Ferns and Mosses of the United States. 295 



6. Capsules exsert. 



* CilicBB. 



10. O. speciosum. 11. O. HutchinsiEe. 



12. O. Ludwigii. 13. O. coarctatum. 



14. O. crispum. 



XX. Bartramia. Hedw. 



1. B. gracilis. 2. B. pomiformis. 



3. B. ithyphylla. 4. B. fontana. 



3. B. Menziesii. , 



XXI. Bryum. Dill. 



Division I. Capsule furrowed. 



1. B. androgynum. 2. B. palustre. 



3. B. arrhenopterum. 



Division II. Capsule smooth. 



A. Teeth of the outer peristome shorter than the inner one, 



4. B. triquetrura. 5. B. trichodes. 



B. Teeth of the outer peristome as long as the inner one. 



t Leaves without any thickened margin, 

 6. B. pyriforme. 7. B. erudum. 



tt Leaves with their margins thickened. 



16. B. punctatum. 17. B. rostratum. 



18. B. marginatum. 19. B. hornum. 



20. B. cuspidatum. 21. B. ciliare. 



22. B. turgid um. 23. B. affine. 



XXII. TiMMiA. Hedw. 



1. T. megapolitana. 



XXIII. BuxRAUMiA. Linn. 



1. B. aphylla. 



