With your first fruit (lemon), how does the fruit taste compared to your other Meyer? How does it compare to a Eureka? Meyer tastes a lot different than Eureka. How does a crushed leaf compare in fragrance to that of the ther two? Because of the deep yellow color, it looks like a Meyer to me, but I'm not there to compare. I say, the proof is in the taste. Also, the taste of the peel. I have a Meyer and do not particularly care for the flavor of the fruit. Medicine-y aftertaste. Now, I'm probably letting it stay way too long on the tree. But I am a big fan of regular Eureka or Lisbon.

Regarding your other 'lime', Persian can have some thorns....just probably never those 3 to 4-inch ones you can see on other citrus. Key Lime is definitely thorny. Do crushed leaves smell/taste like lime? If so, then at least we know it's some kind of lime. Otherwise, I don't think you'll be able to ID it until you get fruit.

Your photos are better quality than many, so I will believe the orange colour I am seeing is correct. This is absolutely typical of a ripe Meyers Lemon, which is actually believed to be a hybrid of lemon and orange. The shape of the fruit and the smooth, slightly shiny surface is also 100% correct for Meyers Lemon. The taste of this variety changes and deteriorates quite rapidly as it ripens so you are probably comparing fruits of different maturity.

It is impossible to be certain from just looking at a leafy shoot, but again everything suggests that this is probably a Persian/Bearss Lime. The leaf shape, some with slightly scalloped edges and the tiny thorns - which are near enough thornless - are typical. The fruit are normally seedless.

A meyer will have a lot of purple tones in the flowers. Lisbon/eureka does not. Meyers flowers are also much more fragrant than most other citrus.

Thank you all for the insight! The Meyer has a sweeter floral smell and different taste to this lemon. This lemon has a slightly floral smell too but its not as strong or sweet. The leaves, when crushed, have a slightly vegetal scent. I've also including a cross-section of a fruit incase it helps further narrow things down.

Regarding the potential Bearss, the leaves have a strong lime-y smell. I'm only accustomed to baking and cooking with key/Mexican limes so I don't have another point of reference (and this tree is definitely not a key lime anyway). I would describe the smell as similar to those fairly acidic smelling packets of the Mexican "Limon" candy/salt. I am thinking it is a Bearss to the light serrations of the leaves, as some of you have mentioned. I really don't think people should advertise Bearss as being nearly thornless. The thorns on these are definitely there, except smaller, so they are easy to miss and even more painful...

You are correct, the inside does not look like a Meyer. I can't say what it is however. How does the juice taste?

The juice is acidic but not overly acidic. But that's about it. It's very one note. Not floral or sweet at all.

Grafted lemon or seedling? I have a buddy not far away that has a rather unique lemon.... its a mature seedling and we cannot match it to a popular variety.