BARNES NORTH AMERICAN MOSSES. 249 



Plants small (usually less than 5 cm.). 

 Perichaetial leaves plicate. 

 Inner perichaetial leaves costate. 



Alar cells not distinct * H. fertile, 391. 



Alar cells large, hyaline H. Waghornei, 565. 



Inner perichaetial leaves ecostate . . . H. kamulosum, 391. 

 Perichaetial leaves not plicate. 



Alar cells not enlarged H. suhimponens, 393. 



Alar cells quadrate or vesicular, enlarged. 



Leaves narrowly acuminate, faintly bicostate H. depressulum, 391. 

 Leaves long subulate, ecostate . H. circinale, 392. 



2. Plants irregularly branched. 



[H. callichroum, may be sought here.] 



* Leaves quite entire. 



Alar cells not different H. pseud oar cticniu, 584. 



Alar cells enlarged, oblong rectangular. 



Teeth hyaline margined, cilia appendiculate H. arcnatiforme, 576. 



Teeth not hyaline margined, cilia nodose . . H. pratense, 2 397. 

 Alar cells quadrate. 



Plants erect, fastigiately branched . . . H. Bainbergeri, 397. 



Plants prostrate, irregularly pinnate . . H. incnrvatum, 600. 



* * Leaves serrulate or denticulate above. 



[J2". pseudo-arcticum and -H. incur vatum may be sought here.l 



Perichaetial leaves costate, and plicate or sulcate. 



Costa geminate, reaching middle H. reptile, 390. 

 Costa geminate, short. 



Middle leaf cells long (1 : 12-15) . . H. cupressiforme, 3 394. 



Middle leaf cells shorter (1 : 6-8) . H. Vauchefi, 4 570. 

 Costa single, or wanting. 



Inner perichaetial leaves long subulate (1 : 12) . H. Moseri, 559. 



Inner perichaetial leaves lanceolate (1:5) . H. fast igia turn. 564. 



i "Blattflugelzellen sehr gross, aufgeblasen, wasserhell bis gold gelb," sec. Milde, Bry. 

 Siles. 359. Not according to Bryol. Eur. pi. 591, from which this character is taken. 



a See Appendix, no. 578. 



8 See Appendix, no. 569. 



4 The character of the perichaetial leaves is unknown to me, but since the species is 

 so closely related to H. cupressiforme, it is placed in this position. 



