PHYSICAL GEOGRAPHY 311 



Thjorsa, Skafta and Myrdalsjokull which are desert-like in character, 

 and here there are also several bare tun-ridges with numerous peaks. 

 The sand is constantly drifting through the valleys and destroying 

 all vegetation ; only upon the highest ridges and peaks, which cannot 

 be reached by the coarser grains of the drifting sand are seen se- 

 veral yellowish-green patches of mosses, and also along streams and 

 around springs the moss-vegetation is sometimes fairly luxuriant and 

 forms rather large green patches in places where very few or no 

 phanerogams have been able to gain a foothold. Around Tjaldvatn 

 (588 metres) in Veidivotn there is a considerable vegetation of differ- 

 ent species; in 1889 I collected here the following plants: Carex ri- 

 gida, Poa pratensis, Festuca ouina, Salix glaiica, Montia rwularis, 

 Ranunculus acer, Batrachium paucistamineum , Thalidrum alpinum, 

 Koenigia islandica, Empetrum nig rum, Rhodiola rosea, Parnassia pa- 

 lustris, Chamcenermm latifolium, Hippuris vulgaris, Euphrasia latifolia. 

 Near Thorisvatn (591 metres) which is situated in the centre of 

 large sandy deserts quite bare of vegetation, I found only Salix 

 glaiica, Chamcenerium latifolium and Carex rariflora. On Blesamyri 

 (535 metres) near Tindfjallajokull I found Carex rigida and C. rari- 

 flora. Near Hitalaug (650 metres) east of Torfajokull, in the neigh- 

 bourhood of hot springs I found Coeloglossum viride, Saxifraga stel- 

 laris, Sibbaldia procumbens, Pirola minor, Vaccinium uliginosum, Ve- 

 ronica alpina, Gnaphalium Noruegicum, G. supinum, Hieracium alpi- 

 num. Near Hvannabotnar (434 metres) in the neighbourhood of 

 Skafta I collected: Equisetum palustre, Luzula campestris, Carex ri- 

 gida, Calamagrostis stricla f. borealis, Anthoxanthum odoratum, Sib- 

 baldia procumbens, Epilobium lactiflorum, E. Hornemanni, Gnapha- 

 lium Norvegicum. Though the above list is naturally very incomplete 

 owing to the author having had other work in hand (geographical 

 survey and geological investigations) which left him no time for tho- 

 rough botanical investigations or collections, yet these notes have 

 been included here as these parts of the plateau are very difficult 

 of access and are hardly ever visited by naturalists. 



Outside the deserts in central Iceland, and nearer to the sea, 

 there are also many, large and small, high-situated rocky areas and 

 broken groups of rocks, pieces of plateau, and isolated peaks in the 

 numerous mountain-spurs which extend between the branching val- 

 leys and fjords. The vegetation of these rocks is also very little 

 known, but it resembles very much that of the plateau, only, it is 

 usually richer in species. Highest up on the mountains, at an alti- 



