452 A. HESSELBO 



mixed with other mosses, and as a rule sets fruit, which ripens late in 

 August or early in September. It is most frequent in the low land up 

 to about 300 metres above sea-level, but is also met with, although 

 scantily, and often sterile, as far upwards as to the mountain heights, 

 for instance on Isafjardarheidi, about 600 metres above sea-level. 



Forms which must be referred to var. brevifolia Lindb. et Arnell 

 occur commonly together with transitional forms to the type. Near 

 Seydisfjordur the variety was found abundantly in reddish brown, dense 

 tufts, about 5 cm. high, in rock-fissures filled with soil. 



Note. Didymodon tophaceus is recorded by Lindsay from Ice- 

 land, but no specimens are in the collections and the record is pro- 

 bably due to an erroneous determination. 



56. Didymodon rufus Lorentz. 



E. Iceland: Stafafell!; Geithellir!. N. Iceland: Stadr near Hrutafjor- 

 dur!; Akureyri, at an altitude of 900 metres!. W. Iceland: Lundur! 

 Breidabolstadr in Rej^kholtdalur!. 



The plant, which was only found sterile, grew in all the above 

 localities in loose tufts, a few cm. high, on damp gravelly ground, as 

 a rule rather scantily. Near Akureyri it grew scantily among Sphcero- 

 cephahis turgidus and Rhacomitrium hypnoides. 



57. Leptodontium flexifolium (Dicks.) Hampe. 



N. Iceland: Grimsey (O. D.)! (f. compacta}. 



Enumerated in Lindsav's list, but neither the name of the finder 



t> 



nor the habitat is given. 



58. Trichostomum littorale Mitten. 

 Mollia littoralis (Mitten) Braithw. 



S. Iceland: Helgafell on Vestmannaey, on blocks of lava!; Hafnar- 

 fjordur, in a lava cave!; on warm clayey flats near Reykjanes light- 

 house (Ostf.)!, associated with Preissia, Riccia and Archidinm. 



59. Tortella inclinata (Hedw.) Limpr. 



Mollia inclinata (Hedw.) Lindb. 

 E. Iceland: Vallanes (H. J.)!. 



(H). Tortella tortuosa (L.) Limpr. 

 Mollia tortuosa (L.) Schranck. 



Very common all over Iceland. 



This species has its main distribution in the low land up to about 

 400 metres above sea-level. It appears to be rare everywhere at higher 

 levels, and hardly ascends higher than about 600 metres. It grows 



