Annual or perennial plants. Rhizome often sturdy, horizontal, frequently producing stolons, which may end with tuber or bulbil. Leaves reduced; lowest open sheaths loosely surrounding stem base, scarious, soon disintegrating; above them two closed sheaths tightly surrounding stem base; blades 0; ligule 0. Inflorescence a single spike, glumes spirally arranged, all fertile or lowest 1-2 sterile. Flowers bisexual; perianth bristles 3 to 8, conspicuous or small, retrorsely barbed, occasionally absent; stamens 3-2; stigmas 2-3; stylopodium persistent on top of mature nut, distinguished by its softer, often spongy texture, in most cases bulbous and clearly separated from nut by constriction. Nut 0.5-2.5 mm, excl. stylopodium, trigonous or lenticular.
Eleocharis resembles Schoenoplectus in having reduced leaf blades, characteristically, there are two closed sheaths at stem base and inflorescence is a single spike. Style base is swollen as in Abildgaardia and Fimbristylis, but in these genera the stylopodium is caducous, in Eleocharis it persists. The style base in E. quinqueflora is conical and stylopodium tissue is visible only when wet. The small stylopodium of Bulbostylis may be persistent, but Abildgaardia, Fimbristylis and Bulbostylis species all have well-developed leaf blades. Trichophorum is also unispikate, but characterized by short leaf blades and by absence of stylopodium. For subgeneric division, see Kukkonen, Ann. Bot. Fennici 27: 109-117. 1990, Gonzalez-Elizondo & Peterson, Taxon 46: 433-499. 1997.