Hi John - well as you correctly surmise that specimen is a hybrid - but based on what you present all I can suggest is that it is either F. solandri x F. fusca or F. solanrdi x F. truncata - you need to show close ups of the leaf undersides, upper surface, margins etc to make a more accurate call. Nevertheless others out there may wish to be more definitive on your image but I won't. Cheers