244 BULLETIN OF THE UNIVERSITY OF WISCONSIN. 



HYPNUM. 1 



I. Leaves spreading, or complanate, not secund. (II on p. 247.) 

 A, Leaves costate half way or more. (B on p. 245.) 



i. Leaves acute or acuminate. 

 Margins denticulate. 



Decurrent and auricled, suddenly acuminate H. chloropterum, 562. 

 Neither decurrent nor auricled, gradually acuminate. 



Cells uniform throughout . . . . H. Columbia?, 542. 



Alar cells dilated, distinct H. Columbico-palustre, 588. 



Margins entire. 



Leaves acute or short acuminate. 

 Alar cells few. 



Costa Yz length or double and short . . H. palustre, 398. 

 Costa vanishing just below apex H. polare, 589. 



Alar cells more numerous, reaching costa, 



large H. psendo-montannm, 593. 



Leaves long acuminate. 



Erect or spreading H. polgamum, 2 379. 



Reflexed squarrulose. 



Decurrent H. decursivulum, 8 541. 



Not decurrent. 



Plants in dense tufts . . . H. imicostatum, 8 540. 



Plants in loose, intricate tufts . . H. chrysophyllum, 8 378. 



2. Leaves obtuse, 4 entire. 



* Cells enlarged at the basal angles. 5 (* * on p. 245.) 



Costa sub-percurrent. 



Monoicous, sparingly branched, alar cells gradually en- 

 larged H. cordifolium, 402. 



i Including subgenera XVII to XXVI of L. & J. Man. 377-406. 



9 See Appendix, nos. 544, 545. 



3 The separation of these three species is very unsatisfactory. H. chrysophyllum is a 

 very variable species and from the inspection of barren material of H, decursivulum 

 and H. unicostatum and comparison with the characters as given by Kindberg, it seems 

 probable that they can not be regarded as distinct species but only as forms of If. chryso- 

 phyllum. 



* Sometimes apiculate in H. sarmentosum. 



6 H. torrentis C. M. & Kindb., Appendix, no. 586, falls here. 



