Taste will surely be definite. Also size, shape, texture, color of fruit and seediness, maybe rind thickness, number of fruit sections, maturity period, etc.

You can't tell any differences in leaves on the branches in question?

Do you know what variety was used as rootstock?

Confirming that rootstock is poncirus trifoliate flying Dragon. I got confused as it is not a satsuma but a grapefruit. It was originally potted and transplanted b/c afraid it would crack my precious container. Need to ck my journals as I lost tag. Here is pic of foliage with my fist for reference

Here is pic of fruit, notice point. I don't remember grapefruit a having a point. This fruit is from one side of tree

Here is fruit from opposite side which is definitely from below graft. Looks same as prev pic

Oops

Probably not Satsuma, Grapefruit, or Flying Dragon.

If you have a branch that comes from below the graft, Flying Dragon would be VERY distinctive.

Do you have a picture of a leaf that clearly shows the petiole?

Branches, leaves, and fruit all look like some type of lemon to me.

ill go do it right now. And I also think I have a lemon. ugh, I have limes and lemon, don't really have room for a third lemon, hate to yank it but...

Does this help?

Another

Try again

If lemon, the foliage should have a lemon scent when crushed. Lime leaves are also uniquely lime-scented.

Grapefruit leaves should have a winged petiole I think, which I do not see. So I seriously doubt that is grapefruit. And it is definitely NOT flying dragon rootstock.

I'd too say that leaves, petioles and fruit shape seem to point to a lemon. I do not know of any other group of citrus with such a characteristic nipple on the end. Unless an odd hybrid.

If you have another (known) lemon tree, compare scent/taste of a crushed leaf.

Another distinguishing characteristic of Lemons is purple flowers.

what about Meyer lemons are their flowers purple

In general Meyers don't have that thick/rough a skin; neither do they "generally" have that nipple... BUT, some do.

Yes their flower buds are usually purple Steve

The flowers on both of my Meyer lemon trees are pure white. They appear to be from rooted cuttings. If they were grafted the fruiting branches are lose to the roots so the rootstock could not flower with only 18 inches of wood/bark to the roots. none the less these lemons are from rooted cuttings

Well, I was giving a general answer but I will expound. Some lemons and I believe limes have only faint purple coloring, or initial purple coloring that fades very quickly in hot weather. I have personally observed both purple and green tipped new growth on my lemon at the same time, so it is not a hard and fast rule that the flowers 'have' to be purple, especially with the current season. Just in general they are.