BARNES — NORTEI AMERICAN MOSSES. 243 



B. Leaves not bordered. 



* Costafe to the, apex. 



Leaves acuminate, basal cells abruptly enlarged . A. irriguuni, 374. 

 Leaves acuminate, basal cells not enlarged. 

 Serrate throughout ...... A. compactiim, 375. 



Entire or obscurely serrulate above. 

 Branches mostly erect, leaves loosely spreading when 



dry A. orthocladon, 374. 



Branches mostly spreading, tufts intricate, leaves im- 

 bricate when dry .A. variuni,^ 373. 



Leaves not acuminate, ovate to oblong lanceolate . A. fluviatile, 375. 



* * Costa ceasing at the middle or above. 



[A. coinpncttim may be sought here.] 



Cells near middle of leaf 1 : 10-15. 

 Leaves long acuminate, apex shai-p ... A. riparium,'^ 376. 

 Leaves acute, apex blunt ..... A. Tacillans, 377. 

 Cells near middle of leaf less than 1 : 8. 

 Inner perichfetial leaves short acuminate (I4 length). 



Leaves .65-.85 X .26-.36 mm A. serpens.^ 373. 



Leaves 1.2-1.6 X -S-.? mm A. Kocliii, 5S5. 



Inner perichaetial leaves subuliform acuminate, cells 



vermicular A. porphyrrhizon, 537. 



Kindberg has described four species belonging to this genus from bar- 

 ren specimens. A. fenestratum, App. 522, is probably not an Ambly- 

 stegium. A , s2)eiroj)hyllum, App. 523, may be doubtfully referred from 

 specimens in Can. Musci to A. irriguum. A. distanti folium, App. 529, 

 is very near A. irriguum. A. dissitifolium, App. 530, and A. sub-com- 

 pactum C. M. & Kindb., App. 531, are undoubtedly A. compactum 

 Miill. A. Holzingeri R. & C. is Hypnum (Limnobium) Closteri Aust. 

 A. Floridanum R. & C, App. 534, is so poorly characterized that I am 

 unable to separate it from A. ripariurn. A. Juratzkanum, App. 525, 

 A. hygrophilum (an Amblystegium?), App. 526, and A. Schlotthaueri, 

 App. 528, are subspecies of A. serpei^s, sec. Cardot, Hedwigia 32: 270, 

 271. 1893. A. homalostegium Jgr. & Sauerb., App. no. 536, is so doubt- 

 ful as an Amblystegium [ex deser.) that we omit it. 



1 Hypnum raclicale L. &. J. Man. 373. 

 ' See Appendix, no. 532, 533. 

 ' See Appendix, no. 524-526, 528. 



