Bellis perennis
The flower heads are  in diameter. Although the 'flower' may appear to consist of a yellow centre with white petals, this is not the case. Each individual "petal" is itself an individual flower; these flowers are called ray flowers. In the centre (the "disk") there are also many tiny yellow flowers; these are called the disk flowers. The different colours and styles of flower work together in order to attract insects. The flower heads are produced on stems without leaves that are  tall.