Fragrant flatsedge

Cyperus odoratus sensu lato is an annual sedge approaching half a meter in height on average but known to grow much taller. It usually has some long, thin leaves around the base of the plant. The inflorescence is made up of one to several cylindrical spikes, each resembling a bottle brush. There are 5 to 8 leaf-like bracts at the base of the inflorescence. Each of the spikes bears a large number of flat, oval-shaped spikelets. Each spikelet is usually light brown to reddish-brown and has a few to over 20 flowers. Each flower is covered by a tough, flat scale (a kind of bract) with a visible midvein. The fruit is a flat achene less than two millimeters long. Cyperus odoratus sensu stricto is similar to Cyperus engelmannii. The floral scales of Cyperus odoratus are overlapping. In contrast, the mature floral scales of Cyperus engelmannii do not overlap, that is, the tip of each scale does not reach the base of the next scale on the same side of the spikelet. The mature achenes of Cyperus odoratus are slightly ellipsoid, while those of Cyperus engelmannii are narrow with linear (parallel) edges. The widths of fully developed achenes are 0.5–0.7 mm and 0.3–0.4 mm, respectively. Cyperus odoratus and Cyperus engelmannii are the only two Cyperus species in temperate North America with spikelets that eventually break into one-seeded segments. …

Cyperus odoratus sensu lato is found in much of the tropical and warm temperate world, including South, Central, and North America, Southeast Asia, some Pacific Islands, Australia, New Guinea, Madagascar, and central Africa. It is a plant of wet, muddy areas, including disturbed and altered sites. Cyperus odoratus subsp. transcaucasicus is native to Iran, Iraq, and the South Caucasus.