THE BHYOPHYTA OF ICELAND 465 



102. Orthotrichum Sturmii Hornsch. 



E. Iceland: Hof!; Hornafjordur!. W. Iceland: Hafnarfjordur!; near 

 Hvalfjordur!. 



Growth similar to that of 0. rupestre, and usually found in com- 

 pany with it. Near Hafnarfjordur it was found abundantly on the dry 

 northern face of a dolerite-rock. 



The plant from Hornafjordur forms in regard to the eight coarse 

 cilia a transition to (). rupestre, but the upper half of the leaf consists 

 of two layers of cells instead of only one in O. rn/)cstre. 



103. Orthotrichum Killiasii C. M. 



E. Iceland: Seydisfjordur!. N. Iceland: Asbyrgi!. W. Iceland: Dala- 

 sysla, Melar on a cliff inhabited by sea-fowl (?) (H. J.)!. 



The plant from Melar, which was quite sterile, was determined by 

 C.Jensen, but owing to the absence of fruit the determination is 

 doubtful. 



Near Seydisfjordur, where it grew on rocks close to the sea shore, 

 the fruit was ripe about the 1st of July. 



104. Orthotrichum Blyttii Schimp. 



Iceland (Stp.)!. E. Iceland : Djupivogur!; Seydisfjordur!. N. Iceland : 

 Geitaskard!; Vidimyri (Grl.;!). N\V. Iceland : Arngerdareyri!. W. Iceland: 

 Stykkisholmur! ; Esja (Grl.)!. 



Grows on rocks, especially near the coast. Thus near Djupivogur 

 Seydisfjordur, Arngerdareyri and Stykkisholmur it w r as found abundantly 

 on the rocks of the coast. But it occurs also in the interior of the 

 country; for instance, abundantly in several localities in Blonddalur and 

 eastwards to Vidimyri. 



Gronlund's specimens are determined by Lindberg as Orthotri- 

 chum arcticum, but on comparing numerous specimens af 0. arcticum and 

 O. Blyttii it has not been possible for me to find any real difference 

 between these two forms. Ha gen (Musci Norvegiae Borealis. p. 83) 

 also regards 0. arcticum as a variety' of 0. Blyttii, from which it is said 

 to differ both by its shorter and broader leaves and by the shorter 

 striae of its capsule; but both these features vary so greatly in the 

 Iceland plants, that there is hardly any basis for establishing variety, 

 still less for separating them into two species. The pericha?tial leaves 

 are usually^ about 25 times as long as they are broad, with margins 

 which are revolute from a short distance below the apex down to the 

 base. The capsule is usually striated along its whole length, rarely (as 

 in the plant from Stykkisholmur) in the upper half only. The peristome- 

 teeth are finely papillose, rarely marked with faint sinuose lines in 

 their lower half. 



105. Orthotrichum laevigatum Zett. 



N. Iceland: Grimsey (O. D.)!: Akureyri, 350 metres above sea-level!; 

 Vidimyri!. NW Iceland: Arngerdareyri!. W. Iceland: Kalmanstunga (Grl.)!. 



