I can't decide on B. verna or B. orthoceras
Petit champ près d'une piste cyclable
Loaded up especially for John van den Hoeven (see http://naturewatch.org.nz/observations/2353510). The weather and time finally allowed a lawn massacre (getting into a hay paddock) - at least for now this plant has had a hair cut. It will rise again I am sure.
Stems and leaf margins distinctly hair, upper stem leaves pinnatifid. Weed in lawn, rarely gets to flower before it gets scalped by lawnmower - but I have been a tad remiss with mowing of late so it got to flower....
Not 100% on the ID
Barbarea (winter cress or yellow rocket) is a genus of about 22 species of flowering plants in the family Brassicaceae, native to temperate regions of the Northern Hemisphere, with the highest species diversity in southern Europe and southwest Asia. They are small herbaceous biennial or perennial plants with dark green, deeply lobed leaves and yellow flowers with four petals.