Leucanthemum vulgare Lam.
Plant height 20-70 cm. Flower width 2.5-5 cm.
This one really stands out from the crowd with its large yellow centred and white petalled flowerhead. The bright green leaves are spoon-shaped with coarsley toothed margins. The bracts beneath the flowerhead contain an acrid substance that prevents invertebrates from biting through the nectaries.
It flowers from May to September, and is found in grassy meadows, on riverbanks, roadside verges, embankments and brownfield sites. Common and widespread throughout Britain.