About Cyperus odoratus L.
Cyperus odoratus sensu lato is an annual sedge that averages close to half a meter in height, though it can grow much taller. It typically has several long, thin leaves growing around the base of the plant. Its inflorescence is composed of one to several cylindrical spikes, each of which resembles a bottle brush. At the base of the inflorescence, there are 5 to 8 leaf-like bracts. Each spike holds a large number of flat, oval-shaped spikelets. Most spikelets are light brown to reddish-brown, and hold anywhere from a few to over 20 flowers. Each flower is covered by a tough, flat scale, a type of bract, that has a visible midvein. The fruit it produces is a flat achene that is less than two millimeters long. Cyperus odoratus sensu stricto is similar to Cyperus engelmannii. The floral scales of Cyperus odoratus overlap, while mature floral scales of Cyperus engelmannii do not overlap: the tip of each Cyperus engelmannii scale does not reach the base of the next scale on the same side of the spikelet. Mature achenes of Cyperus odoratus are slightly ellipsoid, while mature achenes of Cyperus engelmannii are narrow with linear, parallel edges. The width of a fully developed achene is 0.5–0.7 mm for Cyperus odoratus, and 0.3–0.4 mm for Cyperus engelmannii. Cyperus odoratus and Cyperus engelmannii are the only two Cyperus species native to temperate North America whose spikelets eventually break into one-seeded segments. When mature, each spikelet breaks into individual segments, each segment consisting of a scale and an achene held together by a section of the floral axis. Cyperus odoratus sensu lato occurs across much of the tropical and warm temperate world, including South America, Central America, North America, Southeast Asia, some Pacific Islands, Australia, New Guinea, Madagascar, and central Africa. It grows in wet, muddy areas, including disturbed and altered sites. The subspecies Cyperus odoratus subsp. transcaucasicus is native to Iran, Iraq, and the South Caucasus.
