KEY TO NEW CALEDONIAN PTISANA MURDOCK
1. Mature plants <50 cm long, sori produced on fronds as small as 14 cm long ................................................. ........................................................................................................ P. rolandi-principis (Rosenst.) Christenh.
— Mature plants bearing fronds up to several metres in length, sori not produced until fronds> 100 cm long ........ 2
2. Stipes purplish-black, wrinkled; laminae of mature plants uniformly 3-pinnate, pinnules with serrate margins, often doubly serrate toward the apex with 2-3 veins per tooth ......................... P. attenuata (Labill.) Murdock
— Stipes mottled green-brown, smooth; laminae of mature plants 3-pinnate proximally but 2-pinnate distally, pinnules with sub-entire or minutely serrate margins, 1 vein per tooth (rarely more) ...................................... ....................................................................... P. soluta (Compton) Murdock & Perrie, comb. nov., stat. nov.