I have acquired a couple of potted thorny trees that may be of a citrus veriety but I an unable to identify either of them. The first is now about six feet tall and the other, (last picture) slightly different, is five feet tall. Please note photos for identification.
The first (pics 54-32 and 55-58) looks like a Tangelo, and the second (57-18 and 55-32) a Lemon. Which specific cultivars, I couldn't tell you.
They do appear to be citrus trees. The first one reminds me of the seedling minneola orange I had. The other one might be a mandarin. Bronze colored new growth would suggest a variety of lemon.