THE BRYOPHYTA OF ICELAND 521 



to occur more particularly in the lava-fields, for instance near Hafnar- 

 fjordur. Thingvallahraun and Kihlhraun. It is found rather frequently 

 in fruit. 



253. Brachythecium glareosum (Bruch) Br. eur. 

 Hypnuni glareosum Bruch. 



E. Iceland: Seydisfjordur, on stones!. X. Iceland: Tvera in Oxna- 

 dalur, on damp gravelh T ground!. W. Iceland: Botnsdalur. on damp 

 rocks!. 



254. Brachythecium albicans (Neck.) Br. eur. 



Hypnum albicans Neck. 

 Commonly distributed over the whole of Iceland. 



V 



This species grows on a dry substratum, for instance on sandy or 

 grass-covered ground, on soil-covered stones, on dikes and on the peat- 

 walls of houses. It is most frequent in the low land up to a height 

 of about 300 metres, but occasionally, for instance near Akureyri, it 

 ascends as high as about 600 metres above sea-level. Only sterile speci- 

 mens have been found. 



255. Brachythecium erythrorrhizon Br. eur. 



Hypnum erythrorrhizon Hartm. 



N. Iceland: Hof near Eyjafjordur (O. D.)!; Ljosavatn!; Tvera in 

 Oxnadalur!. W. Iceland: Esja!. 



Found in all the localities only scantily intermixed in the tufts of 

 other mosses on rather dry ground. Near Ljosavatn it grew in the 

 Betnla nana heath in association with Hylocomium proliferum, Hypnum 

 uncinatum, Heterocladium squarrosiiliim and Lophoiia hjcopodioidcs : in 

 Esja it grew on a slope with a southern exposure, in company with 

 Hylocomium spp. and Hypnum imponens. 



256. Brachythecium rivulare (Bruch) Br. eur. 



Hypnum rivulare Bruch. 



Very common over the whole of Iceland. 



One of the most frequent mosses, which occurs everywhere on 

 damp ground up to about 400500 metres above sea-level. It occurs 

 both in large and small streams, where it covers the stones or the 

 gravell} 7 soil along the banks with its extensive mats, and in bogs, and 

 is also one of the species which is most frequently met with in moss 

 bogs. Occasionally, however, it grows also on a more dry substratum, 

 for instance on soil-covered rocks and among grass. Only sterile speci- 

 mens have been found. 



The Botany of Iceland. Vol. I, part II. *4 



