THI-: BIIYOPHYTA OF ICELAXD 571 



Further northwards near the Bruarå is Sydri Reykjahver. 

 This consists of a large round basin from the centre of which the 

 spring rises, bubbhng up at short intervals and ejecting a consider- 

 able amount of boiling hot water ^vhich flows over the edge of 

 the basin and gathers togelher into a brook which flows into 

 the river. 



On the somewhat higher and eastern side of the basin there is 

 luxuriant grassland, while the lower western side bears a vigorous 

 Brj^ophyte vegetation. Here, next to the water, grew extensive 

 dark-green and reddish-brown mats of Aliciilaria scalaris, Haplozia 

 crenulatd and some Catoscopiiim nigritiim in which bluish-green 

 patches of Fossombronia occurred interspersed, and occasionally ro- 

 settes of Anthoceros punctatiis. Here the temperature of the ground 

 was 25" — 27° just below the surface. Then followed a helt, about 

 2 metres broad, of Sphagnum papillosum, S. cymbifoliiim and fruit- 

 ing specimens of Polytrichiim commune, with a ground temperature 

 of about 20=. 



Lowermost on the steep bank (50—70 metres high) along the 

 outlet grew the usual helt of Hepaticæ consisting of Haplozia, Ali- 

 culaiia and Anthoceros, then an abundance of Oligotrichum hercy- 

 nicum interwoven with Haplozia sphærocarpa, and uppermost along 

 the edge large cushions of Hypnnm stramineum, Hylocominm squar- 

 rosnni and some Sphagnum cymbifolium, and here and there Caly- 

 pogeia Trichomanis. 



In a small bog by the side of the basin, into which the hot 

 water no doubt frequently flowed, grew^, in addition to the usual 

 bog vegetation, numerous large cushions of Sphagnum teres and 

 S. innndatum. 



The Hot Springs in Reykholtdalur. Throughout the whole of 

 Reykholtdalur, on both sides of the river Reykjadalså, there 

 occur very many hot springs, some of which discharge a great 

 amount of water. Near the vicarage of Revkholt rise Dvnkur, 

 Skribla, Snorralaug and other springs, which in part contain 

 sulphuretted hydrogen. Some hundred metres more to the south, 

 on the other side of the river, is Hagindishver, and farther 

 down the valley are other hot springs, of which the largest are 

 Deildatunguhver, Snældubeinstadahver, Stiirlurreykjahver, Klepp- 

 jarnsreykir (probably Gronlund's Kleppholtsreykir) and Vellindis- 

 hver; the last-mentioned is a fountain (geysir), which is situated 

 on a small rock in the river, and is quite bare of vegetation. The 



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