THE BRYOPHYTA OF ICELAND 505 



206. Polytrichum strictum Banks. 



E. Iceland: Hornafjordur. common!. N. Iceland: Husavik!; Akureyri, 

 common to about 600 metres above sea-level!; Hof near Eviafiordur (O.D.)!; 



. . i ' 



common from Geitaskard westwards to Hrutafjordur!. N\Y. Iceland: 

 Common around Isafjordur!; Grunnavik!; Kaldalon!. W. Iceland: Grund 

 in Skorradalur!; Olafsdalur (H. J.)!; Reykholtdalur, common! ; Reykjavik!. 

 S. Iceland: Skalholt!, J 1 ; Geysir (Stp.)!. 



Occurs rather commonly and often abundantly on wet boggy ground, 

 but always sterile. In Reykholtdalur it also grows on warm ground. 



207. Polytrichum commune L. 



Widely distributed on damp ground, both in bogs and along the 

 banks of streams, but as a rule rather scantily. 



In the low land, where P. commune has its greatest distribution, 

 the large coarse form is usually met with. In higher regions, where it 

 is found up to a height of about 500 metres, it usually becomes slen- 

 derer and lower in growth. Thus, near Akureyri, it occurred abundantly 

 in a bog at an altitude of 500 metres as a low-growing, slender form, 

 mixed with Hypmim stramineum. 



P. commune is one of the most frequent species near hot springs, 

 where it grows sometimes mixed with Sphagnum and is then large and 

 vigorous, sometimes in extensive mats interwoven with hepatics and is 

 then usually low in growth with shorter leaves. On a warm substratum 

 it often fruits freely, while it has or else been found in fruit only near 

 Grunnavik in N\V. Iceland. 



Var. fistigittun (Lyl.) Wils. 



SW. Iceland: Svinahraun!, abundantly on damp soil at the edge of 

 the lava-field. 



208. Polytrichum Swartzii Hartman. 

 NW. Iceland: Bseir!, sterile. 



Var. iiif/rescens (Warnst.) Hagen. S} r n. Polytrichum inconstcins Hagen. 



NW. Iceland: Thoroddstadaengjar (St.)!; Dynjandi!. 



The type grew on a damp slope in not-coherent tufts, about 15 cm. 

 high: the plants were quite typical with sharply toothed leaves, and 

 with lamellae, the marginal cells of which had the irregular form peculiar 

 to P. Sivartzii. The variety grew on very wet or inundated ground in 

 company with Hypnum stramineum, H. giganteum and Mnium cinclidioides 

 similarly to P. gracile var. anomalum, and may be regarded as a form 

 similar to the latter; as in aquatic forms of other species, both forms 

 have flaccid-soft leaves with slightly developed stereom in the nerve and 

 broader, slightly toothed leaf-margin; in the plant from Dynjandi the 

 leaf-margin was almost entire. 



The Botany of Iceland. Vol. I. part 11. 33 



