Very cool. Looks like that mutated into a branch. Mine has a single lime at the end of the thorn.

I have never seen a spine giving a flower but often giving a new branch( just cut few yesterday ).

Hey this is Emily
this very very neat i never thought fruit trees could do this has the lime continued to grow

Yes the fruit is about ripe now.

before you pick you should take a picture and show us.

Concerning this bloom that developed on the end of the thorn, I was reading this last night in Volume 1 (page 825) of The Citrus Industry.

"Most species and varieties of Citrus produce thorns, which are actually imperfectly developed branches. Occasionally an especially vigorous thorn shows its true nature by producing leaves and even flowers, and rarely, on a very vigorous thorny shoot, one or more thorns may be replaced by ordinary leafy shoots which develop at the same time as the thorns of neighboring nodes. This shows that thorns are rudimentary lateral branches....."

Here's a thorn trying to be a branch on my TaiTri. I'm torn between wanting to prune it off and wanting to see how it grows. I'm assuming I should prune it off....right? (weak crotch angle, tissue not quite structured like a branch should be...that sort of thing) Anyone ever let one of these grow out?

Pomelo seedling: