All of the flowers above belong to the family of Daisies. The most common is the White Shasta Daisy. Many people consider this flower to be a nuisance. Daisies are composite flowers, which means they are really hundreds of little flowers on one stem. Another familiar composite flower is the dandelion.
The Golden Guide to Flowers says "The Field Daisy is beautiful and abundant in eastern fields and roadsides. The plants, 1 to 2 feet high, grow in clumps, topped by white-rayed, yellow-centered flowerheads. Most of the toothed leaves cluster at the base of the stem.