When I first grew this daisy it was called Chrysanthemum hosmariense (I think), then it became Leucanthemum hosmariense. Now I believe its accepted name is Rhodanthemum hosmariense (Ball).
Whatever its name, it is a great plant for the garden with silvery, finely cut foliage, sparkling white flowers and buds with sepals which are edged in black.
It stays low to the ground when grown in full sun. After it flowers the flowering shoots should be cut back so I guess it should be considered a sub-shrub
cheers
fermi