If it is producing already, it is not a seedling. If it has purplish buds and produces large sweet lemons, it certainly sounds like a Meyer. Some suppliers in your area produce trees from rooted cuttings; it is entirely possible you got two plants in one container.

As for seedlings being close to the mother, if the fruit falls to the ground and is not collected, it is quite common to produce a tree from seed. My Mother, who was less than diligent about collecting dropped fruit, had two new trees from under her Meyer; they ultimately produced "Meyer" lemons... at least, they looked and tasted like Meyers; but they took about 5 years before they produced the first fruit.

My neighbor's Meyer dropped fruit all around and one of the seeds actually sprouted and grew. It's now 17 yrs old, 10' across and 8' high.

I really can't remember when it first started producing lemons, but I believe our first small harvest was when it was about 3-4 yrs old.

Meyer seed is so low in viability as to be almost useless. I've got three Meyers and fruit drop happens all the time. No other Meyers have ever sprouted up except for that once. You're quite fortunate!

I don't know that Meyer seed is low in viability; some years ago I planted 600 seeds and got 580 trees....it is quite a different thing than expecting a seed inside a rotting fruit on the surface of the soil to produce a tree.

Thank you for the information! It really looked like a seedling, very tiny and completely green stemmed. It did take about five years to grow large enough to fruit, but it really does seem exactly like a Meyer. Maybe it was a very small rooted cutting?

I tried growing several of the seeds and only one sprouted, this one with the strange, thin, narrow leaves. Guess I'll wait to use it for grafting stock, until I know it won't make a desirable plant. It's already a little on the thorny side.

Thanks again!