This perennial of the St John's-wort family can be identified by its distinctive square-stems which have definite wings. The pale yellow five-petalled flowers (15 – 20 mm across) are borne in a flat-topped corymb on these stiffly erect stalks. The flowers have pointed sepals which do not have any dots. However, the oval leaves have translucent dots. This plant, which blooms from June to September, grows in damp ditches and marshy places. It is a native plant belonging to the family Hypericaceae.
I first identified this plant in Rath, Co Kerry in 1977 and photographed it in Gibletstown, Co Wexford in 2007.
If you are satisfied you have correctly identified this plant, please submit your sighting to the National Biodiversity Data Centre