THE BHYOPHYTA OF ICELAND 665 



The rocky flat is very widely extended in NW. Iceland, since 

 it comprises all the flats and plateaus above the mountain slopes, 

 and on the north side of the mountains descends as far downwards 

 as to the sea-level. Several rocky-flat plants are therefore more 

 widely distributed here than in the other districts of Iceland. Oliyo- 

 trichnm hercynicnm, Rhacomitrinm sndeticiim, Conostomuin boreale, 

 Lescurcea Breidleri, Gymnomitriiim concinnatum and Pleuroclada al- 

 bescens are very common. Sphenolobns politus, Haplozia sphcero- 

 carpa, Gymnomitriiim revolutum and G. varians have been found 

 only on the rocky flats of NW. Iceland. 



Lescurcea filamentosa is very common and found fruiting on 

 detached blocks and on rocks, and L. patens is also frequent and 

 likewise sets fruit. 



Some few species, which are widely distributed elsewhere in 

 Iceland, are absent here, for instance Scapania dentata, Radula com- 

 planata, Gymnostomum rupestre, Campylopns Schimperi, Scelania c&sia, 

 Mnium Seligeri, Hypnnm ciipressiforme and Hypmim palustre, whilst 

 others are rare, for instance Preissia commntata, Leptobryiim pyri- 

 forme, Catoscopium nigritum, Timmia austriaca and Hypnum falcatum. 







The comparatively abundant occurrence of species of Sphagnum, 

 and the lesser frequency of the last-mentioned lime-loving species, 

 appear to indicate that the soil here is less calcareous than in the 

 other districts of Iceland. 



The Bryophyte vegetation of NW. Iceland has, on the whole, 

 a more decidedly xerophilous and Arctic character than that of the 

 rest of Iceland. 



West Iceland has, with the exception of the southern part 

 as far as Borgarfjordur, been very superficially investigated and, 

 apart from a few scattered collections made by Helgi Jonsson, 

 especially in Budahraun on Snaafellsnes, and my own collections 

 near Stykkisholmur, the whole stretch of coast norlh of Hvalfjordur 

 and around Breidifjordur is, from a bryological point of view, quite 

 unknow r n. 



Several of the species characteristic of South Iceland occur here 

 also, partially decreasing in frequency throughout West Iceland, for 

 instance Thuidium delicatulum, Hylocomium loreum, Eiirhynchium 

 piliferum and (in the South-west) Madotheca Cordceana. Some species 

 have a decidedly westerly distribution in Iceland, being of almost 

 equal frequency in West and South-west Iceland and a few also in 



The Botany of Iceland. Vol. I, part II. 43 



