This is a Universal Potteries cup and saucer set. The line is called Ballerina Mist and the pattern is called Strawflower.
Universal Potteries Co. began production in 1934, in Cambridge, Ohio. They are known for both their Cattail and Ballerina lines. They began producing the Ballerina line in 1956. I could not find an end production date. The company closed in 1960.
I have eight (8) of these cup and saucer sets available for sale, each set separately. They are all in excellent, but not perfect condition. There is a small amount of wear to the platinum trim that is on the rim of the cup and the outside edge of the saucer. The wear is negligible, but I wanted to make sure that I mentioned it.
Take a look at the pictures, and if you have any questions, please e-mail.