242 BULLETIN OP THE UNIVERSITY OF WISCONSIN. 



Autoicous, cilia 2-3, costa double. 



Costa thick, ascending to the middle . . .P. geminiim, 365. 

 Costa thin, reaching half way to the middle P. denticiilatum, var. 367. 



- Capsule inclined or pendent, sulcate when dry.^ 



Leaves oval, narrowly acuminate, monoicous P. psendo-Silesiacuni, 370. 

 Leaves ovate lanceolate, dioicous. 



Suddenly tapering to a long filiform point P. pseudo-latebricola, 519. 



Short acuminate P. decursivifolium, 517. 



III. Leaves secund. 



Costse 2, thick, reaching the middle ... P. geminum, 365. 

 Ecostate or shortly bicostate. 



Leaves entire, seta straight . . . . P. pulchellum, 364. 



Leaves serrulate above, seta arcuate . . .P. Silesiacum, 518. 



P. bifariellum Kindb., App. 520, and P. attenuatirameum Kindb., 

 App. 521, described from barren specimens, are not included in the key. 



AMBLYSTEGIUM, 8 p. 371. 



I. Leaves ecostate or with obscure traces of a nerve. 



Cilia none. 



Perichaetial leaves long and narrow acuminate, entire A. subtile, 372. 

 Perichsetial leaves oval or oblong lanceolate, entire at 



the apex . . .A. Sprucei, 372. 



Cilia 1-2. 



Plants minute, filiform (1-2 cm.). 

 Leaves ovate, long acuminate ... A. confervoides, 372. 



Leaves long lanceolate A. minutissimum, 371. 



Plants large, in wide flat tufts .... A. adnatiim, 375. 



II. Leaves plainly costate. 

 A. Leaves with a distinct border ... A. Lescurii, 376. 



1 P. pseudo-latebricola has a smooth capsule. 



a The assistance of PROF. L. S. CHENEY, who is engaged upon a revision of this genus 

 ia gratefully acknowledged. 



