Reed is the general botanical term used for tall, grass-like plants of wet places. They occur in reed beds. They are all members of the order Poales. Reeds are many polyphyletic species, which have all adapted to this wet habitat by convergent evolution. Phragmites australis, the common reed, is used in many areas for thatching rooves (roofs). When thatched rooves were common, rivers were harvested for reeds every year.