I noticed when Poncirusguy's seedling changsha finally reached maturity and fruited, the tree did not quit, or reduce the thorns. Those are some vicious thorns. I have an in ground mature grafted Saint Teresa lemon that is now almost 9-ft tall and is still producing big 1-inch thorns. Also, Saint Teresa lemon is well know for the size of its leaves. Many are 6 to 7 inches long and 4 - 5 inches wide. Produces great lemons year around, with the largest fruit set in in the summer.