The flowers are probably purple or blue thistle on the large irregularly shaped serving platter.
It was purchased at an estate sale in Washington State and identified as from the 1950s. Its lovely hand-painted design is signed with the initials E.R.
It measures about 15.5" by 13" and is 2.5" high at the rims, sitting on a pottery ring.
It is in very good condition with slight age crazing. The flowers are a blue or purple and look like thistle blossoms. Despite some shadow coloration in our photos, the background is solid white.
It would be a lovely serving platter.