THE BRYOPHYTA OF ICELAND 425 



also occur with more highly thickened cell-walls. In somewhat drier 

 localities it is usually brownish in colour and more compact with more 

 deeply toothed leaf margins, sometimes almost as in S. siibalpina and 

 with more thick-walled cells. Small forms from damp sandy soil often 

 constitute transitional stages to S. curta, while vigorous aquatic forms 

 approach closely to S. undiilata. A very vigorous form with leaves 

 which were as deeply toothed as in S. siibalpina was found in abun- 

 dance in lava-clefts near Thingvellir. 



J* plants are common ; calyces and fruit occur rather rarely. 



Note. Scapania compacta is recorded by Gronlund from Esja, 

 but the specimen in the Botanical Museum is really Scapania irriaua. 



81. Scapania uliginosa (Sw.) Dum. 



E. Iceland: Stod (H. J.)!. NW. Iceland: Gnupsdal in Dvrafjordur!: 

 Sugandafjordur ! ; Isafjardarheidi!; Dynjandi!; Arngerdareyri. 



With the exception of a single localitj^ in E. Iceland this species 

 was found only in NW. Iceland where it is rather common on very 

 wet or irrigated soil along streams, often occurring in great abundance 

 up to a height of about 400 metres. Near Arngerdareyri it grew abun- 

 dantly in a bog in reddish-brown tufts associated with Hypmim spp. 

 The leaf-form and habit in this form were typical, but the leaf-cells 

 had brownish and rather thickened walls and a roughly granular 

 cuticle. 



The plant from Sugandafjordur differed from the type in its leaves 

 being sometimes distantly toothed and the cells very slightly thickened 

 at the angles, in which respects it approached S. irrigna. 



82. Scapania paludosa C. M. 



NW. Iceland: Gnupsdal in the district of Dvrafjordur, c. coles.! Grun- 

 navik <$ \ ; Isafjordur JM. 



In Gnupsdal the plant grew abundantly in the water in small 

 streams, where it formed large, loose, green to brownish mats. The 

 leaves were highly decurrent, with indistinct teeth or entire margins, 

 and thin-walled cells. 



Near Isafjordur and Grunnavik it grew on wet boggy ground. The 

 leaves in both these forms were shortly decurrent and more or less 

 toothed with a broadly reniform or (often in the same plant) cordate 

 postical lobe which was occasionally furnished with a small point as in 

 S. irrigua; the leaf- margin was often reflexed as in S. iindulata; the 

 cells were thin-walled, but towards the margin occasionally somewhat 

 thick-walled. The commissure is typically short and strongly curved 

 with broad wings. 



83. Scapania dentata Dum. 



Scapania purpurasccns (Hook.) Pearson. 



E. Iceland : Berufjordur!; Seydisfjordur!. common up to about 400 

 metres. Kirkjubol (H. J.) !. N. Iceland: StoraGja!. YV. Iceland: Hvammur 



The Botany of Iceland. Vol. I, part II. 28 



