I found the pattern! Or what I suspect is one of many versions of the pattern since the one I found was published in 1959 and I've seen a sources that dates plates like this to the 1920s.
It's honestly not much of a pattern at all, is it? I couldn't bring myself to spend a dollar for the plates I found, but now I'm wanting to make a set of my own. And a bunch of other things from the same book that would have been completely reasonable in their day but seem a bit silly now.