One of my Kucle x Poncirus (say "Citrucle") seedlings got four flowers. It will not impress you when I say after four years. What is remarkable is that it got these flowers at a height of only 1m and had no side branches. So a very small plant. It is still so small because I first planted it at the wrong place, too shadowy and too cold. That was why it lost about two years of growth. All its siblings of the same age do not flower even though some are bigger.
When I created my Kucle hybrids I used a pollen mixture among which was dried and frozen pollen of precocious poncirus (the Laaz-type). I would say I have a hybrid of it!
I pollinated my Citrucle with Swamp Lemon and used it decent pollen on C. ichangensis, Calamondin and last but not least on Swamp Lemon and another better tasting poncirus. We will see what comes out of these further crosses.