Forget me not
It's a poetic expression of "don't forget me." At the same time, there is a flower which is named forget-me-not.
I found a cafe which name is "forget me not coffee" in Japan. At first, I thought they used wrong grammar. That's the reason I looked up this expression on the Internet. They were right!
Refs
idiom, 14-07-01 10:08, 14-07-01 10:09, Yosei