402 A. HESSELBO 



I. LIST OF THE BRYOPHYTA. 



I. HEPATICÆ. 



Fam. RICCIACEÆ. 

 1. Riccia bifurca Hoffm. 



N. Iceland: Hrossaberg (St.)!; Vidimvri (Grl.)!; M,vvatn!. S. Iceland: 

 Near Reykjanes lighthouse (Ostf.)I; Kverkfjall (Wegener.)]. 



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

 hot springs. Near Mwatn — where it grew abundantly around fuma- 

 roles, from which issned aqueous vapours containing sulphuretted hy- 

 drogen — the temperature of the soil was about 40^^ about one cm. 

 below the surface. Near Rejkjanes lighthouse Ostenfeld (Bot. Tid.s- 

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

 — 30°. All the piants investigated bore capsules. 



2. Riccia sorocarpa BischoIT. 



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

 near the Minni Laxå (.F'!; Laugarashver!. 



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

 clayey flåts. Near Laugarashver it was found abundantly on claj^ey 

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

 perature of the soil was about 25°— 30°. All the piants investigated 

 bore capsules which in the jjlanls from Laugarashver were fuUy ripe 

 at the end of July. 



3. Riccia crystallina L. 



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



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

 tered on clayej^ flåts, otherwise bare of vegetation, around some small 

 holes from whence issued boiling water accompanied b\^ vapours slightl}' 

 impregnated with sulphuretted hydrogen. 



Note. Riccia glauca L. is mcntioned by Zoéga and is recorded 

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

 mens of it are to be found in the collectiohs, 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. 



^ Herc and throughout the book the centii,'rade scale is meant. 



