626 A. HESSELBO 



Anthelia flats (Helgi Jonsson, 1900). In damp parts of the 

 rocky flat, especially where the snow-water from the melting snow- 

 flats spreads out over the ground, extensive flats of a greyish-black 

 or bluish-black colour are very commonly met with, and these are 



/ u 



principally formed of Anthelia Juratzkana. Interspersed in this 

 Anthelietum occur several other Bryophyta of which the most 

 frequent are Alicalaria scalaris, A. geoscypha and Lophozia alpestris, 

 while scattered plants of Polytrichum sexangulare, Oligotrichiim her- 

 cynicum and Pohlia gradlis protrude here and there. Pleuroclada 

 albescens is also occasionally met with. 



Although the Anthelia vegetation also occurs in more low-lying 

 tracts, yet it has its main distribution near the snow line, and must 

 therefore be reckoned to the moss associations of the Snow region. 

 There are only a few Bryophyta which occur in the Snow region. 

 At the boundary between the Anthelia-ftais and the drier gravelly 

 flats Dicrannm falcatum occurs in semiglobular cushions, densely 

 matted with rhizoids, but it lies so loosely upon the gravel that 

 one can lift up the whole cushion. Near Dyrafjordur Gymnomitrium 

 varians grew in a similar manner to Anthelia, close to the melting 

 snow-flats. Dicranum Starckei, D. Blyttii, Pohlia cuciillata, P. com- 

 mutata, Oligotrichiim hercynicum and Polytrichum sexangnlare are 

 also common near the snow line but, with the exception of a few 

 species (Dicranoweisia, Andre&a and Rhacomitrium spp.) growing on 

 rocks, the list is thereby exhausted. 



Mountain Bogs 



are extensively distributed in great parts of Iceland, but have not 

 yet been more closely investigated. The vegetation in the boggy 

 depressions often consists of a low, black mat of Hypnacew, mostly 

 Hypnum revolvens, H. exannulatum, H. sarmentosum and H. strami- 

 neum; but the moss covering may also contain other species and, 

 in composition, somewhat resemble the bog vegetation of the low 

 land, although the species are fewer in number. 



Near Akureyri boggy flats, situated 500 600 metres above 

 sea-level, were partly covered with Hypneta and partly with Cin- 

 clidium stygium with scattered cushions of Sphagnum and species 

 of Lophozia. On a wet flat, at an altitude of about 600 metres, 

 there grew Polytrichum commune (in abundance), Hypnnm sarmen- 

 tosum, H. stramineiim, H. Lindbergii, H. iincinatum, Dicranum Starckei, 

 Sphagnum teres, S. Girgensohnii, Meesea trichoides, Bryum ventricosum, 



