—33— 



KEY TO THE SPECIES. 



Stems subsimple or somewhat fasciculately branching, short, tumid ; un- 

 derleaves caudate-lacinulate at base 8. P. Bolanderi. 



Stems more or less regularly 1-3 pinnate. 



Ventral lobes lingulate-oblong to linear-oblong, often somewhat falcate, 

 closely appressed to stem or to dorsal lobes. 



Dorsal lobes and underleaves entire, length of ventral lobes i-f 

 the width of the dorsal i. P. pinnata. 



Dorsal lobes entire, underleaves ciliate dentate at base, length of 

 ventral lobes ^-f the width of the dorsal 2. P. Swartziana. 



Leaves and underleaves repand-dentate 3. P. Wataugensis. 



Ventral lobes broadly ovate to oblong. 



Usually glossy. 



Ventral lobes more or less spurred outwardly at base, mostly 

 linguiform or ovate-oblong, margins plane or lightly re- 

 curved 7. P. Roellii. 



Ventral lobes regularly rounded outwardly at base, ovate, mar- 

 gin recurved 6. P. navicularis^ 



Usually dull. 



Rather flaccid, dorsal lobes subimbricate, ventral lobes long de- 

 current, underleaves distant 4. P. rivularis. 



Somewhat rigid, dorsal lobes rather densely imbricate, vent- 

 ral lobe scarcely decurrent, underleaves approximate or 

 subimbricate 5. P. platyphylla. 



The capsule is nearly or quite spherical, on 

 a short stem, yellowish brown, opening by 

 four irregular valves. The spores are more 

 or less echinulate and the elaters 1-3, usually 2 

 spiral. The general appearance of the plants 

 is shown in figures i and 2, and perianths in 

 figures 2 and 5. Antheridial ^branches are 

 shown at G. in figure 5. 



Fig. 2. A. Pore Ha Bolan- 

 dert {Anst.) Pears. Plant 

 with perianth, X i. 



