48 



THE FERN BULLETIN 



ing. Typical specimens are shown in the accompany- 

 ing illustration. Figure 1 is the simplest of the group 

 with a single ear on the lower side of the basal pinnae. 

 This is usually called the form auritum. It is the 

 exact opposite of the pinnae of the Christmas fern 



(Polystichum) where the ears are on the upper side 



alone. Forms of the polypody with basal pinnae 

 lobed on the upper side only have been reported but 

 the tendency toward lobing is strongest on the lower 

 side and specimens eaied only on the upper side are 



