I have a mandarin tree which grew up in my compost heap about 5 or 6 years ago. The tree was transplanted to a pot at about 2 years old Last year it fruited, but all fruit dropped off at marble size. This year the fruit is still green, but beginning to turn orange, about the size of an egg, but they are hard as rocks - about 10 fruit in all. The leaves are definitely mandarin type. I picked one and cut it open and tasted the fruit - really, really sour. Since it grew up in my compost heap, it had to be something edible. My question, could a mandarin seed have morphed into something else and is there such a thing as a sour mandarin that would have evolved from the seed of an edible mandarin?
Thanks
BILL
