568 A. HESSELBO 



surface of the Sphagnum cushions was usually covered with the 

 orbicular, closely appressed leaves of Hydrocotyle uiilgaris. The 

 temperature in the Spliagnuin cushions was rather high, on the 

 surface of the ground as niuch as 50°, chiefly on account of their 

 feeble heat-conducting power, and the tufts were quite saturated with 

 the moisture from the warm vapours. The Sphagniim-he\t did not 

 extend so far as to the hot water, but everywhere there was a strip 

 (10 — 20 cm. broad), nearest the water, covered witli low dark-green 

 mats of Fossombronia Dnmortieri, occasionally intermixed with 

 Haplozia creniilata or Aliciilaria scalaris. The same vegetation of 

 Hepaticæ was in faet found in all piaces where the banks were too 

 steep to allow Sphagna to gain foothold. The temperature under 

 the Fossombronia-coveving was, as a rule, about 40° (34° — 43°). 

 Where the bank was flatter and on the warm, dry, clayey flåts in 

 the neighbourhood of the springs Archidiiim phascoides grew in 

 great masses, and often formed, without intermixture of other 

 species, extensive, dark-green mats, 1 — 2 cm. deep. It occurred also 

 on the siliceous sinter deposited by the water, and here and there 

 among the Hepaticæ. The temperature of the soil under the 

 Archidiiim-mai was almost everywhere about 40°. In the brook 

 formed by the outlet of the spring there was a small island which 

 was partially inundated by the hot water, and here grew^ a great 

 many large cushions of a peculiar form, a Barbiila fallax (var. læ- 

 vifolia n. var.), and in one spot, on the slope, in the neighbourhood 

 of the basin, grew Anthoceros piinctatiis together with Fossombronia. 



Outside the Sphagniim-heli the ground was perceptibly warm 

 even for a tolerable distance, and the vegetation there was likewise 

 greatly exposed to the warm aqueous vapours. There Hypnaceæ, in 

 particular, grew very luxuriantly on the rather dry substratum. 

 Hypnum imponens and H. Lindbergii were often almost the only 

 species to be found there, the latter growing in a peculiar, erect 

 form, almost branchless. The temperature of the ground under the 

 Hypnwn-coxering was, as a rule, 25° — 30°. 



A little below the spring the brook flowed along a steep bank 

 about a metre high. Here the Sphagnnm-he\t disappeared and was 

 replaced by a more mixed vegetation. Lowermost, at a height of 

 about 10 cm. above the water, grew Fossombronia., Haplozia crenu- 

 lata, Alicularia scalaris, and Anthoceros, then followed thick cushions 

 of Hylocomium squarrosum, Hypnum stramineum, Thuidium delica- 

 tulmn, Sphagnum teres, S. imbricatum and Catharinea undulata, 



