438 A. HESSELBO 



lands and up to 500600 metres above sea -level. Near Akureyri it 

 was found on a damp flat at about 500 metres. Near Barkarstadr it 

 occurred abundantly on boggy ground at about 530 metres, and near 

 Seljaland it was also frequent at an altitude of about 500 metres on a 

 moss-grown gravelly flat. Only sterile specimens have been found. 



FAM. DICRANACE.E. 

 14. Oncophorus virens (S\v.) Brid. 



Very common on damp ground. It grows both on wet humus- 

 covered rocks and in bogs, and also on damp gravelly ground, some- 

 times as unmixed tufts and sometimes mixed with other mosses; it is 

 of equal frequency at all altitudes as far upwards as 600700 metres. 

 It often occurs in great quantities and usually fruits richly. In the 

 lower districts the fruit ripens about July 1st. In S. Iceland this 

 species is either wanting or rare in the lowlands up to a height of 

 about 300 metres (it has not been found on Vestmannaey), but from 

 this height up to the snow-line it occurs abundantly in bogs. 

 Var. .serrfttfts Br. eur. occurs occasionally on wet rocks. 







15. Oncophorus Wahlenbergii Brid. 



One of the most commonly occurring mosses; it is found every- 

 where in damp localities just like 0. virens. It is very common espe- 

 cially in bogs, except in S. Iceland where, like O. virens, it has its dis- 

 tribution from an altitude of 300 metres upwards. 



Var. ft compictus (Punch) Br. eur. E. Iceland: Skreiddal!; Seydisfjordur!. 

 It grew .in both localities on knolls in bogs. 



Var. elottfjatum Hagen. W.Iceland: Nordredalur!. It grew there on 

 boggy ground in association with Sphagnum teres, S. rubellum and S. fim- 

 briatum in loose tufts about 6 cm. high. 



Although typically developed forms of Oncophorus Wahlenbergii and 

 O. virens differ so widely from each other that they are not likely to 

 be confused, yet so many transitional forms occur, especially in Alpine 

 habitats, that very often it is a matter of opinion to which species such 

 a form should be referred. On the same plant leaves may be found 

 which, as regards the cells of the leaf-base, resemble sometimes O. 

 Wahlenbergii and sometimes 0. virens; also the leaf-margin is more or 

 less recurved or plane. 



16. Dicranella squarrosa (Starkc) Schimp. 



E.Iceland: Seydisfjordur!; Skorastadr (H. J.)!. N.Iceland: Husavik!; 

 near Eyjafjordur (O. D.;!), fr. ; Laekjarmot!. NW. Iceland: Very common!. 

 W.Iceland: Vogur (H.J.)!; Esja!; Reykholtdalur!. S. Iceland: Holt!. 



This plant grows almost always in water, especially on inundated 

 gravelly ground by streams, on stones and in moss bogs, more rarety 

 on wet marshy ground. In NW. Iceland it is one of the mosses of 

 most frequent occurrence being found in abundance associated with 



