I inherited 3 trees when I bought my house and all three have thorns on the branches with two trees having what appear to be lemons with orange highlights. When opened they have a very thick skin, are easy to peel and have a light orange and lemon smell. They are not sweet and not as tart as a lemon but edible nonetheless. The third tree has what I think are lemons and limes but they are all small and mostly I think to be limes. I cant seem to find any grafting on the trees, however they are over 5 years old.
What the heck is going on here? Does anyone have any idea what they might be?