Citrus bizzarria rediscovered! Without multi-grafting, “It’s the only citrus tree that produces three kind of fruits (which resemble a cedar, orange, and lemon, respectively) on the same plant.”
It used to be originally a graft between the Florentine citron and sour orange but then a branch turned chimeric where the cells co-mingled into one, so depending upon the composition of the chimeras on the different branches, it can produce a citron, a sour orange, or a lemon (intermediate between orange and citron). No different in principle than the variegated chimeras, but instead of one species that have green pigmented or white cells, there are two species chimera in one plant.
Now this has piqued my interests. Too bad it is too complicated to obtain this rarest species because of citrus quarantine rules everywhere.