I live in the USDA hardiness zone 10a which is Southern California. I purchased my home about a year ago and have found that in addition to orange trees I have a tree that produces what looks like a lemon on the outside, but when cut into looks like a lime on the inside. The flavor is neither lemon nor lime. It is tangy like a lemon or a lime but I cannot distinguish a prominent flavor. There are no lime trees on the property and the leaves on the "lemon" look-a-like tree not those of the orange trees. Anyone know what I have and how might I use the fruit?