402 A. HESSELBO 



I. LIST OF THE BRYOPHYTA. 

 I. HEPATIC^E. 



FAM. RICCIACEiE. 



1. Riccia bifurca Hoffni. 



N. Iceland: Hrossaberg (St.)!; Vidimxri (Grl.)!; Mj'vatn!. S. Iceland: 

 Near Reykjanes lighthouse (Ostf.)!; Kverkfjall (Wegener.)!. 



In all these localities it grows on warm, damp clayey flats near 

 hot springs. Near Myvatn where it grew abundantly around fuma- 

 roles, from which issued aqueous vapours containing sulphuretted hy- 

 drogen the temperature of the soil was about 40 01 about one cm. 

 below the surface. Near Reykjanes lighthouse Ostenfeld (Bot. Tids- 

 skrift, vol. XXII, 1899, p. 239: gives the temperature of the soil as 20 

 -30. All the plants investigated bore capsules. 



2. Riccia sorocarpa BischofT. 



N. Iceland: Reykjalaug in Fnjoskadal (O. D.)!. S. Iceland: Grafarbakki 

 near the Minni Laxa (F.)!; Laugarashver!. 



Like the preceding species, R. sorocarpa grows on warm, damp 

 clayey flats. Near Laugarashver it was found abundantly on clayey 

 slopes stretching down towards the boiling hot spring. There the tem- 

 perature of the soil was about 25 -30. All the plants investigated 

 bore capsules which in the plants from Laugarashver were fully ripe 

 at the end of July. 



3. Riccia crystallina L. 



S. Iceland: Thorlakshver near Skalholt!. (27. 7. 1914). 



The plants, which had fully developed capsules, grew widely scat- 

 tered on clayey flats, otherwise bare of vegetation, around some small 

 holes from whence issued boiling water accompanied by vapours slightly 

 impregnated with sulphuretted hydrogen. 



Note. Riccia glauca L. is mentioned by Zoega and is recorded 

 by Hornemann as occurring abundantly near Geysir. But as no speci- 

 mens of it arc to be found in the collections, and during the search 

 made in 1914. no species of Riccia were found near Geysir, it is im- 

 possible to determine what species is meant. 



Here and throughout the book the centigrade scale is meant. 



