The Common Reed (Phragmites australis) is a species of plany in the Poaceae family.
Description[]
This species is throughout Britain, inhabiting wetlands such as fens, reedbeds, marshes, salt-marshes, rivers, ect. This tall plant can reach 3m (10ft) in height, with long, slender green leaves and a "feathery flower-head". They flower from August to September.
The stems of these reeds are the largest in Britian and are tough enough to be used for thatching.
Common Reed - http://www.flickr.com/photos/qwertyqwertyqwerty/