The listing, Gorham Brooch has ended.
This pin is marked GORHAM. I don't see any other marks. I believe it is silver plate but I haven't tested it. As far as age, I've had it for at least twenty years and I can't remember where I got it, so it could be older. I also tried to find it on the Internet with no results. The flower looks to me like dogwood but this is just a guess. The pin was quite tarnished so I cleaned it up a bit with a silver cloth, and the rest will be up to the buyer. Also, there is a slight bend in the pin bar, but nothing that affects the closing of the pin. It has nice weight to it and measures 3" by 2". This is a really nice piece.