When I popped down to the edge of the River Ely during last Monday’s walk, I was hoping for dragons and damsels. Instead, I saw flowers I’d not seen before; these plants with the rather lovely towers of globular spiky white blooms are members of the Bur-reed or Sparganium family of aquatic plants that grow both in moving and still fresh water.

There are four species of Bur-reed in Britain: Branched, Unbranched, Least and Floating. From the fact that there is a single unbranched flower spike (raceme), with just one group of the smaller, more compact male flowers at the top means that the species I found was Unbranched bur-reed (Sparganium emersum).