I had never seen a Rangpur Lime until a friend of mine in California gave me some from her tree. It's a hybid between a mandarin orange and a lemon.
It is acidic like a lemon that peels just like a tangerine with a deep orange colored flesh.
It was introduced to Florida in the late 19th century by the Reasoner Brothers who had brought back seed from Oneo, India. Today they are planted as ornamental trees.
Tanqueray Gin makes a Tanqueray Rangpur!
I think it would be great to make Lemonchello with these!