THE BRYOI'HYTA OF ICELAND 493 



lower level than about 250 metres, and not until a lieight of about 400 

 metres and upwards is il common. In N. and E. Iceland il is also most 

 frequent in the Alpine region, but grows, however, abundantly down to 

 Ihe low land in many piaces, for instance near Hof in the soutli-east. 

 In NW. Iceland it is very common from the sea-level up to the snow-line. 



It usually grows on dry and stony — more rarely damp — ground, 

 most frequenth' on rocky tlats. wherc it forms exceedingly dense and 

 compact cushions, as much as 10 cm. deep, which occur wedged very 

 firmly into the substratum. The cushions are, as a rule, interwoven 

 with hepatics such as Lophozia aljjcsfris, L. vcntricosa v. porphyroleuca. 

 Pleiiroclada albescens, Ccphalozia pleniceps, etc. 



Like many other Alj)ine species Conostonmm also occurs in the 

 lava-fields, for instance abundantly in the clefts near Thingvalla; the 

 tufts are here considerably looser and less lomentose than in the Alpine 

 form. Fruit, which occurs everywhere, ripens in the first half of August. 



Fam. AULACOMNIACEÆ. 



184. Aulacomnium palustre (L.) Schwågr. 



Sphærocephaliis palustris (L.) Lindb. 



Very common on damp boggy ground along the banks of streåms, 

 and on damp, soil-covered rocks. It occurs most abundantly on knoils 

 in bogs, in company with species of Sphagnum, and among Carices in 

 damp tracts of meadow land. Only sterile specimens have been found. 



185. Aulacomnium turgidum (Wahlb.) Schwågr. 

 Sphærocejjhaliis tiirgidiis Wahlb.) Lindb. 



E. Iceland: Hof!; Seydisfjordur !; Skreiddal!; Herufjardarskard!, at 

 an altitude of 540 metres; Djupivogurl. X. Iceland: Vatnsdalsfjall (St.)!; 

 Lækjarmot!, at an altitude of 350 — 450 metres; Akureyri!, at an alti- 

 tude of about 900 metres. NW. Iceland: Grunnavik!, at an altitude of 

 260 metres; Armuli!, at an altitude of 150 metres. W. Iceland: Esja!. 

 at an altitude of 420 metres. S. Iceland: Holt near Eyjafjall!; in several 

 piaces from the low land up to 400 metres above sea-level. 



This species is rather common especially in E. Iceland, in faet it 

 may almost be called common there; for instance, near Hof in SE. Ice- 

 land it was very frequent and, in several localities, plentiful. It appears 

 to bc of almost equal frequency in the lowlands and on the mountain 

 heights. 



It grows especially on somewhat damp gravelly ground, more rarely 

 on soil-covered rocks, associated with Hylocomiiim, Rhacomitriiim cane- 

 scens, Dicraniim coiujestnm, Hijpmim iincinatum, etc. Near Hof it grew 

 in great abundance along the river, on the gravelly flåts covered with 

 Griinmia canescens. Near Lækjarmot it was common as an intermixture 

 in the Rhacomitriiim hypnoides heath on the mountain slopes, about 

 350—400 metres above sea-level, and near Grunnavik it grew on damp 

 rocks among other mosses. Only sterile specimens have been found. 



