thanks Sam. Yeah I figured it was, but wondering exactly what variety of PT it was. This was the rootstock of a mandarin/orange tree. It is growing so vigorously so I wanted to know what it is.
I have the regualr poncerius trifoliata as the rootstock for orange, but it doesn't grow anywhere near this size and the thorns are not this big. I also have my 30+yr old Flying Dragon so I can recognize that one as well.