666 A. HESSELBO : THE BRYOPHYTA OF ICELAND 



the North-west, whilst they are absent from, or rare in, the other 

 districts of the country. To this group belong: Dicranella cerviculata, 

 Dicranum Blyttii, D. elongatum (western part of N. Iceland around 

 Hunafloi; NW. and W. Iceland), Ditrichum homomallum (common in 

 the South-west), Isothedum tenuinerve, Rhynchostegium rusciforme, 

 Hypnum hamiilosum and Hylocomium parietinum. Finally, Diplo- 

 phyllnm albicans is characteristic of all the lava-fields of West and 

 South-west Iceland. 



