584 A. HESSELBO 



Mniiim serratiim Schrad. Reykholtdalur. 



Aiilacomniiim pahistre (L.) Schwågr. Common, several piaces in 

 abundance. 



Philonotis fontana (L.) Brid. Very common, often in masses. 

 Catharinea iindulata (L.) W. et M. Common. 

 Polytrichnm conimune L. Common. 



— gracile Dicks. Reykholtdalur. 

 Thuidinm delicatuhim (L.) Mitten. Frequent. 



Hypniim mollusciini Hed\v. Abundant near all the hot springs 

 in Reykholtdalur. 



Hypniim Lindhergii (Lindb.) Mitten. Common everywhere. 



Hypniim revolvens Sw. Common near many springs, especially 

 in Reykholtdalur. 



Hypniim chrysophylliim Brid. Geysir. 



— sarmentosnm Whlb. Geysir. 



— stramineiim Dicks. Very common everywhere. 



— exannulatiim Giimb. Reykholtdalur. 

 Acrocladiiim ciispidatiim (L.) Lindb. Common. 



Climaciiim dendroides (L.) W. & M. In many piaces, plentiful near 

 Geysir. 



Hylocomiiim scjuarrosum (L.) Br. eur. Common everywhere. 



proliferiim (L.) Lindb. Common in Reykholtdalur. 



— parietinuin (L.) Lindb. In several piaces plentiful. 



Besides the species mentioned in the above list, several other 

 species are, however, also found as more casual intermixtures in 

 the moss carpet, especially species from boggy soil and from grass- 

 land, for instance Rhacomitriiim canescens, R. hypnoides and Hypniim 

 iincinatiim. 



Mesophilous Bryophyte Formations. 



The Bryophyta, as a rule, play a less prominent part in the 

 plant-covering of soil of a middle degree of dampness, than in that 

 of wet soil, because in the former the higher piants find more 

 favourable conditions of life, and the Bryophyta are consequently 

 driven more into the background and occur only as ground vege- 

 tation between the higher piants. Several other conditions are, how- 

 ever, of essential importance in this connection, for instance con- 

 ditions pertaining to the light, the direction of the slope and the 

 snow-covering. Bryophyta bear shade better than do the higher 



