Phragmites australis, the common reed,'s a large perennial grass found in wetlands throughout temperate and tropical regions of the world. It's sometimes regarded as the sole species of the genus Phragmites, though some botanists divide Phragmites australis into three or four species and in particular the South Asian Khagra Reed (P. karka)'s often treated as distinct. Growth Common reed commonly forms extensive stands (known as reed beds), which may be as much as a square kilometer or more in e… (More on Phragmites)