520 A. HESSELBO 



indistincta, margine leniter dentato. Seta 8 mm. longa, c. 14 mm. crassa, 

 purpurea, in dimidia parte superior! rugosa, inferne glabra. Capsula 

 fusca, obliqua. longe ovata, operculata 1.7 mm. longa, 0.5 mm. crassa, 

 deoperculata sub orificio contracta. Operculum conicum 0.6 mm. altum. 

 Dentes peristomii 0.46 mm. longi, 0.067 mm. lati, pallide lutei, 

 apicibus hyalinis, basi aurantiaci et leniter transverse striati. Sporse 

 0.021- 0.024 mm., papillulosae. 



S. Iceland: Flokastadagil, on stones at the margin of the river. The 

 capsules were empty in the middle of July. 



249. Brachythecium populeum (Hedw.) Br. eur. 



Hypnum populeum Hedw. 



S. Iceland: Vik (H. J.)!, fr. ; Drangshlid!, fr. 



Grew in both the above localities on rather dry tuff rocks. 



250. Brachythecium velutinum (L.), Br. eur. 



S. Iceland: Thingvellir (Grl.;!); Vik (H.J.)!; Holt!, in a cave at an 

 altitude of about 300 metres, fr. 



Near Thingvellir it grew in a lava-cleft, associated with Blepharo- 

 stoma trichophyllum, Plagiochila asplenioides and Plagiothecium silvaticum. 



251. Brachythecium glaciale Br. eur. 

 Hypnum glaciale C. Hartm. 



N.Iceland: Akureyri!, at an altitude of 770 metres. NW. Iceland: 

 Sugandafjordur!, at an altitude of 450 metres. W. Iceland: Dalasysla, 

 Melar, on a cliff inhabited by sea-fowl (H.J.)!. 



On damp gravelly flats. Near Sugandafjordur it grew abundantly, 

 intermixed with Hypnum straminenm, Mniobryum albicans and Philonotis 

 fontana, in cushions 34 cm. deep, on ground saturated by melting 

 snow, and on stones. The plants were about 5 cm. long and irregularly 

 branched with unequally long mostly short branches. The leaves 

 were erectly spreading, not secund, and very longly decurrent with 

 numerous quadrate, thin-walled cells at the basal angles of the leaves. 



252. Brachythecium reflexum (Starcke) Br. eur. 



Commonly distributed. 



This species has its main distribution in gravelly spots on the 

 rocky flat, especially on slopes and dry snowless patches on the moun- 

 tain heights. It is especially abundant in NW. Iceland, where it is 

 everywhere the most frequently occurring species on stony slopes. Here 

 it is usually found associated with Hypnum uncinatum, Lescurcea spp., 

 Lophozia lycopodioides, L. Flcrrckei, etc., and is met with as high as about 

 500 metres above sea-level. In Esja, in SW. Iceland, it was common 

 from about 200 metres upwards. In the low land it is rarer and appears 



