An interesting genus of ferns, unusual for the presence of two distinct types of fronds.
These form shield fronds, also called sterile fronds, which form a nest for the roots. These shields may act to catch leaf litter and organic debris, or they may act to regulate moisture, such as types with closed shields, which tend to grow in very wet areas.
The other type of frond is called a fertile frond, or normal frond. These vary from an entire, rounded frond, such as in P. elephantotis, to much-divided, long fronds.
I hope to build this site soon, but pictures and descriptions of these plants can be viewed at my old website, www.rareferns.com.