Not a plant in danger of being picked to extinction, this is a stiffly erect annual or biennial which is commonly found on waste ground, in hedgerows and disturbed ground. It stands up to 80cm high and bears its tiny yellow 4-petalled flowers (3mm across) in a terminal cluster from May through to October. This cluster of flowers elongates as the fruit develops. The lower leaves are stalked and pinnate with the end lobe being the largest and its upper leaves are narrow and unstalked. The fruits are hairy pods (6-20mm long) which are closely pressed into the stem. This is a native wildflower belonging to the Brassicaceae family.
My earliest record of this plant is in 1976 in Dalkey, Co Dublin and I photographed it in 2007 in Killiney, Co Dublin.
If you are satisfied you have correctly identified this plant, please submit your sighting to the National Biodiversity Data Centre