PTL Pt Pteridium aquilinum var.latiusculum Pterophyllum chengzihense sp. nov. Pteridium aquilinum var. latiusculum Pteridium aquilinum var. latiuseulum Pt-Rh two-element knitted meshwork pterygopalatine sulcus of palatine bone PTDI provisional tolerable daily intake PTC Electrical Symbols Library Wildfire pterygopalatine sulcus of sphenoid bone pterygopalatine fissure of palatine bone