Phragmites, the common reed, is a large perennial grass found in wetlands throughout temperate and tropical regions of the world. Phragmites australis is sometimes regarded as the sole species of the genus Phragmites, though some botanists divide Phragmites australis into three or four species. In particular the South Asian Khagra reed – Phragmites karka – is often treated as a distinct species.
The World Checklist of Selected Plant Families, maintained by Kew Garden in London, accepts 4 species as of August 2013:
Phragmites australis (Cav.) Trin. ex Steud. – cosmopolitan
Phragmites japonicus Steud – Japan, Korea, Ryukyu Islands, Russian Far East
Phragmites karka (Retz.) Trin. ex Steud – tropical Africa, southern Asia, Australia, some Pacific Islands
Phragmites mauritianus Kunt – central + southern Africa, Madagascar, Mauritius