There are more than 80 genera and 4000 species of Cyperaceae, which are widely distributed all over the world. There are more than 500 species in 28 genera in China, many of which are farmland weeds. Morphological characteristics: Herbs, most of which have rhizomes, a few have tubers or bulbs, and the stems are often triangular and solid. Leaves are often 3 rows, long and narrow, and leaf sheaths are closed. Flowers are very small, several flowers are arranged in a spikelet shape, and most of them have scales under them, which are called spikelets, and then arranged into various inflorescences. Each flower has 1 bract (scale or glume), and the perianth is completely degraded or bristle-like. Flowers are mostly bisexual and stamens are mostly 3; The pistil consists of 3-2 carpels, and the ovary is superior, with/kloc-0 per cell,/kloc-0 per ovule and 3 stigmas. Nuts. Identification point: 1. The stems of POTAMOGETON crispus are triangular, and most of them are cylindrical. Cymes are solitary or recurrent, or shortened into heads, and the bracts under the inflorescences are like extensions of stems or leaves. Spikelet flowers are as few as many, and scales are arranged spirally, each scale contains 1 bisexual flowers, or less than 1 to several scales without flowers; Lower bristles 2-9 or absent; Style base does not swell. Schmidt.2 and Cyperus are scattered or clustered, usually triangular. Ye Jisheng. Cymes are solitary or resurrected, sometimes shortened into heads with several leaflike bracts at the base. Spikelets 2 to many, slightly compressed, spikelet rachis persistent; Zoom 2 lines; Without lower bristles. Stigma 3, rarely 2. Nut trigonous. (1) Cyperus (2) Cyperus heterophylla (3) Cyperus alternifolia. Fan worm Kuk3 and Carex are unisexual and have no perianth; Male flowers have 3 stamens; The ovary of female flower is wrapped by a sac (fruit sac) formed by bracts, and the style protrudes outside the sac, with 2-3 stigmas. 4. Water chestnuts are clustered or solitary. Leaves only have leaf sheaths and no leaves, and bracts are missing; Spikelets 1, terminal, usually with many bisexual flowers; The bottom of the style expands into various shapes and persists at the top of the nut. (1) water chestnut (ROXB) Roem et Schult (2) sedge (3) horseshoe (Franch. et Savat。 ) Tang Dengwang: Herbaceous plant with triangular stems and solid leaves. Perianth degenerates and spikelets form various inflorescences; Nuts. It's comprehensive here, and there are many pictures, which should solve your problem (many pictures are not easy to upload): /zhuan tiwang/ziran Wang/kexueb/ Xue Ke-2/zutiweb/zu010/3-02.htm.