This pondweed is like P. natans (Broad-leaved Pondweed) in some respects but the leaves are on the whole narrower and the flower spikes smaller. This one was in a boggy pool on acid soil fed by a mountain stream. P. polygonifolius is very common in Western wales, northern and south western England, Scotland and Ireland but uncommon in the central and south-eastern parts of the country where there is a greater area covered with basic soils.

Cwm Idwal, North Wales 7th June 2005

Added on November 15th 2005, updated 20th July 2011