Oxeye Daisy/Leucanthermum vulgare
Common, all summer, perennial, 1-3 ft. Erect, small somewhat like chrysanthemums. Stems many, seldom branched, from creeping root. Basal leaves with petioles, pinnately lobed and toothed; stem leaves becoming smaller and sessile. Flower head 1 per stem, 1-1 1/2 in. across, with fewer than 22 white ray flowers and many yellow disk flowers. Grows in pastures, meadows, clearings, roadsides, at low to mid elevations. From Paul Noll's webste