Phragmites australis

Phragmites australis, known as the common reed, is a species of flowering plant in the grass family Poaceae. It is a wetland grass that can grow up to tall and has a cosmopolitan distribution worldwide. Phragmites australis commonly forms extensive stands (known as reed beds), which may be as much as or more in extent. Where conditions are suitable it can also spread at or more per year by horizontal runners, which put down roots at regular intervals. It can grow in damp ground, in standing water up to or so deep, or even as a floating mat. The erect stems grow to tall, with the tallest plants growing in areas with hot summers and fertile growing conditions. The leaves are long and broad. The flowers are produced in late summer in a dense, dark purple panicle, about long. Later the numerous long, narrow, sharp pointed spikelets appear greyer due to the growth of long, silky hairs. These eventually help disperse the minute seeds. Recent studies have characterized morphological distinctions between the introduced and native stands of Phragmites australis in North America. The Eurasian phenotype can be distinguished from the North American phenotype by its shorter ligules of up to as opposed to over 1 mm, shorter glumes of under against over 3.2 mm (although there is some overlap in this character), and in culm characteristics. Phragmites australis subsp. americanus – the North American genotype has been described as a distinct species, Phragmites americanus Phragmites australis subsp. australis – the Eurasian genotype Phragmites australis subsp. berlandieri (E.Fourn.) Saltonst. & Hauber Phragmites australis subsp. isiacus (Arcang.) ined. It is a helophyte (aquatic plant), especially common in alkaline habitats, and it also tolerates brackish water, and so is often found at the upper edges of estuaries and on other wetlands (such as grazing marsh) which are occasionally inundated by the sea. A study demonstrated that P. australis has similar greenhouse gas emissions to native Spartina alterniflora.