586 A. HESSELBO 



Hypnnm nncinatnm, Hijlocominm spp., Rhacomitrium spp. and Thu- 

 idium delicatnhim (S. Icel.). These are often associated with several 

 of the xerophilous species, such as Dicranum scoparium , Frullania 

 Tamarisci, Ptilidium ciliare and Antitrichia curtipendula, through which 

 are formed transitional stages to the moss-heaths mentioned below. 

 In South Iceland several of the southern species have their greatest 

 distribution on well-sheltered, grass-covered slopes with a southern 

 exposure, for instance Scleropodmm piirum, Eurhijnchium pilifenim, 

 E. Stockesii, Thuidium tamariscinnm, T. Philiberti, T. delicatnhim and 

 Mninm undulatum. 



Birch coppices grow on a rather dry substratum. The 

 wood-floor is either occupied by grassland or by heather moor, 

 and the Bryophyte vegetation does not differ in any respect from 

 that which occurs on a corresponding substratum outside the 

 coppices. Most frequently it consists of Hylocominm spp. in asso- 

 ciation with Hypnnm nncinatnm and Rhacomitrium spp. (R. canes- 

 cens and R. hypnoides). 



Bryophyla grow only rarely and scantily on tree trunks. Ra- 

 dula complanata and Frullania dilatata have been found in one 

 single spot on a tree trunk, but, as a rule, it is some ground species 

 or other which grows a little way up on the slanting trunks. In 

 some few places Rhacomitrinm fascicnlare has been found on tree 

 trunks to which it had spread from neighbouring stones. 



Laugardalsskogur. This coppice, which is open and of 

 about a man's height, has its floor mostly covered with heather 

 moor, with a thick moss carpet composed of Hylocominm parieti- 

 nnm, H. prolifernm , H. triquetrum, H. sqiiarrosnm , Hypnnm nncina- 

 tnm and Rhacomitrinm hypnoides, occasionally Dicranum scoparinm, 

 Ptilidium ciliare, Lophozia lycopodioides and L. qninqnedentata also 

 occurred. Of quite a similar composition was the moss carpet in 

 almost all the coppices of South and West Iceland. A few other 

 species also belong to this community, but are more rarely met 

 with, for instance Brynm ccespiticinm , Pohlia nntans, P. acnminata 

 and Lophozia barbata. 



Hallormstadaskogur (East Iceland). The floor here rather 

 varies in nature, and is sometimes covered with heather moor and 

 sometimes with grassland or peat. In heathy soil Hylocominm spp. 

 were dominant in connection with Rhacomitrinm hypnoides, while 

 especially Hypnum nncinatnm grew abundantly on grassy ground. 

 Where it was very shady Timmia austriaca grew abundantly on knolls. 



