This member of the Brassica or Cabbage family is one of Ireland’s rare native plants. Growing to about 60cm, with stout, ridged stems, it is a hairless biennial which has tiny, 4-petalled, whitish-greenish flowers (3-4mm) with 6 yellow stamens and which are borne in short racemes on erect, leafy stems. The petals – which are frequently missing - are scarcely longer than the 4 sepals. The leaves are pinnate with 5-9 pairs of sharply toothed, pointed leaflets and conspicuous auricles which clasp the stem at the base of the leaves – these auricles help to identify this plant. The fruits are in long, stiff, ascending, slender siliquas (2-3cm) which carry the seeds in one row and which burst when ripe. Narrow-leaved Bittercress blooms from May to August in shady, damp, rocky places, waste ground and streamsides, usually on calcareous soils, where it forms colonies.
I first came across this protected species in May 2014 and photographed it at that time.
If you are satisfied you have correctly identified this plant, please submit your sighting to the National Biodiversity Data Centre