This plant species is well named – Stinking Tutsan has a most unpleasant smell when the leaves are crushed. At a first glance, it might possibly be mistaken for Tutsan or Hypericum androsaemum. Its very similar flowers are five-petalled, bright yellow and at their centre is an absolute mass of protruding stamens. The styles are longer than the stamens and protrude even further. The sepals curl back and fall off the flower prior to the fruit ripening. The flowers bloom from June to August. A clear identifying feature – apart from the smell - is the stems which are much branched and have four ridges along them making them feel square to the touch. The oval leaves are hairless and opposite. A perennial member of the Hypericaceae family, Stinking Tutsan grows to about 1.5 metres, is a garden escape and favours shady places.
I spotted this growing along the embankment beside the DART line in Dalkey, in 2016 when I also photographed it.
If you are satisfied you have correctly identified this plant, please submit your sighting to the National Biodiversity Data Centre