Some pictures would help, of the fruit, a leaf close-up, and a pic of the whole tree.

But I have a bad feeling from your description that your orange top graft may have died sometime early on, and now the root stock is growing only.

The description of the fruit is pretty spot on for Cuban Shaddock, a dwarfing root stock for citrus.
Cuban Shaddock leaves look more like other citrus than the other most common root stock, Trifoliate orange (Poncirus trifoliata), which has "leaves of three".
The fruit from the , Trifoliate orange, is small, and very seedy, dry with little juice.

The fruit from Cuban Shaddock root stock (Citrus grandis) is edible, it very juicy with a lemon-like juice, very thick white part of the skin and some seeds.

If this is the case, you can decide to either dig it up and replant with a new orange, or enjoy the lemony sour juice of the root stock.

Here's fruit and leaves of a Cubban Shaddock;
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Here's Trifoliate;
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I would pay someone to graft onto your tree before replacing it. Why give up years of establishment? You have a wonderful root system if your getting fruit.

Can you post pictures of the trunk so we can look for the graft line?

Persian limes are large and turn yellow when ripe and they don't taste like regular limes. Could this be what you have?

You guys are awesome. it's definitely not Cuban Shaddock or Trifoliate. The pictures attached were taken a few minutes ago in a dark backyard. Hopefully you can see them clearly. I don't know how to attach multiple photos so they are coming one at a time. The first is of the tree.

The next is of the root stock.

Leaves and fruit close up ...

And finally ... The fruit cut.

Here is the fruit uncut ...

This is a close up of the tree where you can see the fruit yellowing. If I touch that fruit, it will come off the tree. It feels ripe so I'm guessing it's not an orange but is different than my Mexican lime. It's a bit sweet to the taste ... Like a sweet lime almost.

I wouldn't dig it up. It's a pretty tree and the bees seem to like the flowers. I would, however, like to be enjoying the fruit ...whatever that may be.

Again ...thank you!!

I think eahamel is right, that looks a lot like a Persian lime, also called a Bearss lime. It is a little sweeter than a Mexican lime and is seedless.

Nice! It's a great lime, glad it wasn't a root stock takeover!

I'm with Barb, looks like a Bearss lime tree to me.
Evan

Bearss lime :-)

Patty S.

Than you so much. I'm actually kind of excited that it's a lime. Although it does mean I will have to find a nice dwarf orange tree and a place to put it (wink). Again ... You guys are awesome.

Everyone did such a great job on SAguirre's quest, I'm hoping you can help with mine. I realize this is an old post, but am new to houzz and didn't see where to post a new question.

I inherited a citrus from a neighbor who moved away. The fruit never seemed to ripped (it stayed green till it turned brown and the fruit was very hard.) The fruit is sour with a slight sweet orange taste.

Has the tree been kept warm? It is cool weather that causes a citrus fruit to loose its chlorophyll and then turn orange. Citrus in he tropics never turn fully orange.

Looks kind of like a limon mandarina

has stayed warm. This weekend is the 1st time we've had weather get down anywhere close to the sixties.

Citrus limetta may be. In India it is locally called Mousambi. Mild sweet lime taste. But I am just guessing from the picture.

Rezthanin, just because the fruit is not yellow does not mean it is not fully mature. Many mandarins are mature and ready to eat before they turn color.

Only other thing of note is that most of the leaves kinda of have a double lobed shape, with a small leave followed by a larger leaf.