American Pottery Mark - Lily w/ M and Buttercup

by Lisa Howe
(Cincinnati, OH, USA)

Hello
I have this piece of pottery my husband bought that I am rather entranced with. It is in the shape of a lily pad, and to my eye the green glaze looks uneven (See attached picture). I have been unable to find out anything about the piece, even if I do some searches using the little bit of info I see on the pottery mark (See second attached picture).

I think the mark is an M, with an incised symbol of a buttercup above it. Below are stamped the words "Pat. App. For", which makes me think it is American and not from somewhere else.

Do you have any ideas about the factory the stamped and incised mark might be referring to?

Many thanks for your time and expertise,
Lisa