517 
valves mostly with irregular nodulose thickenings. Elaters com- 
monly 2-(1-—3-) spiral; spores several times broader, more or less 
echinulate. 
Key to the Species, 
Stems subsimple or somewhat fasciculately branching, short, tumid; underleaves cau- 
date-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 1g—9¢ the width 
of the dorsal. 1. P. pinnata. 
Dorsal lobes entire, underleaves cillate-dentate at base, length of ventral 
lobes 14-24 the width of the dorsal. 2. P. Swartziana, 
Leaves and underleaves repand-dentate. 3. £. Wataugensis. 
Ventral lobes broadly ovate to oblong. 
Usually shining. : 
Ventral lobes more or less spurred outwardly at base, mostly linguiform 
or ovate-oblong, margins plane or lightly recurved. 7. P. Roellit. 
Ventral lobes regularly rounded outwardly at base, ovate, margin re- 
curved, 6. P. navicularis. 
Usually dull. 
Rather flaccid, dorsal lobes subimbricate, ventral lobes long-decurrent, 
underleaves distant. 4. P. rivularis. 
Somewhat rigid, dorsal lobes rather densely imbricate, ventral lobes 
scarcely decurrent, underleaves approximate or subimbricate. 
- 5. £. platyphylla. 
I. PORELLA PINNATA L. Sp. Pl. 2: 1106. 1753. 
Porella pinnis obtusis Dill. Hist. Musc. 459. p/. 68. 1741. 
Jungermannia Porella Dicks. Trans. Linn. Soc. 3: 239. 1797. 
Jungermannia distans Schwein. Spec. Fl. Am. Sept. Crypt. 9. 
1821. 
Madotheca Porella Nees, Naturgesch. Eur. Leberm. 3: 201. 
BD. p. 1838. 7 
Madotheca involuta Hampe, Lehm. & Lindenb. in Lehm. 
Pugillus, 7: 10. 1838. es 
Madotheca Sullivantiti Aust. Bull. Torr. Bot. Club, 3: 15. 
1872, ae ) : 
Dark or yellowish-green, rarely whitish, dull: stems usuall} 
bipinnate, sometimes tripinnate or subdichotomous, 4-II cm. — 
long, rather laxly matted; branches obtuse, often subfastigiate : 
dorsal lobes of leaves somewhat distant, contiguous, or slightly 
