I thought it would be interesting to try making bonsai - or at least dwarfed potted trees - at home, so I gathered seeds from local trees and from purchased fruit, and set about trying to sprout them. I'd never had much luck growing citrus of any kind, but I had visited a different grocery and purchased some organic key limes and miniature pink lemons, and to my surprise and excitement I had a very good response, to the point that I had to give away some of the seedlings.
I kept four key lime seedlings, and after a year (warm season outside, cold indoors in a sunny window) three are between 8" and 11" tall. The fourth, though, grew so rapidly that I had to move it out of the fast food soft drink cup I'd started it in and into a multigallon pot. It's now roughly two and a half feet fall, and unlike the others hasn't branched. Lately I've noticed signs that a new branch is budding near the top.
I did a little research and learned a lot about citrus genetics (special thanks to citruspages.free.fr, your site is great!) and was disappointed and intrigued to learn about polyembryony and nucellar citrus. So all my key limes are clones of the original plant, and probably can't be crossed with most other citrus types available to me, oh well. But that fourth...
I know for a fact it came from the same key limes as the others, and its leaves are similar enough that I'm sure it's the same species. But its behavior... they all ought to be more or less identical, right? How can I tell if I have a mutant or polyploidic version of the key lime? And if this plant really is genetically different, what are the chances that it might be worth keeping? (Not in a monetary sense, but as an interested gardener.)