember the main differences between the three: "Sedges have edges, rushes are round. Grasses have nodes from the top to the ground."
The water chestnut, Eleocharis dulcis, probably is the most commonly known edible sedge and is considered a staple in Oriental cooking. The papyrus sedge, or Cyperus papyrus, is almost equally well known, and it has been used in various ways since the times of ancient Egypt. The pith of the papyrus plant was most notably formed into a type of paper on which ancient texts were written. Some parts of the plant are edible as well. The stems are highly buoyant and often were fashioned into boats.
In many areas, sedges are used as ornamental plantings to provide texture, movement, color and interest in landscaping. Sedges are very hardy and thrive in shady areas with a lot of moisture. The sedge is considered a nuisance weed in many locales. Sedges are extremely difficult to get rid of after they have infiltrated lawns, because most herbicides have little to no effect on them.