474 A. HESSELBO 



in bogs and on damp rocks. Var. glacialis grows always in cold water,, 

 especially in moss bogs, where in company with Philonotis it usually 

 forms the bulk of the vegetation. In the Alpine region Pohlia albicans 

 occurs abundantly, even at a height of about 600 metres. There it 

 grows especially in and along watercourses, often filling up their 

 during summer dried up beds by growing in large cushions both on 

 the ground and on stones. As in P. commutata, the Alpine forms be- 

 come more compact, with shorter, concave, appressed leaves and looser 

 cell-tissue. Such forms have been found, for instance, near Dyrafjordur 

 at an altitude of 300400 metres, Esja at an altitude of about 500- 

 600 metres and near Seljaland at an altitude of about 500 metres. Fruit 

 occurs rather rarely, and in the type, as a rule, in a small quantity 

 onlv. Fruiting specimens of the type were collected near Akureyri (ripe 

 July 22), Holt (ripe July 19) and Breiddal (hardly ripe June 19). Var. 

 glacialis was collected in fruit near Eyjafjordur ((). D.) and near Kaldalon 

 in NW. Iceland, where the plant grew abundantly on inundated ground 

 along small streams, and was often covered with fruit which was not 

 quite ripe at the end of June. 



133. Bryum purpurascens (R. Br.) Br. eur. 



E.Iceland: Seydisfjordur!, common; Vallanes! (H.JO. N. Iceland: 

 Mwatn (Grl.)!; Akureyri!, common; Husavik!, common. NW. Iceland: 

 common about Isafjordur and Jokulsfjordur!. W. Iceland: Reykholtdalur 

 (Grl.)!; Nordredalur !; Grimstunga (Grl.)!; Bardshellir (Grl.)!. S. Iceland: 

 Traustholtsholm in the Thjorsa (F.)!. 



Grows on damp peaty or sandy soil, especially near the coast. It 

 occurs abundantly chiefly in places where the peat has been pared off. 

 Near Seydisfjordur it was collected up to a height of about 400 metres. 

 The fruit ripens in the beginning of August. 



Bryum purpurascens varies rather considerably in the form of the 

 capsule and in the structure of the peristome. The capsule is usually 

 symmetrical, sometimes slightly asymmetrical, and then reminds one of 

 B. nliginosnm, from which it is, however, easily distinguishable by the 

 large lid. The base of the peristome teeth ^fundus) is often large and 

 reddish yellow, and in the majority of the plants which have been in- 

 vestigated the lamella? are sinuose in the middle, sometimes as strongly 

 so as in Brijnm Ictpponicum. The dorsal transverse segments are more 

 or less distinctly transversely striated. The spores vary somewhat in 

 size, from 0.024-0.035 mm. 



It is a peculiarity with this species that the capsule, on being cut 

 through and warmed in diluted ammoniacal water, imparts to the latter 

 a substance which is intensely, but temporarily coloured red by the 

 oxygen in the air. The same is often the case also with B. uliginosiim. 

 In the course of time the old capsules turn almost black in colour. 



134. Bryum lacustre Blandow. 



E. Iceland: Berufjordur!; Vallanes (H. J.;!). N. Iceland: Common near 

 Husavik!; common near Eyjafjordur (O. D.;!); Saudanes (St.)!; Svinadalur!;. 



