Nothing is known about these two floral patterns that are so very similar - other than what is shown on the backstamps.
The one on the white clay body was produced in 1934, and if you look closely you'll see a 20 as part of the backstamp, along with Mattson's signature -M- and the date.
We thought at first the one on the Glo-Tan clay body was produced in 1931, and while it lacks the classic -M- signature, there is an M and a 20, making us think these were both samples for the same design. The Glo-Tan plate seems to have thorns on the stems and much more rounded petals.