Hmmm... That's probably correct. I know a fern guy and will ask him shortly. All indications seem to say that you're right. Curiously, IPNI has it both ways:
http://www.ipni.org/ipni/advPlantNa...off&query_type=by_query&back_page=plantsearch
http://www.ipni.org/ipni/advPlantNa...off&query_type=by_query&back_page=plantsearch