ON SOME WATER PLANTS. IO9 
distributed, being found throughout the north temperate 
regions. 
The Great Sedge or Bulrush, Scirpus lacustns, when growing 
in little rivers like the Roding or in the still waters of the Nor¬ 
folk Broads, sends up from thick creeping rhizomes clumps 
of long stout cylindrical stems, some of which bear flowers at 
their summits, while others are flowerless. The leaves form 
short green or brown sheaths, with little or no development 
of a free blade, folding round the stem bases ; but when 
growing in deep water in the Thames or Ouse, abundant float¬ 
ing and submerged ribbon-leaves are produced, from two to 
five feet long, which look like water forests as one passes over them 
in a boat. They resemble the submerged leaves of Bur-reed^ 
