562 A. HESSELBO 



sen's Amblystegium-bog (1910, p. 253) and occurs rather commonly 

 in North Iceland, but more rarely in the other parts of the country, 

 probably because in North Iceland the climate is more continental 

 than in the rest of Iceland. These moss bogs are most frequently 

 composed of Hypnacece, but often Paladella squarrosa, Cinclidinm 

 stygium or Mniam cinclidioides forms an essential part of them. 



5. Isafjordur. The narrow strip of land, below the steep moun- 

 tain slope (almost 600 metres in height) along the western side of 

 the fjord, is covered with sedge bogs right to the head of the fiord. 

 The most abundant constituents of the moss carpet between the 

 knolls were Hypnum reuolvens, H. giganteum, H, exannulatum, Pala- 

 della squarrosa, Philonotis fontana, Mninm cinclidioides, M. panctatum, 

 Cinclidinm stygium and Brynm ventricosum. Here and there in the 

 moss carpet grew Thnidium lanatnm, Catoscopiiim nigritnm, Meesea 

 trichoides, M. triquelra (scantily) and Oncophorns Wahlenbergii. Splach- 

 num sphwricum and S. vascnlosnm grew on cow-dung. The knolls 

 were formed by Sphagnum leres, S. Warnstorffl, Polytrichum striclnm, 

 P. alpinum, Mninm hornum and Dicranum scoparinm. The following 

 hepatics occurred woven into the moss-cushions:- Lophozia quin- 

 quedentata, L. Kunzeana, L. Hornschuchiana, L. qnadriloba, Scapania 

 irrigna, Blepharostoma trichophyllum , Harpanthns Flotowianus , Ce- 

 phalozia pleniceps, Cephaloziella Hampeana and C. rubella. 



6. Seydisfjordur. A boggy flat at an altitude of about 

 350 metres. The ground was covered with a blackish-brown moss 

 carpet composed of Hypnnm giganteum, H. slramineum, H. sarmen- 

 tosum, H. revoluens, H. Rich ardson ii, H. exannulatum and H. uncina- 

 tum, occasionally alternating with patches of Mnium cinclidioides. 

 Tufts of Sphagnum teres and S. Girgensohnii occurred frequently, 

 and Splachnum vasculosum was common on dung. Carex spp. and 

 Eriophorum were abundant without, however, occurring so densely 

 as to cover the ground. This type of Hypnum bog, from which 

 other plants are most frequently entirely absent, is common in 

 North and East Iceland at elevations of about 200 500 metres, on 

 flats where the snow lies long. The moss carpet is, as a rule, thin 

 and bears distinct traces of having been long subject to the pres- 

 sure of the snow-covering, the old stems being pressed closely 

 together, and only the annual shoots growing up into the air. 



Peat Bogs. In the course of time sedge bogs usually develop into 

 peat bogs. Gradually, as the peat layer becomes thicker, the dampness 



